Of all the eye diseases that occur as we age, macular degeneration is the least known, but is most likely to cause vision loss and blindness. Since macular degeneration happens slowly and painlessly, people may not be aware they have a problem until they have significant vision loss.

Macular degeneration happens when the central part of the retina (called the macula) deteriorates, damaging the central vision. It cannot be cured, but there are some ways to slow the progression of this eye disease.

There are several types of macular degeneration. Rarely, the disease begins in childhood, adolescence or early adulthood. These juvenile-onset types of macular degeneration are often inherited and run in families.

Age-related macular degeneration (ARMD) is much more common, occurring in people age 60 and older. About 1.6 million Americans have ARMD.

To diagnose macular degeneration, an eye doctor will examine your eyes and do a test of your central vision. This is often done by having you look at a grid. If any of the straight lines on the grid appear broken or wavy, macular degeneration is likely.

Another test is called fluorescein angiography, in which a dye is injected into a vein in the arm. Photographs are taken as the dye passes through the blood vessels in the back of the eye. This test measures the extent of damage from macular degeneration.

There are two types of ARMD: “wet” and “dry,” which have different symptoms and treatments. Either type can occur in just one eye, so the other eye compensates for vision problems. When macular degeneration advances over time and affects both eyes, it becomes difficult to function normally.

“Dry” macular degeneration is more common and comes on slowly. Often, the first sign is a need for increasingly bright light to read or do other close work. Printed words, people’s faces and anything in the center of the visual field may appear blurry. Some people start to notice a blind spot in the center of their visual field. Colors can appear less bright than normal.

There is no treatment for dry macular degeneration at this time, but researchers are working on ways to slow or reverse this disease.

“Wet” macular degeneration accounts for about 15 percent of cases, comes on more rapidly and is the type that causes most cases of severe vision loss or blindness. Patients with the wet form usually have the dry form first. Wet macular degeneration can also cause a blurry or blind spot, but also causes distortions in the way things look. Straight lines appear wavy, and objects may appear smaller than they actually are.

Wet macular degeneration can sometimes be treated with a laser.

There is no guaranteed way of preventing macular degeneration, but good nutrition can help. Specifically, a diet high in antioxidants is recommended to slow age-related damage to the eye. Antioxidants occur naturally in fruits and vegetables (especially leafy greens). Wearing sunglasses to block out ultraviolet light is also important.

Everyone is at risk for macular degeneration due to aging. Smokers are more likely to develop macular degeneration than nonsmokers. Females are at higher risk than males; whites are at higher risk than other races. Also, people with a family history of macular degeneration, severely overweight people, people with light-colored eyes and those who have poor diets low in antioxidants have a higher than average risk.

Anyone with vision problems should have regular eye exams. A good pair of glasses can optimize your vision. Clocks, telephones, watches, radios and appliances are available with large, easier-to-see numbers and buttons. Large-print magazines and books and books on tape are available at most libraries.

Kathryn B. Brown is a family nurse practitioner with a master’s degree in nursing from OHSU. Is there a health topic you would like to read about? Send ideas to kbbrown@eastoregonian.com.