Can coronavirus affect eyesight? Evidence is lacking, say experts
Speaking to the press on Monday, Dominic Cummings said he drove, with his wife and child, on a 30-mile trip to Barnard Castle during lockdown to see if he could drive safely, concerned that his eyesight might have been affected by coronavirus.
In a press conference later the same day, Boris Johnson also claimed to have experienced problems with his eyesight following Covid-19, brandishing a pair of glasses and saying: “I’m finding that I have to wear spectacles for the first time in years … I think that’s very, very plausible that eyesight can be a problem associated with coronavirus.”
Eye problems are not on the UK’s list of coronavirus symptoms. At present, only a high temperature, new continuous cough, and loss of taste or smell are considered common signs of the disease.
A spokesperson for Moorfields eye hospital, in London, said there was, at present, very little evidence to suggest Covid-19 could affect eyesight.
“Cases where Covid-19 is recorded alongside an impact on eyesight are rare, so we cannot establish a direct causal effect,” the spokesperson said.
Prof Chris Hammond, Frost chair of ophthalmology at King’s College London, who is also a consultant ophthalmologist at Guy’s and St Thomas’ NHS trust, said: “Eye problems with coronavirus, Covid-19, seem to be extremely uncommon and there aren’t any reports that I can find in the literature of anyone having visual loss due to the virus.
“Maybe something like one in 100 people may get a bit of conjunctivitis, which can in theory blur vision. But it is pretty uncommon.” He added that such eye problems were more frequent among patients who had been ventilated.
Conjunctivitis is an inflammation of the thin layer of tissue that covers the eye, and typically has symptoms including pinkness of the eye, watering and a sticky discharge.
Robert MacLaren, the professor of ophthalmology at the University of Oxford, said reports from Wuhan suggested a link between Covid-19 and conjunctivitis, as well as conjunctival hyperemia (red eye), chemosis (eye swelling), epiphora (watery eye) and increased secretions (sticky eye). MacLaren noted such symptoms could affect vision.
A spokesperson for the Royal College of Ophthalmologists said the college was unable to report on an association of vision impairment with Covid-19 due to the lack of evidence. But, they added, the college had previous noted coronavirus might cause conjunctivitis.
Hammond said it would be clear to an individual if they had conjunctivitis. “You would be aware that you had a bit of a pink eye and it was a bit watery and discharging. A bit like a windscreen wiper on a car, you have to blink to clear the muck off the tear film.”
Hammond said a report from Brazil suggested that, from scans, some Covid-19 patients appeared to have some damage to the retina, but the patients did not have any symptoms of eye problems or loss of vision.
Hammond added that severe Covid-19 might mean patients needed their reading glasses more.
“It is true when you have been significantly unwell, that as all your muscles are a bit weaker, the muscles that control the focus of your eyes can be weaker,” he said. But the situation, he noted, applied only to farsighted people, adding that Cummings appeared to wear glasses for short-sightedness – myopia – being unable to see
well in the distance.
As for getting behind the wheel of the car to test your eyesight, Hammond said the Highway Code stated that drivers needed to be able to read a vehicle number plate at a minimum distance of 20 metres. “When you have your driving test to see if you are seeing well enough to be allowed to drive, they test whether you can read the number plate before they allow you in the car,” he said.