Age-related macular degeneration affects nearly 2 million Americans. More than 7 million Americans are at substantial risk for developing age-related macular degeneration. Some estimate that nearly 3 million people will be affected by 2020. Macular degeneration is the leading cause of central visual impairment that affects reading, driving, recognizing faces and performing close-up work among people aged 65 and above.
What Causes Age-Related Macular Degeneration?
The exact way age related macular degeneration develops is unknown. But, oxidative stress of the retina is thought to be a major contributor. The high concentration of oxygen and exposure to intense light seem to make the retina susceptible to oxidative damage.
Smoking is a well known way to deplete antioxidants. Smoking also increases blood viscosity and constricts blood vessels thus reducing the blood flow to the eyes. Every cigarette you smoke does damage to your eyes.
As the name (“age-related” macular degeneration) implies, age also plays its part. The aging of the retinal pigment epithelial layer and Bruch’s membrane (the layer below the epithelial layer) can allow the accumulation of debris and drusen. And, any existing abnormality typically worsens with age causing further damage and dysfunction of the retinal pigment epithelial layer.
Once the retinal pigment epithelial cells are damaged they secrete several growth factors including vascular endothelial growth factor (VEGF) which encourages the growth of new blood vessels (choroidal neovascularization) that cause problems in the “wet” form of age-related macular degeneration.