These habits tire eye muscles but won't permanently damage vision.

When outdoors during the day, wear sunglasses that screen 100 percent of UVA and UVB rays.

A deficiency severe enough to cause night blindness is rare, but any disease or condition that interferes with the body's vitamin A absorption can affect night vision.

Lawnmowers cause more than 5,000 eye injuries each year, according to Prevent Blindness America. Stones and other objects can shoot out from beneath a mower, ricochet off a curb or foundation, and hit the person mowing. An errant basketball can fracture an eye socket, scratch a cornea, or cause other eye damage. Household chemical can damage the eyes if the chemicals accidentally splash. Be cautious when opening and using detergents, bleaches, ammonia, and oven and drain cleaners.

Glaucoma, diabetic retinopathy, and some forms of age-related macular degeneration can be successfully treated if diagnosed early enough. That's why it is important to have your vision routinely checked by an eye care provider.

In most cases, increased pressure inside the eye causes glaucoma. Unless this pressure is controlled, it can damage the optic nerve and lead to permanent vision loss. People at risk for developing glaucoma include African Americans older than 40, anyone older than 60, and those with a family history of glaucoma.

Scientists have identified a higher correlation between the development of cataracts and diabetes, use of steroids such as prednisone and aging. Smoking and prolonged exposure to extremely bright sunlight, such as that experienced by fishermen, also seem to increase the risk.

In AMD, the cells in the macula (the central portion of the retina) gradually cease to function, causing a person's central vision to become fuzzier and eventually make it impossible to read, drive, or do close-up work. Most people with AMD retain their peripheral vision.

Make sure your diet includes plenty of these, as well as other vegetables and fruits.

A high-dose combination of these elements reduced the risk of advanced stages by 25 percent, according to the study, which was sponsored by the National Eye Institute. Zeoxanthin, a carotenoid found in spinach and greens, also helps. The wet form of AMD, the less common form, can also be treated with laser therapy or medication. Two drugs have been approved by the Food and Drug Administration to slow or block the growth of new blood vessels in wet AMD, thus preserving sight. Both are injected into the eye. Pegaptanib, a drug that is injected every six weeks, was approved in 2004; ranibizumab, which is injected monthly, was approved in 2006.