The authors adopted a 'common sense' approach early on in the Covid-19 pandemic, such as using eye shields on slit lamps, and minimizing conversation between the patient and doctor while using the slit lamp. Whilst waiting for more robust data on how to reduce infection risk, many units around the world including our own, introduced such measures.
The possibility that bowl perimeter visual field testing (such as the Humphrey Visual Field analyzer) may be a particularly insidious source for infection spread was an immediate concern for glaucoma departments. Certainly, the postponing of such investigations, as the authors have suggested, will eliminate this risk but is not a sustainable solution. The advice on cleaning of the perimeter is welcome although cleaning of machines between patients will undoubtedly have an effect on the throughput of patients. Presently, there are no data to advise how long we should wait between patients, as droplets may persist in the relatively enclosed area of the bowl. Staff cleaning the equipment will need to wear gowns, gloves and appropriate masks, perhaps N95 or similar. These measures may have financial implications for clinic running costs.
As regards to measurement of intraocular pressure (IOP) using the Goldmann Applanation Tonometer (GAT), the risk of Creutzfeldt-Jakob prion transmission led some clinics to adopt the use of disposable tonometer tips for all patients. The Icare tonometer is a reliable instrument that minimizes contact between patient and practitioner and has a disposable tip. The ease of use and size of the instrument make it an attractive alternative to both slit lamp mounted GAT and Non-Contact Tonometry, with the added bonus of being the least likely of the three options to transmit the COVID virus.
In our department in Singapore, the cleaning of equipment is undertaken by the nurses and cleaning staff using various chemicals depending on the area to be cleaned. All slit lamps/investigation machines are cleaned after every patient using alcohol wipes. The Goldmann Applanation Tonometers are cleaned with hydrogen peroxide solution. From our experience, the cleaning of the inside of the Humphrey Visual Field analyzer with 70% isopropyl alcohol in water causes staining of the bowl and hence may cause problems with the testing. Omitting testing is a short-term solution but eventually physicians will want to restart and this could be a real problem.
As the world adapts to the 'new normal' with the risk of recurrent epidemics breaking out and asymptomatic reservoirs of infection in the community, the approach to limiting disease spread needs to be holistic. The disinfecting guide in this article is essential but continuous adherence may be difficult once lockdowns are eased. As congested centralized specialist outpatient clinics for eye patients with long waiting times, multiple assessment stations and close contacts between patients and healthcare providers, may lead to an increase in COVID-19 infections, we need to think of new models of care to reduce this risk. Outsourcing of investigations in several locations in the community combined with telemedicine is one way of achieving this aim, whilst maintaining good, appropriate quality of care for glaucoma.