key: cord-0695216-9oj4ococ
authors: Maxime, Delbarre; Pierre-Marc, François; Jérémy, Adam; Jean-Baptiste, Caruhel; Françoise, Froussart-Maille; Hossein, Khonsari Roman
title: 3D-printed shields for slit lamps produced during the COVID19 pandemic
date: 2020-11-23
journal: nan
DOI: 10.1016/j.stlm.2020.100004
sha: da9e65a3f94279c5c9542b1e96b9cb8a5d525806
doc_id: 695216
cord_uid: 9oj4ococ

Additive manufacturing has been extensively used during the COVID19 pandemic to design and produce protection equipment. During clinical examinations using slit lamps, ophthalmologists are at risk of being contaminated, and the device itself is exposed to viral contamination. Several solutions have already been proposed for fixing transparent shields on the physician’s side. Here we propose a 3D printed device fixed on the chin rest on the patient’s side, aiming at limiting viral spread both on the lamp itself and towards the physician.

Clinical examination using a slit lamp is at high risk of SARS-CoV-2 contamination due to the proximity of the physician with the face of his patient. Several types of home-made disposable protection screens were developed at the beginning of the COVID19 pandemic ( Figure 1 ), located on the side of the physician [1] . Due to the need for long-term protection against the virus, we aimed at designing a permanent shield fixed on the chin rest, that could also be used in various devices without optics. This protective device aimed at preventing the patient side of the slit lamp from being contaminated.

The 3D COVID initiative, launched by the trust of Greater Paris Hospitals (Assistance Publique -Hôpitaux de Paris) and Université de Paris, offered a unique platform with 60 professional Fused Deposition Modeling (FDM) 3D printers that allowed fast prototyping and production in response to the pandemic. The design of the shield was performed by a group of dedicated engineers (Bone3D, Paris) and prototypes were tested at Hôpital d'Instruction des Armées Percy, Clamart ( Figure 2 ). The devices were printed on J120, J170 and J370 FDM machines from Statasys (Eden Prairie, MN, USA). Layer thickness was 0.33 mm, with a filling density of 32 % and a wall thickness of 2 mm Average printing time was 2 hours. The average price in raw materials for a single shield printed in acrylonitrile butadiene styrene (ABS) was 6.5 euros. The current shield was designed for Height Streit BQ 900 slit lamps J o u r n a l P r e -p r o o f ( Figure 3 ) and the STL files were made available for free on the dedicated website of the APHP / Université de Paris initiative.

During the COVID19 pandemic, an urgent need for protection devices triggered a fast development of 3D printing initiatives [2, 3] . Several types of devices share a global common structure but need slight specific shape characteristics for each model, such as hand-free door openers adapted to different types of door handles [4] or protection shields for slit lamps. For these specific cases, where several models are required in moderate quantities (several hundreds to several thousands), injection moulding is not an adequate technique due to the need of numerous different moulds that will each be used for limited production. In this context, 3D printing is an ideal technique and was specifically adapted to respond to the need of protection devices in ophthalmology departments within APHP and other hospitals such as Hôpital d'Instruction des Armées Percy.

Regarding the specific case of the shield for slit lamps, two engineers from 3D COVID were sent onsite at Percy Hospital in order to collect data on the chin rest of the Height Streit BQ 900 slit lamp. After several minor adjustments performed based on exchanges with the 3D COVID engineering team, a final design was approved by ophthalmologists with 24 hours and produced in 15 copies that could be used without major technical issues.

Of note, it has recently been shown that SARS-CoV-2 can survive up to 72 hours on plastic surfaces [5] and that a large range of surfaces within hospitals carry viruses [6] . We propose that the 3D printed shield should be cleaned between every clinical examination of a different patient by 62-71% ethanol, 0.1% to 0.5% sodium hypochlorite or by commercial products J o u r n a l P r e -p r o o f responding to the EN14476 norm (virucidal activity in the medical area). ABS is compatible with such treatments.

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Protective shields for ophthalmic equipment to minimise droplet transmission of COVID-19

Abramowicz S (2020) 3D printing of face shields during COVID-19 pandemic: a technical note

Helmet modification to PPE with 3D printing during the COVID-19 pandemic at Duke University Medical Center: a novel technique

3D-printed contact-free devices designed and dispatched against the COVID19 pandemic: the 3D COVID initiative