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

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

A deficiency severe enough to cause night blindness is rare. But any disease or condition that interferes with how the body absorbs vitamin A 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, bounce 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 (AMD) 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 glaucoma include African Americans older than 40, anyone older than 60, and those with a family history of glaucoma.

Scientists have found a close tie between 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 central portion of the retina (macula) gradually stop working. This causes a person's central vision to become fuzzier. Eventually AMD makes it impossible to read, drive, or do close-up work. Most people with AMD still have their peripheral vision.

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

A high-dose combination of these supplements lowered the risk for advanced stages by 25%, according to the study, which was sponsored by the National Eye Institute. Zeaxanthin, 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 medicine. Three medicines that are injected into the eye have been approved by the FDA to slow or block the growth of new blood vessels in wet AMD, thus preserving sight. Pegaptanib was approved in 2004, ranibizumab was approved in 2006, and aflibercept was approved in 2013. Bevacizumab is a fourth medicine that is commonly used. It is similar in structure to ranibizumab, and is also injected in the eye. Bevacizumab was approved by the FDA in 2004 for cancer treatment. It is used off-label to treat wet AMD.