Solar and UV Burns
If peered at long enough a bright light can cause damage to the nerve tissue layer that forms the inside lining of the back wall of the eye. This clear layer is known as the retina. It’s what stands between us and blindness.
The human eye concentrates light and heat about the same as a 40 power magnifying glass. Most of the time too much light simply makes the retina edematous, or it swells. This may cause things to look blurry or distorted. Usually in a few days the edema recedes, and the vision returns to normal.
The most common source of light causing this kind of vision problem eye is the sun. The condition is called solar retinopathy, and because it most commonly occurs during eclipses it is sometimes called eclipse blindness. If a sun gazer looks for a short time the damage resolves. If it is too long the damage is permanent.
How long is too long? A second or less can make a difference. It's better to never look at the sun under any circumstances.
Even though the sun’s intensity is greatly reduced during an eclipse, and people find it easier to stare – the amount of harmful rays remains immense. The damage that can happen during the observance of an eclipse can be permanently debilitating.
There are some other types of light sources that are known to cause solar retinopathy, but the damage is rarely permanent.
Another problem that sometimes happens with light and the eyes is with excessive ultraviolet (UV) exposure. This is sometimes called welders burn because the UV from an arc welder damages the surface of the little clear dome on the front of the eye (cornea).
This is commonly caused by welders, but it can also be caused by to much sun exposure especially when reflected off the snow (snow blindness) or by UV lights sometimes found in laboratories. UV burns are seldom serious and people usually recover after a few hours or within a day, although the discomfort during the healing time can be almost intolerable. Oral narcotics may be necessary.
Dan David, O.D.