# Proposal of a new slit-lamp shield for ophthalmic examination and assessment of its effectiveness using computational simulations

## TL;DR

A new slit-lamp shield was proposed and tested using simulations to assess its ability to block respiratory droplets during eye exams.

## Contribution

A new slit-lamp shield design was proposed and evaluated for droplet protection and clinician comfort using computational simulations.

## Key findings

- The standard shield blocked 99.83% of respiratory droplets from reaching the manikin.
- The proposed shield blocked 99.95% of droplets, showing comparable effectiveness to the standard shield.
- The new shield offers similar infection control but with potential ergonomic improvements for clinicians.

## Abstract

This study aimed to use computational models for simulating the movement of
respiratory droplets when assessing the efficacy of standard slit-lamp
shield versus a new shield designed for increased clinician comfort as well
as adequate protection.

Simulations were performed using the commercial software Star-CCM+.
Respiratory droplets were assumed to be 100% water in volume fraction with
particle diameter distribution represented by a geometric mean of 74.4
(±1.5 standard deviation) µm over a 4-min duration. The total
mass of respiratory droplets expelled from patients’ mouths and droplet
accumulation on the manikin were measured under the following three
conditions: with no slit-lamp shield, using the standard slit-lamp shield,
and using our new proposed shield.

The total accumulated water droplet mass (kilogram) and percentage of
expelled mass accumulated on the shield under the three aforementioned
conditions were as follows: 5.84e-10 kg (28% of the total weight of particle
emitted that settled on the manikin), 9.14e-13 kg (0.045%), and 3.19e-13
(0.015%), respectively. The standard shield could shield off 99.83% of the
particles that would otherwise be deposited on the manikin, which is
comparable to 99.95% for the proposed design. Conclusion: Slit-lamp shields
are effective infection control tools against respiratory droplets. The
proposed shield showed comparable effectiveness compared with conventional
slit-lamp shields, but with potentially enhanced ergonomics for
ophthalmologists during slit-lamp examinations.