Sun and Your Eyesight

You probably know that if you stay in the sun all day with no sunscreen or UV-blocking clothing, you will be burnt. Most people also know that if they do this for years, they may have a lovely suntan, but their skin will be damaged and will eventually develop patches of discoloration, wrinkles, and a leathery texture.

Do you also know that the eyes can be sunburnt? If you expose your eyes to too much sunshine for too many years, they can be permanently damaged in ways that will impair your eyesight. Ultraviolet light can be kept from causing eye damage if you:

* Stay out of the sun; or
* Wear polarized and well-designed sunglasses

But most of us love being outdoors on a sunny day; and many people wear low-quality sunglasses if they wear any at all.

If you wear a shady hat, you are protecting yourself partially but not fully. UV rays are reflected off many surfaces, such as snow, water, and cement and will enter your eyes from beneath your hat. However, good sunglasses plus a hat will protect you well. The best sunglasses have polarized lenses and frames with protection at the sides and top.

Three Types of UV Rays

* UVA rays – These have the lowest energy but can travel through the cornea (clear front part of the eye) to the lens and retina (“camera film” at the back of the eye) and damage your eyesight.
* UVB rays – These have higher energy but are partially filtered by the earth’s ozone layer. They stimulate the skin to produce more melanin (pigment), thus giving you a suntan; but in higher doses they contribute to cancer formation on the skin, growths on the eyes, and “snow blindness”, which is temporary vision loss caused by burned corneas.
* UVC rays – These have the highest energy but the ozone layer blocks most of them.

UV Rays and Eye Problems

Too much UVA exposure has been linked to cataracts – clouding of the lens that blocks light from reaching the retina and thereby reduces vision. Left untreated, cataracts will cause total blindness. UVA rays have also been linked to macular degeneration – deterioration of the retina’s central area that gives us our color perception and our sharpest vision in bright lighting conditions. Macular degeneration also causes total blindness.

The cornea blocks most of the sun’s UVB radiation, protecting the lens and retina from harm. But too much UVB exposure can cause growths called pingueculae. They are yellowish lumps on the sclera (white part) close to the cornea. Usually they occur in older people but depending on how much sun exposure there is, they can be found in young people and even children. Dryness, dust, and wind can inflame them, causing pain and redness.

In some cases, pingueculae lead to pterygia, which are wedge-shaped growths that may extend right into the cornea and directly impair your eyesight. They are quite visible to others, affecting your whole facial appearance.

Sun damage to the eyes is cumulative. That makes it important to protect your children’s eyes so that when they reach mid-life their eyesight might be free of the above problems.