Ultraviolet lamps meant to kill viruses and bacteria seem to be causing unfortunate eye damage in some people. In a new paper this month, doctors report several cases where people developed inflamed corneas due to UV radiation exposure from “germicidal lamps” put in place during the covid-19 pandemic. Some of the patients weren’t even aware the lamps had been installed.
UV lighting has gotten plenty of attention as of late, since the radiation can degrade the stability of many unwanted germs. Specialised lamps have been used in the past to control outbreaks of other potentially airborne diseases, including tuberculosis. Now many businesses and hospitals are using UV light to disinfect rooms and equipment.
The trouble is that UV radiation can harm humans, too, as anyone who’s ever gotten a sunburn well knows. Exposure to UV rays can damage both our skin and our corneas, the transparent and protective outer layer of our eye. When this happens, it causes a painful inflammation called photokeratitis.
In this new paper, published in the journal Ocular Immunology and Inflammation, the authors describe seven cases in which people developed photokeratitis several hours after exposure to UV lamps. All the cases were seen by doctors at the Bascom Palmer Eye Institute at the University of Miami Miller School of Medicine.
In addition to irritation and redness, some patients experienced mild symptoms such as feeling like there was something stuck in their eyes. Others experienced severe, painful burning and a sensitivity to light. In three cases, the lamps had been installed at home, while three of the patients had been exposed at work. In all these cases, the patients reported making direct contact with the lighting without eye protection (a seventh case involved someone exposed to UV lighting at a dentist’s office).
Thankfully, people’s symptoms were short-lasting following treatment — usually a combination of lubricating eye drops, antibiotics, and steroids — and most recovered completely within two or three days. But these injuries aren’t the first of their kind to be seen during the pandemic. Earlier in April, the authors noted, doctors in Hong Kong reported three similar cases in a single household.
It’s not clear whether UV lighting has really been all that helpful during this pandemic. Enough UV radiation should be able to kill coronavirus lingering in the air or on surfaces and objects, like the protective masks used by health care workers. But the exact type of UV radiation that’s most effective at killing viruses (UV-C) is also very dangerous to people, limiting how useful this disinfection strategy can be in the real world. The World Health Organisation now explicitly warns people to not disinfect themselves using UV lamps for that very reason.
“Installation of UV-C air disinfection in medical facilities requires well-trained technicians to avoid direct exposure of occupants,” the doctors wrote. “The authors caution all persons to avoid direct exposure to UV-C germicidal lamps and follow manufacturer recommendations closely.”
While this current study isn’t intended to weigh in on the effectiveness of UV lamps for covid-19 prevention, it does reinforce why people should be careful around them at all times.