EAST HANOVER, N.J.To people who suffer from age-related macular degeneration (AMD), looking at a book or a photograph or TV is like looking at a black hole in space, said Reza Haque, M.D., principal clinical scientist at Novartis Ophthalmics North America. They can see around the edges of the black hole, but dark or empty spaces block their central vision. AMD affects central vision, but not peripheral vision, Haque said.
According to Prevent Blindness America, there are more than 13 million cases of AMD in North America, making AMD the leading cause of blindness among people older than 65 in the Western world. Every year, approximately 200,000 new cases of the severe wet AMD are diagnosed.
In AMD, there is abnormal growth of new tiny, fragile blood vessels under or on the retina, said Haque. In the wet form of AMD, these vessels often leak blood and fluid that damage the retina even further. Early detection of AMD is very important because treatment should begin when the disease is in its early stages.
Once vision is lost due to the growth of abnormal blood vessels, says Haque, it cannot be reclaimed by treatment. Individuals over the age of 50 should get their eyes examined regularly by an ophthalmologist or an optometrist to make sure that they are not candidates for AMD.
Scientists do not yet understand why people develop AMD, said Haque. Blurred vision may be the first symptom. Straight lines begin to appear crooked. Eventually, dark or empty spacesthe black holesmay block ones central vision, which is essential for most visual activitiesfrom reading to driving to watching television or sports.
AMD usually affects older people between the ages of 65 and 75, said Haque. People with light-colored irises have more risk, and AMD affects more women than men.
According to Haque, there are other risk factors as well. People who smoke. People who do not protect their eyes with sunglasses that block UV rays. Heavy consumption of alcohol is also thought to increase the risk of AMD.
Scientists are trying to learn more about AMD and diet, said Haque. There may be a dietary component to the risk of AMD. Eating lots of fruits and vegetables, especially dark green, leafy vegetables such as spinach and kale, may help prevent AMD. These vegetables contain an antioxidant called lutein that is thought to protect the eye from AMD.
While there are no current treatments for dry AMD, said Haque, there are two types of treatment for wet AMDlaser photocoagulation and photodynamic therapy. Laser photocoagulation uses a hot laser to seal off the leaking blood vessels. While this treatment is effective, the hot laser causes a scar, and vision is lost from this scar.
Photodynamic therapy is a two-step procedure that can be performed in a doctors office. First, a drug such as Visudyne (verteporfin for injection) is injected intravenously into the patients arm. A non-thermal laser light is then shined into the patients eye to activate the drug, which stops the leakage by disrupting the growth of the abnormal blood vessels.
For more information about AMD, please visit www.visudyne.com.
From the May 11-17, 2005, issue