Age-Related Macular Degeneration
Age-Related Macular Degeneration (AMD) is an ocular disease in which the central part of the eye, the macula, is damaged. This can occur either because of the accumulation of deposits of debris called drusen, or atrophy of the outer retinal layers. With the accumulation of drusen, there is decreased oxygen supply to the retina which increases the risk of neovascularization, the formation of new blood vessels. Although it may sound like the new blood vessels are a good thing since blood flow may increase oxygen supply, these new vessels are weak and leaky, causing bleeding and swelling in the retina. New blood vessel growth, or neovascularization, is characteristic of wet AMD. If left untreated, it can result in permanent vision loss. Treatment for wet AMD involves injecting a medicine into the eye to reduce the swelling and prevent further neovascularization. The sooner treatment is initiated, the better the visual outcome. It is important to note that this is not a one-time treatment but rather is a course of injections that is extended over many months. With atrophic AMD, vision loss occurs because of the death of the retinal layers. In the past, there was no treatment for atrophic AMD. However, a medication that is injected into the eye has recently been approved to potentially reduce progression of retinal atrophy and vision loss.
Smoking is the biggest modifiable risk factor for development of AMD and progression to wet AMD. Other risk factors include the following: family history of AMD, increased age, hypertension, and a diet high in saturated fats. The AREDS and AREDS2 studies found that a certain combination of vitamins may help to reduce progression of dry, intermediate stage AMD to wet AMD. This combination of vitamins was not proven to prevent onset of AMD. Commercially available formulas based on these two studies are available. It is important to note that Beta-carotene increased risk of developing lung cancer in smokers; therefore, people who smoke should take the AREDS2 formulation which does not have Beta-carotene. Annual eye exams are important in detecting AMD before there is vision loss.