What is Macular Degeneration?
Macular degeneration is the breakdown and damage of the central retina, or macula. This small area in the back of the eye is responsible for crisp, detailed vision. If there is damage to the macula, the central part of our vision becomes distorted, blurry, or dark leading to difficulty reading, watching TV, driving, identifying faces, doing detailed work, and other daily tasks. It is the leading cause of vision loss in people over the age of 65 in the United States. Macular degeneration affects both near and distant vision. Although macular degeneration affects the central part of vision, it does not affect peripheral vision. As a result, macular degeneration alone does NOT lead to total blindness. People continue to have some useful vision and are able to take care of themselves.
Types of Macular Degeneration
There are two main types:
Dry (atrophic) macular degeneration
This is the most common type and is seen in 90% of cases. It is caused by aging, degeneration, and thinning of the tissues of the macula. Vision loss is usually gradual and not as severe. The loss of vision is related to the amount and location of the retinal thinning. There are no good treatments for this condition. This type only accounts for 10% of blindness related to macular degeneration.
Wet (exudative) macular degeneration
This is present in about 10% of cases, but is responsible for 90% of the blindness associated with this condition. It results when abnormal blood vessels leak fluid or blood under the central retina. These changes can cause rapid and severe vision loss with possible permanent scarring and the creation of blind spots.
The onset and progression of macular degeneration does not follow any pattern. Also, it is possible to develop both forms at the same time, in one or in both eyes.
Symptoms vary from person to person. Sometimes, one eye loses vision while the other eye continues to see well. Some common visual symptoms include:
- Dark or empty areas (blind spots) in the central part of vision
- Straight lines appear distorted and wavy
- Words appear blurred when reading
Diagnosing Macular Degeneration
This requires a thorough eye exam that may include special vision tests, high magnification views of the retina, and occasionally special diagnostic tests and photographs. Your doctor may be able to detect early signs of macular degeneration, before any symptoms develop, through a regular eye exam.
Causes and Risk Factors of Macular Degeneration
Many causes of macular degeneration are a result of aging and natural deterioration of the eye tissues. There are also some genetic markers that are becoming tied into developing some of the severe types of this disease. Macular degeneration is more common in women and Caucasians. Over 14% of adults between the ages of 70 and 79 have some form of macular degeneration.
Other factors that may increase your risk for macular degeneration include:
- High fat diet
- Prolonged sun (ultraviolet light) exposure
- Light eye color
- High blood pressure
People can minimize their risk of macular degeneration by practicing a healthy, active lifestyle that includes regular exercise, a balanced diet, no smoking, use of good sunglasses, and regular eye exams.
Despite extensive research, there is still no cure for macular degeneration. The best treatment depends on the severity and type of the condition, as well as how much, if any, vision loss has occurred.
The Age Related Eye Disease Study (AREDS) demonstrated a benefit in slowing the progression of macular degeneration by taking anti-oxidants, minerals and vitamins. Specifically, they used vitamins C and E, beta carotene, zinc and copper. Other newer studies suggest that lutein may also be beneficial. A variety of vitamin formulations are available over-the-counter or by mail order.
“Wet” macular degeneration can be treated with special intraocular injections that are often successful in stopping abnormal blood vessel growth. These regular injections can control, and in some cases improve, the damage from wet macular degeneration. In addition, lasers can sometimes be combined with these intraocular treatments to try and improve the results. Despite proper medical treatment, many people with macular degeneration still experience vision loss.
A wide range of support services and rehabilitation programs are available. Since peripheral vision is usually unaffected, this remaining vision is very useful. Often, people can continue with many of their favorite activities by using low vision optical devices.