Sun can damage eyes in unexpected ways

If your eyes feel tired, sore and gritty after a day at the beach, skiing or boating, you may have experienced UV radiation exposure.
Although direct sunlight can be extremely damaging to eyes, reflected UV rays can be even more dangerous. For example, grass, soil and water reflect less than 10 percent of the UV radiation, but fresh snow reflects as much as 80 percent, dry sand about 15 percent and sea foam about 25 percent.
And, because you're more likely to look down than up, there is a difference in the amount of UV light reflected directly into your eyes. Hats with brims offer no protection from UV rays reflected up from surfaces such as pavement, sand and water.
The time of day also influences the available UV rays, but eye exposure to it is quite different than for skin. At noon, the UV dose can be as much as 10 times higher than the dose three hours later. But because the eye is naturally shaded by the brow ridge when the sun is high in the sky, the highest ultraviolet radiation exposure for eyes is actually in the morning and mid-afternoon, rather than at noon, as it is for skin. Sun exposure to the eyes tends to be more constant in fall, winter and spring, when the sun is lower in the sky.

While sunglasses are definitely a good idea when it comes to eye protection, not all sunglasses are created equal. Choose sunglasses that limit transmission to no more than 1 percent UVB and 1 percent UVA rays. Sometimes the information on the glasses will say they block at least 99 percent of the UV rays. That's OK. Other things to look for:
Lenses large enough to completely cover the eye and prevent as much light as possible from entering through the edges of the glasses. Wrap-around sunglasses are best.
Darker lenses are especially beneficial for those who are more light sensitive.
Gray lenses provide the least color distortion but not any better protection than other colored lenses.
While most sunglasses can help block UV rays from entering through the lenses, most frame styles do not prevent rays from reaching the sides, top and bottom of the glasses.
UV blocking contact lenses can also provide an important measure of additional protection. The level of protection can vary.
Contact lenses that help protect against transmission of harmful UV rays are classified into two categories: Class 1 and Class 2. Class 1 UVblockers provide the greatest measure of UV protection.
Researchers estimate that a significant amount of lifetime exposure to UV rays may occur by age 18 and that children's annual dose of radiation may be up to three times that of adults. Children have larger pupils, allowing more light into their eyes, and clearer lenses, and are outside without eye protection much more frequently and for longer periods than most adults. That's why it's so important to protect children's eyes with appropriate eyewear.
More is better when it comes to protecting your eyes from the sun, according to eye experts. If you're planning to be out in the sun, protect your eyes with a combination of quality sunglasses, UV-blocking contact lenses and a wide-brimmed hat.
Sources: American Optometric Association, and American Academy of Ophthalmology