Evaluation of the Slit Lamp Shield to reduce droplet exposure.

EDITOR: The current COVID‐19 global pandemic has brought infection control measures to the forefront of international attention. Patients with SARS‐CoV‐2 infection may be asymptomatic but infectious. The face‐to‐face proximity of clinicians and patients during slitlamp examination potentially places eye‐care providers at a high risk of aerosolised particles from respiratory droplets.1 Similarly, patients may be at risk from an unknowingly infected clinician, which could have disastrous consequences, especially in a busy clinic with a large proportion of elderly patients.

Recognising this potential risk, we recently designed – and had urgently manufactured – the Slit Lamp Shield, made in Australia from clear acrylic (plexiglass). Our Slit Lamp Shield is distinct from other slitlamp breath guards by having angled side‐wing panels that provide a large physical barrier while still allowing access to the slitlamp controls.

The use of slitlamp barriers has become increasingly common during the current COVID‐19 global pandemic. The American Academy of Ophthalmology has recommended the use of commercially manufactured barriers that can be regularly disinfected.2

We decided to evaluate the ability of the Slit Lamp Shield to reduce potential droplet exposure. In our simulation (Video S1), a clinician attired in personal protective equipment including surgical mask and face shield was positioned in the examination position. A staff member in the patient position executed a single release of a commercially available fluorescent dye spray (VeriClean; Diversey Inc, Fort Mill, SC, USA). This was performed both without and with the Slit Lamp Shield.

Without the shield, dye was found on the clinician's face shield, mask, gown, gloves, desk and the machine itself. When the experiment was repeated with the shield in position, most of the dye was located on the outside of the shield, with smaller amounts on the clinician gloves, desk and machine (Figure 1). Importantly, there was no dye on the clinician's face shield or mask. We repeated the experiment on several occasions and obtained similar results.

Figure 1

Fluorescent dye is concentrated on the outer aspect of the Slit Lamp Shield, while there is no dye on the mask or face shield of the clinician

We acknowledge the limitations of our methodology including that it is not validated for the projectile direction, speed and turbulence of a true cough and is performed in an artificial experimental setting. Nevertheless, this demonstration illustrates the potential benefit of using a barrier shield during slitlamp examination. It is important to remember to continue to use other personal protective equipment as guided by local protocols, and that frequent disinfection of the shield, equipment and surfaces is still required.

Video S1. A simulated evaluation of the effectiveness of the Slit Lamp Shield.

Click here for additional data file.