The macula is a part of the retina in the back of the eye that is responsible for our reading or central vision. It is the most sensitive area of the retina and is critical to our day-time color vision. Age-related macular degeneration (AMD) is primarily a genetic disorder (meaning that it runs in families) that results in damage and, ultimately, loss of cells critical for visual function of the macula. As retinal tissues begin to weaken and die, central vision loss occurs. Patients may experience a blurry, smudged or distorted area in the center of their vision.
AMD is the leading cause of vision loss in the United States and other developed countries. Macular degeneration, fortunately, rarely causes total blindness because it does not often affect the peripheral vision. Risk factors include genetics, age, diet, smoking and, possibly, sunlight exposure. Regular eye exams are highly recommended to detect macular degeneration early and prevent permanent vision loss. Specific vitamin supplements may be recommended to reduce the risk of vision loss in certain individuals. Symptoms of macular degeneration include:
- A gradual loss of ability to see objects clearly
- A gradual loss of color vision
- Distorted or blurry vision
- A dark or empty area appearing in the center of vision
There are two forms of AMD: dry (non-neovascular) and wet (neovascular). AMD initially begins as the dry form with gradual thinning of the retina, loss of retinal pigment and the formation of small, round nodules beneath the retina called drusen. Vision loss with dry AMD is slower and can be less severe than with wet AMD although patients with dry AMD may develop significant visual damage after many years with the disease. There is currently no specific treatment for dry AMD although dietary modification and vitamin supplementation may slow the progression of vision loss.
About 10-15% of individuals with the dry form may eventually convert to the wet or neovascular form of AMD. “Neovascular” means new vessels. Accordingly, wet AMD occurs when new blood vessels grow into the retina as the eye attempts to repair the damaged tissue. Unfortunately, these new vessels are very fragile, and often leak blood and fluid between the layers of the retina (thus the term “wet”). Not only does leakage distort vision, but when bleeding occurs, scar tissue often forms beneath the retina. This damages the retina and creates a dark spot or smudge in the central vision.
Recent advances in retinal research allow doctors at NBVC to successfully treat many patients with early-stage wet AMD with the help of intraocular medication and, sometimes, lasers. These new treatments have greatly improved the prognosis for patients in the early stage of the disease. The presence of effective treatment also increases the importance of early detection. Early detection is more likely with regular retinal examinations and if the patient seeks prompt attention when new symptoms arise.