Macular degeneration is a potentially blinding disease of the retina, the light-detecting tissue within the eye.

The macula, the area of the eye affected by macular degeneration, is a small and unique region of the retina where fine-detailed vision is possible as a result of a higher concentration of light-sensitive cells. Macular degeneration is common in older adults, with as many as one in four patients over the age of 65 being affected, and over one-third of those over age 80. Although the majority of patients with macular degeneration will not lose substantial vision from the disease, it remains the leading cause of blindness among older Americans.

The underlying cause of macular degeneration is not completely understood, although research suggests that inflammation and genetic susceptibility play prominent roles in its development. Certain individuals are at increased risk of developing macular degeneration, including older persons, smokers and those with a family history of the disease. Caucasians are much more likely to develop macular degeneration than those of African or Hispanic descent. Some studies have linked short-wavelength light exposure to an increased risk of macular degeneration, but these findings are not well substantiated.

There are two distinct threats to vision in macular degeneration. Vision loss in the most common form of the disease – often called “dry” macular degeneration – results from progressive disruption and wasting away of the outer retina, which plays a critical role in vision. In the less common form of the disease, often called “wet” macular degeneration, growth of abnormal blood vessels into or underneath the retina occurs, causing swelling and bleeding into the area of best vision that later results in scarring. If left untreated, nearly all eyes with wet macular degeneration progress to central blindness.

There is no cure for macular degeneration; however, certain treatment options are available. For the wet form of the disease, the most effective treatment involves injection of medication into the eye to control new blood vessel growth. Often repeat injections are needed and are given as often as once per month, sometimes for years.

For the more common dry form of macular degeneration, treatment is much more limited. There is evidence that certain dietary supplements containing vitamins C, E, beta-carotene and zinc may help slow the progression of the disease to advanced stages associated with more severe vision loss. Unfortunately, the supplements appear to be of no benefit in preventing macular degeneration for those who do not yet have the disease. Additionally, studies show that individuals with an early form of macular degeneration are also not helped by thesesupplements. Only people who have already developed moderate to advanced macular degeneration in one eye may benefit from the supplements, and of these, only a small percentage (10 percent) will actually benefit – the supplements do not appear to modify the course of the disease in 90 percent of these patients.

Related studies have looked at whether adding additional supplements like lutein/zeaxanthin and omega-3s may also help slow progression of macular degeneration. This question was recently answered in a well-designed study that showed lutein/zeaxanthin and omega-3s to be of no additional benefit, although the question is likely to be studied further for lutein in certain subgroups of people with the disease.

Individuals who are current smokers or former smokers should be cautioned about taking supplements with beta-carotene as it may increase their risk of developing lung cancer.

For those who have lost vision from macular degeneration, there is still hope to restore function and maintain or improve quality of life through low vision therapy.

Low vision therapy focuses on allowing people with vision loss to read, write, perform hobbies or occupational functions, and sometimes even drive by utilizing magnification and other devices.

Individuals with macular degeneration who have experienced a loss of visual function are encouraged to seek out a low vision practitioner with specialty training in this area as well as contact the Oregon Commission for the Blind to explore available options.

Patients who are at higher risk for macular degeneration should consider regular dilated eye examinations from an optometrist or ophthalmologist to monitor for signs of the disease even in the absence of a need for vision correction.

Dr. David Glabe in an optometrist at La Grande Family Eye Care