Age-Related Macular Degeneration

Age-related macular degeneration (ARMD), also referred to as Senile Macular Degeneration (SMD), is one of the most common causes of poor vision after age 60. ARMD is a deterioration or breakdown of the macula. The macula is a small area at the center of the retina in the back of the eye that allows us to see fine details clearly and perform activities such as reading and driving.

The visual symptoms of ARMD involve loss of central vision. While peripheral (side) vision is unaffected, with ARMD, one loses the sharp, straight-ahead vision necessary for driving, reading, recognizing faces, and looking at detail.

Although the specific cause is unknown, ARMD seems to be part of aging. While age is the most significant risk factor for developing ARMD, heredity, blue eyes, high blood pressure, cardiovascular disease, and smoking have also been identified as risk factors. AMD accounts for 90% of new cases of legal blindness in the United States.

Nine out of 10 people who have ARMD have atrophic (dry-type) ARMD, which results in thinning of the macula. Dry ARMD takes many years to develop. Antioxidant vitamins (high-dose Beta-carotene, Vitamin C, Vitamin E, Zinc) have been studied and shown to slow the progression of dry ARMD in "high-risk" patients. While the clinical studies only focused on a narrow group of patients with AMD, many physicians recommend vitamins to any patient with ARMD to reduce risk of progression. However, smokers should not use beta-carotene due to a reported increased incidence of lung cancer. If you are already taking vitamin supplements, you may want to consult with your doctor or pharmacist before starting additional vitamin therapy due to the potential for toxicity.

The most effective screening tool for progression of ARMD is the amsler grid (below). With one eye closed, look at the dot in the center of the grid. Notice if any lines are wavy or missing. Then check the other eye. Using the amsler grid only takes a few seconds per eye and is a sensitive measure for detecting small variations.




Exudative (wet-type) ARMD is less common (occurring in one out of 10 people with ARMD) but is more serious. In the wet form of ARMD, abnormal blood vessels may grow in a layer beneath the retina, leaking fluid and blood and creating distortion or a large blind spot in the center of your vision. If the blood vessels are not growing directly beneath the macula, laser surgery is usually the treatment of choice. The procedure usually does not improve vision but tries to prevent further loss of vision. For those patients with wet ARMD whose blood vessels are growing directly under the center of the macula, a procedure called photodynamic therapy (PDT), which causes fewer visual side effects, is sometimes used. Intravitreal injections of certain medications can also be used in these cases.
Promising ARMD research is being done on many fronts. In the meantime, high-intensity reading lamps, magnifiers, and other low vision aids help people with ARMD make the most of their remaining vision.