Age-related macular degeneration affects 35 percent of Americans over the age of 80, and is the leading cause of visual deterioration and legal blindness for those over age 60. Age is the major risk factor, but there are other factors that we can control. Recent medical literature reports that vision and artery health tend to follow the same path with aging.
The macula is the part of the retina that processes our central, most high-resolution vision. Age-related macular degeneration has an early stage, which can begin as early as age 40, and a late state. The late stage is divided into two groups:
1. The “dry” form has slower deterioration and better preservation of vision. However, it can progress to the more serious “wet” form.
2. The “wet” form is also called exudative, and includes growth of new abnormal blood vessels which can leak and bleed into the macula, causing irreversible damage to the photoreceptors.
The classic sign of early macular degeneration is subretinal pigment epithelium deposits called drusen. These deposits have a molecular composition very similar to the atherosclerotic plaques that clog blood vessels. In the Rotterdam Eye Study, patients with carotid artery plaques were five times more likely to have late-stage macular degeneration, compared to patients without these plaques.
Some things you can do to prevent macular degeneration:
1. DO NOT SMOKE! Other than age, smoking is the strongest risk factor.
2. Watch your blood pressure and cholesterol.
3. Protect your eyes from the sun. Wear hats and/or cover-all sunglasses as much as possible when you're outdoors.
4. Get plenty of antioxidants in your diet. Zinc and vitamins B, C, and E slowed the rate of progression from dry to wet macular degeneration in the Age-Related Eye disease study.
One approach to treating macular degeneration is the use of medications targeting vascular endothelial growth factor, or VEGF. Drugs include ranibizumab (Lucentis) and bevacizumab (Avastin). These are both monoclonal antibodies, which are classified as biologics. They are proteins which must be administered by injection. The Lucentis Web site includes an option to increase the print size: good idea, I think, for patients with vision problems!
There is a genetic component to development of macular degeneration, which is still under investigation. Whites are more at risk than other ethnic groups, and women are affected more than men.
References:
Ehrlich R et al, “Age-related macular degeneration and the aging eye”, Clinical Interventions in Aging 2008; 3(3): 473-82.
Lucentis treatment:
http://www.lucentis.com/lucentis/index.html
Linda Fugate is a scientist and writer in Austin, Texas. She has a Ph.D. in Physics and an M.S. in Macromolecular Science and Engineering. Her background includes academic and industrial research in materials science. She currently writes song lyrics and health articles.