RE 
 73 
 157 
 1921 
 
 OPTO L C T I O N S 
 >ERATING 
 
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INSTRUCTIONS 
 FOR OPERATING 
 
 T/je Universal 
 Ophthalmometer 
 

 OPTOMETRY 
 
 Copyright 1921 
 
 by the 
 
 General Optical Co., Inc. 
 
 Mount Vernon, N. Y. 
 

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7 'he Unive? 'sal Ophthab/i offi cte? ' 
 
 LOCATING FIRST PRINCIPAL MERIDIAN (FIGURE a) 
 
 THE Universal Ophthalmometer is an instru- 
 ment of precision and its principle is optic- 
 ally correct. Unless the operator handles 
 the instrument properly, much of its value will be 
 
 lost. 
 
 Remember that the Universal is a carefully con- 
 structed instrument, and with ordinary care will 
 last indefinitely. Handle the instrument freely and 
 smoothh', but never attempt to force or jerk it into 
 position. 
 
 The manipulation of the instrument is simple. 
 Observe the following rules and >ou will have no 
 difficulty in obtaining the accurate results made pos- 
 sible by the Universal Ophthalmometer. Be sure 
 the ophthalmometer has a substantial support, one 
 that may be quickly and smoothly raised or lowered. 
 This is important, as the accuracy and speed to be 
 gained in using the Universal may be offset by a 
 make-shift support. 
 
 First: — Switch on lights by turning switch (part 
 10) on base of instrument. If you wait until after 
 the patient is properly seated to turn on the light, 
 the noise of the snap switch and sudden flash of 
 light in the mire boxes may startle her and cause 
 her to move out of position. 
 
DOCTOR GUIIIING PATIENT'S HEAP INTO POSITION 
 (EICUUE b) 
 
 Second: — Then look into the adjustable eyepiece 
 (part 11) and turn it until cross lines appear sharp 
 and distinct. (See figures D and E.) 
 
 A good way to focus hair lines is to hold a piece of 
 white paper before end of telescope while turning 
 eye piece. This will make the hair lines stand out 
 clearly and distinctly. (See figure F.) 
 
 Third: — Adjust the oiihthalmometer table so that 
 with arms folded in a natural position on table top, 
 
 PATIENT S EYE ON LEVEL WITH DOT 
 (FIGURE C> 
 
 PAGE THREE 
 
CROSS IIATRS OUT OK FOCUS 
 (FIGURE Ii) 
 
 the forehead and chin of patient are comfortably but 
 firmly placed well into the head and chin rests. (See 
 figure A.) When patient places forehead against 
 head rest (part 2), instruct her to raise eyebrows. 
 In this way, the cornea is fully exposed and eyebrows 
 do not interfere with the images. It is well not to 
 depend on patient properly placing her head in rests. 
 The operator or the nurse should guide patient's 
 head into the proper position. (See figure B.) 
 
 Fourth: — Raise or lower chin rest (part 1) by turn- 
 ing small adjusting screw (part 13) at operator's 
 end of instrument, so that face is in an upright posi- 
 tion and outer canthus of eye is in line with white 
 spot (part 4) on inside of head rest. This will 
 bring the horizontal meridian of the eye in line 
 with the horizontal position of the instrument when 
 adjusted. (See figure C.) 
 
 CROSS HAIRS IN FOCUS 
 (FIGURE E) 
 
 V A G E FOUR 
 
FOCUSING THE HAIR LINES 
 (FIGURE F) 
 
 Fifth: — Turn dial so that both sight holes (part 
 14-14) are in horizontal position. This will bring 
 the figure 45 on the large dial to the top of the 
 instrument. Then raise or lower instrument until 
 white spot (part 4) at side of head rest is visible 
 through the sight hole , in dial. [This is done by 
 turiung large adjusting screw (part 12) at oper- 
 ator's end of instrument. See operator's left hand 
 in figure C] [Be sure locking handle (part 9) is 
 
 [MAGES CENTERED ON CROSS HAIRS 
 (FIGURE G) 
 
 PAGE FIVE 
 
LOCKINC. THE INSTKUMENT 
 (FICUUK II ) 
 
 loose.] Swing blinder (part 3), attached to head 
 rest, so that it covers patient's left eye. Then swing 
 telescope until patient's right eye is in position di- 
 rectly before it. Instruct patient to look into tele- 
 scope for the rellection of her own eye, and to look 
 steadily at it . 
 
 SixtJi: — Operator then adjusts telescope by raising 
 or lowering or turning from side to side until images 
 of mires are located and central images are centered 
 on cross hairs. (See figure G.) Disregard the two 
 outer images. 
 
 Scvcntli: — Then lock telescope by pulling toward 
 the operator the locking handle (part Q) on right 
 side of upright. (See figure H.) 
 
 mires just touching 
 (figure j) 
 
 P A G E SIX 
 
LOCATING SECOND PRINCIPAL MERIDIAN 
 ( FIGURE k) 
 
 Eighth: — Now turn focusing wheel (part 8) on side 
 of telescope until images are focused clearly and 
 distinctly. 
 
 Ninth: — Locate the first principal meridian by tak- 
 ing hold of the rough grip section (part 7) and 
 revolving the telescope until the black lines running 
 through the center of each mire are in a straight line, 
 as in figures J, L or M. 
 
 Tenth: — Grasp one of the convenient pegs (part 
 6) on the disc (see operator's left hand in figure 
 A) and turn disc either way until the inner edge 
 of step mire just touches the inner edge of the oblong 
 mire. ( See figure J.) 
 
 The white double pointer (part lb) now registers 
 
 mires separated 
 (figure l) 
 
 MIRES OVERLAPPED 
 (FIGURE M) 
 
 P A G E S E \' E X 
 
the first principal meridian on the small dial and 
 its dioptric value on large dial. Write down this 
 finding. For example : 
 
 45. D. in meridian 0° 
 
 Eleventh: — Locate second principal meridian by re- 
 volving telescope until black lines running through 
 the center of each image are again in a straight line. 
 Again grasp one of the convenient pegs and turn 
 disc either way until inner edge of step mire again 
 just touches inner edge of oblong mire. The white 
 double pointer (part 16) now registers the second 
 principal meridian on small dial and its dioptric 
 value on large dial. Write down this finding. For 
 example : 
 
 47. D. in meridian 90° 
 
 ^ ou have now located the two principal meridians 
 and their dioptric values represented by the follow- 
 ing diagram: 
 
 90 
 
 
 
 45. D 
 
 A7. D 
 
 To avoid confusion, figure from here on from this 
 diagram instead of from the dials of the ophthal- 
 mometer. 
 
 FACE K I C, II T 
 
Twelfth: — If you use minus cylinders the power of 
 the minus cylinder will be the difference between 
 the two dioptric values on the diagram and the axis 
 will be the meridian associated with the lower di- 
 optric value. In the abo\e example — 2.00 axis 0°. 
 
 If you use plus cylinders the power of the plus cyl- 
 inder will be the difference between the two dioptric 
 values on the diagram and the axis will be the 
 meridian associated with the higher dioptric value. 
 In the above example 4- 2.00 axis 90°. 
 
 Repeat above operations when examining the left 
 eye. 
 
 Bear in mind that the ophthalmometer findings indi- 
 cate the exact cylinder that would correct the corneal 
 astigmia if the lens could be placed on the cornea. 
 Rut, inasmuch as the correcting lens, in order to 
 clear the lashes, must be set away from the cornea, 
 its power must naturally be changed to produce a 
 similar effect. 
 
 However, the cylinder indicated by the ophthalmo- 
 meter affords the proper basis from which to start 
 all other tests, subjective or objective. 
 
 ly^e Green a fid Red Markers 
 
 The green and red markers (parts 17 and 15) are 
 purely auxiliary and confusing to most, but some 
 operators who do not write down their findings use 
 the green marker to mark the first principal meri- 
 dian and the red to mark its dioptric value. 
 
 PAGE NINE 
 
Form B~5 
 

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