Screening cataract patients may shed light on COVID-19 rates

Routine screening of cataract surgery patients for COVID-19 could help improve understanding of community infection rates, says new analysis from the Centre for Eye Research Australia.

Writing in Clinical & Experimental Ophthalmology, CERA researchers argue that cataract surgery patients are good candidates for ‘sentinel surveillance’ COVID-19 screening and testing programs.

They say this group of patients could provide a good indicator of the rate of transmission because they may be more susceptible to COVID-19 infection and they are also at higher risk of complications as many also have diseases such as diabetes or asthma.

“Cataract surgeries are one of the most common elective surgeries in the world, so could enable the widespread screening of a very large and representative segment of the at-risk population,” says lead author Dr Joshua Foreman.

“The procedure used to conduct these surgeries can also be high-risk for surgical staff, so pre-screening could also benefit healthcare workers and patients.”

Dr Foreman explains that while in Australia some patients are pre-screened for COVID-19 this may change over time and is not always the case overseas.

This makes the recommendations useful for the development of large-scale testing programs and infection control measures internationally.

“Importantly, we are not suggesting that anyone who needs cataract surgery should put off seeking care – the testing process we recommend is simply a way of improving understanding of the pandemic.”

What is a sentinel surveillance screening?

Sentinel surveillance screening tests a subset of the population to help health authorities understand the rates of transmission and prevalence of a disease, as well as predict outbreaks.

Dr Foreman, from the CERA and the University of Melbourne, explains they are an important public health screening measure.

“Generally, estimates of the number of infected people are based on symptomatic people or their contacts who present for screening – which means there are potentially many asymptomatic or pre-symptomatic people who are not being detected,” he says.

“In a pandemic it’s not feasible to test everyone for COVID-19 and random testing of asymptomatic people can be costly and inefficient.

“It makes sense to test a subset of the population to gain an idea of the rates of transmission and the prevalence, as well as to predict outbreaks. You can think of sentinel surveillance as the canary in the coal mine.”

High-risk patients

To determine whether cataract patients were at higher risk of poor outcomes from COVID-19 authors Dr Myra McGuinness, Associate Professor David A. Mackey and Associate Professor Peter van Wijngaarden used data from two major Australian epidemiological studies – the National Eye Health Survey (NEHS) and Melbourne Collaborative Cohort Study (MCCS).

They compared risk factors in NEHS participants who had undergone cataract surgery and those who had not. They did the same for MCCS participants who had reported cataract diagnosis in the preceding year compared to those who had not.

They found:

  • NEHS participants aged 40-98 years who had undergone cataract surgery in the past year were more likely to be 65 or older, have diabetes and a history of stroke.
  • MCCS participants aged 40-80 years who had a cataract diagnosis in the previous year were also more likely to be 65 or older and have a history of asthma, hypertension, and diabetes.

“These findings indicate that people undergoing cataract surgery are a group with risk factors for transmission, infection, complications, and death from COVID-19,” the authors said.

They said screening questionnaires before surgery and testing at around the time of surgery would yield dual benefits of protecting patients and healthcare workers whilst supporting infection control amongst a high-risk segment of the population.

What’s next?

Dr Foreman says he hopes the group’s analysis will contribute to the public health debate about COVID-19.

“COVID didn’t come with a handbook,” he says. “It took us by surprise. The global community is still trying to figure out what to do and the best way forward. This may be one piece of the puzzle.”

Read the full article

You can read the full article Cataract surgical patients as candidate sentinel population for SARS-CoV-2 surveillance Joshua Foreman PhD, Myra McGuinness PhD, David A. Mackey MD FRANZCO and Peter van Wijngaarden PhD FRANZCO.

DOI: 10.1111/ceo.13844

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