UV lamps meant to kill viruses and bacteria seem to cause unfortunate eye damage in some people. In a new paper this month, doctors reported several cases of people developing keratitis due to exposure to ultraviolet rays from “germicidal lamps” that were placed during the Covid-19 pandemic. Some patients were not even aware that the bulbs were installed.
Ultraviolet lighting has recently gained a lot of attention, as the radiation can stabilize many unwanted germs. Specialized lamps have been used in the past to control outbreaks of other potentially airborne diseases, including tuberculosis. Now many companies and hospitals use UV light to disinfect rooms and equipment.
The problem is that UV rays can also harm humans, as anyone who has had a sunburn knows very well. Exposure to UV rays can damage both our skin and our corneas, which is the transparent, protective outer layer of our eyes. When this happens, it causes a painful inflammation called photodynamic keratitis.
In this new paper, published in Ocular Immunology and Inflammation, the authors describe seven cases in which people developed photodynamic keratitis several hours after exposure to UV lamps. Doctors saw all of the cases at the Bascom Palmer Eye Institute at the University of Miami Miller School of Medicine.
Slit lamp imaging of both eyes of a patient who developed keratitis after exposure to a UV lamp. (Photo: Singelo, et al / Immunology and ocular inflammation)
In addition to irritation and redness, some patients experienced mild symptoms such as the feeling of something stuck in their eyes. Others experienced severe, painful heartburn and sensitivity to light. In three cases, the lamps were installed at home, while three of the patients were exposed to work. In all of these cases, patients reported direct contact with illumination without eye protection (Case 7 exposed someone to UV illumination in a dentist’s office).
Fortunately, the patients’ symptoms were short-lived after treatment – usually a combination of lubricating eye drops, antibiotics, and steroids – and most recovered completely within two or three days. But these infections are not the first of their kind seen during the epidemic. Earlier in April, the authors noted that doctors in Hong Kong reported three similar cases in one home.
It’s not clear if UV lighting was really helpful during this pandemic. UV rays should be sufficient to kill the Corona virus in the air or on surfaces and things, such as the protective masks used by health care workers. But the precise type of ultraviolet light that is most effective at killing viruses (UV-C) is also very dangerous to people, which limits how useful this disinfection strategy can be in the real world. The World Health Organization now explicitly warns people against disinfecting themselves with UV lamps for this very reason.
Doctors wrote: “Installing UV-C air disinfection in medical facilities requires well-trained technicians to avoid direct exposure to occupants.” “The authors caution all people to avoid direct exposure to UV-C germicidal bulbs and closely follow manufacturer recommendations.”
While this current study does not aim to evaluate the effectiveness of UV lamps for preventing COVID-19, it does reinforce why those around them should be vigilant at all times.
