Black lights emit UV radiation that can be harmful to the eyes and can affect vision over time. Although the eyes do have some built-in defenses, these weaken over time and some of the defenses themselves can affect vision.
Black lights emit UV-A radiation and what is known as blue light. Elaine Kitchel, a Low Vision Research Associate, says that these light rays have been found to prevent the retinal cells from forming cytochrome oxidase. This chemical transports oxygen to the cells involved in vision. Without cytochrome oxidase and without oxygen, the cells of the eye begin to die. The lesions that occur may be scattered so it isn’t until many have formed that vision loss is noticed.
Limiting exposure to black lights and UV radiation is thought to limit possible harmful effects, but Kitchel explains that time has nothing to do with it. It’s not how long or how frequently your eyes are exposed to such light that matters. Researchers have found that retinal damage is a feature of exposure to these wavelengths, regardless of duration or frequency.
The Canadian Centre for Occupational Health and Safety says that UV radiation can result in conjunctivitis and photokeratitis. Conjunctivitis is inflammation of the membrane covering the whites of the eyes and the inside of the eyelids. Photokeratitis is inflammation of the cornea. The watering of the eyes that occurs because of these conditions can blur vision. Both of these are temporary conditions.
Dan Roberts, Director of Macular Degeneration Support, says that over the years, cellular debris buildup in the retina can make the eyes even more sensitive to damage from light exposure. Cataracts, the protein clumps in the lens of the eye, are actually the eyes' defense mechanism. This cloudy, pearl-like effect limits UV radiation damage to the retina but also increasingly limits vision.
The eyes use a number of chemical defenses against UV radiation, says Dan Roberts. There are multiple built-in chemical defenses, and antioxidants in the diet such as vitamin C and E can also help to protect the eyes from black light. These defenses weaken with age, disease, neglect and poor nutrition.
As we age, the lens of the eye begins to yellow. This darkening of the lens helps filter black light and other UV radiation. Children, however, haven’t developed this protective yellowing and are more at risk for retinal damage from black light and UV radiation. Surgery to remove cataracts also removes the protective yellowing.