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iAGNUS and WUBDEM

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THE LIBRARY

THE UNIVERSITY

OF CALIFORNIA

LOS ANGELES

MEDICAL BOOKS
1814 W. HARRISON ST. CHICAC

Visual Economics,

WITH RULES FOR

ESTIMATION OF THE EARNING

ABILITY AFTER INJURIES

TO THE EYES.

H. MAGNUS, Med. Dr., of Breslau, Germany,

(Professor of Ophthalmology in the University
of Breslau, etc., etc.,)

AND

H. V. WURDEMANN, M. D., of Milwaukee, Wis.,

U. S. A.,

(Professor of Ophthalmology to the Milwaukee
Medical College, etc., etc.)

FOR THE USE OF THE MEDICAL
AND LEGAL PROFESSIONS,
BUSINESS CORPORATIONS AND
INSURANCE OFFICIALS

Published by

C. FORTH, 105 Grand Avenue, Milwaukee, Wis., U. S. A.

1902.

copyr;ighted, i 902,

by
C. PO RTH,

Milwaukee, Wisconsin.

DEDICATED

to the

HON. JOSEPH V. QUARLES,

Senator of the United States of America
and Member of the Wisconsin Bar.

PLATE L

FOR TRANSPOSITION OF THE SCIENTIFIC STANDARD OF VISUAL
ACUITY INTO ECONOMIC TERMS.

100
95
90
85
80
75
70
65
60
65
50
45
40
35
30
25
20

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5 10 15 20 25 30 35 40 45 50 55 60 65 70 ^ 75 80 85 90 95 100

The coarse full line (I) denotes the course or curve of the Visual
Acuity according to the Scientific Standard,

The fine full line (II) is the Economic valuation for vocations having
higher visual demands, and the broken line (III) the Economic valuation
for lower demands.

(See text Chapter VI., § 12, and Chapter VIII., § 17.)

PREFACE.

HE great interest and large circulation with which the original
edition of Magnus' work, "Leitfaden fiir Begutachtung und
Berechnung von Unfallsbeschadigungen der Augen," was re-
ceived after its publication in 1894, the legal standing which
this and the second edition of 1897 has achieved in Germany, the
fascination which the reading of the original work had for the American
author, and the practical use which he has made of the formulas and
maxims of Magnus, led him, in May, 1900, to request the permission
of Prof. Magnus to allow of a translation, adapted to the legal, medical
and economic requirements of America, to be published in this country,
which was cheerfully given May 11th. The American editor at first
made a literal translation of the work, but owing to the virgin field, as
yet untouched in English medical literature, and almost unthought of in
insurance circles, and the special demands of American law, it was
believed that a simple translation would not meet the requirements of
American and English readers. Therefore, with the consent and aid of
Prof. Magnus, the work has been entirely re-written by the American
author. The introduction and all of Chapters 1, XIX and Part 111 are
new. A large part of Chapter VI, i. e., that more particularly relating
to American railway employees, and interpolations in many places
throughout the text are new. The formulas and calculations are adapted
from those in Magnus' second edition. We are greatly indebted to
Dr. Howard F. Hansell. of Philadelphia, for hints and extracts from
his paper, "Estimation of the Amount of Injury to the Earning Capacity
of the Individual from Partial or Complete Loss of Vision"; likewise
to Dr. Frank Allport. of Chicago, for information relating to classes
of railway employees, and to Senator Joseph V. Quarles, of Wisconsin,
for assistance upon the forensic portion of the work.

The reason for the publication of Magnus' original essays was the
passing of a Benefit and Accident Insurance Law in 1884, in Germany,
which placed upon the already overburdened shoulders of the physician
entirely new and difficult problems. The estimation of the damage
from eye injuries and indemnity to be allowed therefrom had heretofore
only been made from a philanthropic standpoint. Zehender was the
first to try to give a mathematical expression to such estimations, fol-

lowed later by Magnus, Groenouw and others. Magnus' calculations
are the only ones that are founded upon anatomical and mathematical
data. He called to his aid an expert mathematician, Dr. Hugo Rohr,
who gave valuable assistance in the compilation of the tables. Magnus'
methods, which have been adapted to the use of American and English-
speaking peoples in this edition, may be carried out in actual practice,
so that a method for estimation of the damage to any workingman's
capacity from ocular injuries and the indemnification to be given there-
for, may be figured in a manner just to the workman, the person respon-
sible for the damage, to his employer or to the casualty company. We
hope that this work will not only prove acceptable to the medical pro-
fession of America and Great Britain, but also be received with interest
by that of the law, by insurance companies and by corporations which
are responsible for pecuniary indemnification in the case of accidents to.

the eyes.

H. MAGNUS,

Breslau.

H. V. WURDEMANN.
Milwaukee.
Jan. 1, 1902.

CONTENTS.

Frontispiece. Plate I, For Transposition of the Scientific Standard of
Visual Acuity into Economic Terms. Preface pages I and 2.

PART FIRST.

Introduction'. Legal Status of the Physician in Relation to Accident
Insurance and Indemnity for Accidents. — Different Methods for
Estimation of the Loss of Earning Ability from Ocular Accidents.
General Principles for Estimation of the Relaton of Ocular Injures
to the Earning Ability. — Conception of the Earning Ability and of
Injuries Thereto. — Estimation of the Damage to Economic Vision.
Method of Mathematical Calculation 9

Introductiox. Full Earning Ability Synonymous with Visual Earnin3
Ability. — ^Standard Established by. this Work for Scientific Esti-
mation 11-12

Chapter I. The Legal Status of the Physician in Relation to
Accident Insurance and Indemnity for Accidents 13

§ I. The Legal Status of the Physician in the United States of
America and definition of Damages 13 (a). — Indemnity claims ad-
justed according to medical advice 13. — Expert evidence in general
13. — lledico-legal experts 13. — Basis of expert testimony 14. — Legal
measure of damages 14 (b). — Nominal damages 14. — Compensatory
damages 14. — Factors entering into damages 14. — Earning ability
only fixed factor 14. § 2. Accident Insurance in America and Es-
timatioti of Indemnity for Accidents to the Eyes 14.- — -Estimates
by American accident insurance companies arbitrarily figured
14 (a). — U. S. Bureau of Pensions fix rates arbitrarily 1(3 (b).
§ 3. The German Accident Insurance Law 16 — Provisions of the
act 16. — Explanation of its wording 16. — Inability to follow trade
only considered therein 16. — Indemnification not for injury itself
but for impairing of earning ability 16. § 4. The Determination
of the Corporal and Economic Damage from Injuries belongs to the
Physician, Estimation of the Monetary Compensation to the Cor-
porations and the Courts 17

Chapter II. The Different Methods fob Estimation of Loss of

the Earning Ability from Ocular Injuries IS

§ 5. Zehcnder's Formula 18. — The formula and its development
18. — Calculation improperly made with three eye values IS. — Nor-
mal man given equivalent of three eyes 19. — Formula cannot be
scientifically applied 19. — Zehender pioneer in mathematical est'-
mation 19. § 6. Groenouw's Formula 19 (a). — Explanation of
the fornuila and development 19. — Mathematical consideration 20
lb). — Contains two unknown quantities and is mathematically in-
solvable 20. — He forces his formula 20 (c). — Formula applied to
monocularism 20. — Properly used makes tlie value of vision in a
one-eyed man equal to nothing 20. — Its principle is improp?r 21.
Confounds physiologic with anatomic conditions 21. — Accordingly
he makes human beings with nine hypothetic eyes. — Anothfr
mathematical view makes a cyclops 21. — The formula is a fluctu-
ating equation and cannot be mathematically considered 22.
The fictitious values generalized by his use of the formula 22. — Tlie
formula cannot be iised for scientific purposes 22. § 7. The For-
mula of Hcddaeus 22. It is not scientifically constructed 23. His
high estimation for the loss of binocular vision is preposterous 23.
Refutation of his claims 23

CONTENTS.

Chapter III. § S. General Principles for Estimation of the Ee-

LATiONS of Ocular Injuries to the Earning Ability 24

The ocular earning ability is one of the corporal functions and
should be measured and treated as such 25

Chapter IV. The Conception of the Earning Ability and Injuries

Thereto 23

§ 9. The Meaninfi of Full Earning Abiliti/ 2o. — Composition of its
factors 26. — Position occupied by the ability to compete 27. — Work-
ing ability not synonymous with earning ability 28. — A general
formula for the full earning ability 28

Chapter V. § 10. Determination of the Amount of Injury to
THE Earning Ability According to ;Magnus 29. — Working for-
mula for the earning ability 2D

Chapter VI. § 11. Estimation of the Damage to Economic Vision ZO

The earning ability F of our formula 31. — The factors entering
into the visual act 32. — Relation of the central visual acuity to the
ocular working ability 32. — Relation of the visual field to economic
vision 32. — ^Relation of tha ocular muscles to the visual field 32.
Relation of the ocular muscles in monocular and binocular vision
to working vision 33. — Relations of these factors to each other 33.
Formula for binocular economic vision 33. — Formula for monocular
economic vision 33. § 12. Estimation of the Economic Limita-
tions of the Central Visual Acuity 33. — Physiologic and economic
limits not synonymous but vary according to business demands 34.
Table A — The vaiious trades and professions arranged according
to their visual demands 37. — Group I — Trades requiring higher
degrees of visvial acuity 37. — Group II — Ti-ades requiring lower de-
grees of visual acuity 37. — Economic visvial limitations of railway
employees in Germany 39. — In America 40. Table B — Scitntific
standard for visual acuity converted into economic terms: I. for
vocations demanding higher vision; II. for vocations den:anding
lower vision 42. — Descrij^tion of Plate I for transposing the scien-
tific standard of visual acuity into economic equivalents 42. § 13.
The Economic Limits of the Visual Field and Their Estimation.
Division of the visual field into three zones 43. § 14. The Econom ic
Relations of the Ocular Musculature and Their Estimation 44.
The muscles have their individual values 44

Chapter VII. § 1.5. The Me.vning and Estim.\tion of the Arility

to Compete, K of Our Formula for the Earning Ability 46

The ability to compete is composed of dift'erent elements 46. — The
part that is furnished by the individual himself 47. — The part that
depends upon his employer or environment 47. — Special estimation
of the ability to compete 48. — Working formula 49

Chapter VIII. The Method of C.\lculatio.\ with the Formula of

Magnus 51

§ 16. What does this Formula Mean? 51. — It is th^ numerical ex-
pression for the normal ocular earning ability 51. — On this account
its mathematical estimation must be complex o2. § 17. Can Fi(j-
uring with the Formula Be Made More Convenient ? 52. — The fac-
tors of the formula may be estimated from a mathematically made
chart in Plate III 52. — Both algebraic estimation and the ratings
give the same results 53. § 18. Calculation irith the Formula
53. — By the use of the curves in the charts the estimation is made
a simple example in multiplication 56

CONTENTS.

PART SECOND.

Special Consideration of Various Ocular Injuries.

Chapter IX. § 19. The Eelati\-e Importance of Disturbaxces of

THE Visual Field 58

Estimation of the various forms of visual field defects with remaining
normal central visual acuity 59. — Summary in table form 61.
§ 20. Disorders of the Visual Fields Complicated by Injury to the
Central Visual Acuity of Different Degrees in Either Eye 62.
Rules for its estimation 62. — Auxiliary data for estimation of the
earning ability Avhere the central acuitv of both eyes is impaired
differently ' 63

•Chapter X. The IiiPAiRiiENT of the Earxixg Ability FROii In-
juries TO THE Extrinsic Ocular Muscles 65

§ 21. General Remarks Regarding the Importance of Injuries to
the Extra-Ocular Muscles 65. — Formula for the Binocular and
monocular acts of vision 65. § 22. The Estimation in Paralysis
of the muscles Uncomplicated by Other Visual Disorders 66. — Damage
caused by paralysis of one rectus externus 67. — Summary of the
earning ability and impairment thereof in uncomplicated disorders
of the extrinsic ocular muscles 68. § 23. Epicritin Remarks Con-
cerning the Foregoing 69

Chapter XL § 24. What Action Is Necessary If the Injured

Person Has Previously Had the Use of Only One Eye? 70

Scientific and economic monocularism 70. — Mathematical estimation
of original monocularism 71. — Estimation of ability to compete 71.
Formula for earning ability in monocularism 71. — Injuries to the
monocular visual field 72

Chapter XII. Estimation of Accident.\l Injuries in Cases in
Which One or Both Eyes Did Xot Possess Before the Acci-
dent Si:fficient Normal Central Visual Acuity 74

§ 25. The Meaning of Weak Vision from an Economic Standpoint.
74. § 26. Estimation of the Earning Ability in Case Weakness
of Vision Existed Before the Accident Which Can Be l^^umerically
Fixed Through a Former Functional Examination 76. — ^Modified
visiial acuity 76. — Division of weakness of vision into four groups
79. § 27. Group I. One Eye Is Xormal, the Other Originally
Weak-Sighted. Five examples 79. § 28. Group II. Both Eyes
Are Originally Equally Weak-Sighted. Four examples 81. § 29.
Group III. Both Eyes Are Originally Weak-Sighted to a Different
Degree. Four examples 82 § 30. Group IV. One Eye is Blind,
the Other Originally Weak-Sighted. One example 84

Chapter XIII. The Loss of One Eye Through Accident 85

§ 31. Estimation of the Vision in the Case of Loss of One Eye 85.
Visual acuity 85. — The visual field 85. — The muscles 86. — Loss of
power to estimate distances, etc. 86. — Annuity for the loss of one
eye should only be provisional 86. § 32. Estimation of the
Ability to Compete After the Loss of One Eye 87. § 33. Estimation
of the Earning Ability Where One Eye Becomes Blind 88. Differ-
ent valuations in monocularism 90. — Decrease of annuity after one
year 91. — Revision of the older rates 91. § 34. Concerning the
Supposed. Greater Danger of the One-Eyed Person Becoming To-
tally Blind and Its Relations to Indemnity 92. Danger from

CONTENTS.

atrophy of the optic nerve and ghiucoma 03. Few one-eyed per-
sons become blind through injury 93. — Complaints of one-eyed

persons.

Chapter XIV. § 35. Accidental Injuries to the Crystalline

Lens. Aphakia 94

Chapter XV. § 30. Injuries of the Eyelids, Conjunctiva and

Cornea 96

Chapter XVI. § 37. Should the Danger of Sympathetic Ophthal-
mitis Be Considered in Estimating the Impairment of the
Earning Ability 97

Chapter XVII. § 38. Injuries of the Cornea Through Foreign

Bodies 98

Chapter XVIII. § 39. Accidental Impairments of the Accommo-
dation 99

Chapter XIX. § 40. Common Diseases of the Eyes of Local

Origin That Impair the Earning Power 100

PART THIRD.

Chapter XX. § 41. Estimation of the Pecuniary Loss to the
Individual by Reason of Visual Imperfections Resulting from
Injuries 104

Estimation of the relation between the amount of visual acuity
and the loss of earning capacity 104. — The earnings of the profes-
sional and business man 10.5. — The earnings of the artisan 105.
The earnings of the laboring class 105. — Table C containing ex-
amples illustrating the monetary valuation of the remaining earn-
ing ability in the case of the average professional or busine^^s man
suffering from accidental loss of visual acuity figured for the five
decades of working life 106. — Table D. the earning ability in the
case of the artisan 107. — Table E. the earning ability in the case
of the laborer 108. — Examples 110-115. — The use of our rules and
tables for physicians, la\\'yers and insurance officials 115

PART FOURTH.

Tables for Estimation of Different Forms of Damage to the Visual

Earning Ability 116

One Eye Xoimal, the Other Injured but Not Blind.

Table I. Vocations with higher visual demands 117

Table II. Vacations with lower visual demands 117

One Eye Blind, the Other Weak-Sighted.

Table III. Vocations with higher visual demands 118

Table IV. Vocations with lower visual demands 118

Both Eyes Suffering Injury of Equal or Different Degrees.

Table V. Vocations with higher visual demands 119

Table VI. Vocations with lower visual demands 120

Table VII. Earning ability and its impairment in disorders of the

visual field with normal central visual acuity.... 121

CONTENTS. •

Table VII (a) Ability to compete and impairment of visual fields for
vocations \<nih higher and lower visual demands,
figured separately 1"22

Earning Ahiliiy in Defects of Both Eyes xvith Equally Diminished
Visual Acuity.

Table VIII. Vocations with higher visual demands 123

Table IX. Vocations with lower visual demands 124

Table X. Earning ability and impairment from non-complicated

disorders of the external ocular muscles 125

Earning Abiliti/ in Complicated Paralysis of the Ocular Muscles
u'ith Disturbances of the Visual Acuity.

Table XI. Vocations with higher visual demands 126

Table XII. Vocations with lower visual demands 126

Earning Ability and Impairment in Disturbances of the Visual
Acuity in an Originally One-Eyed Person.

Table XIII. Vocations with higher visual demands 127

Table XIV. Vocations with lower visual demands 127

Table XIII (a) Earning ability and impairment if the injury of one
muscle has to be valued correspondingly higher, in
special vocations 128

Earning Ability and Impairment in Disturbances of the Visual
Acuity in an Originally One-Eyed Person, in a Scientific Sense.

Table XV. Vocations with higher visual demands 129

Table XVI. Vocations with lower visual demands 129

Table XVII. Earning ability and impairment in disturbances of the

visual field of an originally one-eyed person 130

Table XVIII. Of the external ocular muscles of an originally one-
eyed person 130

Earni7ig Ability of cwi Originally One-Eyed Person with Disturb-
ances of the Visual Acuity Complicated with Defects of
the Visual Field, in a Professional Sense.

Table XIX. Vocations with higher visual demands 131

Table XX. Vocations with lower visual demands 131

Earning Ability of an Originally One-Eyed Person with Disturb-
ances of the Visual Acuity and Visual Field, in a Scien-
tific Sense.

Table XXI. Vocations with higher visual demands 132

Table XXII. Vocations with lower visual demands 132

Bibliography 135-136

Alphabetical Index 139-144

Plate II. Jaeger test types for near vision with transposition of the
scientific standard into economic terms.

Plate III. Snellen test types for distant vision with transposition of
the scientific standard into economic terms.

Plate IV. Xormal and damaged visual fields ^^^ith economic valuations.

Plate V. Curves for valuation of the visual field, of the muscular action
and of the ability to compete.

PART FIRST.

Introduction. Legal Status of the Physician in Relation
to Accident Insurance and Indemnity for Accidents.
Different Methods for Estimation of the Loss of Earn-
ing Ability from Ocular Accidents. General Prin-
ciples for Estimation of the Relation of Ocular Injuries
to the Earning Ability. Conception of the Earning
Ability and of Injuries thereto. Estimation of the
Damage to Economic Vision. Method of Mathe-
matical Calculation.

INTRODUCTION.

As the subject of which we treat in the following pages enters
into the domain of legal medicine and from its technical side no
one in America or among English-speaking peoples has yet had the
temerity to exhaustively treat it, and with the exception of a brief
essay which the American editor as chairman (2) had arranged
for the Section'on Ophthalmology of the American Medical Asso-
ciation and which was ably given by Hansell (17), some medico-
legal excerpts and scraps here and there in medical journals, the
literature is almost entirely German; we will, therefore, be obliged
to deal mostly with the facts and theories that have been brought
forth b}^ German writers, more especially those of Magnus, the
status of this subject in xA.merica in the law courts with the Acci-
dent Insurance Companies and the United States Pension office, and
then take up the German Accident law, after which we will proceed
to the scientific estimation of the visual earning ability.

In this work we start with the supposition that the earning
ability for any gainful vocation requiring eye sight is practically
synonymous Avith the visual earning ability, and that injuries to
the eyes affecting the vision have a direct detrimental effect upon
the earning capacity of the individual (See Chap. lY., § 9, p. 26;
Chap. YL, § 11, p. 30; Chap. YI., § 12, p. 36). It is self-evident
that a totally blind person is absolutely incompetent to work at any
trade or in any profession which demands eye-sight, and that the
vast majority of blind people are not only incapable of earning
anything, but are a charge upon their families and upon the
community. But even the blind man, provided that he has had the
necessary education and experience, need not remain absolutely
idle or be perfectly dependent ; for in some vocations where the use
of the mental powers is the chief factor, such as banking, some mer-
cantile pursuits and professions where knowledge may be assimi-
lated through the eyes of others or by methods peculiar to the
blind and by the actual work being done by employees, some spe-
cially well placed and talented individuals may continue to be
economic factors. But these are exceptions, and there can be no
doubt that the possession of good eye-sight is the prime factor for
full earning abilitv for the greater majority of gainful human

12 INTRODUCTION.

vocations, and any injury to it is usually followed by a lessening
of the earning ability and of the resultant compensation. We con-
sider that with laborers or artisans, in fact any of the so-called
working classes, who may by accident acquire some defect of eye-
sight, ranging from partial to complete blindness in one or both
eyes, that the effect of this visual defect upon the earning ability
will be identical with the percentage of the loss of eye-sight or
visual earning ability.

A decision of this character has not yet been reached in Ameri-
can courts of law, but we have no doubt that it must soon be made,
and when such a precedent is established, the damage to economic
vision will, in every case, be estimated in a scientific manner and be
given a prominent position in judging the amount of damages to
be allowed in personal damage suits, of which a considerable num-
ber relate to the eyes. We likewise hope that the factor of visual
economic damage will be sometime taken into consideration in
insurance circles and by the United States government in estab-
lishing the rates of insurance and pension annuities. We are con-
vinced that this factor has been estimated in the following pages
in a scientific manner and we confidently assert that in any given
case where the eyes have been injured we can figure the amount
of damage to the earning ability. It is fortunate that the state
of ophthalmic science allows of a definite estimation of the working
powers of the eye. This is not so in respect to other corporal func-
tions, for instance, the economic loss of an arm or a leg or the loss
of the sense of smell or of hearing certainly cannot be as exactly
estimated as that of the sense of sight. Upon the latter depends
our earning power and the others but partially and temporarily af-
fect it. Gainful occupations may only be followed when the sense
of sight and the mental faculties are unimpaired. The loss of the
visual powers invariably has a deleterious effect upon the calling
dependent upon the degree of damage and the nature of the voca-
tion which may be shown in dollars and cents.

The work that we present may perhaps establish a standard for
the use of courts of law and accident insurance companies, which
now have no uniform methods of estimating the value of an in-
dividual's sight.

EXPERT EVIDENCE. 13

CHAPTER L

THE LEGAL STATUS OF THE PHYSICIAN IN RELATION TO

ACCIDENT INSURANCE AND INDEMNITY

FOR ACCIDENTS.

§1. The Legal Status of the Physician in the United States of America
and Definition of Damages.

Most indemnity claims in America are adjusted according to
the opinion of a reputable physician, more especially on the advice
of the official medical adviser or examiner of the insurance, traffic
or manufacturing company, or of the U. S. Pension office physi-
cian, or upon the s-vvorn statements of those deputized for exami-
nation of the special case, with the exception of contested cases
and suits for damages, etc., which are settled in the courts of law.
In most of the States of the Union, the physician or oculist may
be compelled to testify as a common witness or may be brought into
the case as an expert; in either event he may be required to give
expert testimony.

The principles of expert evidence and medico-legal expert testi-
mony are outlined by Sinkler (Baudry 4) as follows :

(a) As TO Expert Evidence in General. — A principle of the
law of evidence is stated by an authority on the subject as follows :
''The fact that any person is of opinion that a fact in issue does
or does not exist is deemed to be irrelevant" (Stephen 42). But
the same writer notes an exception to this rule. "Matters of
opinion are admissible." "Where there is a question as to any
point of science or art, the opinions upon that point, of persons
specially skilled in any such matter, are admissible." The words
science or art are taken to include all subjects on which a course
of special study or experience is necessary to the formation of an
opinion. "But opinions of experts are admissible only in relation
to their art, and not as to matters of common knowledge."

Medico-legal Experts. — The opinions of medical men are con-
stantly admitted as to the cause of disease or death or the conse-
quences of wounds, or the treatment of sickness ; and as to the sane
or insane state of a person's mind as collected from a number of
circumstances, and as to other subjects of professional skill (Tay-
lor 43.) But his special knowledge must be established and his
examination confined thereto (Greenleaf 9.) "A physician may
testify as to cause of death (or disease), from personal examination
or knowledge, but his testimony extends no further than the im-
mediate cause, because, manifestlv. that is the limit of science."
(Wis. Eepts., Vol. 101, p. 278.) (50)

14 DAMAGES.

As TO What Should Form the Basis of the Expert's Testi-
mony in a particular case; the opinion, to be admissible, must be
founded either on his own personal knowledge of the facts testified
to in court or upon an hypothetical question (Bell 6.) His evi-
dence as to facts must be the result of his own examination. A
physician may not give his opinion as to a case in, which he was
called into consultation and where his knowledge of the case is
derived solely from the discussions with his fellow-consultant. A
physician's opinion is not admissible if based on statements made to
him by parties out of court and not under oath (Lewis 23.)

(b) Legal Measure op Damages. — Damages is defined by
Taylor (44) as "the injury or loss for which compensation is
sought," and the measure of damages refers to the amount or ex-
tent of such injury or loss. Three distinct kinds are recognized
and awarded to suit the merits of the case :

First. ISToMiisrAL Damages, or some trifling sum which is
awarded when a breach of duty or infraction of the plaintiff's right
is shown, but no serious loss is proven to have been sustained.
Such are awarded for violation of a plaintiff's right, but where no
damages are shown by the evidence.

Second. Substantial or Compensatory Damages. — These
are such as are designed and awarded to compensate for the actual
loss or injury sustained. The jury weighs the evidence and fixes
the amount which in their opinion properly compensates the in-
jured party for the loss suffered.

In this work only the after-effects of the accident, the economic
damage, is figured. In addition to this, American courts allow the
amount actually expended in the necessary treatment following the
accident, the monetary valuation of the time lost, the amount of
injury to the business of the individual, and indemnity is claimed
and allowed for tlie mental effect, the pain and anguish suffered
by reason of the accident. The amounts of all these factors are
arbitrarily allowed together by the courts. The only factor that
can he fixed with scientifi.c exactness is the actual loss to the earning
ability which follows the accident, the estimation of tvhich is the
business of this hooh and which should be the principal basis fori
settlement of all claims.

Third. Exemplary or Punitive Damages, also termed vin-
dictive. This class exceeds the loss actually sustained, and is given
as a kind of punishment to the defendant.

§3. Accident Insurance in America and Estimation of Indemnity
for Accidents to the Eyes.

(a) The Estimates Made by the American Accident In-
surance Companies are now based upon empiric ideas and the
results of experience, such as the proportion of eye injuries to those

RULIXGS OF ACCIDENT IXSURAXCE COMPAXIES. 15

of the other parts of the body, upon the ratio of losses to the whole
number of insured, and upon the amount of premium the insured
is willing to pay in ordinary risks. In other words, the general
principle of insurance is the foundation for the incurring and set-
tlement of eye cases (Hansell 17.) For example: "When the
loss or partial loss of vision totally disables the insured from per-
forming all his duties, total disability is paid. When it disables
him from performing one or more of his duties, partial disability
is paid. This ruling naturally holds in cases of disability from
other than ocular causes" (Preferred Mutual.) The Travelers'
Insurance Co. said: "There is no general method of estimating
the pecuniary disability in cases of partial loss of vision for several
reasons. One will sutfice. Xo accident policy ever written has
undertaken to estimate such disability. On the contrary, the in-
surance contract is either a valued policy, fixing a definite sum in
the event of loss of vision in one or both eyes, or it names a definite
sum to be paid as weekly indemnity for total or partial loss of time
resulting from eye injuries." The Aetna Co. replied : "The
method of estimating pecuniary indemnity in cases of partial or
complete loss of vision from accident, depends upon the form of
2X)licy which the insured has purchased. If his occupation is such
as to entitle him to insurance in the select or preferred class, the
indemnity payable for total loss of sight of both eyes woiild be
ec|ual to the full amount of his insurance, being therefore placed
upon the same basis as a fatal accident. The loss of the entire
sight of one eye is compensated for by the payment of one-eighth
the amount that would be paid for the loss of both eyes. If the
loss of sight is partial (temporary') and its temporary loss results
in the insured being unable to perform the duties of his occupation,
he is indemnified for such loss of time simply, just as though he
were injured in any other organ. As to loss of vision from dis-
ease: under our special health policy provision is made that in
such an event an amount equal to 100 weeks' indemnity for
total disability will be payable. Payments made bv insurance com-
panies for such loss Avere originallv arbitrarily fixed and the ex-
perience of the companies has not been of such nature as to make
it necessary to modify the same materially."

Thus bv agreement between the insurance companies and the
insured, the former assume the risk of being called upon to pay
sums ranging from $600 to $1,000 for one, and $5,000 for the loss
of both eyes, provided the insured pays a certain yearly sum. The
amount is determined by the ratio of eye injuries to injuries of
other parts of the body and to fatal injuries, taken from a large
number, and the willingness of the insured to pay a yearly
premium commensurate with his own conception of the pecuniary
value of an eye and of vision and of the risk he believes he incurs.
This is a purely mutual and financial arrangement and is made in-
dependently of age, sex, occupation (excluding special risks) and
annual income.

16 U. S. BUREAU OF PENSIONS — GERMAN LAW.

(b) The United States Bureau of Pensions has fixed the
rates of pension for disability arising from disease of the eyes thus :
"Total blindness of both eyes $72.00 per month; loss of one eye
$17.00 per month; loss of sight of one eye $12.00 per month. In
cases of disease of eyes causing defective vision, the rates vary
from $6.00 to $50.00 according to rank and pay." (17)

§3. The Oerman Accident Insurance Law.

July 6, 1884, there was an accident insurance law passed (von
Woedtke 46) which is now in force in the German Empire. § 5
defines its intention as follows: Compensation for the loss re-
sulting from bodily injury or death is to be adjusted according
to the following provisions :

1. The cost of necessary treatment commencing at the begin-
ning of the 14th* week after the accident.

2. A regular income to be paid to the injured person from the
beginning of the 14th week during the time of his inability
to work.

The wording of the law shows that neither the injury itself
nor any temporary results, such as the detention from work or the
expense of treatment up to the 14th week thereafter, is considered
grounds for indemnification, but it relates solely to the effects when
they have had a more permanent detrimental influence upon the
earning powers.

Section II, § 5 shows that the law-makers had nO' other inten-
tion and the law should not be interpreted in any other sense. The
law does not mean that under all circumstances injured persons
should receive indemnification.

We agree with Mooren (29, p. 29) when he says, "The presence
of an ocular imperfection does not constitute a claim for indemni-
fication, but only the existence of inability to follow a trade or
profession resulting from such imperfection can be so considered."
If the physician desires to do his duty, he cannot depart from this
interpretation of the law. While there is no doul)t that the effect
of this Accident Insurance Law is not to indemnify the insured for
the injury itself, but only for the impairing of the earning ability,
it has not yet been definitely decided who shall be the authority
for determining the extent of this loss of earning ability and es-
pecially the amoamt of the indemnification. Some claim that this
is the duty of the physician, others that it is the exclusive right
of the courts and the insurance officials.

•It will be noted that this Insurance Law deals only with the results of accidental
injuries after 14 weeks have elapsed from the date of the accident. The reason for this may
lie in the fact that most German manufacturers pay their City Hospitals certain sums,
(which have been retained from the workman's wages) for the care of their sick employees
and indemnification for accidents is considered due only after the lapse of 14 weeks.

What is an eye worth in America ? To any of us sisht is priceless, but the courts
award from $1,0(10.00 to $8,000.00, the latter being the highest indemnity yet given. See Dela
Vergne Refrigerator Co. vs. Stahl, Court Civil Appeals, Texas, 1901, Journal A. M. A., 1901.

DETERMINATION" OF DAMAGE BY PHYSICIANS. 17

§4. The Determination of the Corporal and Economic Damage
from Injuries Belongs to the Physician, the Estimation of
the Monetary Compensation to the Corporations and the
Courts.

Foerster (7, p. 16) considers that the duty of the physician is
only to attest to the kind of injury, leaving the estimation of its
effect upon the earning ability to the trade assoiciation. To this
we cannot agree; for instance; what help will it be to the in-
surance officials or to the average juryman if we inform them
that a certain injured person has suffered from "a paralysis of the
musculus externus sinistra?" In order to properly judge of the
relations between the laming of an ocular muscle and the earning
capacity, technical physiologic knowledge is certainly needed, and
verily, we cannot expect a tradesman to have a scientific mind.
A physician can much sooner acquire a knowledge of the technical
peculiarities of the different trades than the trade association can
get even a modicum of medical knowledge. There are but few
vocations with which a physician does not come in contact. Wag-
ner (38, p. 21) states that it is the duty of the physician to acquire
some knowledge of the trades of the patients with whom he deals,
as by this means he is enabled to estimate the relation of the injury
to the loss of the earning ability. To the foregoing we heartily
agree. It is the province of the physician to estimate the propor-
tional loss to the earning ability resulting from disease or trauma-
tism, for who among men is, from his training and daily work, so
well qualified, and whose business brings him into closer relations
with such economic problems? The question of monetary com-
pensation, the sordid matters of dollars and cents, may be left to
the business corporations and the courts of law.

18 zehender's formula.

CHAPTER IL

DIFFERENT METHODS FOR ESTIMATION OF LOSS OF THE
EARNING ABILITY FROM OCULAR INJURIES.

§0. Zehender's Formula.

Zehender was the first who' tried to make a rule for the esti-
mation of the loss of the earning powers from ocular injuries (53.)
His publication provoked a series of papers by other German writ-
ers who declared that liis premises were incorrect and his calcu-
lations illogical. We, therefore, give a critical resume of the
several methods of mathematical computation that have been pro-
posed, showing their errors, and then proceed to the exposition of
the method of Magnus, which for accurate scientific work seems
to us to be the most satisfactory. Zehender gave a formula founded
upon a suppositious case where the sight of one eye is entirely
lost while that of the other remains normal. He supposed that
such a normal eye acquires a much higher value (even double)
than formerly.

To compute the amount of vision left after the loss of one eye

by his method, three eye values must be considered, two for the

normal eye and one for the blind one, which he places in the form

2 >< 1 + 2
of an arithmetical equation thus, = -^, The visual

faculty in such a ease is, therefore, two-thirds of normal.

If Zehender's supposition be right and if after the loss of one
eye, we really had to figure with three quantities, there would be
nothing to say against its correctness, but it is arithmetically in-
correct in its conception, for, if we double the value of any object,
we do not make by this manipulation two different ones but one
which is only of a different value and therefore by such an equa-
tion applied to eye values we only change the quality of the two
eye values, the number remaining the same. Although this fact
may be self-evident, we will exemplify it as follows : Supposing
a man owns a house which thro'ugh some fortunate event would be-
come twice as valuable as formerly, would anybody believe in this
ease that the man now owns two houses? Let us vary this ex-
ample and suppose that this man owns two houses of equal value,
one of these increases in value to double, the other through some
accident depreciates entirely, would anybody conceive the idea that
this particular man now owns three houses or claim that he would
have to figure with three houses in the valuation of his property?
Zehender however has come toi such a curious conclusion, so that,
by his formula, we would have to figure, in the case of the one-
eyed man, with three eye values. He has made a one-eyed person

GROENOUW'S FORMULA. 19

into a three-eyed one. Zehender's error is in supposing that he
really creates by the enhanced valuation of one thing, a new and
second self-existing object. Thus, if we woaild express the earn-
ing ability by his speculative proposition and arithmetical example,
but avoiding his serious mathematical and logical errors, the for-

2-1-0
mula would be : rni^i * ^^^' ^^ ^^^^ formula would give for the

earning ability, notwithstanding the loss of one eye, the full value
O'f one, the consequence is that Zehender's expression cannot be
used in the proper mathematical way. Thus Zehender's formula
belongs only to history. jSTevertheless, he should be accorded the
honor of having first shown that the mathematical method is the
correct way for estimation of the ocular earning ability.

§6. GroenoHw's Formula.

(a) Groenouw (12, p. 34) uses a formula which likewise does
not give the normal physiologic and economic value for vision, but
like that of Zehender's, it rests upon a pathologic process of injury
to the faculty of sight. He begins with the supposition that the
stronger eye possesses a greater economic value than the weaker
one. If the difference of the visual powers of the eyes be some-
what great, then the better eye would alone be accustomed to work
while the weaker would count very little in regard to earning abil-
ity. Groenouw expresses this supposition l)y taking first an arith-

O-pi I op

metical proportion of the visual power of both eyes, , -. in

which Se stands for the better and se for the poorer eye, and by
this formula the better eye (Se) is given m times greater value
than the poorer one. We would therefore transpose the foregoing

formula into ^L><S^_±^. He also adds to this expression the

M -f 1
value of the visual field P making the expression for the earning

,.,., ^ mXSe + se^
abilitv, E = r^ P.

' M + 1

As Groenouw's formula does not represent the value of normal
physiologic vision for earning purposes but rather the value of an
already pathologically changed faculty, therefore, it cannot be
used for a general expression of economic vision but only for some
certain special case. In Groenouw's equation E stands for the
earning ability which is the unknown quantity and the results to
be sought by all the equations considered in this book, m stands
for the greater value acquired bv the sound eye after injurv to its
fellow. This enhancement is likewise unknown. Se is the cen-
tral visual acuity of the better eye which can be ascertained by
functional examination, se is the visual acuity of the poor eve
which is likewise to be found. P is the value of the visual field
which can be ascertained. We have now in Groenouw's formula an

20 GROENOUW'S rOEMULA INAPPLICABLE.

equation with two unknown quantities, E and ]\r, and three known
quantities, Se^ se and P. But such an equation has numberless
solutions, as it is possible to compute from the values given to one
unknown quantity separate values for the other (the exceptions are
only the so-called diophantic equations which cannot be considered
in this connection.) As this formula admits of numberless solu-
tions we ma}' therefore consider it inapplicable for our purpose,
for we would be unable to tell which of the numberless possibilities
would be the right one in a given case. An equation which is able
to give a single precise answer is the only practical one. Thus,
from the very start, with his equation containing two unknown
quantities, Groenouw got into a desperate position because he pro-
posed a formula which cannot be treated in a correct mathe-
matical manner.

(b) The estimation of ocular damage by Groenouw's formula

. ,, • • 1 p -n M X Se + SE „ . , ., ,

m the original form, E = r^, P is not possible,

° M + 1 ^

because the two unknown quantities contained therein cannot be
figured out of this one formula. Groenouw, however, extricates
himself out of tliis disagreeable situation by forcibly pressing his
formula into a more desirable form, which allows of a certain kind
of estimation of the damage to central and peripheric vision. Be-
fore we can take up the subject of these cases in which there is
partial damage to the visual faculty but no actual blindness, we
must first regard the working of this formula in the case of a
one-eyed man.

(c) We are of the opinion that Groenouw's formula cannot be
properly used in the ease of monocular vision : For he conceives
that there is a certain proportional value between the ]x>wer of
sight ill the better and that of the poorer eye, the better eye having
M times earning value over that of the poorer (12, pp. 35, 36, 37),
i. e., that the better eye (13) exercises an m times greater influ-
ence upon the earning ability than the poorer, but if one eye is en-
tirely blind, this proportional valuation is simply impossible be-
cause a blind eye is never of any assistance to the earning ability
and does not, therefore, possess an earning value; then the poorer
€ye cannot have an m times greater value than the blind one, for
the earning value of the blind eye is equal to nothing, and m times
this is also nothing; therefore, the mathematical rule which
shows that the multiplication of a number value with naught makes
it alwavs l)ecome naught, render? Groenouw's calculation a mathe-
matical absurdity, in that according to his rules a one-eyed person
must be entirely incapable of earning anything.

In Groenouw's formula E, the earning ability, and :m, the en-
hancement of the earning value of the better eye, is unknown.
Se. the sight of the healthy eye, equals 1 ; se. the sight of a totally
blind eye, disappears entirely out of the formula : P, the visual field,
is given by him a value of 9-10, which has been found by exact

GROENOUW'S FORMULA. 21

physiological examination and wliicli we will here accept in a case
of monocular vision, Groenouw constructs the following formula:

M + 1

This formula is constructed in an arithmetical equation similar
to that of Zehender's. As long as both eyes could see, the better
63^6 with the power Se would have m times value over and above
the poor eye, se^ thus the numerator of the arithmetical equation
would be:MXSE+SE. But if one eye grows blind, its faculty of
seeing is then entirely omitted, the numerator then becomes m X Se
or because Se is 1 it equals ii ; the simplified formula thus being :

E = ^P.

M + 1

If the value se^ one of the two values out of which the arith-
metical proportion is formed, is entirely omitted, its influence is
•exerted not only in the numerator but in the denominator of our
fraction. Thus the numerator of the formula would be reduced
to M + 0, as the numerical earning value of the blind eye is o.
Whether a blind eye is in the head or has been removed by an opera-
tion is entirely foreign to this subject, as, if it is blind, it must be
regarded as non-existing as far as it relates to the earning ability
and must be treated accordingly in the denominator of the arith-
metical proportion, which is, therefore, m + o. Groenouw, however,
■calls the denominator m + 1, whether one eye can be counted or not,
and thus in the formula which should represent solely the physio-
logic earning value rates a blind and therefore non-existing eye
with a positive earning value of 1.

Groenouw has confounded the physiologic with the anatomic con-
ditions; for the physiologic purposes a blind eye is practically the
same as if it were non-existing, and because he has done so he pre-
sents in the further course of his calculations with human beings
who have theoretically nine seeing eyes, for instance, in a concrete
ease in which one eye has visual acuity of ^ and the other l/l , the

8 + - + -
earning ability is expressed thus : E = * ^ 1, and this is

nothing else but the arithmetical proportion of the faculty of
vision of a being who has nine seeing eyes. The outrage upon com-
mon sense is none the less if the human being be likened to a cyclops
or to a nine-eyed monster. One of the two suppositions has to be
chosen if Groenouw's formula be used, because it does not admit
of the consideration of a normal being having two seeing eyes.
"We have shown that the text of Groenouw's formula is erroneous
and will now regard the manner in which he uses it to express the
earning abilitv of the one-eved person, for which his formula is,

E = ^P.'

M + 1

22 FORMULA OF IIEDDAEUS.

In this formula E and the enhancement of value of the sound
eye, :m, are unknown. Here is again an equation with two un-
known quantities which has no fixed but numberless solutions.
Such mathematical difficulties are passed over by Groenouw in the
following manner: He first supposes that the income of a one-eyed
person is 33 I/3, therefore the earning ability must be 3-^ , and with-
out any reflection he inserts this arbitrary value into his formula

thus : ^ = — r-- Mo. In this equation m can be figured with-
M + 1 ^ *=

out any difficult}^, which would be about 3. But we can, of course^

have as great a number of values for m as that for E, but for

which Groenouw has made an arbitrary valuation, ys or /^ (7,p.35),

and which anybody has the privilege of changing. If we would

figure b}^ his method, we would form such a fluctuating equation

that E could not be mathematically considered.

(d) Groenouw further handles these doubtful and fictitious val-
ues in the following way : For the estimation of injuries in which
the central visual acuity has been injured, but total blindness not
resulting: Here he does not hesitate to generalize the values for
M which he forced into his equation in the case of one-eyedness
and uses them in the calculation of other cases in which both eyes
see, despite the fact that the value of the vision in the seeing eye
in one-sided blindness is quite different from that of the better eye
in another case where some sight remains. The earning ability
of a one-eyed person is quite a different thing from the earning
abilit}' of a normal being, and these terms are not interchangeable.
Thus, Groenouw's formula, being based upon fictitious values and
improperly formed, cannot be used for the scientific estimation
of the economic value of vision.

§7. The Formula of Heddaeus.

Heddaeus (18) bases his calculations upon the indisputable
fact, that if the faculty of sight be reduced to one-half, the re-
mainder represents a proportional greater amount of earning ability
than that which has been lost. This observation causes him to sup-
pose that the loss of earning power is equal to the square of the loss
of Wsion. We cannot see Avhy only the square and not the cube
or the fourth or any other power should not designate the above
proportion. This is simply an arbitran- decision of Heddaeus and
is not founded on the real proportion. In his writings, he does
not give any mathematic, physiologic or economic proofs of the
correctness of his proposition. Heddaeus makes one assertion to
which we must most emphatically protest, for he brings the factor
of binocular vision in connection with ocular injuries into a most
unwarrantably prominent ])osition. In the case of acquired mo-
nocular vision from accidents, he asserts that the diminution of the
earning abilitv is onlv affected bv the loss of binocular vision and

FORiLULA OF HEDDAEUS INAPPLICABLE. 23

that this factor and the loss of the power to estimate distances
correctly, is the most essential factor for the loss of the earning
power. This supposition is ridiculous ! Although, immediately
after the loss of one eye, the faculty for estimation of distance
and size of objects is lost for a while, and is detrimental to the
earning ability, and therefore should not be underestimated, it dis-
appears entirely in a comparatively short time.

By examinations (Magnus 26, p. 38) of the one-eyed laborers
among the iron and steel workers in Silesia, it was found that fully
70 per cent, of those who were blinded in one eye had learned to see
■easily and estimate distances correctly. As this faculty is restored
to every one, it needs only passing consideration.

24 GENERAL PRIXCIPLES OF MEASUREMENT.

CHAPTER III.

§8. General Principles for Estimation of the Relations of Ocular
Injuries to the Earning Ability.

The fact, that during the last few years so many different
propositions for the estimation of the economic value of vision have
been proposed, shows that the general principles involved in deter-
mining the earning ability are not yet clearly understood. We will,,
therefore, search for and explain certain general principles for
this estimation which will serve as a basis for that relating to the
visual act which is one of the functions of the general organization.
We will give the visual earning ability a prominent part in our
considerations.

If in a given case we desire to mathematically determine the
amount of power of any bodily function, we first have to find a
general expression for the normal ability of the particular organ.
We usually determine such expression by taking the average of a
large number of measurements of the particular function and
designate this average as an expression of the normal powers. In
this way we have formed the standard of visual acuity, of the visual
field, of the normal light and color sense, etc. Starting from this
average value, we measure the power of the organ in any special
case. The difference between its power and our standard is a
fraction which in the case under examination may represent the
amount of damage done to the function. This we do in the estima-
tion of the pathologic diminution of central visual acuity and with
limitations of the visual field. When we succeed in creating such
an average normal value of the function of an organ or bodily
power, we can then estimate the amount of individual acts, as if
measuring a piece of cloth with a yard-stick. This method is used
in the other natural sciences as well as in medicine. Therefore, we
must first fix an expression for the normal ocular earning ability
before we can estimate the amount of individual cases. The objec-
tion that the application of this principle to the act of vision and
the resultant measurements Avould be arbitrary, holds good to
but a limited extent, for where a conception of the normal func-
tion has been developed from a series of definite measurements
from which the average value has been estimated, we do not speak
arbitrarily, especially where this conception has been upheld by
other findings, the products of searching inquiries of a scientific
character; but we must remember that a function of a body or a
natural power is a need which cannot be weighed with the scales
or measured bv the yard, and therefore we cannot entirely do with-
out certain arbitrary suppositions.

GENERAL PRINCIPLES OF MEASUREMENT. 25

In our opinion thei'e is only one way for the establishment of a
formula for the normal ocular earning ability, and that is, by the
separate estimation of the value of each physiologic factor form-
ing the sense of sight, and by the addition of these component parts
the normal value of vision may be established. The construction
of such a formula is facilitated by the fact that we already have
established the physiologic value for the more important factors
entering into the visual act, i. e., the central visual acuity and the
field of vision. But the normal physiologic act of vision is a com-
posite quantity formed of different factors which have more or less
relation to the economic value of the eye. We may exclude those ■
factors which are without economic importance for the salce of our
subject. We thus form out of the composite act of seeing a reduced
or economic estimation of the visual act. In order to do this we
must fuse, bring into or eliminate certain of these factors to satisfy
our purpose. As we have placed the visual earning act in a normal
position (chap. IV., § 9), we will use the same method for deter-
mination of its factors. Damaged ocular earning ability will al-
ways be considered as a fraction of the normal power. This
method, which permits of a mathematical estimation of each por-
tion of the visual act as a fraction of the normal, must be consid-
ered to be complete, as it is in perfect harmony with the principles-
laid down by the natural sciences in measuring the work of any
organ or power.

Judging by this standard, we must consider that the proposi-
tions of Zehender, Groenouw and Heddaeus were on the wrong track
from the very start. None of these authors developed an expres-
sion for the normal physiologic act of vision. Their formulae for
expressing the economic value of vision stand absolutely on patho-
logic grounds and they introduce self-constructed pathologic sup-
positions into the calculations, instead of looking at the earning
ability as a quantity resulting from a combination of the different
parts composing the physiologic act of vision. Thus these for-
mulae are not expressions for existing conditions, but are nothing
but the mathematical sediment of intuitions arbitrarily conceived
by these authors. As they have departed from the physiologic and
only reliable ground for arbitrary hypotheses, their theories are
shown to conflict, in a most humorous manner, with the physiologic
ocular conditions in a healthy person. Thus, according to Zehen-
der's calculation, a human being would have three seeing eyes, and
Groenouw acts as if nature had given him nine eyes or put him into
the world as a eyclops.

26 THE EARXIXG ABILITY.

CHAPTER IV.

THE CONCEPTION OF THE EARNING ABILITY AND INJURIES

THERETO.

§9. The Meaning of Full Earning Ahility.

If we would conceive of an injury to the earning ability as a
quantity which can be given a mathematical value, we would have
to start from an estimation of the complete earning ability, which
in a healthy normal individual is a comj^osite quantity resulting
from three factors : —

(1) The unimjjaired functional power of the bodily organs.

(2). The technical knowledge which is necessary for the carry-
ing on of the vocation.

(3). The ability of the individual to compete in the labor
market.

In an opinion given by the Imperial Insurance office Xov. 26,
1887 (Becker 5, p. 10), the meaning of the earning ability is thus
stated :

''In judging the earning ability the bodily and intellectual con-
dition of the injured person has to be considered in connection
•with the preparatory education and. also his capacity for earning
a living." In this definition, "bodily and intellectual condition,"
is the same as the first of our elements (1), the unimpaired func-
tional ability of the bodily organs ; the so-called "preparatory edu-
cation," would correspond with our (2), the technical knowledge
necessar}' to the calling; and our (3), the capacity or ability to
compete in the labor market, is defined in the official definition as
^'capacity for earning a living."

These elements cannot be regarded as equal in value. Doubt-
less the functional condition of the bodily organs is of the first im-
portance for successful work. The preparatory education or knowl-
edge is of nearly equal value. Much less importance should be
given to the third element, the ability to compete in the labor
market. This is dependent upon the value of the two others, be-
cause the ability of an artisan to battle against competition de-
pends largely upon the condition of his health and his technical
knowledge — our two first elements. We have divided the concep-
tion of the earning ability into its three fundamental elements
solely because such an analysis makes it possible to put the normal
earning ability into a mathematical formula. Thus we designate
the eamincr ability itself E ; the first of our elements, the func-
tional abilitv. F ; the second, the necessary knowledge, Y ; and the
third, the ability to compete. K. In this formula we put the two
quantities, F and Y, in their full value and accept K as a root

FACTORS OF EARNING ABILITY. 27

value. There would be nothing c-haaiged in the total value of the
formula itself because as the root of 1 is always 1, and we regard
F, V and K as 1, it is immaterial for the formula itself if we
take one of the three quantities as a root or not, but this proportion
immediately changes when the part introduced as a root grows
smaller than 1, as happens in each ocular injury, because the root
of each genuine fraction is always greater than the fraction itself.
Thus the influence of K, after being introduced as a root value, if

K K

it has fallen off by an injury to - cannot be any more

but must be greater, for instance, " . Therefore, the damage to

the total value of the formula will be smaller if we take K as a
root value. By the total elimination of K the earning ability
will not be diminished, but it will be by a smaller damage, according
to the influence the damage of K shall exercise upon the value of the
total formula. We will have to choose the exponent of the root
as smaller or greater, according to its rating. The value of a root
of a genuine fraction is much great^* if its exponent is small.
Therefore, if we wish to lower it considerably, we take a small, if
we wish to effect it less, a greater exponent for Iv. While the
ability to compete, K, is comparatively very little impaired through
minor ocular injuries, it is very much so through the loss of one
eye; we suit these conditions by choosing a greater exponent of
the root in slight injuries, but a smaller exponent for serious ones.
We will adopt for the slight injuries K as the 10th root and
for serious ones according to the demands of the profession,
the 7th root or the oth root. We will more fully explain this in
one of the following chapters. An exact calculation of such a
changeable quantity so dependent upon the individual cannot be
made. The calculation of the competing ability cannot be waived
entirely, as does Groenouw, who submits in each case the estimation
of this important factor to the pleasure of the examiner. We have
started out to make a practical mathematical formula, but should
include all factors that are relative; as we will show further on, the
peculiarities of the individual case may ahvays be considered.

When we express the earning ability through the three factors,
F, Y and Iv, we present E, not as a sum. but as the product of these

quantities, as multiplied thusly : E=FVV' K, in which the exponent
X changes with the degree of the functional damage. E must al-
ways be regarded as a product and not as a sum, to meet all possi-
bilities occurring in practice. If Ave add F. Y and Iv, the formula
would give wrong practical results, as we see in the following ex-
ample: Supposing both eyes were lost in an accident, the quantity
F of our formula would be 0. If we had connected F, Y and K

with the +, flncl added, even if K would have become 0, Y -\-V K^
which is the remainder of the eamins- abilitv. would have been left.

28 -WORKING ABILITY AND EARNING ABILITY.

This would be entirely wrong, because a lalwrer who has lost his
functional ability, especially the sense of sight, should be regarded
in an optical way as entirely unable to earn. Taking the same ex-
ample and using our formula with F=0, E immediately becomes
0, because each product is always if one of the factors is 0. If
we would leave Y out of our formula, E of course =0, and actual
practice confirms this, because even the most simple hand work
requires a certain amount of preparatory education. Finally, if
we drop the third factor, the 10th root of K, the normal earning
ability according to our formula becomes 0, which is likewise
shown by practical experience, because, even though an indi\ddual
is in good health and by reason of preparatory education has the
skill to work, if his work is not needed, his economic value is nil.
He may possess the power of working, as the factors F and V are
present, but he only has earning ability when he can dispose of the
work in the economic market. Therefore, if from our formula

(E=F V K K ) we take away the factor V K (the ability of the
individual to dispose of his work), the remainder, which is the for-
mula for the working ability (A), would be A==F V.

The "working ability*" is not synonymous with "earning ability,"
although some -authors would have it so, for instance, Becker
(5, p. 9) : "The words "working ability' and 'earning ability'
may be regarded identical in meaning, because in each worker the
latter depends upon the former.'' Even if this be so, the two con-
ceptions are not the same, and such a rendition obscures the concep-
tion of the earning ability, our definition of which should be
clearly understood.

The calculation of injury to the earning ability proposed by
us starts from the formula for the full earning ability :

E = F V K K.

DAMAGE TO EARNING ABILITY. 29

CHAPTER V.

§10. Determination of the Amount of Injury to the Earning
Ability According to Magnus.

When one or more of the factors forming the earning ability
is injured, an idea of the amount of damage to it may be formed
if we first consider to what extent tlie single factors are injured.
We will find that the application of mathematics to tliis subject
will prove somewhat complicated, as we will have to first separately
■estimate the damage to the different factors and then fix the value
of the total formula. Under certain conditions, this task may
become decidedly complicated, as some of these factors forming the
complete earning ability are composed of several elements which
have to be figured separately. This is especially the case with the
act of seeing (F of our formula), which, as we will see directly,
•consists of three separate parts, each of which may be damaged in
a different way. To ascertain the value of the factor F, we have to
solve three mathematical problems, but in return, our method of
•estimation does not alone offer the possibility of giving a mathe-
matical expression to the different forms of damage to the ocular
apparatus, but also allows us to do this in an accurate manner,
with due consideration of the different individual conditions in
■question, and finally our method solves the mathematical prob-
lems (chap. Ill, §8) in a satisfactory manner. It starts from
the physiologic ocular earning ability and designates the damage
thereto as fractions of the normal value, making our method right
in its principle and easy to comprehend. The calculation of our
formula is simplified by the fact that our factor V (the prepara-
tory education), may be entirely cut out in estimating injury to
the earning ability. As important as this factor may be to the
normal earning ability, we may put it aside in a case of accidental
damage. The technical education in itself will not be injured di-
rectly. It is only indirectly affected by accidental injury. Cer-
tainly the visual function may be diminished to such an extent that
the realization of the technical knowledge becomes limited, but this
injury to the earning ability in such a case does not rest upon a
diminution of the knowledge and the capacity, biit limitation of
their use. We calculate the extent of such limitation, according to
our method, directly bv the factor F, i. p., from the performance
of the visual act, which is the essential factor in the full eaminij
ability, damage to which is synonymous with damage to the total.
Calculating F we have already used Y. For simplicity's sake
it would be better to omit T entirely. The n'orl-tng formula for

the earning ability then would be : E=F V K.

30 VISUAL FACTORS.

CHAPTER VI.

§11. Estimation of the Damage to Economic Vision.

Normal physiologic vision consists of a series of difEerent fac-
tors : the central acuity, the visual field, light and color senses, the
adaptive faculty, the muscular movements and the cerebral proc-
esses^ all acting together in creating the sense of sight. We may,
therefore, regard the act of seeing as a sum whose numerals are
formed by the different functions; if one numeral be taken from
the sum which represents the complete act of seeing, then the
balance will be left, i. e., vision will be damaged to the extent of the
loss of one of these visual functions; but vision is yet in existence
in a limited way. In the manufacture of a formula for physiologic
vision we would have to consider that in losing simultaneously the
two most important factors, central and peripheric vision, the act
of seeing would be nil ; but from an economic standpoint we could
not get along with this idea. The different secondary functions
forming sight have different valuations. In calculating the injury
to the visual earning ability we will have to exclude cerebral vision
because accidental injuries affecting the cerebral centers will hardly
ever be of such limited extent that the valuation thereof would be
done by an oculist. In such a case the neurologist would be de-
manded. The sense for light and color and that of adaption are
not themselves to be considered in estimating accidental damage
to the ocular earning ability. An injury limited exclusively ta
these functions is not known. Theoretically such injuries might
be possible, but practically they are not recognized. Such trau-
matisms would generally be connected with disturbance of other
portions of the visual act, especially that of visual acuity and the
visual field. Therefore, we include the functions of the light and
color sense and of the adaptive power, when we treat of the dis-
turbances of the visual acuity and visual field, as thereby the estima-
tion is rendered less complicated. The visual acuity, the field of
vision and the muscular movements are of so much more impor-
tance that we think we can properly estimate the results of ocular
traumatisms by taking into consideration only these latter three.
These are to be regarded as the factors of a product and multiplied.
Practical experience shows us that we must do this under all cir-
cumstances, because for the following of a vocation, none of these
factors could be damaged or left out, for without them the earning
ability would disappear. If a person loses the central acuity of
both eyes, then we certainly have complete earning disability; not
even the common laborer having lost his central acuity could do
his former work. Such an individual could only take very low
grade positions, such as that of a messenger. The possibility of

VISUAL FACTORS. 31

doing much work in the several trades after the loss of central
acuity is so completely excluded from consideration, that it would be
extremely incorrect if we did not consider an artisan who had a
large central scotoma, i. e., lost his central visual acuity, entirely
unable to pursue his vocation and earn anything. If peripheric
vision is lost in both eyes, working at trades is likewise excluded, as
is readily seen in cases of double-sided hemianopsia. A working
man with total paralysis of all the outer ocular muscles is likewise
totally disabled. In such a case he Avill stare into vacancy and
cannot work in a binocular manner. He would lose the ability to
estimate distances and the size of objects, and could only have a
certain degree of monocular vision, which could be imagined to be
useful only in certain special cases, as that of a nearsighted clerk.
Such a ease might be looked upon as a curiosity and would be
rather an exception, so that it could not be used to refute our view
that the ocular muscles are absolutely necessary for the earning
ability. Even the closing of one eye, which Groenouw holds in readi-
ness as a remedy for the restoration of the earning ability, will
help nothing, for the other will stare immovably if its muscles are
paralyzed. The adjustment that is noted in congenital defects
cannot be likened to that of acquired ones and cannot be considered
in their influence upon the earning ability. The physiologic process
out of which an adjustment and an increase up to the earning
ability, which has been asserted by Groenouw (13) to have occurred
in a case of acquired paralysis of all the ocular muscles, is certainly
very strange to us. Therefore, in the case of an artisan with an
acquired paralysis of all the outer ocular muscles there is total
disability to work.

In building up a formula for the act of seeing in relation to
earning, we denominate the central acuity with the letter C and
the visual field with P. The valuation of the muscular motions,
M, offers certain difficulties, because the influence of a distur-
bance of the function in a single ocular muscle, from a professional
standpoint, is quite a different one, AA'hether we take into considera-
tion monocular or binocular vision. The monocular act is but
slightly affected by paralysis of one ocular muscle, as it only dimin-
ishes the motility of the eyeball, but in binocular vision the factor
of diplopia comes in and this is of the greatest importance, as it
excludes, temporarily at least, retention of working binocular vision.
In formation of our formula wo would, therefore, treat the factor
of muscular movements in a different manner, when treating of
binocular vision, than we would for the monocular act. In the
formula for binocular vision we take the muscular movements of
each eye as the product of different factors, each of which corres-
ponds to the activity of a particular muscle. Now, if we mark the
muscles of one eye with ( mi m-z m.{ m^ ms mc ) and those of
the other ( mi' m^ ms' m,' ms' me' ) etc., we would represent

32 THE VISUAL FIELD AXD OCULAR MUSCLES.

the whole muscular activity as (mi m2 irirj m* ms me) (m/ m./ m/
m/ m^'' me')- ^^ this conception the whole product would
be 0, by losing one single muscular motion, and therefore
the binocular act would be negative. In monocular vision the mus-
cular activity should be conceived as the sum of the single per-
formances, because by losing one of them only an ocular detriment
has been created and not total earning disabilit}', thus mi + mj +
ms + mi + ms + me-

A few remarks about the relations of the different fac-
tors entering into the visual act are here advisable. The
central visual acuity is, under all circumstances, the most important
element for the function of vision. Any injury which reduces the
central visual acuity below the lowest limits required in the pro-
fession, produces a total disability for that work. Peripheric
vision is of less importance and has not as much influence upon the
visual act, and injuries to it have a smaller influence to the entire
act of vision than the degree of injury of the visual field itself. If, for
instance^ the remaining peripheric vision, P, should be denominated

with a greater fraction than — , Ave may do this by introducing P
as a root value like we did with the factor K for the earning ability

Y Y

(Chap. IV, § 9). The root of — would then be greater than -^

2y ^ ^

for instance . The damage to the total value of the formula
X *=

would be smaller, if P be taken as a root value and the value of the
act of vision would not be diminished to the value of P, but to a
smaller extent.

The same is the case with the action of the muscles, but even to-
a greater extent, as they are much less important for the monocu-
lar act of vision than is the visual field. We will, therefore, add
the action of the muscles M as a root value in the formula, but we
will take the exponent of this root to be much greater than the
exponent of the root value of the visual field. According to
mathematical principles the value of the root of a proper fraction
increases with the amount of its exponent, thus, if we introduce
M with a greater exponent of the root than P, in the case of damage
to M, it will exercise less influence upon the total value of the
formula. We believe that we may place the relative value of the
visual field and the muscular movements by choosing as exponent
of the root in the former 2, and in the latter 4. Of course, these
are arbitrarily chosen, as it is an undisputed fact that the central
visual acuity, peripheric vision and the muscular movements have
different nieanings in the act of. vision, the proportional valuation
of which cannot be put into figures from observation nor from meas-
urement, it is certainly allowable for the mathematician or the phy-
sician to estimate the amounts of these exponents differently, but
the formula itself will not be changed. We thus reserve for the

FORMULA FOR BINOCULAR AND MONOCULAR VISION. 33

examiner in each case, the right to make allowance for his individ-
ual conception, which factor we regard as a great advantage in our
method. Thus our formula for the hinocular act of vision would

be : S2 ^ C V' P V (mi mz ms m* m5 me ) ( m/ m/ m/ m/ m/ me' )

In this formula C is considered the central visual acuit}^ in the
better eye, which under normal conditions will always equal 1.

In case of double-sided damage to the visual acuity, if we desire
to condense this formula into that for the monocular act, we should
consider that the peripheric vision as well as the activity of the
extra ocular muscles M, enter into the monocular act in a some-
what different form. The monocular field of vision is a fraction
smaller than the binocular. It is commonly only ^ (Groeuouw ^o)
of the latter. (An exhaustive explanation of these conditions will
be found in the chapter treating of monocular vision.) The extra-
ocular muscles have smaller value in monocular vision than in
binocular, because in the former those functions of the outer mus-
culature of both eyes that are essential in estimating distance and
the relations of objects, etc., are missing. Therefore, we here con-
sider the value of the musculature as less and estimate it at ^ of
the binocular value. This smaller valuation of M may be ulti-
mately neutralized if a monoculism caused by accident has existed
a considerable period. We compute the formula for the monocular
act of vision from the binocular one as follows :

Si = C Vye P V ^.(mi + m., + ms + m* + ms + me.)

§12. Estimation of the Economic Limitations of the Central
Visual Acuity.

The central acuity lies within well-known physiologic limits.
When it falls below these, the function itself is damaged, but the
conditions met with in practice are not such that the physiologic
and earning limitations of the central visual acuity are interde-
pendent; if it were so, the claim of Zehender (53, p. 266) would
stand ; then the smaller the damage of the former, the greater the
earning value of the latter, and vice versa. If we desire to have a
general rule for the ability of every single ocular function, an aver-
age value must be found by many single measurements, but such
average values permit of many exceptions and cannot be designated
as the average limiting value of the earning ability, for. if such were
the case, each variation therefrom might be termed a damage to the
earning ability. This may be done by individual measurement of
each factor ineach case, but such always bears an individual stamp.
We must not forget that while the limit values of every function
have a scientific meaning, the conditions met in actual practice are
different. Science calls an individual blind only when perception
of light has entirely disappeared, but in actual practice, he is blind
if the faculty of sight has been weakened to such an extent that

34 ECONOMIC MEANING OF BLINDNESS.

the organ of Aision cannot be used to earn a living (Magnus 24);
The meaning of blindness as used in daily life is much narrower
than that of science.

Xow and then extremely great demands may be made upon
the action of certain organs which may reach to its highest ability.
Jn actual practice we are satisfied with the amount of labor which
does not strain the powers. Zehender's (53, p. 266) principle, that
the full earning ability existed only Avith full acuity of
vision and every diminution of the highest limits means
at the same time a diminution of the earning ability,
cannot be accepted. Xot alone do we raise scientific
scruples against the acceptance of a proportional relation be-
tween the earning ability and the scientific meaning of visual
acuit}', but also practical experience is entirely against such rela-
tion. There is hardly any vocation Avhich demands the extreme
limit of sight (according to scientific figures), as a condition of
success. In each vocation a great many individuals may be found
who have comparatively poor sight but the same earning ability
as those with normal eyes (Groenouw 11). Josten (20, p. 526) is
correct when he says that Zehender shifted with his principle not
alone the limits of the earning ability, but created a new and arti-
ficial meaning. Neither the lowest nor the highest points of sci-
entific visual acuity correspond with that used in business; the
lowest point of the latter is not as low as the lowest point laid
down by science, while the highest point of the functional range
that may be regarded as normal, must be considered greatly below
the highest scientific limit. The highest as well as the lowest de-
mands of the different professions upon the central acuity differ
greatly and we have no proper standard for their exact numerical
estimation.

Groenouw has proposed that it would be suitable to gather exact
observations concerning the minimum of visual acuity sufficient for
a certain vocation by examining the vision of workingmen in differ-
ent factories and comparing the same with the work done on the
wages earned. We would certainly gain a knowledge of what
functional qualification may be necessary in a certain trade, but
we do not believe that we can gain an exact knowledge of the lowest
demands of the different professions upon the ocular functions, as
we can only find out by such examinations the case which has the
lowest vision and how high is the earning value of this vision. So
that, if among the personnel of a certain trade one workman with
a visual acuity of ^/^ has been al)le to earn a living, it may be possi-
ble that in the workmen of another factory a still lower acuity of
vision, even ^ , may have allowed a certain individual to earn a
living. But. if by exhausting the complete examinations of large
numbers, we have eliminated the probability of finding lower values,
even this might not preclude the possibility of finding the very low^
est degree of vision which is sufficient for this particular trade.

ECONOMIC LIMITATIONS OF VISUAL ACUITY. 35

kind of work the individual may follow-. In the case of a day
laborer whose visual functions are not much taxed in his work, the
sudden reduction of whose vision to lo the normal would probably
not prevent his working, but if the vision of a skilled mechanic
should suddenly be reduced to 1/2, he will certainly have to stop, as
lie is used to work with clear retinal impressions. In acknowledg-
ment of these conditions, the courts have lately given opinions in
which the demands of the particular professions have been consid-
•ered. The German Imperial Insurance office (3, p. 250) seems to
favor such principles.

Considering the above, it is advisable to give movable boundaries to
the economic limitations of vision. Letus accept the maximum limits
as between •% and 3^ of the normal scientific standard for the visual
acuit}' and in the following our estimations will be made with these
two values. The loAvest professional limit of visual acuity is not in
concurrence with the minimum scientific limit, for when the acuity
of vision sufficient for working purposes has ended, there still re-
mains an acuity that may be judged by the scientific standard.
Zehender's proposition (53, p. 268), where he considers the lowest
limit value of the professional acuity as Moo of the normal scien-
tific value of vision, cannot be supported. Professional work is
impossible with only Moo of the normal visual acuity. "We would
regard even a far higher degree of acuity as too low and believe that
a standard for complete inability to earn should be fixed at Mo
•of the normal visual acuity. In many cases even this limit of Mo
would be too low, because there are vocations in which a higher
limit than V20 would be insufficient. Silex (39 separate edition,
p. 6) thinks that in certain branches of the railroad serAice and in
•certain other trades or professions a visual acuity below Ve would
be insufficient. It is, therefore, advisable to make the lowest eco-
nomic limit of visual acuity a movable one and not to fix an un-
changeable value. We therefore adopt for the lowest economic
limit of the visual acuity two values, 0.05 ( Mo) and the standard
of Silex, 0.15 (about M or M of the normal visual acuity).

Out of these four limit values the two maximums (0.75 and
0.5) and the two minimums (0.15 and 0.05), we may construct two
ranges within which the professional or economic limits may lie.
One of these spheres or ranges would have as its highest limit 0.75
(Mi), as the lowest 0.15 (about Mr), while the other range would
be between 0.5 ( M ) and 0.05 ( Mo) of the normal scientific stan-
dard for visual acuity. It is not necessary that the said maximum
and minimum limit values exist in both eyes; it is sufficient that
they be shown in one eye, the other having a lesser acuity than that
which we have declared as absolutely necessary for professional
optic demands. We believe that if the second eye in trades having
higher visual demands, retains an accuracy of vision of M , and in
those having lesser demands, M • we may speak, in a professional
sense, of "sufficient visual acuitv."'

36 ECONOMIC LIMITATIONS OF VISUAL ACUITY.

The least acuity of Adsion found would only demonstrate with what
small degree oi vision an individual could learn a trade or by long
practice be able to follow it, but it could not show how low the
visual acuity of a former normal person might suddenly depreciate
without making him unfit for his trade. Any one entering a pro-
fession while young with a certain amount of defective vision may
gain by practice full earning powers. The highly characteristic
examples given by Groenouw (11) show how much weakness of
vision acquired in youth may exist without marring the earning
capacity.

There is quite a difEerence, hoAvever, in the case of a person,
starting to learn a trade, having congenital \X)ov sight or acquiring
it in earl}' youth, and therefore used to indistinct pictures on the
retina, and a case of a man with normal vision, accustomed to Avork
with clear retinal pictures, who, after an accident, may have to
suddenh' depend upon indistinct visual impressions. The same
degree of vision sufficient in the former case Avould not be enough
for the latter. It is, of course, possible that in the latter case,^
long continued practice might finally lead to sufficient recovery of
the earning ability and the degree of visual acuity here existent
might be considered as the least compatable Avith the profession.
But such a rule could not be made general. For the recovery of a
certain degree of the earning ability after diminution of the visual
acuity is not dependent u]X>n the Avill of the individual, but upon
other decisiA-e factors. The age of the individual plays an im-
portant role in this ultimate comi>ensation. A younger man may
easily OA-crcome a high degree of disturbed vision and by practice
rec-over the lost earning poAver; but in an older individual even a
lesser degree of visual disturbance AA'ill never be overcome. Any
intellectually gifted individual AA'ill be able to make use of indis-
tinct retinal impressions in his work to a far greater extent than
an intellectually dull one. The above factors shoAv that a certain
degree of visual acuity Avould be sufficient in one person for a cer-
tain vocation, AA'hile another could not Avork by it.

Although exact figures as to the limits of the Avorking acuity
cannot be found by examination of patients, yet certain estimafions
may be made from experience. Josten (19b, p. 528) refers to the
A'isual limits acceptable for military service. The instructions for
military service (8, p. 96) designate a diminished visual acuity to
^2 of the normal as, "a small disalulity which does not destroy
the general fitness." A Ansual acuity in both eyes that is betAveen
/^ and M 1^5 called "conditional"; and if it is Vi or below, it i&
called "absolute unfitness." Josten (19 b, p. 528) adopts the mili-
tary standard to business life as folloAvs : "Diminution of the
earning ability does not take place if there is 3^ the normal visual
acuity in both eyes." But, although this proposition of Josten is
very simple and acceptable, yet in certain cases a shifting of the
visual standard above 3^ is necessary. This depends upon the

TABLE OF TRADES SHOWING VISUAL DEMANDS. 37

According to this standard we submit tables which divide the
followers of the different manufacturing vocations into two groups :

TABLE A.

THE VARIOUS TPxADES AND PROFESSIONS ARRANGED ACCORDING TO
THEIR VISUAL DEMANDS.

GROUP I.

Trades requiring liigher degrees of visual acuity. Range 0.75 to
0.15 (scientific standard).

The higher professions.

Medicine.

Theology,

Law.

Art.

Engineering.

Students of all professions.

Fine mechanics.

Iron and steel workers.

Eolling mill workers.

Machinists and metal workers.

Precious metal workers.

Musical instrument makers.

The linen industry.

The textile industry.

The silk industry.

Paper workers.

Leather workers.

Garment makers.

Printers.

Marine employees.

Railway and steamship employees (including city roads).

Soldiers and sailors.

Telegraph operators.

Skilled labor generall}^

GROUP 11.

Trades requiring lower degrees of visual acuiig. Range 0.50 to
0.05 (scientific standard).

Glass blowers.

Mine workers.

Quarry men.

Builders.

Pottery makers.

Brick makers.

Workers in mechanical industries.

Employees in gas and water works.

38 DIFFERENT' VISUAL DEMANDS IN TRADES.

Paper makers.

Wood workers.

Mill empIoA'ces.

Manufacturers of food articles.

Sugar factory employes.

Brewers and maltsters.

Tobacco workers.

Chimney sweeps.

Street railway employees (horse cars).

Employees of elevators and Avine cellars.

Teamsters.

Bargemen on inland waters (rivers, etc.).

Farmers, etc.

Day laborers, etc.

Unskilled labor generally.

Individual members of certain trades do not have exactly the
same visual demands made upon them; some under certain cir-
cumstances may have much higher and others lower visual
requirements. In the course of our work, in certain cases,
we must remember this fact and not judge all the members of the
some trade by the same standard. The railroad employees have
been officially divided into fixed classes, and if the other trades
could be so treated, the physician would know exactly into what
class he should put the individual case. We do not desire to force
our propositions upon the associations, physicians or officials. . We
desire, however, that the foregoing shall be considered before gen-
erally adopted principles be introduced into practice. It is cer-
tainly advisable to reach some definite agreement as soon as possi-
ble, as liitherto there has been a disposition among oculists to
consider only the results of the scientific examination of the visual
acuity as the basis for the valuation of the conditions arising in
practical life. If the estimation of the result of the amount of
damage arising from ocular injuries is to be made in a just man-
ner according to actual conditions, this custom must be abandoned.

Our views regarding the difference between the scientific and
working standards of visual acuity can claim far more extensive
practical consideration than that which relates alone to the sub-
ject in hand of ocular injuries (Chapter XIX). All profes-
sions or vocations which make admission dependent upon a certain
degree of vision would do well to remember that practical visual
acuity and that of scientific standard are entirely different things
and that an individual may have, for working purposes, a full
amount of vision who by the scientific standard shows a deficit.
This fact has been ignored in the past, it being considered that an
individual with defective visual acuity according to the scientific
standard must have the same defect in his working life. Individu-
als have been refused admittance to trades on ocular grounds, al-

CLASSIFICATION OF RAILROAD EMPLOYEES. 39

though if their vision had been measured according to the economic
and not by the scientific standard, they could have pursued their
vocations. The authors have many times seen how much at vari-
ance the purely scientific examination of the visual acuity could
be with the demands made by practical work. The management
of the German roads have lately taken this into consideration,.
Magnus' suggestions having been accepted since January 1, 1893, in
the Breslau Eailroad Company as regards the qualifications of
railroad employees. Their requirements do not now include "nor-
mal" acuity of vision by the ''scientific standard," but only "suffi-
cient visual acuity/' the authorities having thus acknowledged that
an estimation of the vision required in railroad employes should
be made by the practical economic or professional standard rather
than that of the scientific. Schmoeckel (36) and Silex (39) have
lately divided the employees of railways into two classes similar to
our proposition. In these, one eye is to have at least -^^ (Schmoec-
kel) or ^ (Silex) and the other /4 ; and in the other class one
eye must have at least ^ (Schmoeckel) or 3^2 (Silex) and the-
other 3^ or 3^ of the normal visual acuity. Schmoeckel thus
divides the different branches of railway employes according to the
visual demands made upon them, into the following groups :

Group I. — Without glasses on one eye at least a visual acuity
of 5^ , on the other l^ of the scientific standard : Locomotive em-
ployees (engineers and firemen), station employees, switchmen,,
flagmen, yardmen.

Group II. — With or without glasses on one eye at least a visual
acuity of 3^ and on the other 3^3 of the scientific standard:
Wipers, wagonmasters, brakemen, guards, conductors, baggage-
masters, warehousekeepers, freightmasters, porters, watchmen, des-
patchers, roadmasters.

The two groups proposed by Silex contain about the same di-
visions, only he puts brakemen into Group I., whereas they are put
into the second group by Schmoeckel.

In America the tendency is to demand the highest visual quali-
fications from prospective railway employes, the full scientific stan-
dard of -%x (1-0) being required by many railroads and being
demanded as essential by the consulting oculists of the principal
systems. It must, however, be observed that what we call normal
visual acuity is a very relative term, so that ^%x, the usual
standard, may in a good light be read by a young person with re-
duced visual acuity, when his real economic standard is -%v , or
2% (Thomson 45, p. 349).

Allport (1) recently inquired into the conditions existent in
the United States relative to the vision required of railroad em-
ployes, and in response t« a circular letter received specific answers

40 VISUAL RAILROAD REQUIREMENTS IX THE UNITED STATES

from 64 railroads operating 90,950 miles of road; there being 244
prominent railroad companies in the United States which cover
205,638 miles of road. Fifty-three out of 64 roads exacted systematic
eye and ear examinations, about 50 per cent, requiring such examina-
tions of all men directly engaged in moving and operating trains,
in giving and receiving signals, such as engineers, firemen, con-
ductors, brakemen, j^ardmen. signalmen, switchmen, etc. This
examination is made by a railway employee, such as the superin-
tendent, trainmaster, etc., and doubtful cases are sent to the eye
and ear surgeon. Nine roads have a regularly employed oculist.
In three the men are examined by the railway surgeon, and doubt-
ful cases are referred to an oculist. In three the examinations are
made by surgeons of Railway Eelief Associations. The standard re-
quired is various. In 23 it is claimed that "perfect eyes" are re-
quired of both old and new employees. In 16 perfection is required
in new men and reasonable concessions made to old employees. In
one road engineers and firemen must possess of ^^x in one eye
and 2^xx in the other; conductors, flagmen, brakemen, switch-
men, must have a vision of -%xx in one eye and ^y^-L in the
other; all others must have ^o^^^ in both eyes. One road demands
75 per cent, of the normal function, etc. This shows that the'
scientific standards required are decidedly different. We are, how-
ever, fast coming to the conclusion that a practically perfect U'ork-
ing or economic standard of visioti should be required for new men
and that they should not have any grade of refractive error, such
as hyperopia over 2.5 D, which would ultimately render their
distant vision poor, as owing to the dust and exposure of railway
service, the vision should be normal without the correction of any
refractive error by glasses.

Allport (1) divides the railway employees into two classes ac-
cording to their specific vocations.

Class A. — In which the vision is required to be at least ^%xx
in one eye and ^^l in the other, and which must be reached
without glasses; distance glasses are not allowed on duty.

Class B. — In which the vision shall be at least ^/^l in one
eye and 20^ in the other, and in which the employee is not only
allowed to wear glasses, but is required to do so if the refractive
error is such that it is necessary to bring vision up to the proper
standard-

Class A. — Engineers, firemen, conductors, brakemen, switch-
men, signalmen, switch-tenders and engine-dispatchers.

Class B. — Track foremen, bridge foremen, crossing flagmen,
bridge tenders, gatemen, train baggagemen, telegraph operators,
station agents and station baggagemen.

Williams (48) makes about the same subdivision of the classes
and demands the following;:

ADVISABILITY OF GEXERAL AGREEMENT FOR VISUAL REQUIREMENTS. 41

Class A. — Engineers, firemen. For entrance to the service or
promotion, ^^x or average normal vision in each eye, re-exam-
ination every three years not less than ^%xx '"'ith both eyes
open without glasses.

Class B. — For entrance to the service or promotion -/^x in
one eye and not less than ^/^l in the other and for re-examina-
tion every three years not less than ^^^l with both eyes open with-
out glasses.

Thus in Germany the application of the full scientific stan-
dard to the eases of railway employees has been abandoned and
visual acuity of ^ or ^ is regarded as sufficiently high, and,
therefore, we may consider this quantity as the normal economic
standard or 1.0. As these considerations will be ultimately ac-
cepted, it is perhaps advisable to adapt our test letters to the pro-
fessional standard. This may be easily done on the examination
cards now in use, if we would mark the lines on Jager's types or
Snellen's cards (see Plates II., III.), which are equivalent to ^
or ^ of the scientific standard as the full professional acuity for
the higher trades and ^ or ^ that for trades demanding less
visual acuity. The German Ministry of Railroads (38) has lately
divided its employees into dilferent classes as regards their visual
demands and has therewith given the examining physician a basis
for judgment of the ocular earning ability in the individual case.
It would be desirable that the Accident Insurance Companies and
Railroads of America and the managements of other vocations de-
manding specific visual qualifications, would do the same thing with
all applicants.

When we have thus placed the meaning of economic visual
acuity within materially narrower limits than that which the sci-
ence of ophthalmology permits, we must not forget that our charts
used for estimation of the visual acuity correspond only with the
scientific standard. Thus in each case the remaining degree of
visual acuity according to the scientific standard found by the
physician in the case of the injured person should be transposed
into that of the economic standard before it may be used for esti-
mating the damage to the earning ability. This is done in the
following table :

CONVERSIOX OF VISUAL STANDARDS.

TABLE B.

THE SCIENTIFIC STANDARD FOR VISUAL ACUITY CONVERTED INTO
ECONOMIC TERMS.

II.

Scientjtic
standard.

Econoniif
vocations

standard for
demanding

Scientifle
standard.

Kconodiir
vocations

standard for
demanding

lii^he

- degrees.

lesse

- de^^rees.

0.75 =

0.50

0.70 =

0,9166..

^Mo

0.45

0.8888..

= ^

0.65 =

0,8333..

'%2

0.40

0.7777..

= V9

0.60 =

0,750 ..

0.35

0.6666..

= Y^

0.55 =

0,6666..

yi2

0.30

0.5555..

= V^

0.50 =

0,5833...

0.25

0.4444..

= y^

0.45 =

0,500 ...

/12

0.20

0.3333..

= H

0.40 =

0,4166...

yi2

0.15

0.2222..

= ^

0.35 =

0,3333...

yi2

0.10

0.1111..

= H

0.30 =

0,250 ...

0.05

0.000

0.25 ==

0,1666...

0.20 =

0,0833...

0.15 =

0,000

In tables which follow, by which the state of the earning
ability in cases of different ocular injuries is estimated, the calcu-
lation is always based upon the values altered as above, but
as this valuation is not yet generally accepted and the fixing
of the acuity of vision is generally done according to the method
of Snellen, we have also given the degrees according to scien-
tific standard. It must be remembered that in all our tables the
amounts of visual acuity correspond with the scientific values
transformed as above into the professional ones. Thus with visual
acuity of 0.4, its economic value is not 0.40 but 0.7777 . . , if the
injured person has a profession with slight visual demands; but
if it requires a higher degree of vision, the scientific standard
of visual acuity, 0.4, would be transformed into 0.4166 . . , with
which the calculation is made.

We show, figuratively, the relations between the scientific and
the economic visual acuities in Plate I. (Frontispiece). In this
drawing the degrees of vision in the absciss and the ordinate axis
are marked, at intervals of 0.01, so that five of these are always taken
together; the absciss as well as the ordinate axis are divided by this
into 20 equal parts. The curve of the scientific visual acuity is
marked as a coarse black line d) and because this progresses gradu-
ally, it has been equally divided. Economic vision will not suffer
very much if the acuity falls off 0.05, because the difference
between 1 and 0.95 is so little that it will scarcely be noticed. But,
if the acuity falls off further, a point will soon be reached where

ECONOMIC LIMITS OF VISUAL FIELD. 43

every loss affects the working capacitj'^, and if the vision falls be-
low this point, for instance, to 0.005, tlien it has no economic value
whatever, and when it reaches this lowest point and further de-
preciates, vision will be professionally of no importance. Corres-
ponding with these facts, the two curves of the economic visual
acuities should not be marked as grades ; the beginning and end of
the curves should deviate, as we have shown, but these deviations
are so little that we have divided them similarly to that of the scien-
tific standard. The fine line (II) shows the course of economic
vision for higher, and the broken (III) line for trades having lesser
visual demands. As the drawing shows, both curves start together
with the absciss-axis, and then when the climax of the demands is
reached, they run parallel.

We have also evolved test types corresponding to those of
Jager for proximal vision and to Snellen's for distant vision (see
Plates II and III). The ordinary Snellen test cards may be used
in the same way by reducing the scientific standards to economic
terms.

§13. The Economic Limits of the Visual Field and their Estima-
tion.

The limits of peripheric vision are to be regarded from either
a scientific or an economic standpoint, and as has been shown in
discussing the visual acuity are quite different. Peripheric limita-
tions or even greater defects of the field of vision, if only in one
eye, and under certain circumstances, a moderate limitation of the
visual fields of both eyes, will not impair their earning capacity. We
would only regard limitation of the field of vision as entitled to
an indemnification, if the limits for white in the binocular field are
temporal 70°, superior 40°, inferior 60° ; and in the monocular
type, temporal 70°, nasal 45°, superior 40°, inferior 65°. This
corresponds to those limitations which Haab (15, Table I., figure
la) adopts as the narrowest ones admissible under normal condi-
tions. The suggestion of Schroeter (37, p. 16) is very useful in
estimating the amount of economic damage to the field of vision.
Therefore, like Schroeter, we divide the binocular field into three
zones of 30° each: the first from the outermost periphery to 60°,
the second from 60° to 30°, and the third from 30° to the point of
fixation (Plate IV., figure 1). It is evident that these three zones
do not have the same value functionally; the inner one has the
most, the outer the least, but nevertheless as it complicates the
subject too much we do not give them a different value like
Schroeter does. We are of the opinion that the functional differ-
ences of these zones can hardly render itself felt economically, for
the outermost zone of the field of vision represents a much greater
range of the retina than the central, and the intermediate one
represents a greater range than the inner one. But what the outer
zone lacks in functional ability compared with the two others, it

44 ECONOMIC LIMITS OF MUSCLES.

makes up by its greater extent, so that for practical use the ex-
tent of the different zones is compensated for by the relative differ-
ence in the functional ability; therefore we give each of these
zones the same value. The entire binocular field of vision P, would
be composed of three factors of equal value. According to this all
defects of the field of vision could be given their numerical valua-
tion, for instance, with the loss of one eye we would lose I/q of the
binocular field, with a homonymous hemianopsia f^e, etc. In
paragraph 11 we have noted the reasons for introducing the visual
field as a root value into the formula for the visual act.

§14. The Economic Relations of the Ocular Musculature and
their Estimation.

The outer ocular muscles have their peculiar relations to the
earning power. In view of the fact that the binocular act of
vision in its earning relations may only be regarded as preserved if
all the ocular muscles be unimpaired, the functional disturbance of
one single ocular muscle is a bad one, because with the paralysis of
one muscle diplopia appears and immediately suspends the binocu-
lar act, causing thereby complete exclusion of the affected eye.
Therefore, if both eyes are functional and the act of vision was
binocular, a paralysis of one ocular muscle should be regarded
from an economic standpoint in the same light as the complete
loss of one eye, and the diminution of the earning ability
must be the same as the loss of one eye, even if it
be only temporary. Less consideration should be claimed
for the loss of the function of one ocular muscle if the
act were previously monocular. In such a case the loss of one
muscle is only- an inconvenience or may be termed a small injury.
We regard the action of the outer ocular musculature as a sum of
different muscular actions, corresponding with the number of the
outer muscles, which makes a sum of six individual functions.
By omitting one muscle, the muscular action will appear in the
formula for the act of vision as a fraction, ^ . The fact that the
six outer muscles of the 63^6 are not of the same relative value for
the earning capacity has also to be considered. Quite different
demands are made by certain vocations ; for instance, in the case
of miners, the rectus superior is particularly needed (N'ieden 31),
while in other trades it is but little used. In all factors demanding
clear vision in the distance, as that of sailors, the rectus externus
is more used than in those professions whose work is near the eye ;
in the latter the rectus internus is the most prominent muscle and
for general use we think that the internal rectus should be given
the most prominent place as regards the earning capacity. This
varying value of the outer ocular muscles in the difPerent pro''es=ions
makes the valuation somewhat difficult; for, if we gauge the mus-
cles by the standard put for one certain vocation, we would make a

THE INTRINSIC MUSCLES. 45

mistake. For instance, if we give the valuation to the rectus
superior that is needed in the case of a miner, it would be over-
valuation f oi' most of the other professions and an under-valuation
of the other muscles. It is, therefore, for ordinary purposes, neces-
sary to regard the outer ocular muscles as of equal value and to
give each ^ of the total. But in special cases we can do justice to
the demands of the different professions and when necessary value
them higher, for instance, 5^ or /^ . We have deemed it necessary
to introduce the muscular action as a root value m the full formula
for the act of vision (§ 11, p. 30.)

In only exceptional cases could injuries of the intrinsic muscles
(affecting the accommodation or the pupil) have any special in-
fluence upon the earning ability, because, by the use of suitable
convex glasses, the derangement may be overcome.

46 THE ABILITY TO COMPETE.

CHAPTER Vn.

§15. The Meaning and Estimation of the Ability to Compete.
(K of our formula for the earning ability.)

As we have explained in Chapter IV. the ability to compete is
one of the three factors composing the full earning ability. We
have shown that this is the least valuable of the three and that it
should be inserted into the formula with a smaller value than the
other factors. We will make a few remarks regarding the position
this factor takes in the estimation of the injury to the ocular earn-
ing ability.

When an individual receives an accidental injury, especially
that of vision, the damage to him is a double one. First, there is
the impairment of his working ability from the results of the acci-
dent in that he cannot perform as good or as much work as for-
merly, and second his chances for obtaining work quickly and
easily are less. This second factor is not so unessential as one
might suppose. Practical experience shows that the one-eyed per-
son not only has more difficulty in finding employment, but that
in some factories his visual disorder makes it difficult for him to
retain his employment. Workmen with sound eyes are preferred
by most employers of labor and from their standpoint, certainly
not without reason. The injured person, therefore, has a right to
claim not alone a compensation for the impairment of his capacity
for work but also the difficulty which he encounters in making the
most of this capacity. Therefore, in estimating the impairment
of the earning ability, we have always and under all circumstances
to consider the diminution of the ability to compete.

The ability to compete is a conception resulting from a com-
bination of heterogenic elements of which a part lies in the indi-
vidual himself and is affected by the condition of his health, his
knowledge, etc., while another portion is beyond his control. It is
this latter element the world values in judging the ability of the
individual. The ability to compete in the labor market, the possi-
bility of finding employment, is fixed, therefore, by the physical and
mental ability of the individual as well as by the way others judge
of it. If we apply this reasoning to the organ of vision, the ability
to compete of each individual will depend firstly upon the ability
of the visual organ and secondly upon the way others are judging
its condition; an example should render this clear. Supposing
some one has suffered an injury to one eye and seeks employment,
his chances of obtaining the desired work will depend first, upon
his visual powers and secondly, upon the way the employer judges

THE ABILITY TO COMPETE. 47

them. The employer will be willing to give or refuse work to this
particular individual according to how he regards the injury of the
eye as detrimental for the performance of Ms particular work. If
we desire to state the ability as a numerical quantity, we must con-
sider such conditions, which we think we can do by the following:

The Part of tiie Ability to Compete That Each Indi-
vidual Supplies by Himself, in our case the ability of his organ
of vision, we bring forward into the formula under normal con-
ditions when we insert the expression for the normal act of vision,

C V F V M, but in the case of accidents the impaired value of the
act of vision should be put in as the lowest value in the root. In
Chap. IV, § 9. we have given the reasons for accepting the ability to
compete as the lowest value and we have likewise shown that the
ability to compete is of less value in the formula for the earning
ability E than the other factors, i. e., it has a smaller influence upon
the value of E than the others. We have, therefore, adopted the
ability to compete K as a root value. For, if K be reduced by an
impairing of the act of vision, it becomes a proper fraction, for in-

K
stanc^, . ISTow the root of a proper fraction is always greater

Z . " . .

than the fraction itself; the value of K. after the impairment if it

is taken as a root vahie can not any more l)e but it must be

2K ^

greater, for instance, - . By taking K as a root, its value, in the

case of a visual impairment, is greater than it would have been if
K without root would have been taken into the calculation. And
as the amount of the earning ability is directly fixed by the
amount of the ability to complete, K exercises less influence upon
the earning ability than the other factors, as soon as we insert K as
root in the formula for the earning ability. The full formula

being: f^ = V ^^^^^

The Part of the Ability to Compete Not Depending Upon
the Individual, in Our Case Not Upon the Condition of the
Eyes, but Upon the JuDorENT of the Employer, we ren-
der by the exponent of the root which we chose for K; taking

K
a small exponent the value of will be enhanced to a less extent

and if we take a large exponent to a higher extent. If we enhance
the value of the ability to compete by taking a greater root ex-
ponent, as the earning ability increases as much as the ability to
compete becomes greater, the earning ability will he. greater accord-
ing to the size of the root exponent. If we would indicate that the
employer regards a certain ocular impairment as an iuiportant di-
minishment of the working cajisicity we would take a smaller ex-
ponent, but if we intend to show that an ocular impairment is of

48 ELASTICITY OF OUR METHODS.

less importance to the employer, avc would take a greater one. We,
therefore, choose for all slight and moderate visual impairments
a different root exponent than for tlic serious ones; therefore, for
the slight impairments we give the ability to compete the root ex-
ponent 10, but if the impairment of central vision is serious, i. e.,
in the case of professions with higher visual demands if it falls be-
low 0.15 and in those with less demands below 0.05, and instead of
the root exponent 10 we take the exponent 5 for these professions
with greater visual demands and the exponent 7 for those with less.
The same is to be done in the case of the complete loss of one eye
or in the case of the loss of the eveball. If we think that the aes-
thetic dilferences between simple blindness of the scientilic standard
without injury to the looks of the eye and the loss of the eyeball, or,
for instance, the formation of a bad looking eye, as leucoma or
staphyloma are greater, we may give expression to our opinion by
choosing a great root exponent for the ability to compete in the case
of simple blindness without deformity. By leaving the selection
of the root exponent to the judgment of the calculator, sufficient
room is given for the individual conception of each case; thus our
formula adapts itself to the peculiarities of the individual case and
to the judgment of the physician, avoiding thereby a rigid form and
doing justice to both parties. Therefore, in forming a special esti-
mation of the ability to compete we first fix the amount of the
injury to the act of vision in each case, and upon this depends that
part of the ability to compete which the individual furnishes him-
self. As regards the second part, in certain cases it will be found
that while there is no or but little actual injury to the visual sense
itself, yet certain injuries of the eye disturb the relations of the
individual to the employer.

Such a case as the following is often experienced in practice:
A man has his cornea burned by lime which leads to the formation
of leucoma and diminishes the visual acuity of that eye to 0.25 of
the normal, the other eye remaining well. Thus, although such an
individual is not optically impaired for his work because the normal
eye allows the undisturbed following of his trade, the chances of his
finding work have become less. A great many employers would
hesitate to take into their service a man with a bad looking eye,
who shows so plainly the effects of the injury or who, he knows,
can see normally only with one eye; in spite of the fact that in such
a case an actual impairment has not taken place the ability to com-
pete is certainly diminished. We are consequently in the peculiar
position of estimating an ocular impairment of the abilitv to com-
pete when there is no real defect of working vision. Thus we think
we can meet these difficult conditions in the best manner if we ex-
press the diminution of the ability to compete in all cases by the
arithmetical proportion of the visual acuity of both eyes. The
ability to compete is in fact a quantity which is almost identical
with the act of vision but not dependent upon it as the maximum

IMPAIRMENT OF ABILITY TO COMPETE. 49

of the visual acuity in both eyes. In our example we suppose that
the vision of one eye remains normal while that of the other was
diminished to 0.25, consequently the numerical expression for the
ability to compete would be :

1 + 0,25

V F V (mi ma m., m* m.^ ms) (mi" m/ m/ m/ m/ m/)

The reasons for expressing the impairment of the ability to
compete by the arithmetical proportion of the central acuities of
both eyes are the following : Even if a diminishment of the binocular
acuity of vision cannot be proven scientifically where one eye is
alone affected, professionally the binocular vision has not the same
value as formerly. If we unite the normal vision of the one eye
and the impaired one of the other by the mathematical expression
of the arithmetical proportion, the value of the normal acuity will
be diminished by the size of the injury to the other eye; we then
use this arithmetical proportion as the root value with the exponent
10 and thus provide that the normal vision is but slightly reduced
by the impairment of the vision in the other eye. By this means
the practical conditions may be satisfactorily considered. If one
of the other factors entering into the economic act of vision be im-
paired, for instance, the peripheric vision, while all the other fac-
tors as well as the central acuity remain untouched, the impairment
of the factor in question should be used in such a manner that we
first insert it into the expression for the normal act of vision as
the tenth root in the calculation. For instance, from an accident
only the field of vision has suffered and if it is only two-thirds of
its original range while the central acuity and the muscles remain
imchanged, we enter into the formula for the normal professional
act of vision for the field of vision P the value two-thirds. The
formula for the ability to compete would thus be:

ex K % P K (mi m. m:! m^ m.^ mfi) (m/ m./ m/ m/ ms' m/)

If several of the factors be damaged at the same time, the
amount of such damage has to be inserted into the formula as the
xth root. For instance, the central acuity of vision in both eyes
diminishes to 0.30 (scientific value), while the field of vision be
limited to one-third, these values for the acuity and the field would
have to be first entered into the formula of the working act as an
arithmetical proportion, being changed correspondingly while the
numerical value of the muscular action would remain the same, the
formula then would be :

0,30 + 0,30

2 VV^ P / (mi mo m:, m4 m-, mr.) (m/ mo' m/ m/ mr,' m/)

50 USE OF DIFFERENT ROOT EXPONENTS.

and if we enter this below the tenth root, the formula would be'
transposed into :

0.30 + 0.30

VV&PV (mi ma ms m* m, me) (m/ m/ m/ m/ m./ m/)

If one eye be entirely lost, the disorder of the visual act would
be represented, in vocations with higher visual demands, the fifth
root, and in such with less demands the seventh root. The same
calculation may be done for serious disorders which have the same
relations as the loss of one eye.

THE FORMULA OF MAGNUS. 51

CHAPTER Vm.

THE METHOD OF CALCULATION WITH THE FORMULA
OF MAGNUS.

§16. What Does this Formula Mean?

In Our Formula for the Ocular Earning Ability, E=F/K

the visual act being F and V'K the ability to compete, by resolving the
act of vision F into its physiologic factors necessary' for the earning
ability, C is the maximal central visual acuity, P the visual field and
M the muscular action (Chap. VI., § 11-14), we had acquired the

expression: F=C (max.) V P 1^ M for the physiologic act wliile

for the ability to compete v'^we had (Chap. VL, § 11-14) :

VY=f^^^'^^V'¥VlL

The complete formula for the ocular earning ability being the
following :

E = C („,ax.) V P V M f ^' '^^' V P V' M.

At the first glance it might seem that our formula has too much
of the mathematical stamp and that its handling does not seem
easy nor convenient, and it has been called "too complicated"
(Groenouw 12). But this reproach only shows that those making
it did not comprehend or understand its meaning. This formula
is the numerical expression for the normal visual earning ability,
and while this is a composite quantity its mathematical expression
must, of course, be composite. This is especially true, for each of
the factors entering into the normal visual earning ability may be
impaired and must have an individual influence upon the calcu-
lation. If we try to simplify the complicated relations they could
only be forced, and an arbitrary speculation substituted for its own
composite character. The formulas of Zehender and Groenouw
are certainly not real mathematical expressions for the ocular earn-
ing ability, but only mathematical results of arbitrary supposi-
tions. By the construction of such seemingly simple foi-mulas we
depart entirely from the line of conduct nature itself follows and
get into devious tracks of arbitrary hypotheses. Our duty is to
give expression to the ocular earning ability in a mathematical

52 CONVENIENT FIGURING WITH THE FORMULA.

manner according to its nature, but in doing this we must not
create a formula made easier to handle, but which is nothing but an
arbitrary conception. Arithmetical simplicity could only be arrived
at by the waiving of the natural relations. While an exact mathe-
matical rendering of these may not be so very convenient, we may
expect that results may be gained which correspond with the actual
conditions. By doing so, such reductio ad ahsurdum cannot be
found, as is the case with the simple hypothetic formulas of Zehen-
der and Groenouw. The arithmetical results of introducing human
beings with three seeing eyes, or nine eyes, or cyclopia, or arriving
at the conclusion that one-eyedness is identical with the entire loss
of the ocular earning ability, cannot be excused or made acceptable
by the arithmetical simplicity of the formula.

§17. Can Figuring ivith the Fonnula Be Made More Convenientf

In our last paragraph we had to defend our formula from the
reproach of being too complicated, but, under all circumstances, it
is the truest mathematical expression of natural conditions and has
to be made the starting point for every calculation. We may, how-
ever, try to make it more convenient, as it must be admitted that
the separate figuring of the individual factors with the root values
certainly offers difficulties to the inexperienced mathematician and,
therefore, a way has to be found which, while retaining absolutely
the formula, materially facilitates and simplifies the calculation.
This we do as follows :

In plate V we delineate each of the factors of our formula in
a curve in such a manner that the individual curves give the con-
dition of this factor within its working range. For instance, in
plate V, line I shows the geometric course of peripheric vis "on. if
the scientific value of P as absciss and the economic value V P are
taken as ordinates : line II represents the geometric course of the
muscular action, if the scientific value of ^I as absciss and the
economic or actual value *V M arc taken as ordinates. The three
lines. III, TV and Y, show in an analogous manner the ability to
compete in its different values, using the oth, 7th or 10th root. By
the assistance of these curves we may ascertain, in a given case, the
economic value of the impairment of every factor of our formula.
We first ascertain the amonnt of impairmeut on the absciss repre-
senting the scientific valuation, then we trace vertically the corre-
sponding line from this point on the chart, and at the intersecting
point where we meet the ordinate on the left of the. curve, is the
economic value of the damage. By this method, the very incon-
venient handling of the root values and separate figuring of the
single factors of the formulae mav he avoided. Thus, with any
great amount of mathematical calculation, we may estimate the
economic value of each damage of the different factors shown in
the tables.

EXAMPLE, VISION IMPAIRED IN ONE EYE. 5S

In comparing the estimation found in this way, with that re-
sulting from actual calculation, we will find a certain difference
which might be even in unfavorable cases as much as 1, 5 or 2.0,
but which will be generally much less. Such a difference can hard-
ly be avoided, because the drawing of the curves and the mathe-
matical calculation can not be exactly in congruity ; but as in the
fourth part of this book we give a tabular exposition of all values
gained arithmetically, we are always" enabled to compare these with
those found in the curves. Exact reading of the curves leads to
accuracy of the result. By this method, the handling of our for-
mula is materially simplified, so that its use offers no difficulty
whatever. In order to prove this, we will present some cases to
show the reader its convenience.

§18. Calculation with the Formula.
To recapitulate our formula :

E = c Vv 1/ M j/'^ii:^ WVHi

C being the maximal central visual acuity. 1^ P the visual field, and

VM. the action of the extrinsic muscles and \ — — ^ — V P 1^ M

is the ability to compete'. The latter is composed (Chap. VII.,
§ 15) of the arithmetical proportion of the central visual acuity of

both ej'es ^-^r — ^ , the peripheric vision /Ip and the muscular ac-

tion Y^ > with the provision that we make the root exponent higher
or loAver, as the case may be, of the value 5, 7 or 10. Let us now
figure some examples by the aid of this formula :

Example I. In a simple case, one eye having suffered a trau-
matic diminution of the visual acuity which has a value of V^ or
0.5, according to the scientific standard. This injured person fol-
lows a trade which has higher visual demands, for instance, is a
skilled iron worker. In such a case the maximum C, remains un-
changed, becanse this is the higher visual acuity of the sound eye
which remains the same. C, is therefore = 1, V P the visual field,

and }f M the muscular action, remain unchanged. These three
factors represent each the value 1. In this case the unknown quan-

tity is the ability to compete, 1/ ^^ ' ^^ V^/ll

C -4-C
' ^ " being the arithmetical proportion of the central visual

acuitv of both eves C, the uninjured eye, remains = 1;C.,. the in-

54 EXAMPLE^ VISION IMPAIRED IX BOTH EYES.

jiired eye, should be reduced according to our supposition to 0.5
of the scientific standard. Looking now on plate I on the absciss
for the scientific value 0.5 trace this line upwards until we meet
the economic curve (II), and from the point where the line cuts
the curve we go to the left and find there on the ordinate the
economic value of the scientific estimation for the acuity of vision.
As the plate shows, this is about 0.58. By inserting this value in

the arithmetical proportion of the acuity for both eyes, into '^ *

we hav? - — ^^— = 0.79. This we insert into the factor

y ^'"t^Y p"K¥ ; ^'"^ t^^e^ ^^^'6 y 0.79 / P J^M in which V P

4 X

and V M are each = 1; the whole value is then V 0.79 X 1 X 1.
As this is only a slight injury the ability to compete cannot be
impaired very much, consequently we make the root exponent

X = 10. This value V 0.79 x"! >< 1 we can find in plate V,
curve V. We look simply on the absciss for the value 0.79, trace
the line from there upwards until we meet curve V, going from
there to the left we find on the ordinate the value 0.972. If we
insert this value into the formula we would find E =
1 X 1 X 1 X 0.972, and as E, in our formula, has always been
a fraction of ], it must be multiplied by 100 if it would be repre-
sented as a percentage. We have then for E==97.20. If we compare
this value 97.20 with the example I (given in the first edition,
Magnus, p. 90), which was 97.69, we observe that the difference
between the two values is very small.

Example II. As a second case we will take impairment of the
visual acuit}' in both eyes, one having only scientific standard of
0.3, the other of 0.4. The injured person may have a vocation de-
manding higher visual powers. How would we here figure with
our formula ?

E = c ...ax.v p /M |/Cjf_a^— j.-^

The factor C (maximum) i. e., the highest value of binocular
visual acuity or what is in this case the same thing, the visual
acuity of the better eye. As the scientific value is equal to 0.4, on
plate I we look on the absciss for this value, go to the curve and
find that it is professionally equal to 0.41. The professional valu-
ation of the different' values for the visual acuitv mav also be found
on Table B, p. 39.)

The factor K P remains unchanged == 1.
The factor |/^M remains unchanged = 1.

REAL SIMPLICITY OF THE FORMULA. 55

The factor )/ ^ "^^' x/PX/M which is the ability to compete

C I C

will be changed only in the part — r— ^ because the field of vision

and the ocular muscles are not impaired; both will, therefore, be=l.

C + C
This part ^ — ^ would resolve itself in the following manner as

the scientific acuity in one eye has diminished to 0.4 and in the

other to 0.3, as we find out by the curve, the scientific standard

C 4- C-
0.4 corresponds with 0.41 and 0.3 with 0.25; — - — ^ is therefore

equal to ^^^^^i^— =^=0.33. The entire factor of the ability

T xKTl^ would be, if we enter the values in

place of each part: K 0.33X1X1, and the economic equivalent of
this value we can find directly on plate V. We have only to decide
if the eyes have been disfigured from leucomata of the cornea re-
sulting from the injury and if from the aesthetic standpoint the
ability to compete has suffered. If this be the case, we take for
the root exponent 5 and look on plate V on the absciss for 0.33;
from there we trace upwards till we meet curve III and read to
the left on the ordinate the economic value 0.806. The ability to
compete would, therefore, be equal to 0.806. If we now enter all
the values we found into our formula we transpose it as follows :

E=c„.ax.xi/p xVm X\^-^X\/ ? XVM.

E = 0,41 X 1 X 1 X 0.806 = 0.33046 which in the form
of a percentage equals 33.064 per cent. But, if we should take in
the foregoing example a slighter impairment of the ability to com-
pete and figure it, not with the exponent 5 but with the exponent
10, we would receive the result E =37.331 per cent. The earning
ability in this case would be 4.285 per cent greater. These ex-
amples should be sufficient to explain our methods.

We now see that calculating with our formula is really simple.
All we need is to insert the values of the individual factors into the
formula as we find them on the plates. When this simple pro-
cedure is done, the formula has been reduced to an easy multipli-
cation example. As we have said before, by reading the curves
the values found are often a little different from those by full calcu-
lation; but as this difference is not great and may be avoided to a
great extent by a careful reading, this fact deserves but little con-

56 SIMPLICITY OF THE FORMULA.

sideration. Besides this, the values found by reading the diagrams
may at any time be regulated by comparing them with the tabulated
values compiled in part IV.

We believe that by construction of the curves, the calculation
has been so simplified that in spite of the seemingly complicated
composition of our formula, it can be done by even an inexperienced
mathematician. Reservation must be made in cases where the in-
jured person had possessed before the time of the accident only one
eye or was weak sighted. In such cases special modifications of
the calculation have to be made which will be explained in the fol-
lowing chapters.

PART SECOND.

Special Consideration of Various Ocular Injuries
and Visual Defects,

58 INJURIES OF THE VISUAL FIELD.

CHAPTER IX.

§19. The Relative Importance of Disturbances of the Visual Field.

In estimating defects of the visual field we should remember
that two-thirds of the binocular field belongs to and is controlled
by both eyes (yellow area of Fig.l, plate IV.) Under certain cir-
cumstances these disorders have only monocular effects. For in-
stance, in the case of nasal hemianopsia (Schroeter 38, p. 19 and
our Plate IV, Fig. 3.) Such limited disorders are not considered
detrimental to the earning ability because the field of vision does
not suffer restriction of its normal limits.

An experienced calculator may easily ascertain the arithmetical
values of the different defects of the visual field, but for complete-
ness' sake we here develop these values for a series of disorders
which may be inserted into the formula for the earning ability.
The following explanations are considered only for the binocular
field of vision :

1. Concentric peripheric contraction of slight extent with nor-
mal central visual acuity not extending to 70° (Chap. 7, § 13) is
of no importance in this relation and thus may be omitted. If it
exceeds 70° but does not go beyond 60°, the field of vision P is to
be inserted as two-thirds, into the formula for the earning ability.
The earning ability is then 80.012* ; its impairment being 19.998.

2. Concentric peripheric contraction of a greater extent with
normal central visual acuity inaterially exceeding 60°, reaching 30°
causes two-thirds loss of the binocular field, the remainder of which
should be considered as one-third in the formula for the earning
ability; consequently the earning ability drops to 54.65 (55 per
cent.) ; the impairment being 45.35 (45 per cent.) The same esti-
mation is given for any limitations between 30° and 60°.

3. Concentric peripheric contraction of the highest degree with
remaining normal central visual acuity always means, according to
our supposition, an entire inability to earn (Ch.V, § 11). Schroeter
(37, p. 21) takes for granted that in such cases an earning ability
of 25 per cent, may still exist and that the impairment would only
be 75 per cent., but according to our practical experience, we can-
not share this view with Schroeter. A man who has only central
vision left is, under all circumstances, entirely unable to work and
should be allowed 100 per cent, indemnity for the loss of his earning
ability. Practically such cases are -not frequent, at least not as

•For simplicity's sake the calculation may be made with the whole numbers 80 percent.
and 20 per cent.

COXTKACTIOX AXD HEMIANOPSIA. 59

accidental injuries. The double-sided hemianopsias which are like-
wise very infrequent (Magnus 24) and of which there has only
been reported one traumatic case (Schmidt-Eimpler 35, p. 181)
are considered in the same category.

4. Concentric peripheric contraction of the field of vision in
one eye causes diminishment of the entire field of one-sixth, as only
the exterior portion (the red or blue area in Fig. 2) is monocular.
The sound eye will equalize the disorder of the common portion of
the field of vision caused in one-sided concentric contraction. Even
very serious concentric contractions limited to one eye will impair
the total value of the field of vision to but one-sixth; the earning
ability in such cases is 90.45& (90 per cent.) ; the imiDairment
9.542 (10 per cent.)

5. Homonymous hemianopsia dextra vel sinistra causes loss
of 11/2 the binocular field of vision, the earning ability becom-
ing, according to our estimation, 68.302 (70 per cent.) ; the im-
pairment 31.698 (30 per cent.) We make no difference between
right or left-sided hemianopsia, but for the purpose of indemnifica-
tion give them the same value. Schroeter (37, p. 17-18) proposes
to allow 45 per cent, for right-sided hemianopsia and 30 per cent,
for left-sided, because, according to his idea, the right half of the
field of vision is professionally of more importance than the left one.
While it must be admitted that the loss of the right half of the field
of vision is especially embarrassing in the beginning for certain
occupations, for instance, reading and writing, and is more in-
convenient than in case of the corresponding loss of the left half,
we would not indemnify hemianopsia on the right side higher than
the left, for it is always a question whether or not the above diffi-
culties are more of a psychical character (Knies 16, p. 28) than
due to the actual loss of vision ; then again those men who are gen-
erally exposed to accidental injuries do but little reading or writing
in their business; and then the person ultimately becomes accus-
tomed to using the left sides of the visual fields. Besides this
there are many occiipations in which the loss of the left field would
be as bad as that of the right and for left-handed persons the loss
of the left side would certainly be inore inconvenient than that of
the right. We, therefore, do not advise a higher valuation of the
right field of vision.

6. In the case of vertical homonymous hemianopsia the loss
is equivalent to that of the horizontal forms: Schroeter (37, p. 20)
complicates the matter again in that he makes a difference in the
valuation of the upper and the loAver half of the field.

7. The loss of both the temporal halves of the field of vision
leaves two-thirds of the binocular field, but this is not any more
a common field : the left half belongs to the right eye and the right
half to the left (Plate IV, Fig. 2) : but this condition does not seem
to produce special disorders in actual practice. We enter the value
of this field of vision as two-thirds P in the formula for the earn-

60 he:miaxopsia and partial defects.

ing ability which results in the value 80.012 (80 per cent.) ; and for
its impairment 19.988 (20 per cent.) Schroeter (37, p. 19) gives
this value as 20 per cent., making our figures about the same.

8. By the absence of both nasal halves the common field suffers
much restriction, as there are no more peripheral portions common
to both eyes. The two temporal halves of the field of vision left,
touch each other at the point of fixation (Plate IV, Fig. 3), the
right half of the field (blue in Fig. 3) belongs only to the right eye,
the left half (red in Fig. 3) only to the left. Because the field of
vision has not suffered a restriction and there is no acuity from this
condition, the earning ability is not curtailed.

9. Absence of the nasal half of the field of vision in one eye
does not cause diminution of the entire field because both the nasal
halves are in the common binocular field (yellow area, Plate IV,
Fig. 1.) If one nasal half be lost, for instance, that of the left
eye, it only causes a change in the form of the binocular field. The
right half of the heretofore common field would now be monocular,
belonging only to the right eye; the left half of the entire field
would have the peripheric portion belonging to the left and a cen-
tral one common to both eyes while the right half to the full extent
of the field of vision belongs only to the right eye (Plate IV. Fig.
4). An impairment of the ability to earn could not be deduced
from this condition because the extent of the total field of vision
has not suffered restriction. Cases occurring under the headings-
of 8 and 9 could be used to prove that accidental injuries do not
always cause impairment of the earning ability or allow of claims
for indemnification. This is noted in the German Accident Insur-
ance Law, Chap. I., § 3.

10. Loss of the temporal half of the field of vision of one eye
from the point of fixation to the outer part, for instance, of the
light eye (Plate IV, Fig. 5) affects only the range of the total
field of vision supplied by the right eye (blue area. Fig. 1) Ac-
cording to our classification, the binocular or total field would be
diminished by one-half of the exterior concentric zone (Fig. 1)
which would he one-sixth of the total field. The field of vision left
would represent five-sixths of the original amount, but the right
balf of the common field would now be only a monocular one be-
longing only to the left eye ; the left half of the common field would
be unchanged, the field would then take the form of Fig. 5, Plate
IV. According to our calculation the ability to earn would be
90.458 (90 per cent.) ; the impairment thereof 9.542 (10 per cent.)
Sehroeter's estimation (38, p. 21) for the latter is 10.8.

11. Partial defects in the field of vision in only one eye are
very seldom injurious to the working ability, if they affect only the
common range of the total field (yellow area, Plate IV, Fig. 1),
because the portion lost in the one field is compensated for by that
of the other. But, if the particular defect reaches into the mo-
nocular part of the total field (into the red or yellow part of Fig 1),

TABLE OF VISUAL FIELD DEFECTS.

a diminution and -u-itli it a disorder of the field of vision could be
shown. In such cases "vre suggest an estimation according to the
quota for the loss, for instance, if it comprises one-half the monocu-
lar part of the field, the earning ability would then be 90.458 (90
per cent.) ; the impairment thereof 9.542 (10 per cent.)

12. Partial defects of the binocular field should be valued ac-
cording to their extent. The physician may settle how much is left
after deducting the defect from the binocular field.

13. Total loss of the field of vision of one eye causes diminish-
ment of the binocular field by only its peripheric part, one-sixth
(the red and blue parts, Plate IV, Fig. 1.)

We condense these different results in a tabular form :

THE EARNING ABILITY AND THE IMPAIRMENT THEREOF IN

THE DIFFERENT DISORDERS OF THE FIELD OF VISION

WITH REMAINING NORMAL CENTRAL

VISUAL ACUITY.

VARIETY OF DEFECT.

; _ 2 ^^.2 ; Percentage.

o o a ««
•- o

"I % g-ojEarning Impair-
'h'3 S'®; Ability, meut.

f Partial defects in the field of one eye ")
I Concentric contraction of the field of |
1. { one eye )■

1 Absence of the temporal half |

1^ Absence of the entire field of one eye }
{ Concentric contraction of both fields ^

rt I reaching to 60°

' 1 Absence of the temporal half of both \

I fields _ J

o I Homonymous hemianopsia dextra \

' \ vel sinistra superior vel inferior J
. (Serious concentric contraction of

■ \ both fields reaching to 30°

c I Total concentric contraction of both )
( fields reaching to 5° j

{ Absence of the nasal halves of both \

g I fields 1^

■ I Absence of the nasal half of one (
L field j

^ 90,458 9,542

80,012

19,988

68,302

31,698

1/3

54,650

45,350

\ ^

0,000

100,0

100,00

0,00

The foregoing figures are made for both higher and lower
visual demands where the central visual acuity remains normal.
In cases of serious injury to the field of vision where the ability to

62 COMPLICATED riELD DEFECTS.

compete suffers it is necessary to figure for the higher demands
where the oth or 7th roots may be used. This is done in table
Ylla, in the IVth part of this book.

^20. Disorders of the Visual Fields Complicated hy Injury to the
Central Visual Acuity of Different Degrees in Either Eye.

As in practice the peripheric "^dsion as well as the central acuity
in one or both eyes may be found injured, it is necessary to explain
such relations. In the following table the different disorders of the
field of vision and the value of the remainders are given in the two
left columns, while in the right column we find figures which serve
for estimation of the earning ability, in all cases where there are
disorders of the field of vision in connection Avith damage to the
central acuity, differing in either eye. We first settle what is the
arithmetical value of the remaining field of vision, for instance, it
might be five-sixths ; then we find the value that the earning ability
would have if the otherwise complicated disorder of the visual
acuity alone existed. We then read from tables Y or VII of the
fourth part without an}' trouble; if, for instance, one eye has a
Aisual acuit}' of 0.55 and the other 0.25, according to table V, the
earning ability would be 61.078; if the injured person follows a pro-
fession demanding high vision. Xow we multiply this value G 1.078
with the number in the table on page 63 next to the field of
vision; as in our example the arithmetical value of the field of
vision Avould be five-sixths we would then have to multiply 61.078
with 0.90-158; this would give us an earning ability of 55.250.

Let us take another example; in concentric contraction of the
field of vision reaching to 30° in both eyes the arithmetical value
of the remaining field would be one-third; if one eye has central
acuity of 0.40, the other of 0.20 and the demands in the profession
of this pai-ticular individual are high, both the central acuities of
the vision would have an earning ability of 36.273 ; this value we
would multiply with the number we find in the table next to the
corresponding value of the field of vision, i. e., next to one-third
— 0.5465, from wdiich the earning ability would result in 19.823
and its impairment 80.177.

If one eye be entirely lost while the other suffers impairment
of its central acuity, the numerals given in the table on page 63
do not hold good, we would have to use those on page 64; the calcu-
lation is the same. We first ascertain (if for instance one eye be
totally blind and the other has only a visual acuity of 0.4 and a
field of vision of two-thirds, provided we have a profession with
higher visual demands), the degree that the earning ability would
have if the field of vision would not have taken part and if the
acuity of vision of l>oth eyes had suffered to the above extent, which,
according to table V, part IV, would be 24.166; this value we mul-
tiplv with 0.57708 and get 13.946 as an expression for the degree
of the earning abilitv. If the profession demands less vision we
would multiply by 0.59238.

TABLE FOR COMPLICATED FIELD DEFECTS.

AUXILIARY DATA FOR THE ESTIMATION OF THE EARNING

ABILITY IN DISORDERS OF THE FIELD OF VISION

WHERE THE CENTRAL ACUITY OF BOTH

EYES IS IMPAIRED DIFFERENTLY.

Variety of Defect.

r3 O

o <v

•-r!^

o +=•

U O

P=R

1..

['Partial defects in one field.

Concentric contraction (higher
and lower degrees) in only
one field.

4.
5.

y\ %

Absence of the temporal half |
of one field. j

Small concentric contraction")
ofboth fields to 60°. |

Absence of the temporal half |
ofboth fields. J

Homonymous hemianopsia
dextra vel sinistra superior
vel inferior.

Great concentric limitation of
both fields reaching to 30°.

Total concentric limitation of
both fields reaching to 5°.

0.00

Percentage.

0.90458

0.80012

0.68302

0.000

f Absence of the nasal halves of ^

I both fields. |

I I

I Absence of the nasal half of \
y one field. j

Aa these disorders of
the field of vision do
not condition an im-
I pairmentof theearning
ability, only the disor-
der of the acuity of
vision would have to
be indemnified.

64 TABLE FOR LOSS OF ONE EYE AND VISUAL FIELD.

AUXILIARY DATA FOR THE ESTIMATION OF THE EARNING

ABILITY IN LOSS OF ONE EYE COMPLICATED WITH

INJURY TO THE VISUAL ACUITY AND

VISUAL FIELD OF THE OTHER.

These four numerals are given by the following operation; whether
the peripheric vision P is limited or not, we always have for the
earning ability :

= c VTili]/^^yThi==cyFhK^^^~^

==cvMy

p _|_ p i 20

^^^^ Vm vt V^

The quantity C V M [/ ^^- Vll , in which the

muscular action M has to be regarded as abnormal, for a case in
which one eye is lost, is taken directly from table V. or table VI. ;
to find E it must, therefore, be multiplied as follows :

p = 5^ multiplied with f^ V % = 0.90458.

p = 2/3 - " YJ4 VVs = 0.80012.

P=>< " " 1^ 3^ V'l^ = 0.68302.

P = >^ " " V34 v"r = 0.54650.

Where we have to figure the earning ability in the case of the
loss of one eye, we have to multiply thus :

For Group I. I For Group II.

10 H

P=3^withl/ 3^ J^ 3^ =0.73602 P=5^with|A3^ K 5^ =0.74685

10 14

P=8^5 " /K5KM5=0.65580 P=X5 " /Ms 1^5=0.69832

10 14

P=^ " /% V' ^ =0.57708 P=^ " V" 2^ 1^=0.59238
Eegarding these fractions see Chap. XI., § 23.

PECULIAE KELATION OF OCULAR MUSCLES. 65

CHAPTER X.

THE IMPAIRMENT OF THE EARNING ABILITY FROM INJURIES
TO THE EXTRA-OCULAR MUSCLES.

§21. General Bemarhs Regarding the Importance of Injuries to
the Extra-Ocular Muscles.

The ocular muscles have a peculiar position, for the binocular
act can only exist so long as all the extrinsic muscles of both eyes
are functionally undisturbed ; as soon as one becomes paralytic, with
the beginning of diplopia, monocular vision ends and for profes-
sional purposes only one eye is at the patient's disposal. For the
person with two normal eyes, a paralysis of one muscle is practi-
cally identical, for professional purposes, to the loss of the eye and
must be so considered in determining an impairment of the earn-
ing ability. If the injured person have only one eye, the condi-
tions are quite different ; for such a case a paralysis of one external
muscle means a perceptible, but in a visual sense, a relatively insig-
nificant impairment. For such a case the professional act of vision
is not annulled, but is more or less disturbed. For exhibiting this
peculiar relation of the ocular muscles, we considered in the for-
mula for the professional binocular act of vision, the extrinsic ocu-
lar muscles as the factors of a product, to meet this demand ; with
the paralysis of only one muscle the binocular professional act en-
tirely disappears and is changed into the monocular form because
the product becomes if only one factor becomes 0. In the for-
mula for the monocular act of vision we express the arithmetical
value of the extrinsic ocular muscles as the sum of 6 numerals, cor-
responding with the number of the ocular muscles. If one of these
be lost, the sum only loses this numeral. In the monocular act
of vision, as well as in the binocular, we introduced the numerical
expression for the extrinsic ocular muscles as the 4th root, to be
able to give expression to the different values of the ocular and
muscular functions (Chap. VI., § 11). The other visual functions
have a different value than the muscular movements, which may
be considered only auxiliary functions of the visual act; profes-
sionally and arithmetically this fact cannot be neglected and so the
ocular muscles have a root value in our formula. The formula for
the binocular and monocular professional acts of vision have been
made as follows (Chap. VI., § 14) :

Binocular Vision

^^S2=C f^ P I' (mim2m3m4m5m6) (m/m2'm3''m/m5'm60

Monocular Vision

=Si=Cy ^ P y 3^mi + mo + m3 + mi + m5 + m6

66 UXCOMPLICATED PARALYSIS OF OCULAR MUSCLES.

§22. The Estimation in Paralysis of Muscles Uncomplicated hy
Other Visual Disorders.

Ill the foregoing paragraph vre again developed the formiUas
for binociilar and monocular vision. We will now try to figure
the extent of the earning ability in disorders of the extrinsic mus-
cles of originally normal eyes. As shown already, the earning
abilit}' is composed of the two factors of the act of vision and the
ability to compete; the formula of the visual act is shown in the
foregoing. In order to figure the value of the earning ability we
will now have to state the formula for the aljility to compete, which
is the xth root of the visual act (Chap. IT., § 9; Chap. YIL,
§ 15) ; in every ocular injury considered aside from the central
acuity, the latter has the greatest influence upon the visual act
and is placed with the arithmetical proportion of its two values into
the formula for the ability to compete. If the injury be slight we
choose the root exponent 10; when serious the exponent 5 or 7. In
the case of the loss of one eye, we proposed to take 5 or 7 as the
root exponent. As the binocular process is annulled for economic
purposes, the individual has to be regarded as blind in one eye;
but in fact there is really a difference between an actual one-eyed
person and one who has to suddenly rely upon the monocular act
of vision on account of paralysis of the muscles, because there is
not only a chance of having the paralysis cured but later there
may be some use of the eye which has been excluded from the
binocular act for peripheral vision, as soon as the patient has
learned to suppress double images. In cases of paralysis of the ex-
trinsic ocular muscles we would insert into the calculation the
ability to compete with the root exponent of 10 which we have
chosen for ocular injuries of a slight or moderate degree. The
formula for the ability to compete in the monocular act woiild
thus be :

y^'^'^i^j

-A. (mi + m-; + ms + m4 + ms + me)

and the formula for the earning ability in the monocular act
would be:

Vj^pf

E=lcr^Pr^im + m + ....)

l/lC + 0-,A V

"Yz (m: + mz + TCiz + mi + ms + me)

After having developed in the foregoing formula the expression
for the earning ability for a one-eyed person, we may figure by

PAIJALYSIS OF l^ECTUS EXTERXUS. 67

concrete examples the impairment of the earning ability in case
of disorders of the mnscles.

Supposing somebody suffers by an accident a paralysis of the
rectus externns of one eye; the binocular act of vision would be
immediately excluded, because if the individual wishes to work
at all he must cover the eye and therefore exclude it from the act
of vision. The ability to earn which is left should be expressed
by the above formula and this may be figured by using the curves
in plate lY. ; by inserting the different values the formula would
be thus :

E=l X 0.913 X 0.904 X fO.5 X 0.913 X 0.904=0.8254 X J^O.4127
= 0.8254X0.915 = 0.755241, or in percentage E equals 75. 524,
the impairment of the earning ability Avould be 24.476 per cent.

Suppose the external recti become paralyzed, then binocular
vision is abolished and here the calculation of the amount of dam-
age to the working vision would have to be started from the mo-
nocular standard. In figuring the professional loss we woiild con-
sider that the value of the muscular action (as stated in the formula
for the monocular act as ^ mi + m2 + m.j + m4+m.-,+mfi), would be
diminished. Because the muscular action of the one eye used for
seeing, if the rectus externus be impaired, would be represented
by 5 and not by the full action of 6 ; it would therefore be :

ys (mi H- m2 + ms + mi + ms)
or more simply, two-thirds of five-sixths M. Entering this value
into the formula for the monocular act of vision it would be:

r=^p7?^"j^Mf-i-^«y^"j/^

Transposing this by the assistance of the curves in plate T., the
algebraic formula would be numerically expressed by the following:

10 10

E = 1.093 X 0.863 V 0.5 X 0.913 X 0.863 = 0.78792 V 0.39396
= 0.7879 X 0.911 = 0.717795 or E = 71.78 per cent.
If in a case having the same acuity of vision more muscles bepara-
lized in one eye than in the other, this eye should be regarded as
excluded from the binocular act and the calculation may be made
with the better. If one eye have a lower degree of vision, both hav-
ing paralysis of the exterior muscles, that eye which has the better
acuity should be regarded as the one which may be used in the pro-
fession, though its ocular muscles were more completely damaged.
In the following table the earning ability and impairment thereof
are given for different cases of paralysis, it l>eing considered therein
that the eye used for the profession has a working acuity of at least
0.75 for those vocations demanding higher vision and at least 0.50
for those with lower demands.

VALUATION OF OCULAR MUSCLE PARALYSIS.

EARNING ABILITY AND IMPAIRMENT THEREOF IN UNCOM-
PLICATED DISORDERS OF THE EXTRINSIC
OCULAR MUSCLES.

VARIETY OF DEFECT.

t> CO

2^ «

< o

.2^.2
o >,£

a
'3

or::
* i*

1—0.75

Paralysis of the extrinsic muscle of or

only one eye, 1 1 — 0.50

Paralysis of the extrinsic muscles of I

both eyes; of the one eye used 1 — 0.75

for working only one muscle is or

paralyzed, ^ 1 — 0.50

Paralysis of the extrinsic muscles of I

both eyes; of the one eye used ' 1 — 0.75

for working two muscles are par- or

alyzed, X 1—0.50

Paralysis of the extrinsic muscles of
both eyes; of the one eye used
for working three muscles are
paralyzed,

75.496

1—0.75 I

1—0.50 62.395

Paralysis of the extrinsic muscles |
of both eyes; of the one eye used
for working four muscles are par-
alyzed, I 2^

Paralysis of the extrinsic muscles
of both eyes; of the one eye used
for working five muscles are par-
alyzed, I }4

Paralysis of all extrinsic muscles of
the eye used for working, i

1—0.75

1—0.50

1—0.75

1—0.50
1-0.75

1—0.50

24.504

71.805 ' 28.195

67.530 32.470

37.605

55.811 ! 44.189

46.125 I 53.875

0.00 1100.00

EPICKITIC KEMAEKS. 69

§23. Epicritic Remarhs Concerning the Foregoing Results.

It may perhaps at first sight be deemed remarkable that we
find such a great difference between the earning ability in the case
where 5 extrinsic muscles are paralyzed and the valuation of com-
plete paralysis, for we have put down for the first instance an im-
pairment of 53.875 while we state the latter as 100 per cent. The
latter figure is certainly correct, for it is impossible for an artisan,
even though he have normal acuity of vision, who suffers paralysis
of all the extrinsic muscles which move the eyeball to be able to
earn. The consensus of authorities gives the same opinion (Chap.
VI., § 11). In specific cases, where only one muscle remains func-
tionable, for instance, the rectus superior, a greater impairment
of the working capacity might be found, for this muscle has but
little influence upon the average vocation. If the rectus intemus
remains, the working capacity would be greater, for this is used
much more often. Therefore, we might give each of the extrinsic
muscles a different valuation (Chap. YL, § 13) in considering
the specific demands of the vocations in which the injured person
has previously labored, or we may get around this point by giving
a higher valuation in such cases to the ability to compete ; thus
figuring not with the 10th but with a 5th or 6th root (table Xllla,
part IV).

By such a method we are enabled to simplify our mathematical
calculations in specific cases, even though we treat all the ocular
muscles equally. Thus by choosing the root exponents arbitrarily,
the physician is allowed to express the individuality of each
case. General calculations applicable for the individual values of
each muscle cannot be given without doing violence to the pecu-
liarity of the particular profession. Thus we hold it for the best
to give each of the extrinsic muscles the same valuation, that is,
one-sixth of the total value. "We regard these figures as generally
applicable as the lowest standard of the earning ability or the im-
pairment thereof, leaving it to the calculator to change them event-
ually according to specific demands of the particular case. That
paralysis of the levator palpebrae superior might suspend the use
of the affected eye is self-evident and such a case should be con-
sidered professionally as one of monocular vision.

70 ACTION IX moxoculaeis:m.

CHAPTER XL

§24. What Action is Necessary if the Injured Person Has Previ-
ously Only Had the Use of One Eye ?

The scientific and economic conception of monocnlarism is not
the same. "While, from a scientific standpoint, a person is to be re-
garded as one-eA'cd whose eyeball has been removed or who is other-
wise hopelessly blind, the meaning of one-eyedness (monocnlarism)
developed for professional life, has a much wider range. For eco-
nomic purposes a man must be regarded as possessing only mo-
nocular vision who has but the one useful for the earning of his
living, if the other has insufficient vision for this purpose. Tlie
condition of the poor eye and the degree of its visual acuity is
immaterial in this consideration. If it is not a useful eye, that
person may be considered to have but monocular vision for the
purpose of earning his living, for he could not follow his trade if
he lost the more normal eye, and would be in the same position as a
man who had originally one blind eye or non^ at all. Although
there is an optical and scientific difference, the economic conse-
quence would be the same ; both would be unable to work, although
the weak and professionally insufficient eye in the one case, not
being entirely blind, is of inestimable value to him ; but this would
have nothing to do in judging his ability to earn ; he would be pro-
fessionalh' incompetent if the uninjured eye is unequal to the de-
mands of the trade. Therefore, for our purpose, we would regard
many individuals as possessing but monocular vision who, ac-
cording to the scientific standard, can see more or less with both eyes.
Those who squint and suppress the image of one eye, those who
have sufficient refractive error, which cannot be corrected or which
lowers the acuity of vision to 0.15 or 0.05 (according to the visual
recpiirements of the trade), those who have congenital monocular
amblyopia, etc., belong to this class.

In the case of an individual whose previous condition would
be professionally regarded as that of monocnlarism, who suffers
an injury to his more normal eye, how would we estimate the earn-
ing ability? In the calculation of such a case the previous con-
dition has to be considered and there is here a material greater
impairment to the earning power than in the case of a person
with two normal eyes. In the case of an ocular accident hap-
pening to a workman, we must not only consider his own peculiar
ocular conditions but the side of the insurance company, employer
or defendant from whom he may be seeking indemnification for his
injury, so that we must be sure that the second parties are not bur-
dened with the blame for an impairment which the laborer had be-
fore the accident. "We solve this difficult problem with a just and

ABILITY TO COMPETE IX MONOCULARISM. 71

fair consideration of tlie claims of botli parties, when we start with
the supposition that with those workmen who originally possess
only the working use of one eye, the condition should be regarded
as normal, and therefore, for them the monocular act of vision is
the normal one and equal in value to the binocular act of the person
with two normal eyes. Thus out of fairness to the employer and
the Insurance Company and the workman himself, we would not
arithmeticall}' consider the scientific standard of binocular vision
in the case of a workman who has entered into his employment
with only one working eye and who has suffered an injury to it.
We calculate his claims in the same manner in which we figure
the ability to compete (Chap. IV., § 9; Chap. VII., § 15), wliich
is equal to the visual act and acuities of vision of both eyes in an
arithmetical proportion thus:

^' + ^' VTVm.

As in estimating the ability to compete of a person possessing
monocular vision who has suffered injury to it through an accident,
we put the visual acuity of one eye with its 'full va'lue C under the

V ; thus the formula for the ability to compete of the one-eyed
person would be :

t' •' P VK

This formula leads to the same results as that which we get for
injuries to the visual acuity in binocular vision ; as by this method,
a man who has originally one eye would be impaired through an
accident to his working eye to the same extent that occurs in a
binocular case. When an employer hires an individual who is
originally in possession of but one eye or who has practically only
monocular vision, he does this under the supposition that this de-
fect does not hinder him in his Avork and regards this condition
as the normal for this particular individual. If this be the case,
the ability to compete of such a man may be deemed normal and
in estimating his earning ability we would take his ability to com-
pete as the 10th root of the normal binocular vision of the man
Avith two eyes. But regarding the chances of obtaining work we
Avould repeat that there is a difference even in cases of monocular
vision; for instance, if a person has in one eye an irregular astig-
matism which diminishes the acuity below the working standard
so that he cannot use this eye in a profession with higher ocular
demands, for economic purposes he would professionally be deemed
one-ej^ed, but he would be able to find work much easier than
another laborer who has a bad-looking blind eye, for instance cor-
neal staphyloma, through blenorrhoea, etc. Therefore, we would
make an aritbmotieal difference between such cases, takins: as the

72 EXAMPLE OF INJURY IN MONOCULARISM,

exponent of the root for the ability to compete the number 10,
where there is a good-looking eye and one not entirely blind ; but in
the case of a person with a bad-looking blind eye, for the higher
ocular demands, we would take the exponent 5, and for lower ones
7 ; which are the same values that we took in the case of a workman
who had originally two normal eyes. We give the following ex-
ample : Supposing the vision of the sound eye in the case of a one-
eyed workman be reduced to 0.65 (scientific standard) our for-
mula would be the following :

E = C / P K^nii + m2 + m3 + mi + ms + me)

^ GVvr

(m, + mo + ms + mi + m.^ + m,-,)

As in this ease the visual field and the ocular muscles are not
impaired, and therefore 1, the reduced formula would be :

= G]riv iM G\' 1}/ 1

Substituting the professional valuation of the scientific standard
for 0.65 from our curves on plate I equals 0.833, and entering it
now into the formula which would be:

E = 0.833 X 1 X 1 K 0.833 X 1 X 1

the value ]/ 0.833 will be found in the curves of plate Y. ; if for

instance, we take the root exponent x:=10, then y 0.833 =0.982,
which leaves the formula thus : E = 0.833 X 0.982 = 0.818006
or E=81.801 per cent.

In the case of injury to the visual field in an originally one-
eyed person we would figure according to the following: the field
of vision of a one-eyed person, as we have seen in Chap. VI., plate
IV., Fig. 1, is narrower by one-sixth than the field of vision
of a normal person. If the right or left eye is gone, either the
right or the left temporal segment of the common field of vision
blue or red in Fig. 1, plate IV.) would be missing. Thus accord-
ing to our arrangement, the monocular field contains 5 parts of the
binocular one, which are 3^ of zone I, 3^ of zone II and ~A of
zone III. Thus if we desire to make an arithmetical calculation of
the limitation to the monocular field of vision, we should start with
this five-part arrangement and express the impairments by fifths.
The different estimates of damage to visual field would thus have
the following values :

VISUAL FIELD IN MONOCULAKISM. 73

Loss of the temporal half there is retained 3^

Loss of the nasal half there is retained j/s

If the concentric contraction reaches 30° the value
remaining is 3^

If the limitation on the nasal side is more than 45°, on the
temporal side 70°, below 65°, above 40°, the value of the remaining
field of vision is ^5.*

In calculating the amount of damage to' economic vision from
injuries to the monocular field, we insert in our formula for the
earning ability of the monocular act of vision for the value P the
valuation of the remaining field of visison. Our formula being :

E = C ]/YV (mi + m7+ ms^ m7 + ms + me)

] C VYV (mi + mo + m3 + m, + mr, + m,)

Supposing the remaining portion of the field of vision equals two-
fifths, the central visual acuity C and the valuation of the ocular

muscles V (nn + ms + ms + m* + ms + ms) remain unimpaired,
being equal to 1, the reduced formula would be :

E = 1 lA 2^ ]/ rf 1 vi^ /T

and as each 1^1, the resultant formula would be :

^ = iv yk 1 y 1 r'H 1

and which can be readily figured, or, if preferable, the valuation
can be easily found with the assistance of the curves in plate Y.

•The value ^is above figured is thus explained : The limitation reaching temporally
to 60° from the fixation point leaves -45 of the field of vision, of which a part is lost when
the limitation above is over 40°, below over 65° and on the nasal side over 45°, which
we estimate as a % loss of the remaining % of the field; therefore, there remains %
ofy5 = %5-

74 MEANING OF ECONOMIC WEAK VISION.

CHAPTER Xn.

ESTIMATION OF ACCIDENTAL INJURIES IN THOSE CASES IN

WHICH ONE OR BOTH EYES DID NOT POSSESS, BEFORE

THE ACCIDENT, SUFFICIENT NORMAL

CENTRAL VISUAL ACUITY.

§25. The Cleaning of Weah Vision from an Economic Standpoint.

There are many cases to which trauma occurs in which the
eyes had some previous disorder or disease affecting the visual
acuity, field of vision or the ocular muscles. It is more especially
defective visual acuity that is here considered. A recent article by
Walther (47) who reported upon the examination of the eyes of
2,672 active workmen (printers, metal workers, wood workers, glass
and porcelain workers, woolen workers, electrical and gas workers)
fouiul that exclusive of refraction defects that could be corrected
by lenses, 611 were more or less amblyopic. Of these 347 (63 per
cent.) had congenital defects; 224 (36 per cent.) acquired defects:
95 being of doubtful origin. In 15 per cent, the poor sight had
been caused by the work. Every practitioner knows how common
are opacities of the cornea and other disorders of the ocular media
whicli affect the visual acuity in those classes of people that fur-
nish laborers and artisans. Considering further how many cases
of strabismus, anisometropia, high grades of astigmatism and re-
fractional anomalies which are accompanied by weakness of vision
of one or both eyes, we will have to admit that many cases of ocular
accidents have previously had weak sight and whose acuity of vision
did not reach the economic limit, i. e., 0.75 or 0.50. If the physi-
cian, who is called to estimate the amount of visual damage, finds
inflis]-)utable proof that there was weakness of vision before tbe
aeeifleut, what should be his action in fixing the ability to earn?
If after an accident to both eyes, he finds only a visual acuity of
0.40, he must decide regarding the previous condition of the eyes,
for the weakness of vision after the accident may not be solely
the result of the trauma, but due in part or whole to causes not
connected with it. In such cases particular care must be observed
in the arithmetical estimation of the resultant damage to vision ; we
are certainly not justified in drawing conclusions from uncertain
suppositions about the earning ability before the accident. If we
cannot get reliable information concerning the injured person of
the results of previous examinations, our estimation would depend
entirely upon the impression gained by the present condition of the
eve. There are many individuals who combine an astonishing

IMPRACTICABILITY OF GENERAL VISUAL EXAMINATIONS. 75

amount of working and earning ability with exceptionally low visual
acuit}', as has been shown by Groenouw's examples. Therefore, we
cannot give each individual, whom we suppose had a weakness of
vision before the accident, an earning ability in proportion to
the hypothetic degree of this weakness. The possibility or
even probability is, that this weak sighted individual pos-
sessed a greater ability to earn than might be supposed accord-
ing to objective results. Therefore, the physician should only con-
sider reliable communications, such as an exact functional examina-
tion of the eyes, regarding the previous extent of the weakness of
vision in the particular case. If he has no such data, each person
suffering from an ocular accident should be regarded as formerly
normal; for even if there is a conviction that there was formerly
a weakness of vision, justice demands that an arithmetical valu-
ation of the former condition could be secured only by a previous
functional examination. But this general rule, of course, may be
laid aside in those cases in which there are decided opacities of the
ocular media, congenital defects, which, through their appearance,
have evidently existed for a long time previous to the accident, etc. ;
the physician may positively know that such have precluded the
possibility of previously existing good working conditions. As this
German Accident Insurance law was passed with benevolent inten-
tions of protecting the workingman, we divine that his interest
should be placed foremost. If we do this, we should stick to the
principle that a former weakness of vision should diminish the
claims for indemnification of injured workingmen only in such
cases where the extent of the weakness of vision before the accident
has been fixed by a reliable functional examination. Certainly
the Utopian idea of examination of the eyes and other organs of all
workingmen before taking employment and at stated intervals
thereafter, according to Zehender and others of our colleagues,
would fix this matter, but such is impractical except for the rail-
road, army and other kindred services. A systematic examination
could only be made by a qualified oculist, and it would be impos-
sible, as many factories are in small towns that cannot support an
oculist. Likewise the financial question renders it impractical, for
neither the workingman nor the employer is at present willing to
stand the expense, and surely the physician should not be jequired
to give his time for nothing, especially considering that he would
have to write a certificate and accept responsibility in every single
case. Then again, one examination is not sufficient : each one
should be re-examined from time to time, as has been done in the
railroads. For the latter service, re-examinations are conducted
every few years or upon applications for promotion. Such examina-
tions are certainly demanded for this class of workmen, for upon
their eye-sight and physical condition depends the lives of many
others.

76 WEAK VISION" EXISTING BEFORE THE ACCIDENT,

§26. E.-itiinaiion of Hte EaruiiKj Abililij in Case Weakness of
Vision Existed Before the Accident, Which Can Be Nu-
merically Fixed Through a Former Functional Exami-
nation. \

If a workman suffers impairment of his visual acuity by an ac-
cident and data exists of his former condition, this weakness should
be taken into account in estimating the damages caused by the acci-
dent. If in such a case we had based our estimation upon the
ocular conditions of the formerly normal-sighted person, the injury
would then receive an indemnification which is too high; beiug
recompensed for the loss of a something which he never possessed.
To prove the correctness of this assertion, let us look at the follow-
ing case :

A w^orkingman coming under Group I who had in one eye for-
merly only 0.60 visual acuity, suffers an injury which diminishes
this to 0.40,should he be indemnified the same as if he had formerly

normal visual acuitv? This num has still -*^^>^ of his former

0,60

vision, but if his former weakness would not l)o considered, he

would be indemnified as if his resultant vision was only ^^-^^^

Thus allowances for the former visual acuity in cases will have to
be made where it is known. Thus, in the estimation of such a case,
we W'Ould not enter the quantity 0.40 into the formula, for this
would result in too great indemnification, but another X, which
bears the same ratio to the unity of the particular group (here
higher visual demands, 0.75) as the remaining acuity of vision
after the accident (0.40) to the former (0.60) as in the follow-
ing proportion :

X : 0,75 = 0.40 : 0,60

X = 0.75 X^40 = 0,50
0,60
As in those cases the use of such an auxiliary C[uantity is neces-
sary, we wall introduce for it a special expression :

Definition: If n is the normal acuity of vision (for working-
xnen with higher visual demands n = 0,75 ; for workingmen with
lower demands n = 0,50); ni the original acuity of vision of the
weak-sighted and Ci the acuity of vision after the accident.*

We would understand under "modified visual acuity," an acuity
Ci' which suffices for the proportion Ci':n =Ci:ni from which we get

the equation : Ci' = n - .

^ ni

tin forensic praetice the following examples will be seldom found. Considerable space
is siven for such eases here to show that our rules are universal and adapted to the most
tomplicated as well as the simpler cases.

*In naine the readinp; tables, the reranininp: visual acuity after an injury would be the
scientific standard and would have to be changed into the professional one.

CALCULATION OF CASES OF PREVIOUS WEAK VISIOX. 77

This expression would be used for the original visual value un-
der the following circumstances : if a person begins a trade or
vocation with a weaker normal visual acuity than n which we
would denominate ni, and then has this eye injured so that ulti-
mately there is a visual acuity of Ci, the estimation of his indemni-
fication should be based upon the modified visual acuity c/ and
not the original acuity Ci- Tf the person be weak-sighted in both
eyes, n2 and C2 mark the values for the second eye, corresponding
to the quantities iii and Ci ; thus the modified visual acuity c/ must
be introduced, as the act of vision is, in this case, dependent upon
two modified acuities c/ and c^ . One of these quantities would
generally be greater, if both be equal, it is immaterial which we
choose; one should be marked Ijy c'max. The formula for the visual
act would thus be :

4
S2 = C',„ax. VTVlL

As at present we only deal with the factor of visual acuity, consid-
ering in our examples that the peripheric vision and muscular
action are normal, thus estimating their value as 1 in the equation :

S2 = C'„,ax. X 1 X 1.

We have now found a value for the visual act S and will have
to consider the second factor, the ability to compete K, for the esti-
mation of the ocular earning ability E. This quantity K we have
identified for our purposes with the act of vision itself but with a
difference, whereas we made this factor dependent only upon the
miximum of the central acuities of both eyes, we introduced into
the other in its stead the arithmetical proportion of the central
visual acuities. And as in our case we must regard the modified
acuities c/ and c/ as ideally existing, it would seem at first glance

as if we had to figure with these and to insert for K the value

gj' _j_ g^' " _ *

K = g , where we again disregard the (juantities |/ p and ]/ M.

Such a supposition would be in opposition to statements previously
made. Indeed, the ability to compete is a quantity which depends
more upon others than upon the individual himself, and while w^e
had to say in figuring the visual act : The visual acuities Ci and C2
have for the individual the valu'^ c,' and C2' ; we cannot definitely
assert a value for this quantity as it is dependent, to a small degree,
upon the individual himself. If in the estimation of K we would
take as auxiliaries, the modified visual acuities c/ and d' we would
express therewith the idea that the acuities of vision Ci and C2 have
in other cases these modified values and this supposition is not sup-
ported by facts. This simple reflection forces us to accept K in the

78 CALCTLATIOX OF CASLS OF PREVIOUS AVEAK VISIOX.

form K = -^- — ^ and inserting this and the value of the f(jrmer

^ X

vision into the general formula for the earning ability E = S ^ K
the result would be :

p _ .. 1/ Cl + C2
tj C ,„ax. V

It would seem almost as if a great many tables were desirable for
figuring the above formula, because c'max. and -~^ — ^ may have many

different values and allow of numerous combinations, but it is
possible to make use of the above expression for E without going
into such detail. "We will use the former expressions and mark
for c max. the greater of the two visual acuities Ci and C2 ; then if,
for instance, n = 0.75 or 0.50, we estimate from our two main
tables Y. or VI., part IV., as an auxiliary quantity an earning
ability E which is given in the proportion :

E = C,„ax.f^+"*

out of this we get the value of the 10th root

}

Cl + C2 E'

■< C max.

and bv insertino; this value into the above formula for E we get

E — c' l/ ci + C2

•L' <- max. W ~

which reduced to the extremely simple equation,

Ti C' max. ^ E^

C max.

whose figuring is possible without any difficulty. As we have
already shown the quantities c max. and c' max. must be replaced by
their professional values. How these can be readily estimated in
eases where table II. is not available will be shown by examples.

Of course, the above formula for E has been deduced under
the supposition that the visual field and muscular action remains
normal. The same method may be readily used for finding the
reduced visual field or reduced value of the ocular muscles. In-
deed, the reduced quantities P and M, which were omitted in our last
formula for the earning ability E, will form with the same amount
part of the auxiliary quantity E' and are taken as such in our

EXAMPLES. 79

table, which furnishes the visual aciiitics of ci and Cg with re-
mainders of P and M, the vakie E'. Therefore, we do not need to
estimate the impairments of P and M separately.

In order to quickly ascertain in all cases of weakness of vision,
the corresponding ability of earning, the following has to be done :

We take the earning ability E' belonging to the really existing
visual acuities ci and Ca from one of the corresponding tables,
figure the modified acuities of vision c max. and c' max., multiply E'
with the greater figure c' max. and divide the product, by the greater
of the two values ci and Cg (c max.), but the two quantities c max and
c'max. have to be inserted in their professional values; the resulting
quotient is the desired earning ability. To show how simple the
calculation really is we will exhibit one example each of the differ-
ent possibilities which we divide into the following four groups :

Group I — One eye is normal, the other originally weak-sighted.

Group II. Both eyes are originally weak-sighted to equal
degrees.

Group III. Both eyes are originally weak-sighted to different
degrees.

Group lY. One eye is blind and the other originally weak-
sighted.

To each of these four groups may be added the accidental in-
juries in their different forms. In the following we will explain
the single groups with the different accidental possibilities.

§27. Group I. One Eye is Normal, the Other OriginaUij Weak-
Sigh ted.

In all the example? of thi;^ group we deal with an individual
Avhose work requires higher ocular demands (thus n^O.75) and
whose eye 1 has at least a visual acuity of ni = 0.75 and whose other
has perhaps only ni;=0.60.

Example 1. *The normal eye remains sound (ci=0.75). the
acuity of vision of the other eye 2 is diminished through an in-
jurv' to C2= 0.30 the modified visiial acuities are:

c/=n ''-=0.75^.11=0.75,
ni 0.75

c/=n ''^=0.75 ^•|^= 0.375.
n2 0.60

Table Y. of the fourth part gives the earning ability E belonging to
c, = 0.75 and c? = 0.30 as E' =95.41.

The maximum of the real acuities of vision is Ct = 0.75, of the
modified acuities of vision alsoc/= 0.75, and as both values cor-
respond according to the table on p. 42 with 1, the desired earning

ability E will be : E = "" ' '""" ^' - L>< ^M^ =95.41.

*In these example.'* figures taken from tables in Part IV refer to theTIGermaneditionof
Maprniis'book in which the perpentaces are worked over to the thousandths. For practical
UKe the American Author only accepts them to tenths and has thns published the tables.

80 EXAMPLES.

Example "2. If the eye 1 is sound (ci = 0.75) while the acuity
of vision of the other eye 2, is reduced to C2=0, the modified acui-
ties are :

c, „^_0.75 „^_
Ci=n = 0. <o „ „^ ^0. it>,
ni 0. r5

c,, = n = 0. / o .^ „ „ = 0.
n-i 0.60

to Ci=:0.T5 and Ci'=U belongs according to table Y., part IV., an
earning ability E' = 60.09T. "

The maximum of the acuities of vision are as above Ci = 0.75
and c/ =0.75 to which belongs professionally the figure 1, there-
fore, the earning ability is :

E = ^'"^^' = L><69:CI97 ^ ^^^^^^^

C max. J-

Example 3. If the normal eye 1 suffers such an injury that
there only remains a visual acuity of ci =0.50 while the other eye
2 remains uninjured (c3 = 0.60) the modified acuities of vision are:

, Ci 0.30

Ci = n — = 0.75 ^r-^^ = 0.30,
ni U,75

, c. ^^0.60

c> =: n = 0. < o ^ ^„ = 0.75.
Ho O.dO

According to table Y., part lY., the acuities of vision Ci =^ 0.50
and 02 = 0.60, for the earning ability E' =: T2.02 and because
Cmax. = C2=:0.60, c' ,„a.x := C-/ = 0.75 arc figures to be replaced by
0.75 and 1, which is (see tal)le) the looked-for earning ability:

^ c',n.x. E' 1X72.02 _„_
E= = ,^ ^. = 96.02 (.

Cmax. 0. / 1)

Example 4. If the normal eye 1 l^ecomes totally blind (ci = 0)
and the other remains uninjured (c> = 0.60) the modified visual
acuities are:

Ci = n =0. (t»„^^=0.
Hi O./o

c. .„.0.60 „„_
Ci = n = 0. / ,. ^., = 0.7o.
nj .60

whose maximum is c-/=O.To. while C2=0. 60 represents the maxi-
mum of the real visual acuities. In table Y., part lY., we find as
belonging to ci=0 and c-,.= 0.60 an earning ability E':=48.925.
so that according to table on p. 42 the figures 1 and 0.7o b?long
to 0.75 and O.GO the earning abilitv is:

J, _ C „„. EJ^lX 48.925 _g. 233

Cmax. O.^O

EXAMPLES. 81

Example 5. If both eyes suffer injuries and in 1 there remains
only a visual acuity Ci = 0.-t5, on the other 2 only Ca^0.40, the
modified acuities are :

Ci 45

c, ^^_0.40 „.^^
c/ = n = 0. ( o „ 7.,, = O.oO.
n-; 0.60

Cmax. = Ci= 0.45 and c' max. =^ c/ =0.50 are figures which correspond
(see table, p. 4'?). with the values 0.50 and 0.5833 to Ci and C2.
According to table V.. jiart IV., there belongs an earning ability
E' = 46.284, the final result is:

^ c' „,ax. E' 0.583....46.248 ..^ ^_^

C max. O.oO

§28. Group II. Both Eyes are Originallij EqifaUij Weal--Sighted.

In the following cases we will suppose that the trade has only
small ocular requirements (n=U.50) and that the workman origi-
nally possessed visual acuity of only ni^nj= 0.40 in both eyes.

Example 1. If eye 1 be uninjured (ci^0.40) and the other
suffers an impairment to about c> = 0.20, the modified visual acui-
ties would be according to the following formula:

, Ci 0.40

Ci' = n = O.oO ., . „ =0.oO.
ni 0.40

c/= n ^' = 0.50^^=0.25.
n,. 0.40

of which the maximum isc'„,a.x. =Ci' = 0.50, while the real acuities
are Cmax. = Ci= 0.40. According to tal)le VI.. part IV.. Cj and c.

E' = 73.338.
and as the \alues according to tal)le. p. 42. correspond to the figures
1 and O.TTT • • • . the resulting earning ability is:

g __ c max. E ^ 1 X 73^38 __ „ . 2Q2

Cmax. 0.777 ....

Example 2. If one eye be totally l)lind (c>= 0) while the
other be uninjured (ci= 0.40). the modified acuities are as follows:

c/ = n ^' =0.50^4^=0-50.
Hi 0.40

c/ = n ^' = 0.50^^,^= 0.
n< 0.40

82 EXAMPLES.

as above, Cmax. = Ci= 0.40 and c'max c = 0.50; table VI., part IV.,
gives as belonging to ciaiid c--, E' = 54.538, and as a Avorking valu-
ation we get for the earning ability :

^ _ c'„ax. X E _ IX 54.538 „ , ^

Cmax. 0.777 . . .

Example 3. If both eyes suffer the same injury so that there
only remains a visual acuity of Ci = C2=0.20 then the modified
acuities develop as follows :

c/ = c./ n ^ - = n ^- = 0.50 ^^ = 0.25.
ni Vii 0.40

in which equation Cmax.= Ci=C2=0.20 and c'max=Ci' = c/= 0.25, to
which figures belong the working values of 0.333 . . and 0.4444 . . .
For ci and C2 , table VI., part IV., we find an earning ability of
E = 29.865, from Avhich we find the real earning ability:

^ c^n.ax. E^ 0.444 29.865 _ „„ ^^

Cmax. \J.666 . . .

Example 4. If the injuries in both eyes are different, the re-
sulting acuity of ci= 0.20 and of ca = 0.30 we find that the modi-
fied acuities of vision Cmax.= c^ =0.30. wdiich are professionally
0.555 . . . (p. 42), the calculation for the modified vision would b?:

c/ = n ''= 0.50 J^-^!^= 0.25.
ni 0.40

/ C2 „0.30 c\^n-

c> = n = 0.50 „ . ,. = 0.3 /o.
n2 0.40

in which the luaximum isc'max. = C2 = 0.375; and as this figure is
exactly between 0.40 and 0.35, the middle value of the professional
quantities 0.777 . . . and 0.666 . . . , i. e., 0.7222 will correspond.
To Ci and C2 belongs E' = 51.228, the earning ability is:

E = ?:=H_E' ^ 0,722^. . . . 51.228 ^ gg -gg

Cmax. 0.555 ....

§29. Group III. Both Ei/cs of ike Individual are Originally
Weak-Sighted to a Different Degree.

In the following cases we deal with workingmen whose profes-
sions have liigh visual requirements (n=0.75) but who have origi-
nal visual acuity in one eye n i=0.65 and in the other n2 = 0.55.

exa:mples. 83

c/-

■- n

c/ =

Example 1. Eye 1 is uninjured (ci = 0.6o) while the visual
acuity in the other has been impaired by injury to 0,,=^ 0.20, the
modified acuities are:

,, ^ ^0.65 „ r-r

o.< 0x^-^ = 0.75.

U.bo

0.75 X^?? = 0.27.
0.00

the maximum c'„iax.= Ci'=0.T5,while we get for the maximiim of the
real acuities Cniax.= Ci^ 0.05. The first vahie should be replaced
professionally by 1 according to the table on p. 43 ; the second by
0.833 ... To Ci andc2, table T., part IV., furnish us the quantity
E':^ 77.079, the earning ability is therefore:

Cmax. 0.8334. , . .

Example 2. If one eye becomes totally blind (c2= 0) while
the other remains uninjured (ci=0.65), the modified acuities are:

c/ = n X ^' = 0.75 X ^ = 0.75.

c./ = n X ^' = 0.75 X ^ = 0.

Cmax.= Ci^ 0.65 andc'max.= Ci'^ 0.75; table Y.,part IV., shows for
Ci and C2, E' = 55.519, the professional values are the same as in
the former example ; the earning ability is :

T-, C max. -Cj iX.00.Oiy ^^ rrto

Example 3. If both eyes suffer injuries of which the vision
of one eye is reduced to Ci = 0.50, and in the other to 0^=0.40,
where Cmax.= Ci=0.45 (professionally Cmax.= 0.50), the modified
acuities are according to the following formula :

, ^ Ci ,-, ^ ^ 0.45 „ -^

c/ = n X - - = 0. 1 o X T^TT. = O.o2.

Di 0.60

c./ = n X — = 0. ( o X TT^- = 0.06.
T\-i 0.55

whose maximum c'raax.=C2'=0.5<j, which professionally represents
a valuation of (table V.)*

lOOcg' — 15 100 X 0.56 — 15

60 60

= 0.6833,

•The profpssional values belonging to the scientific visual acuities are obtained by the
following formula:

^ lOOe— 15 ^ „ 100c— 5

Group I. — ~^ Group II.

60 "^ 45

84 EXAMPLES.

To Ci and c-j Ijoloiiii- according to tabic \'., part IV., E =4:0.24:8,
from which we deduce the earning ability of :

^ c'„,ax. E 0.6833 .... 46.248 „„ „_
E = — = _^ =63.206.

Cna.v 0.50

ExAirPLE 4. It' both, eves be injured, but in sucli a manner
tliat one becomes totally blind ci^ 0, while the other is reduced to
Ca=0.30, the modified acuities of vision h.ave the following values:

c/ = nX" =0.75X^^^=0.
ni 0.65

c/ = n X — = 0.75 X [J-|^ = 0.41.
n-z 0.55

Cmax. =C2 = 0.30 (professionalh' = 0.25) and c'max.=C2'= 0.41 (to be

, . , 100X0.41 — 15 ", ,.,., X 1 , 1 • + ^

replaced by ~ .r=r0.4o3 . . .) and as belonging to Cj and

02, we take from table Y, part IX.^ E' = 13.091, which quantity
allows us for the ability to earn :

g ^ c^,„xj' ^ 0.4 33 13.091 ^ 22 691

Cmax. U.ZO

§30. Group IV. In These C'ascs One Eye Was Or'ujinally Blind
and the titer WeaJc'Sighted.

We suppose that we have to deal with an individual whose pro-
fession has only low visual requirements (n^ 0.50). The one eye
is totally blind (ni= 0) while the other possesses a visual acuity of
n2-= 0.45.

If the seeing eye be injured and there remains only a visual
acuity of C2=0.25, because Ci = has to be used, there is c,„ax. =C2
^=0.25 (professionally = 0.444 . . .)and the modified acuity of vision
c/ = 0, the maximum of both values will be :

C2'=n X — = 0.59 X ^'^l = 0.28 . .
na 0.45

which corresponds professionally with the figures:
100 X 0.28 — 0.5

= 0.511

To Ci and C2 belong according to table XA'L. part IV.. E' = 39.582;
the earning ability is therefore :

^ c,„ax. E' 0.511 ... 39.582 ,_ ..^
E= = ^ ... = 45.019.

Cmax. 0.444 . . .

LOSS OF ONE EYE. 85

CHAPTER XIII.

THE LOSS OF ONE EYE THROUGH ACCIDENT.

Claims for damages in the case of accidental loss of an eye are
•of frequent occurrence and we will therefore give this subject ex-
haustive consideration.

§;j1. Estimation of the Vision in the Case of the Loss of One Eye.

In Chap. A'l., § 11, p. , we gave the following professional
calculation for the binocular act of vision. Our object is now to
estimate in what manner the individual factors of the formula are
impaired in value by the total loss of one eye. The formula for the
binocular act was :

^, = CV?V (mi m2 ms m* iHo me) (m/ m/ ms' m/ nis' ms)
In the case of the loss of one eye, the central acuity (C of our
formula), is so little affected that the slight loss from the taking
away of the vision in one eye may be ignored. The clearness of
sight is just as good in monocular vision as in binocular. Ze-
hender (54-, p. G28) says that the. one-eyed condition does not offer
any ohstacles for following a trade from the visual point of view,
but this expression should be understood as only pertaining to the
visual acuity and not to the other factors. "We, therefore, put the
visual acuity in such cases with the valuation of the trade.
Of course, we must remember that diminution of the acuity
a little below the scientific standard but not encroaching on. the
trade limits, should not be regarded as injury incurring a liability,
for we have shown in Chap. YI., § 12, that a visual acuity of 0.75 —
0.50 should be regarded professionally as normal. In professions
with higher visual demands, a visual acuity of 0.75 is regarded as
normal equals 1, and in trades with smaller demands a visual
acuity of 0.50 is regarded as normal equals 1. If the injured per-
son liave a visual acuity of 0.75 or 0.50 we should not immediately
state that his working powers have sulfV'Vcd l)ut sliould examine into
the visual requirements of his trade. If we Ijelieve, that the voca-
tion requires fine vision, we would regard a visual acuity of 0.75
as normal. l)ut if the eye work is less. 0.50 may be regarded as
normal or 1.

The peripheric vision is but little affected through the loss of
one eye. because the extent of the monocular field of vision is but
a little narrower tb.an that of the ])inocular field. Only one seg-
ment is missing after the loss of one eve. According to our ar-
rangement of the entire field of vision into three concentric zones

86 MUSCLE VALUES IN LOSS OF ONE EYE.

(})lato IV., Y\g. 1), the loss would be one-sixth of the whovc field
(eitlicr the blue or the red part of the drawing.) Therefore, after
the loss of one eye five-sixths of the field would remain which Ave

would insert into the formula as w — V

r 6 •

The action of the muscles will be materially impaired, because
estimation of distances, stereoscopic vision and judging of dimen-
sions are dependent upon binocular vision and are lost when it is
disturbed, but these functions are only temporally lost. A child
losing an eye at an early age, learns immediately to estimate dis-
tances, dimensions and relations of objects; an adult recovers more
or less of these functions, and as a rule in a very short time ; for di-
mensions, distances, etc., are known to him through his former ex-
perience Avith binocular vision. The muscular sense becomes more-
developed for the remaining eye, and the estimation of distance*
and size of objects is restored. Although Moorcn (29) disregards that,
our OAvn rather consideral)le experience Avould alloAV us to relate of
numerous persons who finally had these functions restored so that
they were ultimately able to estimate distances, the form and the
relation of objects just as well as persons Avith tAvo eyes. Similar
experiences have been noted by other authors (Guillery l-i, p. 215)..
Besides this, avo find enough one-eyed persons in every trade Avho can
do their duties as Avell as those Avho have tAvo eyes. In an examina-
tion (Xieden, 31), of 85,000 miners in Bochum. 310 one-eyed per-
sons Avere found Avho could folloAv their trade as Avell as the others. As
a result of this examination the management of the mines in the
Bochum district does not noAV regard the one-eyed condition as an
obstacle for the mining trade, and one-eyed persons are accepted as
miners, and those Avho lose an eye Avhile working arc alloAved to re-
main. Under certain circumstances an exceptional individual may
be found Avho does not regain the functions in question to a suffi-
cient extent, but as a general rule the muscular disorders from the
loss of one eye are only temporary, and in figuring impairment of
the earning ability this should be considered. For a time Ave may
giA'e this impairment an expression in our calculation, but it should
be reduced or removed in calculating the latter conditions. One-
year is sufficient liberal allowance for the individual to adapt his
monocular vision to the demands of his profession. A re-examina-
tion and ncAv calculation may be made one year afterAvards, and the
parties interested in the case should be informed that the alloAvance-
Avould be less after one year.

To form the muscular action M into an arithmetical quantity,
Ave divide it into three separate functions, Avhich Ave intend to regard
as of equal value; {. e., 1, into the part for moving the right eye;
2, the left eye ; 3, the binocular part. For our purposes both eyes
must be regarded as of equal value. Wlien one eye becomes blind,,
the tliird part used to estimate distances, etc., is entirely omitted,.

MONOCULAR BLINDNESS AND ABILITY TO COMPETE. 87

but the other two factors remain, even if one only has to do with
the movement of a blind eye or of a stump, for in the latter case
it serves as a support for an artificial eye. therefore, the muscular
action remaining in the case of loss of one eye would be entered
into the formula for the act of vision as:

^M.

The formula for working vision in the case of monocular blind-
ness would be :

It should be remembered that in professions with higher visual
demands the visual acuity C should be regarded as 1 even if it is
only three-fourths of the scientific standard and in lower demands it
is considered as of normal value if only one-half of the scientific
standard.

§32. Estimation of the Ahilifij to Coinpctc after ttic Loss of
One Eye.

In estimating the ability to compete after the loss of one eye,
the impaired values of the different factors entering into the act
of vision should be considered (Chap. YIL, § 15). The value of

the visual field would be 1' P and of the musclar action f--M.

The central acuity, from the professional standpoint, is not con-
sidered to have suffered, but still there is an impairment of the
earning ability (Chap. YL, § 11, p. 33.) The formula for the
ability to compete is taken as a root value, as it is of less import-
ance than the others, and its exponent is made a changeable one,
to agree with the seriousness of the ocular injury, as we have shown
in Chap. VII. , § 15, p. 48. "We will l)rieffy refer to the^e condi-
tions : The ability to compete is dependent not only on the condr-
tion of the ocular apparatus of ihe particular individual but also,
and even much more, upon the judgment of the employer. Accord-
ing to the seriousness of the injury, the employer becomes more
rigid, and if one eye be lost will even refuse work on this account.
An employer may be willing to employindividuals with slight ocular
disorders, but will frequently draw the line with the one-eyed. He
may occasionally employ a one-eyed man for roiigh work, but for
finer work will always prefer a man with two eyes. There may be
exceptions, as there may bo employers who regard one-eyed individ-
uals as able as normal sighted ones, but a normal siiihted one will

88 EARXIXG ABILITY IX MOXOCULARISM.

most always Ijo preferred. Tliese eoiulitions must not be overlooked
in order to do justice.

The ability to compete, according to our conception, is a proper
fraction, because it is a ])roduct whose factors are either proper
fractions or equal to 1. If a proper fraction be taken as a root we
are able to raise or diminish its value by choosing the exponent
of the root; with a raising exponent the root value enhances, and
vice versa. If we adaj)t the ability to compete in one case as the
10th root and in another as the oth root, in the first case the value
would be greater and in the latter smaller. Thus by enhancing the
ability to compete, tlic earning ability increases while the other way
it diminishes. If in the ease of slighter injuries we use the ex-
ponent 10; by taking a smaller exponent, for instance, o, to reduce
its own and the value of the earning ability, it would meet the re-
quirements of the loss of one eye in those trades having higher
visual demands, whereas for coarser trades we may take 7 as the
exponent. (See Cha]). YH., S I-'- P- ■+^)- In fl^(^ fii'>t case, we
would get for the ability to compete the following expression :

r^rii^P^

and in the second case

r'f^Wi^i.

§33. Esiliiiafiuii of iJte Edniiiuj AhlUtij Where One Eye Be-
comes Blind .

According to the formula for the earning ability E = F + V K.

I. In professions with higher visual demands for the first year
after the injury :

B=-r^r^'r^^7Ff^;

and after the first vear:
E = IC

n^f-fw^Wff,

FORMULA FOB EARNIXG ABILITY IJf MONOCULARISM. 89

II. In professions with lesser visual demands I'or the first year
after the injury :

--F^r^.rv"yy7y|^

and after the first vear

E^icf|7fMfiV^«|y7y

The calculation of these formulas has been made, by the as-
sistance of our curves, so simple that it is reduced almost to com-
mon multiplication. Let us figure the first formula:

E =

^^ij^w^p'r^T^'^ju.

C the ceutral maximal visual acuity remains 1; l/-— pmay be

read on plate A' without difficulty; as more convenient we change
the fraction % into a decimal — 0.833, and V 0.833 P according

to our curves equals 0.913. V M 'j^ing' changed into a decimal

0.666, is found on plate Y. as 0.004. The equation for the ability
to compete* would thus be :

should be first figured into its single factors before we can find the
total value in plate III.; when we do this, we get for the central

acuity ^- the value equals 0.r)0; |/ ^ p = 0.913 aud

1/2

w -- M. = 0.904. The equation for the ability to compete would

5 _ ^ ___ ___ fi

thus be: K 0.50 X 0.913 X 0.904= V 0.4127 and this figure we

yrj _j_ Q 4
F P r M *'^^ factors

Cj and Cg should ahvii.v.s be replaced by their professional valuation.

90 PERCENTAGE OF LOSS IN MONOCULARISM.

find on plate V., curve 3, the valuation equals 0.838. We state
again the original formula :

which has been reduced to : 1 X 0.913 X 0.838 = 0.69145, which
in percentage is 69.145 per cent., which is the full earning ability
and therefore its impairment is 30.855 per cent. Should Ave have
worked this equation out entirely by figures, we would have found
the values 69.097 per cent, and 30.903 per cent., which differ imma-
terialh" from those given by our curves. This example shows that
our curves simplify the calculation without materially changing
the results.

According fo our calculations for trades with Irigher visual de-
mands ice find that a one-eyed person after being cured of the ocular
disease has an impairment of the earning ability amounting to
30.903 per cent., and after one year of 21.960 per cent., while for
vocations demanding less vision the values would be 21 .315 per cent,
and 18.3SS per cent. Of course, it would be left to the manage-
ment of the Insurance Companies as well as to the physician to
change these proportions more or less according to the circumstances
of the case. Approximately we may say that a one-eyed person has
lost 30 per cent, of his earning ability for the first year after the
accident and 20 per cent, afterwards for the higher class of trades
and for the lower class the proportion would be 21 per cent, for the
first year and IS per cent, thereafter. Certainly there is a difference
between the individual who has been employed in fine handiwork
and one doing common manual labor, and justice demands that a
difference should be made in judging the indemnity. The system
in vogue was an unfair one, as it over-estimated the valuation for the
loss of one eye, the Imperial Insurance Office (3) having given
33 1-3 per cent, indemnity. Heddiius (18) had fixed the indemnity
at 25 per cent.; Groenouw (12) accepts the sliding scale as made
by Magnus, his values fluctuating between 20 and 30 per cent., and
are therefore very close to the indemnity proposed by Magnus ; but
they must be regarded solely as arbitrary estimations and not the
result of exact calculations as have been given in this book. Ex-
amination of all one-eyed persons in the iron and steel trades in
certain districts in Germany showed that there was an actual im-
pairment in the amount of work done and the wages earned of 26
per cent, at the highest (Magnus, 26). Examination of the Miners'
Association in Halle a. S. (41) showed only 20 per cent.

All these facts speak for a revision of the 33 1-3 per cent, rate
now granted by the German Insurance offices. No real difference
should be made for the values of the right or the left eye, although
it is shown that the left eye is injured much more frequently (Ot-

GRADUAL LOSS OF SIGHT IX OXE EYE. 9]

linger 33, p. TO) ; the left eye being injured in 60.2 per cent and
the right in 39.8 per cent. It would be perhaps well for the work-
jnan after losing the less endangered right eye to avoid vocations in
which injuries to the eye are frequent.

Our valuations of 30.903 per cent, and 2T.315 per cent, admit
after one year of a reduction, because those muscular functions
whicli were formerly executed by both eyes are partly or entirely re-
stored. The iigures of 21.97 per cent, or 18.39 per cent, should be
regarded as the maximal limit to which the damage may be reduced.
This reduction should not be obligatory in every case but the in-
dividnal should receive full consideration. In the case of older
men, a reduction may perhaps never be made because an old man
will never acquire new functions as will the younger one. The in-
telligence of the person is a factor and the profession itself should
play a role as regards this reduction of damage, depending upon
the visual demands of the vocation. In the case of smaller ocular
demands we need not be so considerate.

A further important question is whether the sudden total loss of
one eye does not demand a different valuation for the earning ability
than gradual growing blindness on one side. Accidental blindness
may be caused in different ways; either the eye may be injured to
such an extent that sight is immediately lost or the injury produces
a diseased condition leading gradually to the loss of vision. There
are numerous cases in which passable visual acuity exists for some
time after the accident and blindness only develops after several
years. Such cases occur from blows upon the head causing rupture
of the posterior coats of the eye, causing ultimate detachment of
the retina through cicatricial contraction. Iron and copper splin-
ters in the interior of the eye may, after one or two years, cause
))lindness. Sudden blindness in one eye has certain ocular conse-
(|uences which make the following of the profession more difficult
for the injured, /. e., the judgment of distances, etc., and should be
considered in estimating the impairment of the earning ability. If
the one-sided blindness develops gradually, the lapse of time per-
mits the injured person to adapt himself to the ocular consequences
of being one-eyed. It is, therefore, not more than fair to consider
these conditions in figuring the impairment of the earning ability.
We would, therefore, figure the impairment of the earning ability in
:i case of gradual loss of sight at the lower rates above given. There-
fore the {mpainiient of the earning ahlliti/ from the gradual loss
of the ^ight in one eye following an accident in trades of higher
risval demands is 21.97 per cent., in professions icith lower visual
demands 18.39 per cent.

There Avas a time when 50 per cent, was regarded as the valu-
ation for the loss of one eye (Mooren 29; Golebiewski 10, pp. 129
and 241). But this is only a matter of history, for when the sub-
ject of economic damage from the loss of one eye was first preached,
the valuation of the two eyes was placed at 100, and one-half

92 DANGER OF BLINDNESS IN MONOCULAHI.S:\r.

or 50 per cent, taken off for one eye. There was no scler.-
tific ophthalmologic investigation of the question, and it was
believed that the factors for fixing the amount of an-
nuity or damage sliould be looked for mainly in the
philanthropic-philosophical and not in the ophthalmologic pro-
fessional sphere. Zeliender's (.53) 33 1-3 per cent, and Jatzow's
(19a) 40 per cent, are estimations ))ased upon psychic factors. The
executive boards of the insurance offices and societies generally pre-
fer a much lower indemnity (Moses 30, p. 23). It is very likely
that the present 33 1-3 per cent, rate will share the fate of the 50
per cent, rate and soon will be replaced by a scientific standard such
as we have given it. Our methods are based upon scientific principles
and give the workingman of all classes pro rata indemnity corre-
sponding to the amount of the damage to their working powers.
The employer certainly finds in our system a protection against un-
fair claims of the employed. The badly injured person is really
better off under our S3'stem, for our "total disability of earning" be-
gins with a visual acuity of below one-seventh to one-twentieth,
whereas the old system total disal)ility was when the vision was
under one-hundredth. It is, therefore, just and fair for both em-
ployer and employed.

§34. Conccrninr/ the Supposed Greater Danger of a One-Eyed
Person Becoming Totally Blind and Its Relations to In-
demnity.

Perhaps the reader, in our calculation of the impairment to
the earning al)ility, may have already missed any reference or con-
sideration of the ultimate blindness or of the greater danger of be-
coming blind for the one-eyed person, upon which has been laid
such stress by Zehender (53, p. 269). We do not consider, as he
does, that this danger under all circumstances is double that of the
normal person, for the risk is but little greater. For instance, the
most frequent cause of blindness 1)etween the ages of 15 and 45
years is atrophy of the optic nerve (Magnus 24, p. 24G) and from
45 to 60 it is glaucoma; but we must remember that it is the gen-
eral rule for atrophy of the nerve to be double-sided. The causes
of one-sided atrophy are very rare and are very different patho-
logically from the binocular ones. There is precisely the same dan-
ger from this disease. Zehender's philantrophic feeling brought
him in glaring antagonism to statistics. All he should have said
was, that the possilnlity of becoming blind in certain diseases and
especially in certain injuries of the eyes is greater in the one-eyed
person, for, when the normal human being loses one of his eyes by
an accident, he. of course, retains the sight of the other, Avhile the
one-eyed person in losing his one eye becomes totally blind. Theo-
retically there is nothing to be said against this conclusion, but prac-
tically it is not of much importance. Our experiences show that
but few one-eyed persons lose their other eye through an injury

DANGER OIT TOTAL BLINDNESS. 93

and, at an}- rate, these are so few that there is certainly not double
the danger of becoming blind. Magnus {2-iL, p. 184) states that
only once within the last eight years has he seen a one-eyed person
whose sound eye was injured by an injury ; a fact Avhich is surpris-
ing in view of the numerous losses of one eye of normal-siglited.
Wiirdemann, practicing in a manufacturing district where ocular
accidents are common, has seen but two eases of the loss of the re-
maining eye of a one-eyed person by accident within the last ten
years. The general experience of other practitioners will surely
support the above statements. We do not think that this question
should allow of additional indemnification in relation to fiffuring
the accident insurance or the annuity to be granted in any case to
workmen. Accidents to the remaining eye are more rare than to
persons who have two eyes, for in the first place they have learned to
be particularly careful to shield the remaining eye from injury and
to use it properly. We know one-eyed persons in many vocations,
in some of which the liability to ocular accidents is frequent, for in-
stance, workmen in stone quarries, in mines, in machine shops, etc.,
but we have never heard from any one that the concern about his one
eye hindered him in his profession. Complaints of one-eyed per-
sons are generally quite different and refer to disorders in judging
distances, etc.; often such persons, who try to exaggerate their in-
jury, use other means than the concern regarding their remaining
eye. We must, therefore, exclude the danger of becoming blind
under all circumstances; in calculating the impairment of the earn-
ing ability of the one-eyed person the question of sympathetic in-
flammation should be considered from the same point of view, but
this is so important that wo will treat it in a separate chapter.
(Chap. XVI.)

94 INJURIES TO LENS.

CHAPTER XIV.

§35. Accidental hijuries of the Crystalline Lens. Aphal-ia.

Tn injuries of the crvstallirie lens we have the peculiar condition
that as long as the injiin- lasts and the opaque lens stops the fur.c-
tiou of siffht. there is no doubt regarding the extent of the impair-
ment to the earning ability, but as* soon as the injured lens is
taken out by an operation which clears the pupil and vision returns,
then difficulties appear in the calculation. We have had occasion to
s-tudy many opinions and decisions in order to make satisfactory
judgment of the results of aphakia, upon the Avorking powers. If
one eye be normal and the other became aphakic through the loss O'f
the lens, the unequal refraction of both eyes renders the vision prac-
tically monocular, as the lensless eye is so hyperopic that a concert
of action of both eyes for professional use cannot be had; even
though the refraction be neutralized by convex glasses it cannot
work together with the sound eye. and the subject will always pre-
fer to dispense with the visual acuity on the lenseless side and work
with the normal eye. We, therefore, as long as the other eye re-
mains sound, regard one-sided aphakia in the same manner as that
of an individual having suffered important injuries to the visual
acuity Avhile the visual field and the muscles remain normal. This
assertion cannot be changed by the fact that eventually the visual
acuity of the aphakic eye mav be one-half or more; for if the in-
dividual cannot make use of this acquired acuity of vision in the in-
jured eye. his success in earning remains exactly the same as if the
visual acuity were not sufficient for use. Therefore we put mo-
nocular aphakia in the same position as the eye whose central acuity
is impaired to a high degree and reduced to 0.15 in professions with
higher, and to 0.05 in professions with lower ocular demands. But
we do not consider such an eye in the same relation as one which is
blind, for it forms, as Fuchs says (8a), "A reserve for the future."
But if the operative removal of the lens had not given a satisfactory
result regarding regaining good vision, such an aphakic eye would
not represent a prospective reserve for the future and should be con-
sidered as professionally blind. Thus the valuation of the relations
of the aphakic eye to the earning ability may be made upon sound
principles and with due regard to the individual peculiarities of the
ease. Tables T. and A^I. of part lY. give information regarding
the impairment of the earning ability in the case of one-sided
aphakia. The conditions are as follows : If an aphakic eye has a
visual acuity of 0.15 and over, in professions with higher visual de-
mands, and of 0.05 and over, in professions with lower visual de-
mands, and if the other eye remains normal, the impairment to the
earning ability would be 6.G9 per cent. But if the aphakic eye has a

APHAKIA. 95

visual acuity below 0.15 or 0.05, depending upon the character of
the vocation, tlie impairment of the earninu- ability would be in the
first case 21.9 per cent, and in the latter ca.se 18.3 per cent (tables
v., and yi.. part IV.) These figures may be reduced to 15.5 per
cent., depending upon individual circumstances. For instance, if
the injured person is young and gets along easily with the changed
ocular conditions, the lower figure may be chosen ; the employment
of the injured person, his mental capacity and other factors will
play a role in choosing the higlier or the lower figures. These are
all conditions which should be considered in every case and left to
the decision of the trade boards or the physicians. The foregoing
refers to cases Avhere one eye remains sound; but if a man loses a
lens and the uninjured eye was previously weak-sighted, the con-
ditions are certainly different. If the uninjured eye cannot be used
for working purposes, tiie aphakic eye has to be estimated as if the
individual had been one-eyed. We here start from the fact that
the impairment of the earning ability is determined bv the central
acuity of vision Avhich the aphakic eve has regained. If the origi-
nally weak-sighted and uninjured eye is still able to earn, we have
to regard, in the professional estinuition, the extent of the central
acuity which both eyes possess. The eye whicli is used and which
possesses the higliest degree of acuity must be regarded as nio-t
fitted for earning while the other should be regarded as excluded
from work on account of the difference in the refraction ; the calcu-
lation is then made according to the principles put down in Chan-
ter XII.

There are still cases possilde, and we know of such, in whicli an
individual who became aphakic on one eye through an accident lias
later lost the remaining eye through another accident. The calcu-
lation of the impairment of the earning aliility would then have
to start from the central acuity of vision of the aphakic eye
which is fully explained in tables Y. and VI.

96 IXJUKIES TO EYELIDS, ETC.

CHAPTER XV.

§3G. Injuries of the Eyelids, Conjunctiva and Cornea.

Traiiniatisms of the eyelids^ eoujimctiva and cornea may hinder
vision and their inflnence may he measured by the diminution of
the central acuity and the other factors of the visual act. We have
shown how burns may lead to extensive symblepharou and hinder
the ocular movements. In one case Magnus notes where the symble-
pharon was entirely relieved by operation, the eyelid remained thick-
ened, reddened and without eyelashes and the conjunctiva was read-
ily irritated. The disfigurement of the lower lid was such that the
patient could only get new work with difficulty and when he obtained
a job would soon have to give it up again, as the least irritation
produced a flow of tears which made continuation of work impos-
sible. Xotwithstanding that he had almost normal visual acuity
he had to be regarded as imj)aired for work. The valuation of such
a case had to be left entirely to the physician. We would here
warn against over-estimation of disfigurements ; it frequently hap-
pens that persons who hare lost one eye by a serious accident are not
satisfied with the annuity, indemnity or amount of insurance that
has been paid them and on account of disfigurement may claim a
higher rate, which in certain cases has been given to them. Mag-
nus does not consider such a course justifiable, for by his method
in the valuation of the loss of one eye, the disfigurement connected
therewith is already considered. We have done this in our previous
pages by giving the proper valuation in such cases to the ability to
compete.

DANGER OF SYMPATHETIC 0PHTHAL:MITIS. 97

CHAPTER XVI.

§37. Should the Danger of Si/ in pathetic Ophthalmitis he Consid"
crcd in Estimating the Impairment of the Earning Ability'?

The possibility of resultant sympathetic disease in the uuiniured
eye has been brought up many times in medical and trade assembly
circles and in the law courts in estimating the impairment of the
earning ability. A number of authorities have considered that this
factor was of considerable moment in allowing an increase of the
rating; especially if there is a foreign body in the eye there is
even a disposition to give these conditions an expression in the
amount of the rating. We do not think that this danger should
influence the amount of the impairment allowed of the earning
ability. The possibility of being insured against sympathetic in-
flammation should be undertaken by the laborer himself, the same
as one pays a premium for fire insurance, if it is to be considered
at all. Such a relation between the employer and the employed
cannot be thought of; but if there was positive danger of future
sympathetic inflammation it might possibly be considered in calcu-
lating the impairment to the earning ability, if it really exerts a
hindering influence upon the workman's powers ; for instance, if the
man has to be exceedingly careful not to heighten that danger or to
hasten the outbreak of inflammation and thus has to limit the
amount of work or his working hours, an addition to his annuity
or indemnification might be justifiable and these conditions should
be considered. But the factors which affect the outbreak of sympa-
thetic ophthalmitis are not to be looked for in the performance of
the work and are not favored through the uses of the eye connected
with working life. This has been shown by experience. The youth-
ful eye which has not been used very much in working seems to Be
more exposed to sympathetic ophthalmia than the older eye. The
danger of sympathetic ophthalmitis is greatest in the first few
months after the injury of the other eye. and then it materially
diminishes. From the oculist's standpoint, the danger of sympa-
thetic ophthalmitis cannot be regarded as limiting the earning
ability, for this danger may be entirely removed if the patient sub-
mits to the operation proposed by the physician.

98 ]NJl'I!I1;.S of the COIiXEA.

CHAPTER XVIL

§38. Injuries: of the Conica ThroiKjh Splinters of Iron or Foreign
Bodies.

Injury to the cornea through splinters of iron or emery is per-
haps the most common accident. Special ditficulties are not found in
applying our rules to such conditions. !Most frequently the cornea
is injured hy snuill particles of metal, and such cases arc common
in every oculist's practice and are of daily occurrence in ophthal-
mologic clinics. As a rule cases are immediately cured after re-
moval of the foreign hody and the little scars left are too insig-
nificant to exercise a detrimental influence upon the visual acuity.
Of course, many such accidents may have occurred and the cornea
be spotted with such small cicatrices, but in the course of time the
"workingman usually adapts himself to the increasing loss of vision
and does not feel the loss professionally. There are only excep-
tional cases that might be hindered in work by such accidents, and
the results are best estimated l)y the rules pertaining to the esti-
mation of the visual acuitv.

IMPAIRMENTS OF ACCOMMODATION. 99

CHAPTER XVIII.

§39. Accidental hiipainnoits of the Acconnnodation.

Loss of accommodation without other injuries of the eyes are
very seldom caused by an accident. They mostly develop from
serious contusions of the head, especially of the forehead, contusions
of the iris, etc., and are much more frequently one-sided than
double-sided. They may exist without changes of the pupil, but
usually there is mydriasis. Such injuries should not be allowed
lasting pecuniary compensation, because we are always able to
replace the lost accommodation by litting convex lenses ; and as the
accident insurance law does not indemnify the lost function itself,
but gives a pecuniary compensation only when the earning ability
has sufFered, the impairment of the accommodation is surely not
within the bounds of the accident insurance law, although claim for
small damages might be allowed. There are conditions which are
in favor of granting at least a small indemnity : for instance, if there
be one-sided paralysis of the accommodation as well as of the pupil,
thedazzling and the dimness of the images may cause inconvenience;
but these symptoms ultimately pass away, for the sul)Ject becomes
used to the condition, even though at first he is hindered by such
symptoms. One-sided paralysis of the accommodation may be reme-
died bv the use of convex glasses; if the injured person opposes
wearing these, it is his own look-out, for if he throws away his
chance to regain the lost function, by a little inconvenience like the
wearing of glasses, he should not have a right for an indemnifica-
tion based upon the loss of earning ability. Where there is loss of
accommodation, the individual character of the case should be con-
sidered by the physician, insurance companies and the courts.

100 OCULAR DISEASES.

CHAPTER XIX.

§40. Common Diseases of ihc Eyes of Local Oriyln That Impair
ihe Earning Power.

In addition to the subject of injuries to the earning ability
caused by traumatism, it has been deemed well to give a brief
resume of common diseases of the eyes of local origin that may
impair the earning power. In doing this we quote largely from
Hansen. (IT)

Acute inflammation of lids and conjunctiva being transitory
seldom leads to more than transient disability. The visual power is
decreased in proportion to their intensity. By reason of pain, swell-
ing photophobia and discharge, the patient has no earning power
during their continuance.

Chronic blepharitis and conjunctivitis without actually lowering
the acuity of vision, prohibit sustained near use and cut down the
number of daily working hours and proportionately the income.

Acute inflauimation of the cornea of one or both eyes totally
disables.

Chronic inflammation of the cornea of one or both eyes totally
disables.

Opacities of the cornea of one eye reduce the earning power not
more than 30 to ]8 per cent. (If one eye be rendered entirely
blind for economic purposes by reason of corneal opacity, it may be
treated as a case of monocular blindness, the impairment of the
earning abilitv for which ranges between 18 and 30 per cent..
Chap. XIII., § 33, p. 90.)

Opacities of the cornea in both e3'es reduce th2 earning power
according to the visual acuity.

Acute iritis of one or both eyes totally disables fnr periods of
six weeks or longer.

Chronic iritis with posterior synechia? reduces earning capacity
according to the visual acuity, modified by the number of working
days or hours according to the peculiarities of the case (50 per
cent, by Hansell).

Incipient cataract of one eye, no reduction.

Advancing cataract of both eyes reduces according to the acuity
of vision remaining and is subject to continuous retrogression.

Complete cataract in both eyes completely disables, but after
successful operation on one eye the case is relegated to the catgory
of refractive cases. The earning power is restored according to
the vision regained for far and near. Hansell cites a patient
operated upon for cataract who stated that his earning power had
been gradually reduced from $18.00 per week to nothing. For sir

OCULAPv DISEASES. * 101

mouths after cataract extraction his vision had equalkd 20 jc and
he had earned $9.00 — 50 per cent. loss. Lately he has vision with
a new correction 30|xv and has been able to command his old
wages.

A^itrcous opacities of one eye do not decrease the earning power,
nnless due to the presence of a foreign body causing irritation and
photophobia preventing full working hours, with danger of sympa-
thetic ophthalmia.

Vitreous opacities of both eyes decrease the earning power ac-
cording to the visual acuity plus the liability to total loss, which
juay be estimated at 50 per cent. more.

Detachment of the retina spontaneously or in myopia of one
eye'may be reckoned as total loss of that eye plus the probability
in the latter of total loss and total disability. Spontaneous or idio-
path.ic detachment of the retina of one eye is rarely followed by a
similar affection in the other, hence the probability of total loss is
le?s. 'I'he contrary pertains, however, where it follows as a conse-
quence of scleral stretching and chorioidal atrophy of myopia, whtn
the earning power is seriously menaced. The choice of occupation
is rendered difficult, since those demanding prolonged near use of
the eyes and straining and stooping positions must be declined.

Other diseases of the retina, the result of purely local causes and
limited to one eye, do not decrease the earning power.

Double central retinal chorioiditis reduces the earning power to
that of the average laborer, although the periphery of the fields
may be intact. Exceptions must be made when the earning power
depends upon intellectual rather than ocular acuteness.

Constitutional, acquired, or hereditary ocular disease, such as
albuminuric retinitis, retinitis pigmentosa, tubercular choroiditis,
syphilitic affections of the cornea, iris, vitreous and fundus tissues,
optic nerve atroph}', progressively reduce the earning power in
direct proportion to the loss of vision until the patient's death or
total disability.

Congenital color blindness debars the individual from army,
navy and railroad service, but from few practical pursuits and only
by limiting the selection of occupation does it interfere with his
earniug power. The estimate of the degree is purely arbitrary, but
probably does not exceed 1 per cent.

We compute (Chap. IX.. § 19, p. 58) the loss of earning
power from peripheral limitation of the fields thus :

Loss of 30 degrees Xo loss of e. p.

Loss of 40 degrees 20 per cent, loss of e. p.

Loss of 60 degrees 45 per cent, loss of e. p.

Peripheral limitation of one field only entails loss of e. p. of
10 per cent.

In homonymous hemianopsia Loss 30 per cent.

In bitemporal hemianopsia Loss 20 per cent.

In binasal hemianopsia Loss per cent.

102 OCTLAR DISEASES.

Diplopia from monocular paralysis irremediable by prisms but
removed by occlusion of one eye brings the patient into the category
of the one-eyed, but since a variable amount of time must elapse
before the individual is able to resume his previous occupation and
to regain his old skill, he suffers a loss during this time of his earn-
ing capacitv of 18 to 30 per cent. (/. c, economic monoculism is
produced; see Chap. XIII., § 33, p. 90).

Paralysis of associated movements and double complete ophthal-
]noplegia externa completely disables.

Errors of refraction deserve but scant attention in this paper,
since they are for the most part remediable, and the individual is
subjected to the annoyance only of his dependence on spectacles for
the full nse of his eyes with good vision. This is an inconvenience,
but does not decrease the earning power except as applied to a few
occupations. In the absence of disease persons with any kind of
regular defects can be restored to full earning power. In the case
of an incorrectil)le accommodative and muscular trouble by which
an individual is incapacitated from the full nse of his eyes, the loss
of earning power vrill equal the number of hours daily that he is
unable to work and may be estimated at 50 per cent, of his full
capacity. Conical cornea and irregular astigmatism not being sub-
ject to full correction by lenses diminish the earning ability accord-
ing to the loss of visual acuity.

Foreign bodies in the interior of the eye totally incapacitate for
a variable numlier of weeks and are in the great majority followed
by the loss of the eye. If removed before the stage of chronic irri-
tation sets in and the danger of sympathetic ophthalmia is not pres-
ent, the individual goes into the list of the one-eyed. If allowed
to remain the earning power is lessened 25 per cent, and in many
cases finally 100 per cent.

Foreign bodies in the cornea are readily removed usually with-
out permanent cicatrices. Before extraction the earning power is
reduced 100 per cent. The sudden loss of one eye incapacitates to
greater degree for a time than the gradual loss, because the indi-
vidual loses all judgment of space and he requires time to learn
anew the relation of objects to each other and their size and shape,
since the mental conceptions are changed. Among the trades that
require the higher grades of vision the damage to the earning power
in the gradual loss of one eye is 22 per cent., in the lower 18 per
cent. Zehender (54) says that after the loss of one eye only two-
thirds of the earning capacity remains. ]\Iooren (29) adds to this
the loss of binocular vision 8 to IG per cent., according to tlie dan-
ger of the occupation.

PART THIRD.

Estimation of the Pecuniary Loss to the Individual by
Reason of Visual Imperfections.

104 WAGES AND AGE OF W0I!K:\IEN".

CHAPTER XX.

§-il. Estimation of the Pecuniary Loss to the Individual hij Rea-
son of Visual Imperfections.

In the foregoing we have estimated the economic damage in the
form of percentages. Xow it remains to apply these ratings to the
conditions met Avith in daily life.

Money being the world's medium of exchange and of valuing a
man's work or time, we must reduce the economic damage in each
individual case to its value in dollars and cents or the monetary
medium of the country in which the compensation for damage may
be sought. It goes without saying that the value of men's time and
wages differ greatly, not only in different trades and professions,
but even the various members of the same trade receive varying
wages.

If we wish to exactly estimate the damage to the individual case,
we must, therefore, figure with the compensation that the individual
himself has heen getting and his probable future earnings. It must
bo allowed that this may be done in the case of artisans and the
working classes generally, and that this estimate may be legitimately
used as a basis with which to calculate the pecuniary loss he may
sustain by reason of lessened working and earning ability. In the
case of professional and business men, who do not receive regular
wages or a stipulated income, it might be considered. strict justice
to the defendant to take the average earnings of the class to which
the plaintiff may belong as a basis upon which to figure the in-
demnity.

It should be likewise considered that an old man cannot lose (as
regards earning ability) as much as a younger man, for the elder
has fewer prospectiveyearsof employment and consequent less money
equivalent than the younger. Thus the age of the plaintiff should
always be considered. It may likewise be taken for granted that the
average earning life begins at 15 and ceases at 65 years ; that in the
case of a business or professional man the wages will be doubled
every tenth year until cessation of working life ; that in the case of
working men this doubling will occur for the first two periods of
five years and afterwards the usual rate will be maintained until at
the age of 50, and 15 years thereafter though competition of younger
men and natural infirmities of this period of life then will be a
certain reduction in the wages. Exceptions to this estimate must
be made in the case of girls and women, since their working years
are fewer and their increase of earnings does not follow the same
rule as' that of men; many, perhaps the majority, being employed in
shops, mills and offices and in such positions that increase of skill
and experience are not rewarded by increase of their income.

AGE SCALE. 105

Hansell assumes (1?) that a professional or business man will
double his earnings every ten years, provided his mental and physi-
cal health is preserved, and that he has average intelligence, in-
dustry and ambition. He considers that when the earning jwwer
of the individual falls below GG per cent, of the average earning
capacity, that promotion with increase of income cannot be reckoned
and that when SO per cent, of the visual power is lost the man is
no longer in a position to earn the income that was his before, and,
therefore, not onlv receives no increase, but his wages thereafter
may diminish; and if vision be reduced to counting fingers at 1-3 m.
(Magnus 0.15 to 0.05) the loss is 100 per cent., the individual
earning nothing and also becoming a charge upon his family or the
community. The doubling of the earnings for each decade maybe ap-
plied as a principle to most business and professional men, but in the
ease of laborers and artisans, who receive no promotion after having
attained a certain grade, it must be modified in respect to the
doubling of wages or income every tenth year. This permits of a
decided simplification of the computation, for as Hansell says : (17)
if a man earns $20.00 a week, and will continue to earn that amount
during the remainder of his working years, his loss will depend
upon the age at which the incapacity begins and its degree.

The following table, which agrees roughly with the mathemati-
cal estimations of ^lagnus, has been empirically figured by Hansell :

Visual Acuity. Loss of Earning Capacity.

^%0

Y or 20 per

cent,

2«/^0

Y " 33

^5^00

Y " 50

-%60

Y " 66

20/
/200

Y " 80

^00

4.75" 95

ling fingers at Y m.

Y5 " 100

By adjusting Hansell's age scale for the pecuniar}' earnings to
the estimation of the actual damage figured by the method of Mag-
nus we may arrive at an exact mathematical estimation of the
economic damage to the individual for the loss of vision in any
given case. In the following tables we give the earning power in
dollars and cents for the five decades of earning life.

Table C is adapted for the professional and businesss class
whose earnings as a rule increase until their retirement from busi-
ness.

Table D is for the artisan classs whose earnings remain about
the same during adult life and at the end of the working period
are usually subject to decrease.

Table E is for the laboring classes whose earnings are subject to
much the same law as that of the artisan.

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EXCErTlONS TO 01" H RULES. 109

In cases where ihe blame of an accident may be laid upon the
second party or where, through previous business agreement, an
employer or insurance company has arranged to pay a fixed sum or
a pension in case of accidental injury, the amount of the indem-
nity should be in accordance to a definite schedule based upon the
average wages in the vocation to which the individual may belong.
It should be remembered that partial loss of vision not exceeding
25 per cent, in vocations having higher visual demands and not
exceeding 50 per cent, in those with lower demands does not injure
the earning ability to any degree. Indemnity, for actual disability,
therefore, should be granted only those whose eyes are damaged be-
yond reparation to a greater extent than above named.

It is only in vocations that have visual requirements that a
close estimate of these visual values may be made. In those classes
of business life whose followers are not engaged in manual labor,
whose business capacity relies more upon brains than iipon actual
handiwork, our rules cannot always apply, for even a lalind man
could work with monetary advantage in some trades and business ;
biit for the laborer, for the artisan and for those professions in
which the visual perceptive faculties are necessary, our rules and
tables may be deemed fitting. By adjusting the age scale for the
pecuniary earnings, to the percentage of the actual damage as fig-
ured by the method of Magnus, we may arrive at an exact mathe-
matical estimation of the economic damage to the individual for
the loss of vision in any given case.

It may be well to discuss the value of vision. This may be
summed up in one sentence, "'Sight is priceless, and, lil'e lionor, is
not a marl-etnhle commodity." Even the mere perception of light is
of inestimable value to a person who is economically blind and its
value to him cannot well be calculated. Does this fact conflict with
our propositions ? We do not think it can be considered, as we are
not dealing with any arbitrary value that might possibly bo placed
upon the sense of sight, but sole!}' with the earning capacity
of the eyes, which has to do with the amount and quality
of remuuerative work and the duration of working life. Can we a]i])lv
our rules to the case of non-workers, for instance, to infants, chil-
dren and those whose business does not require eye siuht, or can we
figure upon the ambition or possible prospects of advancement in
any other profession than that in which the person is employed?
It is self-evident that we can not. For instance, one of the children
in a family may some day become a millionaire, whereas one of his
brothers may ever remain a common laborer. There is no means of
foretelling the future . AVe can only figure with facts, and thus our
rules and estimations are based upon the compensation of th':'
person before the accident, and this is the only proposition that can
be received. Indemnification in the case of loss of sight from acci-
dents in children, in the majority of women, in persons who are

110 VALUE OF SIGHT.

working hut U'lnporarily at some vocation, who ex{)eft to enter
another at some later period of lite, will have to he given, as here-
ioJ'ore, by arbitrary decisions of the courts. Such reasonings are
the common rules of bnsiness ; for instance, a man who has no in-
come whatever and can offer no collateral would l)e refused a loan
of money by any bank or business corporatii n. and could not obtain
any money except as an act of charity or for some extraneous reason
foreign to the rules of business. A ])erson with a small income,
for instance, earning $1,000 a year, would be able to borrow a cer-
tain small amount, for instance, $100, but another ]>erson earning
$10,000 a year would be able to borrow a vastly greater amount
upon his prospects. Thus for business reasons we can only con-
sider actual Avage earners to come under our rules. As accidental
injuries involving compensation for damages happen in a very large
majority of cases to persons of this class, all others may be looked
upon as exceptions and such cases may he left to be treated froiu
the philanthropic standpoint.

"While by this method of reasoning we are enabled to exactly es-
timate the amount of money that a given case may reasonably ex-
pect to earn provided he remain in the same business and exercise
ordinar}^ skill and diligence and hence accomplish an average
amount of work, it must be admitted that such figures are hypothet-
ical. However, such immense interests as those of the modern in-
surance companies and many other sociologic standards are success-
fully based upon the same principles and we must here be allowed
to use them. The result to be achieved by all our computations is
not the exact amount that a man will earn, but that which he may
reasonably expect to receive for his labors.

§42. Examples.

We will now take up some specific examples to illustrate the ap-
plication of our methods for determining the amount of economic
damage to the individual from ocular injuries.

Example 1. For our first example Ave take a case that often
comes up in the courts of law. An artisan whose business has high-
er visual demands, Avho has previouly had nornuil vision, receives
an injury to one eye Avhile working at his trade, by which the sight
of the injured eye is wholly lost, the vision in the other remaining
normal. The question then arises. Avhat economic damage has this
man sustained ?

We have shown that in the higher class of trades, during the
first year folloAving the accident, a one-eyed person has lost 30 per
cent, of his earning ability and afterAvards the loss may be reckoned
as 20 per cent. As a matter of convenience Ave Avill suppose that
this man is injured at the 30th year of age. and that he has been
■earning for the previous five years $1,000.00 a year, Avith the expec-

KXAMI'LES. Ill

tation of earning this sum annually until he is 50 years of age, when
for the next 15 years his average earnings, on account of disabil-
ity, due to a^e and the competition of younger workmen, will fall
to $750.00 a year and his working life is to cease at G5 years. His
total earnings for the balance of his life would then be reckoned
as follows : 20 years at $1,000.00 a year; 15 years at $750.00 a year ;
total, $31,250.00. For the first rear after the accident instead of
earning $1,000.00 he may expect a loss of 30 per cent. ($300.00)
and for the following nineteen ^ears instead of $19,000.00 he would
lose 20 per cent. ($3,800.00) and the following fifteen rears in-
stead of $11,250.00 he would lose 20 per cent. ($2,250.00)', making
a total loss for the thirty-fivo years of working life of $6,350.00.
which is his personal economic damage, an amount which he might
reasonably demand as an indemnity for the loss of earning ability
due to the accident if liability of the emplo3'er or djcfendant could
be proven. This sum should be used as the scientific basis for
settlement of contested cases : modified according to American laAV
by a reduction being made in favor of the defendant in case of
extenuating circumstances or contributory negligence and an addi-
tion made thereto for actual expenses incurred by the plaintiff dur-
ing his illness and damages for the pain and anguish suffered by
reason thereof. These amounts must ahvays be empirically esti-
mated by the courts.*

ExAiiPLE 2. If this man were injured at the age of 40 the same
method of calculation would give him a prospective compensation
of $21,250.00 for the balance of his earning life, instead of which,
for the first vear he Avould receive $700.00, for nine vears more,
$7,200.00, and for the fifteen years following $9,000.00; making
a total economic value of $10,900.00, a resulting economic damage
of $4,350.00.

ExA:\rrLE 3. If this man were injured at the age of 50, instead
of his prospective compensation being $750.00 per year for fifteen
years, or $11,250.00, for the first year after the accident he would
be earning 30 per cent, less, or $525.00, and for the following four-
teen years 20 per cent, less, or $8,400.00, making total economic
value^f $8,925.00 and total economic damage of $2,325.00.

By the use of different rates of compensation and different years
other examples could be readily given. The same method of rea-
soning applied to the loss of one eye in case of an artist or other
professional man would yield proportional results. The only dif-
ference in the calculations would bo the fact that such professions
usually become more remunerative as the person grows older. In
the ease of the common laborer, the only differences would be the
lower rate of compensation and the figuring of his economic loss

•Seven thousand doHarn has lieen recently awarded in Texas for the loss of an eyi-.
Court Civil Appeals Texas, I'.iOl, De La Vergne RefriK'-ratin^i Mafhine Co. vs. Stahl.

112 LXA^IIT.KS.

at 20 per cent. I'or the first year after the accident and IS per cent,
thercal'ter.

We will now cro on to the calcnlations involved in more complex
cases where the same principles arc to be used as those which have
been invoked for simple cases :

Example 4. AVe will take the case of an architect or draufi:hts-
man, in his 46th year of life, earning $3,000.00 a year, whose visual
acuity in one eye is reduced by an accident to 0.50, the other re-
maining normal. His profession demands good vision and he is in a
measure handicapped for some of his work, especially that of fine
draughting. We will proceed to work out this case from the be-
ginning and will, therefore, recapitulate our formula:

In this case the maximum remains unchanged because this is
the higher visual acuity of the sound eye=l. V^ p the visual field,

and y M the muscular action remain unchanged ; the three factors
each representing the value I. In this case the unknown quantity
is the ability to compete.

'^'■p'-yYVM.

' — - — ~- being the aritlimelical proportion of the central visual

acuity of both eyes. Ci,the uninjured eye remains = 1; Cs the in-
jured eye should be reduced to 0.50 of the scientific value 0.5, of
the scientific standard. Looking now on plate I. on the absciss for
the scientific value 0.5, trace this line upwards until we meet the
ecnomic curve II. which is for vocations having higher visual
demands, and from the point Avhere the line cuts the curve
we go to the left and find there on the ordinate the economic value
of the scientific estimation for the acuity of vision. This is 0.58;
inserting this value into the arithmetical proportion of the acuity

i. 1 .1 . , C, + C, , 1 + 0.58 ^ ^n rri •

for both eyes, into ' we have =0.79. This we m-

sert into the factor \ ^^^ V P V M : we then have

. f 0.7^

9 VYVIa

EXAMPLES. 1 13

in which V P and \ M are each ^=^1 ; the whole value is then

0.79 X 1 X 1.

As this is a slight injury, the ahility to compote is only

partly impaired, so we make tiie root exponent X=10. Tliis value
1(1

V 0.79X1X1 'wo can find in phite II., curve Y., where we look on

tlio absciss for the value 0.T9, trace the line from there upwards

until we meet the curve Y., going from there to the left oa the

ordinate we find the vahie 0.972. If we insert this value into the

formula we would find E=1X1X1X0.972, which multiplied by 100

gives the earning ability E = 97, 2 "b. This man being injured at

his 46th year, he would expect to have earned $00,000 during the

next twenty years. His earning ability being reduced to 97.2 ])er

cent, he would probably earn $58,320.00, which subtracted from the

reasonable expectations of his business, would leave the sum of

$1,680.00, an amount which he might expect as the indemnity for

the loss of earning ability due to the accident.

Exa:n[ple ."). Ir. the case of a printer who was originally weak-
sighted ; the vision of one eye ni = 0.05 and the other n; = 0.55
(scientific standard) ; eye 1 being uninjured (ci=0.05) while the
visual acuity of the other has been impaired by injury to c-.= 0.20.
He is in his 26th year and has been earning $1,000.00 annually and
would reasonably expect to earn this sum for the next 25 years,
after which his earnings through disabilities of his age, slow-
ness and consequent inability to compete would probably depreciate
to $750.00 a year, making the balance of the money that he might
reasonably expect to earn in the course of his life $36,250.00. Fig-
uring out the earning ability according to our modified formula :*

Cl „ „_ 0.65 r~-

Ci = n = 0. / o „ „^ = 0. ( o.
Hi 0.6o

c> 0.55

c, = n — =: 0.75 ':^ = 0.27,

n.. O.oo

the maximum ci=Ci =0.75 while we get for the maximum of the
real acuities e,„ax. = Ci = 0.65. The first value should be replaced
professionally bv 1 according to table B, p. 42 : the second bv
0.83

•These numbers are found by referring to table r>, part IV without calculation,
coiiiplicatetl cases as these (Cases 5 and ti) wouid be rarely found ia practice.

114 KXAMPLKS.

To Ciandcai'iiriiishcs us tlie quniitity K, '=77. 079, the earning
aliilitv is tliereforo:

c'_.XE'_lX77.079_

cmax. " 0.8333 -•'^•^^'^-
or a permanent disability of 7.505 per cent. The amount that be-
fore the accident be niiglit reasonably have expected to earn during
the balance of his life is $oG,"-50.00, 7,505 per cent, of wliich would
give $2,720.50, which should be the highest amount allowed as in-
demnity for the permanent loss of earning ability due to the acci-
dent subject to reduction for cause and to increase as determined
in Example I.

Example (>. In the case of a la])oi-er who was originally blind
in one eye, the other being weak-sighted (nr=0.45), Avho at the age
of 40 years suffered an injury to the seeing eye, and there remains
only a visual acuity ofc-2=0.25, because ci=0 has to be used, there-
is c,„ax. = C2= 0.25 (professionally = 0.444 . . .) and the modified
acuity of vision Ci=0, the iiiaximum of both values will be:

c/ = n -^= 0.50 JJ-t^ = 0.28
R'i 0.45

Avhich correspoiids professionally with the figures:

100 + 0.28 — 5 ^^,,

45 ^^-^^^

To Ciand Cj belong, according to })late II.. or l)y calculating the root

Ei= 39.582; the earning abilitv is thertd'ore:

^ c„„...E' 0.511 . . . 39.582 ,„.„
E = = r^ , 4 , = 40.519

C ,nax. 0.444

the loss of the earning ability being 54.481 per cent. At the age of
40 years he would be earning $800.00 per year and might reason-
ably expect to earn this amount for 10 years, after M'hich, owing to
physical infirmities and increasing age, his earning powers \vould
probably be less, being reduced to $000.00 per annum; he would,
therefore, expect to earn, if he had remained in good physical
health, the sum of $17,000.00; after the accident his earning powers
being reduced to 45.519 per cent., he would be justly entitled to an
indemnity in proportion, which would be 54.481 per cent, of $17.-
000.00=$9,2G1.77, which would be likewise subject to increase or
decrease according to conditions of the accident as established by
Jaw.

ExA;MrLE 7. A traveling salesman, 45 years of age, who re-
cently consulted me had bi-nasal hemianopsia with a remaining
central acuity of 0.20 i]i both eyes. He stated that he had this con-
dition for a number of years and was enabled to do all his work
satisfactorily until recently when the visiuil acuity had failed, from
what he previously thought was normal, to 0.20. He was now able
to get about and sell some goods, but largely from memory, as he

EXAMl'LHS. 115

could not read Ids biisincs.s catalogues and letters, and was about to
give up his business entirely. His income depended upon sales made
and was about $2,00U.00 a year. Thus for the balance of his work-
ing life his expectations would be for 20 years at $3,000.00 a year,
amounting to $40,000.00. According to his experience he was able
to do all his work until the visual acuity failed and we have
shown (page 60) that nasal hemianopsia does not necessarily in-
cur earning disability. Therefore, we Avould figure his economic
damage from the amount of the reduction of the visual acuity; the
scientific standard, 0.20, would have an economic equivalent of
0.38. Ileasoning from this economic loss of acuity and inserting
same and working out the formula, we find that the value of his
economic powers is about 30 per cent., Avhit-h lias a pecuniary valu-
ation of $600.00 ]ier annum, which agrees fairly well with his les-
sened expectationt^ of earning if his vision should remain as it is,
l)ut if it furtlier deteriorates he will be totally incapacitated.

Example 8. In the case of an iron moulder -iO years of age
receiving a blow upon his head which laid him up from work for a
year and caused permanent homonymous hemianopsia. From the
<^ffects of the accident, he being laid up for a year, afterwards being
obliged to take a lower position in the same line of work, which
])aid him about one-third less, wo would figure his theoretic loss by
means of table on page 61 as 31.i) \h'v cent., which agrees near
enough M'ith the actual conditions of his work, for he was previously
earning $4.00 a day and afterwards was enabled to earn but $2.75
a day, the total economic damage can 1)e readily figured in this ca^e
as in the foregoing.

Examples of such character might be multiplied and cases cited
from the most simple form to that of the most complicated char-
acter. The foregoing are surely sufficient demonstration of the
fact that the percentage of economic loss and its pecuniary equiva-
lent in any given case of ocular injury, may be readily ascertained.
The diagrams and tables offer an easy method for this mathematical
calculation. In but few cases will it be found necessary to figure
out the formula in full, for reference to the proper table in part IV.
will at once give the percentage of earning ability. The relative
values ot the visual acuity, tlu^ \isnal Held and the ocular muscu-
lature must certainly be estimntcil liy a scientific examination of
tlie eyes, preferablv liy nii Dculist : tbese having been obtained the
other factors, the age and business of the workman and his wages
may Ix^ introduced into the formula and the probable pecuniary
]iersona1 damage therel)v r(>adily calculated. Competent practi-
tionei's of law or medicine oi- insui-ance officials mav by thcs >
methods determine with exactness, in a nuinner fair and just to all
parties, the amouni of damage to the earning abilitv of their clients
which may have occurred as a result of accidental injuries to tlio
eyes, and this should be <-(»nsidei-ed tlie ]irinci]-yal factor in the settle-
ment of le<ral claims.

PART FOURTH.

Tables for Estimation of the Different Forms of Damage
to the Visual Earning Ability.

Tables I to VI. Injuries to the Visual Acuity.

Tables VII to IX. Injuries to the Visual Field both Uncomplicated and
Complicated with Damage to the Visual Acuity.

Tables X to XII. Uncomplicated and Complicated Damages of the Ocular
Muscles.

Tablfs XIII to XXII. Various Forms of Damage in Monocularism.

Earning Ability and its Impairment. One Eye Normal, the
Other Injured but not Blind.

TABLE I.

Vocations with Higher Visual
Demands.

The full professional visual
acuity corresponds with the scien-
tific standard 0.75; the ability to

compete is figured with Y until the
\nsual acuity falls to 0.15, then

with ] or y.

TABLE IL

Vocations with Lower Visual
Demands.

The full professional visual
acuity corresponds with the scien-
tific standard 0.5; the ability to

compete as figured with y until
the visual acuity falls below 0.5,

10 7

then with Y or Y-

Degree of

learning

Impairm't

Degree of

Earning

Impairm't

Scientific

of Earning

Scientific

of Earning

Acuity.

Ability.

Acuity.
1—1.50

Ability.

1—0.75

100

0.0

100

0.0

0.70

99.5

0.5

0.45

99.4

0.6

0.65

99.1

0.9

0.40

98.8

1.2

0.60

98.6

1.4

0.35

98.1

1.9

0.55

9S.1

1.9

0.30

97.5

2.5

0.50

97.6

2.4

0.25

96.7

3.3

0.45

97.1

2.9

0.20

96.0

4.0

0.40

96.6

3.4

0.15

95.1

4.9

0.35

96.0

4.0

0.10

94.2

5.8

0.30

95.4

4.6

0.05

93.3

6.7

0.25

94.7

5.3

If the acu-

0.20

94.0

6.0

ity falls be-

84.4

15.6

0.15

93.8

6.7

'low 0.05

If the acu-

without

81.6

18.4

itv falls be-

84.4

15.6

blindness.

low 0.15

without

78.0

22.0

blindness.

*In the German editions of Magnus' work Dr. Hugo Ilohr has carried
out the calculations to the thousandths of a per cent. The figures are too
conaplicated for practical use, and as our calculations are dependent large-
ly upon probabilities which are more or less variable, the American editor
has only accepted the calculations to 1-10 per cent, as jirinted in the follow-
ing tables; where there would be a fractional remainder less than 0.1 per
cent, it has been added to the amount of the impairment: on account of
this simplification the figures are slightly different than those in the II
•German Edition.

Earning Ability and its Impairment, One Eye Bliod, the
Other Weaksighte<L

TABLE III.

Vocations -with Higher Visual Demands.

Full acuity of vision 1, corresponds with the scientific standard
0.75, and the ability to compete is figured with V.

Visual Acuity of

■

Impairment

lieduction Per-

the Weaksighted

Earninp: Ability.

of the

niiesible After

Eye.

Earuing Ability.

One Year.

0.70

62. 2

37.8

29.7

0.65

55.5

44.5

37.3

0.60

48.9

51.1

44.7

0.55

42.4

57.6

52.0

0.50

36.1

63.9

59.1

0.45

30.0

70.0

66.1

0.40

24.1

75.9

72.7

0.35

18.4

81.6

79.1

0.30

13.0

87.0

85.2

0.25

8.0

92.0

90.9

0.20

3.5

96.5

96.0

0.15

0.0

100.0

TABL

.E IV.

■^

/ocations with Low

er Visual Demands

Full acuitv of vision 1, corresponds with the scientific standard

0.50, and the ability to compete is figured with V.

Visual Acuitv of

Impairment

Reduction Per-

the Weaksighted

Earning Ability.

of the

missible Aft^r

Eye.

63.5

Earning Ability.
36.5

One Year.

0.45

28.6

0.40

54.5

45.5

38.7

0.35

45.7

54.3

48.6

0.30

37.1

62.9

58.3

0.25

28.7

71.3

67.6

0.20

20.7

79.3

76.6

0.15

13.0

87.0

85.3

0.10

5.9

94.1

93.3

0.05

0.0

100.0

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ENTIFI
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ISUAL
CITITY.

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TABLE VII.

Earning Ability and its Impairment in Disorders of the Visual Field with Nor-
mal Central Visual Acuity.

VARIETY (^F DEFECT.

fcc .

03X3

f Partial defects in one field ■]

I Concentric contraction of the field of |

1. { one eye i
I Loss of one temporal half of one eye |
t Loss of the full field of one eye J

( Small concentric contraction of both )

2. j fields reaching to 60° (
( Loss of the temporal half of both fields S

3. Hoinonymous hemianopsia dextra veJ

sinistra, superior vel inferior

4. Great concentric contraction of both

fields reaching 30°

5. Total concentric contraction of both

fields reaching to 5 per cent.

g ( Loss of the nasal halves of both fields }
■ ) Loss of the nasal half of one field »

90.4

80.0

68.3

54.6
0.0

i— I o.S

9.6

20.0

3L7

45.4

100.0

1 100.0 0.0

TABLE Vila.

Ability to Compete and Impairment of Visual Fields for Vocations with Higher
and Lower Visual Demands, Figured Separately.

Case.

RemainiDg

Fraction

of P.

K figured with \ for

Higher demands (for
more serious injuries)

K figured with V for
Lower demands (for
more serious injuries)

^ . Impairmeut
Earning ^f the Earn-
Abihty. ing Ability.

Earninp;
Ability.

Impairment
of the fram-
ing Ability.

1
2
3
4
5
6

'A
'A

89.6 10.4
78.4 21.6
65.9 , 34.1

51.7 48.3
100

100

90.1

79.3
67.2
53.3

100

9.9

20.7
32.8
46.7
100

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TABLE X.

EarDing Ability and Impairment from Non-Complicated Disorders of the Exter-
nal Ocular Muscles.

G - «

^ ) > CD

KIND OF INJURY.

o o

o t>,.S

1—0.75

Paralysis of the muscles of only Resp.

one eye 1 1 — O.oO

Paralysis of the muscles of both 1 — 0.75

eyes; in the working eye only Resp.

one muscle is paralyzed yf. 1 — 0.50

Paralysis of the muscles of both I 1 — 0.75

eyes; in the working eye two Resp.

muscles are paralyzed ;K 1 — 0.50

Patalysis of the muscles of both I 1 — 0.75

eyes; in the working eye three Resp.

muscles are paralyzed ^ 1 — 0.50

Paralysis of the muscles of Ijoth 1 — 0.75

eyes; in the working eye four Resp.

muscles are paralyzed 'yi 1 — 0.50

Paralysis of the muscles of both 1 — 0.75

eyes; in the working eye five Resp.

muscles are paralyzed j^ 1 — 0.75

Paralysis of all the muscles used 1 — 0.75

by both or bv the working Resp.

eye .". , 1—0.50

75.4 24.6

71.8 28.2

67.5 32.5

62.3 37.7

55.8 44.2

46.1 53.9

0.0 100.0

1
<

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to
CO

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c<i •.-H o cc CO CO

C<) <M (M ■— — ^

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CO i>^ id CO T-I |>I

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0.45

CO TT lO -^ O lO

id co' — <' ci CO ^

CO CO CO -M (M (M

0.50

t^ CD CO -^^ GO ""T

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0.55

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id (N d id d co'

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0.65

i>. r-- c<i o CD t>-

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t^ -^ O lO OS 1-t

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CO CO CO CO (M (M

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t^ ^ „ t^(M ^

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CD CO to to ■^ -^

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TABLE Xllla.

Earning Ability and Impairment if the Injury of One Muscle has to be Valued
Correspondingly Higher, in Special Vocations.

a
"S

■

K figured with >' (higher de-
mands, only for more seri-

K figured with V'
mands, only

(lower de-
for more

t-i

lous nijunes.

)

serious inj

uries.)

1—1
02

■<3

o
<v

Earning
ability.

Impair-
ment.

Earning

ability.

Impair-
ment.

■
69.1

30.9

72.6

27.4

65.5

34.5

68.9

31.1

61.2

38.8

64.7

35.3

56.2

43.8

59.6

40.4

49.7

50.8

53.1

46.9

1 /

40.4

59.6

43.5

565

•

100

bX)

(X ^

I -"-^

<i» IS

C •-;

O -2

X >

PQ o

< 3

6 s

^ c

< .2

C TS

<-> c

W _

1—1

o o
o2

o
d

id id

0.25

11.6

88.4

0.30

CO 1-^
1-1 GO

26.7
78.3

o
d

34.9
65.1

0.45

43.5
56.5

0.50

52.3

47.7

61.4
38.6

70 8
29.2

0.65

CO tr-

- dc5

00^-

o
I-

90.0
10.0

-d

1—1 o

rt G
Wh^

CU ^

fcC

< :3

Q i:

E -^

u
J

c
a:

•-J

,S2 'iJ .S

o o
d2

0.10

8.1
91.9

^GO

8
d-

28.4
71.6

0.25

lO lO

d d

CO CO

0.30

T-;d

0.35

05 i-H
CO CO

o -
d

-<t CD

CO 1-1

-»J

l-H

TABLE XVII.

Earning Ability and Impairment in Disturbances of the Visual Field of an Orig-
inally One-Eyed Person.

One-eyed condition in a One eyed condition in a

professional sense. scientific sense.

Proliepsioual visual de- rrofessional vifcual de-

Variety ok De- ^13

mands, mands.

FECT OF ^ IS- ^ ^

UAL Field. S ^

Hig

her. Lower. Higher. | Lowt'r.

i5S

Visual Acuity.

1—0.75

1—0 50

1—0.50

1—0.75

1-0.75

1—0.50

1-0.50

E'rning
\bility.

[mpair-
ment.

E'rning
Ability.

Impair- E'rning
nient. Ability.

Impair-
ment.

E'rning
Ability

Impair-
ment.

Loss of the na-

sal half, K

75.5

24.5

75.5

24.5

73.6

26.4

74.6

25.4

Small concen-

tric contract'n

67.7

29.3

70.7

29.3

68.5

31.5

69.8

30.2

L088 of tlie tem-1

poral half, |
Great concentric 2^

contraction, ^

reaeliing; 30°, J

60.4

39.6

60.4

39.6

57.7

42.3

59.2

40.8

TABLE XVIII.

Earning Ability and Impairment in Disturbances of the External Ocular Muscles
of an Originally One-Eyed Person.

One-eyed condition in a One-eyed condition in a
professional sense. scientific sense.

VARIETY OF

Professional visual de-
mands.

MUSCULAR - ^
DEFECT. g ^

Higher. Lower.

Higher. Lovrer.

1 a eg

Visual Acuity.

f.s

1—0.75

1—0.75 1—0.50

1-0.60

1—0.75

1—0.75 1 1—0.50 1— 0..50

E'rning
Ability.

Impair- E'rning
ment. Ability.

Impair-
ment.

E'rning
Ability.

Impair-J E'rning Impair-
ment, i Ability, ment.

Loss of 1 mus-
cle, y.

Loss of 2 mus-
cles, jH

95.1
89.4

4.9
10.6

95.1
89.4

4.9
10.6

94.6

88.5

5.4
11.5

94.9
89.0

5.1
11.0

Loss of 3 mus-
cles, y.

82.6

17.4 82.6

17.4

81.2

18.8

82.0 1 18.0

Loss of 4 mus-
cles, -y; [ 73.9

Loss of 5 mus-
cles, i X 1 61.0

26.1 73.9
39.0 1 61.0

26.1
39.0

71.9
58.4

28.1
41.6

73.0 27.0
59.9 i 40.1

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132

BIBLIOGRAPHY.

1. AlliK))t. Frank. What Amount of Visual Defect Should Disqualify
in Railroad and Steaniship Service. — Journal Ainer. Mcfl. Af<so.. I'JbO.

2. American ^ledical Association, Section on Ophthalmology. — Trans.
1900-1901.

3. Amtliche Xachrichten des Reichs-Versicherungsamts Nr. V. 1.
Miirz 1897, Seite 253 ff. und die Berufsgenossenschaft Xr. G,. 1897, p. 50.

4. Baudrv. S. Injuries to the Evo in Their ;Medico-Legal Aspect.
1900.

5. Becker. Anleitung zur Bestimnnmg der Arbeits-und Erwerbsun-
fiihigkfit nach Verletzungen. Fiir Aerzte. B?rufsgenossense]iaften und Ver-
sich?rungs-Anstalten. 4. Aulf.. Berlin, 1892.

6. Bell. Expert Testimony.

7. Berichte der Aerztekanuncv dcr Provinz Schlesien. III. Sitzung
voni 20. October. 1894, Seite 10.

8. Dienst-Anweisungen zur Beurtheilung der ^lilitar-Dienstlahigke'.t
und der Ausstellung von Attcsten. B.^rlin. 1S77. -

8. Fnchs. Lelirbuch der Augenheilkundc. 1889.

9. Grcenleaf. Evidence, p. 114.

10. Golebiewski. Aerztlicher Commentar ziim l'nfalls-\'trsicheruiigs-
gesetz vom (i. July. 1884. ]\lit praktischtn RAthschliigen zur Untersuchung,
Bchandlung und Beurtheilung von Unfalls-Verlctzten. Berl'n, 1893.

11. Groenouw. Ueber die Vermindeiung der ErwerbsfUhigkeit durch
Sehst.'irungen. Deutsche incdicinische \^'och(nschrift, 1893. Xr. 40-44.

12. GroenouAV. Anleitung zur Berechnung der Erwerbstilhigkeit bei
SehstiJrungen. Wiesbaden. 189(i.

13. Groenouw. Ueber die Berechnung der Erwerbsfiiliigkeit b?i Seh-
storungen. Deutsche. Medicinal -Zeitung. 1897, Xr. 21 und 11. Ueber die
Beurtheilung der Erwerbsfiihigkeit bei S.hstorungen. Deutsche Me lical-
Zeitu ng. 1897. Xr. 10.

14. Guillery. Ueber die Entschjidigungsanspriiche Einaugiger. Kli-
nische iMonatsblatter fiir Augenheilkundc. 1892.

15. Haab. Die wichtigsten Storungcn des Ge<ichtsfeldes. Au-^en-
iirztliche Unterrichtstafeln. heransgegeben von Magnus. Heft. V. Bres-
lau. 1893.

16. Handbuch der Unfall-Versicherung. Die Reichs-Unfall-Versicher-
ungsgesetze dargestellt von jNIitglitdern des Reichs-Versicherung^amts.
Leipzig. 1892.

17. Hansell, Howard F. Estimation of the Amount of Injury to the
Business Capacity of the Individual from Partial or Complete Loss of
Vision. Annals of Oplitlialmology, 1900.

18. Heddiius. Xoch ein \'orschlag zur Scluitzung der Erwerbsunflihig-
keit bei Augen-Verletzungen. Klinische Monatsblattsr fiir Augenhe 1-
kunde. 1895.

19a. Jatzow. I'cber die Bestimmungen des Procentsatzes der Erwerbs-
fiihigkeit bei Schiidigungen in Folge von L'nfall. Tageblatt der 61. Ver-
sammluno- deutscher Xaturforscher und Aerzte in Kciln. KiJln, 1889,
p. 209.

19b. Josten, zur Beurtheilung der f]rwerbs-Verminder>ing nach Augen-
verletzungen. Klin. ^Nbmat. F. Angenhkde. 1889, p. 526.

20. Kaufmann. Handbuch der Unfallverletzungen. Stuttgart. 18!)3.

21. Knies. L'eber die Centralen Stiirungen der willkiiiliihn Au>en-
mu-skeln. Archiv fiir Augenlieilkunde. 1891. Band XXIII.. p. 28.

22. Lewis. E.xpert Testimony.

23. Magnus. Die Blindheit. ihre Entstehun<i und ihre Verliiituno'.
Breslaii. 1883

24. Magnus. Leitfaden fiir Begutaclitunn' und B rcchnung von L^n-
fallsbeschiidigungen der Augen. Breslau. K'-94 und 1-97.

136 BIBT.IOGRAIMTY.

25. MafTiius. Dio .Tii<ion(ll)lin(lli(>it. Wiesbaden. ISSi).
20. Majrniis. Die Kinaujiiykcit in ihien Beziehungen y.ur Eiwirls-
fahipkeit. Breslau, 1895.

27. Magim.s. Zur kritischeii Beleiiclitiing des GiOFiimnv'sclun Buchr s :
Anloitung zur Beieclimin<j der Erweibsfaliigkeit b(i Schstoningi'ii. l)e t-
sche ^Icdifinal-Zeitinig. 1897, Xr. 3; uiid Xr. 21.

28. !Magmis. Die p]rweibsbesch;idigaiiig hi i ^>l■l^Ist e'lies Auges. E'lie
kritische Beleuclitiing dev gegein\;iitig hen scbeiuleii \'eih;iltiiisse mit Vor-
sehliigpii fiir eine Reform derselhi'ii. Aeiztliclie S icliver8t:iiidigeii-Zeitunj^,
1897. Xr. 5.

29. ^looren. Selistthuiigcu uiul EiitscliiUliguiigs-Anspriiehe der Ar-
beiter. Diisseldorf. 1891.

30. Moses. Ueber den (Jrad der Erwerbsinifiihigkeit nneli \'erletzun-
gen eines Auges. Dissertatio Inanguralis. Breslavi. \S9d.

31. Xieden. Der Xystagnms der Bergleute. Wiesbaden. 1894.

32. Xorris and Oliver. System of Diseases of the Eye. 1899. Vol. II.

33. Ottinger. Zur Statistik der Augenverletzungen. Klinisehe Mo-
natsbliitter fiir Augenheilknnde. 1894. p. 75.

34. Sdii'lmiloh. llandbuoh der Mathematik. Enevklopiidie der Xatiir-
wissensehaften. Breslan. 1879-1881.

35. Sehmidt-Rim])lcr. Doppelseitige Hemianojjsie mit Sectionsbefund.
Arehiv fiir Angenlieiiknnde 1893. Band XXVI.. p. 181.

30. Sehmoekel. Ueber das Sehvprmfigen der Eisenbahn-Betrirbs-Beam-
ten. Zeitung des Vereins dentseher Eisenbahn-\>r\valtiingen 1894. Xr. 3-4.

37. Schrijter. Unfallsbeschadignngen des Sehvormogens nnd ilire Ab-
schUtzung. Antritts-Vorlesung. Ltinzig. 1891.

38. Sehvermiigen der Eisenbalm-Bediensteten. Eisenbahn-Veiordnungs-
blatt 1897. Xr. 2, Amtsblatt der kilniidiehen Eisenbahn-D'rfctien zu Bres-
lan. Xr. 20. 1897. 24 :Miirz. Aerztliehe Saehverstilndi->n-Zeitung, 1897,
Xr. 0.

39. Silex. I'eber Selipriifnngen 1)( i Eis?nb;ihnbeamt n. Beiliner Jirzt-
liches Correspondenzblatt. 1893.

40. Sinkler. Charles. See Baiidry.

41. Statistik iiber die Einiiiisrigen Arbeiter im Bezirk der Section IV.
(Halle a. S.) der Knappschifts-Bernfs-Gpnossenschaft. ^Monatsschrift fiir
Unfallheilkunde. 1894. Xr. nnd 7.

42. Steplien. Evidence. Section 117.

43. Tavlor. A. ^f. Evidence. Section 1417.

44. Taylor. A. :\I. The Law in Its Relation to the Physician. 1900.

45. Thomson. Wm. Detection of f'olor-Blindness. See Xorris-Oliver.
40. Von Woedtke. Unfall-Versicheriingsgrsstz vom (i. Jnli, 1884. 4.

Anflage. Berlin. 180O.

47. Walther, "Angennntersiuhungen an 2,500 Arb;itern."" Arehiv. f.
Aiigenhkde. Bd. XLIL. Heft 1 nnd 2. 1900.

48. Williams, Charles. The Vision of Railwav Employees. Journal
Boston Society of ^Fedicine and Science. Marcli. 1899.

49. Williams, Charles. The Vision and Hearing of Railwav Em-
ployees. 1900.

50. Wisconsin Reports. Vol. 101. p. 278.

51. Wiirdeniann. H. V. Tlie Economic Limitations of the Visual
Acuity in ^'ari()us Trades and Professions. See American ^ledical Associ-
ation Section on Ophthalmology, 1901. Trans. Journal Amer. iled. Assoc,
February. 1902.

52. Wiirdeniann, H. V.. and ^lagnus. H. Economic Valuation ofVision.
Annals of Ophthalmology. April. 1901.

53. Zehender. I'eber den zahlenmiissigen Aus Inn k der Erwerbsnn-
fjihigkeit gegeniiber der Unfall-Wrsicherungs-Gesellschaft. Klinisehe Mo-
natsbljitter fiir Augenheilkunde. 1889, p. 205.

54. Zehender. Zur Unfall-Versicherunusfrage. Klinisclie ^lonatsbat-
ter fiir Augenheilkunde. 1889, p. 531.

ALPHABETICAL INDEX.

INDEX.

139

ALPHABETICAL INDEX.

Ability to compete, Definition of. 46

■ — Foi iiiiila 40

— Estimation of 40

— in nionocularism . . 71

— Acquired 80

— Congenital So

— Older valuation of in mo-

nocularisni 91

— Part depending upon individ-

ual 47

— Part depending upon employer 47

— A factor of the earning ability 20
Absciss (see also plates I. and

V). . 42. 52

•Artisan classes 37, 107, 110

Accident insurance —

— German law 10

— Companies in America 14

— Methods of settlement 1.5

— Relation of physician to 21

— Officials' duty to determine

amount 21

Accommodation, Damage to... 44, 99
Accommodation, convex lenses in

paralysis of 45

Adaption 30

Allport, Investigations of vision

of railroad employees 40

— Division of railroad employees

into classes 39, 41

American Medical Association.
Transact. Section on Oph-
thalmology 11

Aphakia 94

Arbitrary fixation of payments
for visual losses by Ameri-
can insurance companies... 14

Arithmetical proportion IS. 32

Atrophia nervii optici, Danger of

blindness from 92, 97

Baggagemen 3n

Baggagemasters 39

Bargemen 37

Baudry, Medical-legal aspects of

injuries to the eye 13

Becker. Estimation • of working

ability 28

Bell, Expert testimony 14

PAGE.

Builders 37

Brakemen 39

Brewers and Maltsters 37

Brickmakers 37

Bridge foremen 39

Bridge tenders 39

Binocular economic vision, For-
mula for 33

Blindness. Economic meaning of. ;j3

— Scientific meaning of 33

Cerebral vision 30

Chemical workers 37

Cliimney sweeps 3y

Classes of railroad employees.. .39, 41

Color sense 24

Color blindness 101

Competition, difficulty of one eyed

men ' . . 87

Conjunctiva, injuries of 96

— • Inflammation of 100

Conductors, railroad 41

Cornea, staphyloma of 96

— Inflammation of 96

— Opacities of 96

— Injuries of 96

Curves. Geometric, for rendering

the calculations and simpli-
fying the f ormulcTe . . . . 42, 52, 55

— Showing scientific and the two

grades of economic visual

acuity (also plate I) 42

— For estimation of the factors

of economic vision (also

plate V) 52

Cyclops, from Groenouw's for-
mula 20, 29

Capacity for earning a living. . 26
Congenital defects. Adjustment

in ■ 31

Convex lenses in paralysis of ac-
commodation . .• 45

Cataract 100

Chorioiditis 101

Constitutional diseases 101

Danger of blindness of one-eyed

persons 97

140

INDEX.

Damages, ]Measure of 14

— Definition of 14

— Relation of physician to 17

— Relation of insurance officials

to 17

— Nominal .' 14

— Substantial, conipensatorv ... 14

— Exemplary, punitive, vindictive 14
Damage to visual acuity (see

tables, part IV. ; see also

visual acuity 30

— to visual field (tables, part

IV.) 30, 58, Gl, 03

- — to ocular muscles (tables, part

IV.) 101. 22. 30, 31. 44, 65

— to economic vision, etc 30

— to earning abilitj^ 24

— to working ability ....'....;.. 28

Day laborers 38

Deformitv resulting from acci-
dent. 4S

Despatchers 39

Diseases, local, impairing earning

power 100

Dutv of phvsieian 17

Diplopia . ." 101

Earning ability. Definition of . . . 26

— Formula for 28

— Factors of 26

— According to German law .... 26

— In normal health 28

■ — How determined 26

— Foersters false estimation...

— Wagner's right estimation. . . .

— Hansen's empirical estimation 105

— Relations of visual acuity to. 32

— Relations of visual acuity to.

Avhen only one eye is injured
(see tables, part IV.)

— Relations of visual acuity to.

when one is damaged and
' other blind (see tables, part

IV.)

Earning ability 11

— in loss of central visual acuity

of both eyes 33

— in loss of central visual acuity

of one eye 33

— in gradually increasing blind-

ness. . . .' 80

— in sudden blindness 89

— in damage to visual field 58

— in Aphakia 04

— in damage to muscles 65

P.\(iE.

Economic limitations of visual

acuity 33

— Improper estimate of Groe-

noiiw 20, 22

Economic limitations of visual

lield 43

Economic standard of visual

acuity 43

Elevator employes 37

Engineers 39, 40

Engineering, Profession of 36

Engine dispatchers 36

Estimation of distances and

shapes of objects 51

Expert evidence 13

Extrinsic ocular muscles 65

— Paralysis of 66

Farmers 38

Fine mechanics 37

Firemen 37, 40

Flagmen 4t)

Foerster, Duty of physician 21

Food article manufacturers 40

Foreign bodies in eye 102

Fuchs '. 94

Fundamental principles for esti-
mation of effects of ocular

injuries 24

Freightmen, foremen, masters... 40

Garment makers 37

Gas and water works employees. 37

Gatenien 40

German accident insurance law. 10, fO

— - Workmen and hospitals 16

German imperial insvu'ance of-
fice 35, 91

Glass-blowers 37

Golebiewski. Loss of one eye. ... 91
— Commentation on accident in-
surance law 91

Greenleaf, Evidence 13

Groenouw, Adjustment in con-
genital defects 31

Groenouw. Formula of 19

its intention 19

— - — has no general application. 20

is mathematicallv insolua-

ble ■ 21

in monocularism 21

nii.xes physiologic with ana-
tomic data 24

INDEX.

141

PAGE.

— Xiiie-oyed monster 21

— Cyclops 21

— One-eyed person hypothetical-

ly earns nothing 20

Guards 39

Guillery, Accidents in one-eyed

persons 86

Haab. Commoner affections of
the visual lield

— Normal limits of visual field.. 43

Hansen's estimates 105

Heddaeiis, Formula of 22

Hemianopsia 59, ()1, 63, 101

— Double sided 59

■ — • Iraiimatic 59

Hyperopia conflicts with R. R.

service 40

Indemnity 11

— Relation of phvsician to 17

— To the one-eyed 14, 86, 90

— Reduction one year after acci-

dent 90

— Reduction of rates in recent

years ?0

Insurance, (see accident)

Intrinsic ocular musculature. . .44, 99

Iron and steel workers 37

Iron splinters, Injuries from. ... i 8

Injury of earning ability 11, CO

Iritis 100

Jaeger's types plate II and 42

Jatzow, Indemnity to the one-
eyed ! 92

Josten, Economic Itmitations of

central visual acuity 34

— In military service 36

Ivaufmann. Eye injuries

Knies. Loss of reading power in

right hemianopsia 50

Law. German accident (See acci-
dent) 16

Leather workers 37

Left eye and monocularism .... 92
Legal status of physician in

America 13

Lens, Injuries of 94

Lewis, Expert testimony 14

Light sense 30

Linen industry 37

Locomotive employees 39

Loss of binocular vision 32

Lids. Injuries of 98

— Inflammation of 100

Laboring classes 37

Magnus. Numerous references...

Machinists and metal workers.. 37

Marine employees 37

Medico-legal experts (see expert

testimony) 13

Medical officers of comiianies. ... 13
ililitary standard of vision in

America 36

— Germany 36

]\[edicine. Profession of 57

]\[ill employees 37

Mine workers 38

-Monocular economic vision, for-
mula for 33

Monocular blindness. Danger of

total blindness in 92

— Ability to compete in 79, 87

— Definition of scientific 70

— -Definition of economic 70

— - Complaints in 93

— Acquired 85

— Congenital 86

— - Central visual acuity in 85

— Earning abilitv in acquired.. 88

— Visual field in* 85

— ilusculature in 86

— Sudden blinding of one eye.. 88

— Slowly increasing blindness cf

one eye 91

— Estimation of distances and

shapfs in 91

Moses. Indemnity to the one-eyed 92

— Loss of sight in workingmen.
Mooren, Muscular powers of one

eye 86

— Indemnity in acquired mo-

nocularism 91

— Opinion on the accident law. . 16

142

IXDEX.

• I>A(iE.

— Loss of binocular vision .... lOi
Muscles of the eyes, ^Muscula-
ture ." . . 33, 4 1

— Intrinsic; 44, !.0

— Extrinsic in the fornuila 44

— Economic relations of 44

— Economic impoitanoe of dam-

age to 44

— Paralysis of (tables in part

IV.) 102, Go

— Damage to complicated with

damage to visual acuity
(tables in part IV.)

— Damage to complicated with

damage to visual field
(tables in part IV.)

— Damage to in acquired nio-

nocularism So

Musical instrument makers 37

Xieden, Xystagmus of miners... 44

— Sight of the one-eyed 8U

Xine-eyed monster from Groe-

nouw's formula 21

Xoyes & Oliver

Ocular muscles, (see muscles of

the eyes)

. Ocular injuries. Relation of, to

earning ability 30

Ocular earning aLilitv. Definition

of '. CO

One-eyedness, (see monocul ir
blindness)

Ottinger, Statistics of eye acci-
dents ' ' 91

Ordinate (see plates 1. and V.) .42, 52

One-eyed person sees nothing by

Groenoinv formula 21

Professional and business clauses 130

Pecuniary loss 104

Paper workers 37

Paper makers 37

Paraly.sis of extrinsic ocular

muscles OG

— intrinsic ocular muscles (ac-
commodation) 44, no

Pension Bureau. United States.. IG
Pensions, rente, indemnity for ac-
cidents . .' *. . .14, IG, 01

Peripheric vision (see visual field)

i'.v(;e.

Pliysician. Relation to accident

insurance — indemnity ...... 21

— Duty to deteimiiiie amciunt of

damage to earning ability.. 21

— Comes under class I., higher

visual demands 37

Porters 38

Pottery makers 37

Precious metal workers 37

Professions, higher, require higli-

er visual demands 37

Printers 37

Pupils 37

Quanymen 37

Quarles (see dedication and
preface)

Railway employees 37

Railroads, German ministry of. 29, 41

Railway relief associations 40

Rectus muscles, relative economic

importance of 45, 32

Road foremen, masters 39

Rolling mill workers 37

— for Visual field 38

— for muscle 38

Root value for ability to compete 30
Relation of age to earning abil-
ity .3G, 104

Retina, Detachment of 101

Refraction, Errors of 102

Schaflfner

Schloemilcli

Schmidt -Kimpler, Hemianopsia

dujilex traumatica 59

Sclunoeckel. Division of R. R.

employees into classes .... 39
Sehroeter,- Zones of the visual

field 43

— Economic valuation of limita-

tions of tlie visual field. ... 59

— Economic valuation in hemia-

nopsia ; 59

Scientitic standard of visual
acuity (transformed to eco-
nomic terms, plate I. and

table) 42

Signal men 39

Silex, Division of R. R. employ-
ees into classes 39

— -Limit of vision in R.R. s.rvice 39

INDEX.

143

PAGE.

Sinkler. Rules of medical evidence 13

Silk industry 37

Snellen types (plate III.) 43

Soldiers and sailors 37

Street car (horse car) employees 38

Street car (motor) employees.. 37

Stephen 13

Station employees 39

Station baggagemen 39

Station agents 37

Statistics of one-eyed workmen . .23, 90

Stephen, Evidence 13

Sugar factory employees 38

Switchmen 39

Switchtenders 39

Symblepharon 96

Sympathetic ophthalmitis. Dan-
ger of 97

Sufficient visual acuity 39

Students ^-. 37

Tabulated values (part IV.) ....

Taylor, Evidence 13

— Law in relation to the physi-
cian 13

Teamsters 38

Telegraph operators 37

Textile industry 37

Thomson, Relative visual acuity
and color blindness, detec-
tion of 39

Tobacco workers 38

Track foremen 39

Three hypothetical eyes from Ze-

hender's formula 19

Theolog}", Profession of 37

Ti'ain baggagemen 39

Vision. Visual act factor of 32

— Physiologic 32

— Binocular 33

— - Economic 30

— Monocular 33

Visual Acuity. Gradual loss of.. 27
Visual Demands, Table for voca-
tions with higher (part IV.)
■ 37, 42

— Table for vocations with lower

(part IV.) 37, 42

Vitreous opacities 102

Visual Acuity —

— Definition of 30

PAGE.

— Scientific meaning of 34

— Economic meaning of 34

— Transposition of scientific into

economic terms, plate I. and
table B 42

— Loss of

— Damage or injury to (tables I.-

II.. part IV.)'. .

— Damage of, in connection with

defects of visual field (tables
VII.-IX.) 66

— Damage or in connection with

defects of muscles 66

— In monocular blindness 73

— Modified 76

— Loss of in both eyes 30

— Economic limit of 33

— Sufficient limit of 35

\'isual Field, Binocular 43

— ^Monocular 72

— Economic limits of 43

— Economic valuation of damage

to binocular 43

— Economic valuation of damage

to monocular 72

— Slight limitation (see plate

IV.)

— ■Great limitation (see plate

IV.)

— Total loss of peripheric vision 58

— Limitation in one eye 58

— Partial defects in one field.. 58

— Partial defects in both fields. 58
— - Zones (plate IV.) 58

— Relative importance of. .... . 58

— Concentric contraction 58

— Disorders of. Complicated.... 62

— Damage or injury to (tables,

part IV.) '.

Von Woedtke, German accident

insurance law 16

Wagner. Duty of physicians.... 21

Wagon masters 37

Walther, Examination of work-

ingmen's eyes 74

Warehousemen, keepers 38

W'atchmen 38

W^eak sight. Acquired in youth . . 34

W^eakness of vision 44

— Congenital 34

— Cleaning of, from economic

standpoint 74

Williams. Division of R. R. Em-
ployees into elapses 40

144

INDEX.

PAGE.

Wipers 39

Wisconsin Eeports 13

Woodworkers and carpenters.... 37

Working ability, Definition of . . . 28
— not synonymous with earning

ability 28

Wiirdemann, Numerous references

Yardmen 37

PAGE.

Zehender. Formula of 18

• — Formula, Basis of his 18

— ^Mathematical value of 18

— The formula now only of his-

toric importance 19

— Examinations of workmen ... 75

— Three hypothetical eyes 19

— Lowest standard of visual

acuity 35

— Loss of one eye 92

— Danger of total blindness in

loss of one eye 92

PLATES II AND IE.

Near and Distance Test Types.

PLATE 11.

JAEGER'S TYPES WITH DISTANCES AT WHICH THEY MAY BE NORMALLY

SEEN AS RENDERED BY THE SCIENTIFIC AND

ECONOMIC STANDARDS.

FOR NEAR TEST OF THE VISUAL ACUITY.

Economic Standard for Lower Scientific Economic Standard for Higher

Visual Demands. Standard. Visual Demands.

0.3 0.6 0,45

Of the seventy=one conventions held here during the present year, thirty=two were
of national associations, and thirty^nine state. Since the annual meeting of a year ago
thirty^nine national conventions have been secured for Milwaukee through the agency
of the Citizens' Business League, three of which were for the present year and have al=
ready been held here, namely: American Society of Mechanical Engineers, United States

0.4 0.8 0.6

Weather Bureau Officials, and the American Banl<ers' Association.
For next year the list includes twenty=eight national and thirty=four
state conventions, and for the year following, we have already booked
eight national and ten state conventions. In addition to those already

0.5 1-0 0,75

secured, we are working with a number of im=
portant associations which we still hope to se=
cure for Milwaukee next year. Every time we
go after a convention, if we do not win out, we

0.75 1-5 1,2

enter a strong wedge to bring it here an=
other year. Among those we are hoping
to secure, selections having been referred
to executive committees, are the Traveling

\J^ 3.0 2.4

Freight Ag^ents' Associa=
tion of the United States,
the National Lumber Com

PLATE III.

SNELLEN'S TYPES WITH DISTANCES AT WHICH THEY MAY NORMALLY

BE SEEN AS RENDERED BY THE SCIENTIFIC AND

ECONOMIC STANDARDS.

FOR DISTANT TEST OF THE VISUAL ACUITY.

Economic Standard for

Xower Visual Demands,

12 meters.

Scientific Standard,
24 meters.

Economic Standard for

Higher Visual Demands,

18 meters.

'St'

3 meters.

-tVi meters.

PLATE IV.

The Visual Field.

PLATE IV.

normal Binocular Uliual Tltld.

The yellow area is tli.- jiortioii lomraf.ii to both eyes; the red belo
to the left and the blue to the luoiiociilar field of the right eye
The heavy black circles divide the fields into three zoues of ec
economic importance. Chapter VI, § 13.

Co» of th( temporal nalcts or Botlt Ulsual Titlds

Valuation of the Remainder is -a nf the Normal.
Chapter IX, « Ifl.

Coss of the nasal fnAm of Both Ulsital TKIds.

A'ahiatiou of the Kemainder is I.
Chapter IX, Uil.

Coss of lilt nasal fialf of tht Ulsual f itld oi ihe Dii eyt.

Valuation of the Remainder is 1 .
Chapter IX, S l!l.

Coss of lite tomporal Half of ihe Ulsual TKid of iitt Rlflbi Eyt.

Valuation of the Kemainder is % .
Chapter IX, S 19.

Normal and Damaged Visual Fields with E,conomic Valuation.

.Mrr.

PLATE V.

Curves for Valuation of the Visual Field, of the Muscular Action
and of the Ability to Compete.

i I 1 I i I i I - s 5 i . 5 I 5 I : I I

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