We all know by now that it’s important to protect our skin from excessive Sun exposure, to avoid skin cancers that can be caused by the Sun’s ultraviolet rays.
But besides our skin, other organs that need protection from the Sun are our eyes.
While protecting skin and eyes from overexposure to the Sun’s UV rays is important year-round, it is all the more essential in the summertime, when the Sun’s rays are the strongest because Earth’s northern hemisphere is tilting toward the Sun.
Just like overexposure to UV rays can burn the skin, it can also burn the eyes’ outermost layer, as well as the corneas and the lenses. Sunburn of the corneas is called photokeratitis; the condition can cause excessive tearing, and it can feel like there’s grit inside the eyes, from layers of cornea peeling after they’re sunburned. In more serious burns, photokeratitis can cause painful, temporary blindness; people describe the sensation as their eyeballs being “on fire.” Because photokeratitis usually occurs in combination with cold wind and snow, it is also called snow blindness. People with lighter-colored eyes are at higher risk for damage to the corneas from too much sunlight.
There is usually no long-term damage associated with photokeratitis. However, long-term excess exposure to the sun’s UV radiation can contribute to chronic conditions, such as the development of cataracts (a clouding of one or both lenses that diminishes vision); macular degeneration (a condition that leads to distortion or loss of vision in the center of the field of vision); certain eye cancers; and growths on the visible surface of the eyes, which can be removed with delicate surgeries, but which can recur. Long-term Sun exposure without protection can also damage the retina; this damage is irreversible.
The Importance of Protecting the Cornea
The cornea is a transparent layer in the front of the eye that covers the iris (the colored part that controls how much light goes in), the pupil (the hole in the middle of the iris through which the light enters), and the anterior chamber (a fluid-filled pocket between the cornea and the iris). But the cornea serves as more than just a protective layer for the eye; the cornea, the anterior chamber and the lens, which is behind the iris, refract (bend) incoming light rays toward the center of the eye, allowing them to enter through the pupil, after which the rays reach the light-sensitive layer that lines the inside of the eyeball, the retina.
The cornea, then, is an important component in our eyes’ ability to form images with the help of light rays. And because it’s first in line, the cornea bears most of the damage when we don’t protect our eyes from excessive UV radiation. (We need to keep in mind that UV radiation is also produced by artificial sources of light, such as household lights, tanning beds, a photographers’ flood lights, welding equipment, etc.)
How Do We Protect our Eyes from Sun Damage?
Sunglasses and a wide-brimmed hat or sun visor are your two best defenses whenever you spend time in the Sun — be it gardening, driving, snow-skiing on a sunny day (snow reflects sunlight, making the likelihood of sunburn greater), and so forth.
With respect to sunglasses, don’t go by price; some inexpensive glasses may offer full UV protection, while some expensive ones may not. The best thing to do is check tags or stickers on glasses, to make sure that they indicate that glasses offer “100% UV protection.” You want glasses that protect against both UVA and UVB rays.
Be wary of ultra-cheap glasses that small vendors may sell, and buy your sunglasses at an established chain store or department store (several companies also sell glasses with full UV protection online). Sunglasses that haven’t been coated to block rays can actually do damage: the dark lenses will cause your pupils to relax and let in even more UV radiation.
Keep in mind that if you wear contact lenses with UV protection, you still need to wear sunglasses, if you’ll be in the Sun (or in a very bright space) for a prolonged period, as contacts don’t protect the white area that surrounds the cornea and iris. Wrap-around lenses, though not necessary, will add protection by keeping sunlight from entering through the sides. If you have children, outfit them with protective sunglasses, too; they need protection from the sun, just like adults.
By Lisa Pecos