In the rush to pack for trips to the beach or to wilderness retreats, some people will forget necessities like their toothpaste or a pillow for napping in the car. Indiana University optometry professor Arthur Bradley wants to make sure people don't forget their sunglasses.
"Exposure to high levels of UV radiation can and will damage your eyes," said Bradley. "The effects can range from an annoying scratchy feeling in your eye that eventually goes away to an incurable blindness."
According to Bradley, the annoying scratchy feeling is the result of a condition called UV keratitis. This condition is caused by damage to the corneal epithelium, the first layer of cells that coat the front of the eye. Bradley said that it takes about six hours after the damage occurs before somebody starts experiencing symptoms: pain, tearing, spasms in the eyelids, and/or blurred vision.
Associate Dean of Optometry Victor Malinovsky said that while UV keratitis is fairly rare, people run the greatest risk when they are in highly-reflective environments, such as when they're boating or water skiing on a bright day.
"In most cases, the damage is very mild," Bradley said. "The symptoms will usually disappear within one or two days."
Malinovsky said that occasionally people will need medical help. "If the symptoms are bad, people should try to go to an eye care professional, either an optometrist or an ophthalmologist," Malinovsky said. "But often, people don't start getting symptoms until early evening, so they end up having to go to the emergency room."
Bradley said that UV poses the biggest danger in that it has been linked to macular degeneration and to cataracts, an opacification of the lens that will eventually lead to partial or complete blindness.
Malinovsky said that most people will develop cataracts if they live long enough, but exposure to ultraviolet light will certainly speed up the process. He added that people who live in the tropics tend to develop cataracts 10-20 years earlier than people who live in temperate regions such as the American Midwest.
Bradley said that although many people are meticulous about slathering on sunscreen before they go out in the sun, they neglect to use anything to protect their eyes. This is particularly dangerous, because while the skin can give itself some protecting though tanning, our eyes obviously don't tan and won't develop any sort of resistance to ultraviolet radiation.
"Perhaps the most dangerous situation is created when there is a thin cloud cover," Bradley said. "Because the clouds absorb more infrared radiation than UV, the sunlight feels less intense. Although the sunlight does not feel hot under the clouds, it is still irradiating you with large amounts of UV," he said.
Bradley said that because of this, many people don't think they need protection on cloudy days and end up with a bad sunburn and painful eyes.
Bradley added that although UV-blocking sunglasses are the best protection for the eyes, not all sunglasses are created equal. He said that some people mistakenly think that very dark shades provide the best protection.
"Because we cannot see UV radiation at all, no amount of visual inspection will tell you how much UV is filtered out by your sunglasses," he said.
Bradley said that people can get UV-filtering coatings put on the lenses of their regular glasses or on their contact lenses.
"The rule of thumb is simple: if in doubt, always wear UV filtering sunglasses or have UV protection incorporated into your spectacles or contact lenses," he said.