Preventative Eye Care: Sun Damage
Everyone knows how dangerous and even deadly the effects of the sun are on the skin, but few people are aware of how damaging the sun is to the eyes and vision. The extent of eye damage caused by the sun can range from short term and extremely painful to permanent blindness.
Sun damage is caused by ultraviolet (UV) rays, not brightness itself. The natural tendency to squint and contraction of the pupil that help to protect the eyes are a reflexive response to brightness that will not protect the eyes on a cloudy day when UV rays can be very strong.
Sunburned corneas (photokeratitis) and sunburn of the inside of the eyelids and eye socket (photoconjunctivitis) are very painful conditions, but they will go away in most cases, and vision will return to normal.
Snow blindness is an extreme form of photokeratitis. Snow reflects about 80% of UV rays greatly adding to UV exposure. Snow blindness is very painful. The outer cells of the eye are killed by the high intensity UV rays and temporary blindness results. Those dead cells slough off, the most painful stage of the injury, and sight normally returns in about 12 to 48 hours. Because it is so painful and debilitating, most people who suffer snow blindness will do whatever it takes to avoid repeating the experience, but some people never learn and eventually are permanently blinded.
Pingueculae is a small raised area on the eye and can turn into pterygium. Pterygium can grow over the cornea and create vision problems. Both feel like a foreign object in the eye all the time and can interfere with proper lubrication of the eye. They look like a chunky spot on the eye. Pingueculae and pterygium are irritating and visually unappealing. They can be surgically removed, but more than half will grow back.
Cataracts, clouding of the lens of the eye, are the leading cause of blindness worldwide. The World Health Organization estimates the up to 20% of cataracts are caused by over exposure to the sun, and therefore are completely avoidable. Cataracts are treated by removing the lens of the eye and replacing it with an artificial lens.
Macular degeneration is the breakdown of the macula, the center of the retina. Prolonged exposure to sunlight breaks down macular cells and can cause both wet and dry macular degeneration. People with light colored eyes seem to be more likely to experience sun damage of the macula.
Cancers and Other Conditions
Over time exposure to the sun can cause cancer of the eyeball and cancer of the eyelids.
Climatic droplet keratopathy, also known as Labrador keratopathy or keratinoid degeneration, is a degenerative condition of the cornea caused by UV exposure.
Preventing Sun Damage
The most obvious way to avoid harm is to stay out of the sun. That idea can be deceptive, however, as an overcast day and reflections from water, snow, sand, concrete, and other ground cover can create significant UV exposure to those who feel they are safely in the shade. Sunglasses with 99% or 100% UV protection should always be worn outside during the day, even on a cloudy day and even in seemingly shaded areas. Sunglasses can still allow harmful rays to reach your eyes through the sides and from the top and below. A hat with a three-inch brim can provide further protection. People who must be outside for extended periods of time should wear wrap-around sunglasses. Glacier glasses have a vented piece of leather around the outside of each lens which prevents light from creeping in around the glasses from any direction and are an excellent choice for skiers.
Parents, with all the best intentions, often insist that their children spend as much time outdoors as possible. Playing outside is good for vision development, as it encourages the constant shift of focus from near to far away objects and back, but without proper protection from the sun it can be very harmful. Children are even more susceptible to sun damage than adults and must wear sunglasses whenever they are out in the sun. It is very important that children wear real sunglasses with UV protection, not toy sunglasses that can actually be more harmful because they deter the squinting reflex and natural aversion to bright light.
If you are not sure if your favorite sunglasses provide sufficient UV protection, your eye doctor can test your lenses. Talk to your eye doctor today about UV protection for your eyes and your children’s eyes.