Dec 10, 2013
Sun Damage: Darker Lenses Possibly More Dangerous
Posted on Jul 11, 2013
Darker sunglasses that don’t protect against ultraviolet light allow more of these higher-energy waves into pupils that are overly dilated because of low-light conditions, leading to greater probability of injury, experts say.
“Dark shades cause more harm because you lose that protective reaction: you don’t squint, your pupils don’t constrict,” Edward Kondrot, an ophthalmologist in Dade City, Fla., told MedPage Today. “And you get excessive amounts of sunlight into the eyes.”
The key, he says, is to choose a pair of sunglasses that is guaranteed to block UVA and UVB rays.
On the electromagnetic spectrum, ultraviolet light occurs in the range of 100 to 400 nanometers. Most of the UV light that reaches the earth’s surface is UVA, from 315 to 400. Light in this range can alter chemical bonds in skin molecules, as seen in sunburn.
Like the skin, the eye also absorbs UV. Shorter and more dangerous wavelengths are caught by the cornea, with longer wavelengths potentially reaching the lens and retina, experts say. That’s why ophthalmologists insist that UVA and UVB protection in sunglasses is more important than the intensity of their tint.
—Posted by Alexander Reed Kelly.
Previous item: Snowden Says He Gave No Secrets to China or Russia
New and Improved Comments