NAVIGATION

INFORMATION REQUEST

Types of Macular Degeneration

Age-Related Macular degeneration occurs as two distinct types, dry and wet. Most AMD starts with the dry form which may or may not develop into the wet form.

Dry AMD may also be called atrophic or non-neovascular macular degeneration. Dry AMD is the more common and milder form of AMD, accounting for 85% to 90% of all AMD. The key identifier for dry AMD are small, round, white-yellow lesions in the macula called drusen. Vision loss associated with dry AMD is far less dramatic than in the case of wet AMD. There is currently not a treatment available for dry AMD.

Wet AMD is less prevalent than the dry form representing 10% to 15% of AMD cases. The term wet denotes choroidal neovascularization (CNV), the development of abnormal blood vessels beneath the retinal pigment epithelium (RPE) layer of the retina. The potential for significant vision loss is much greater. Wet AMD is characterized by the development of abnormal choroidal angiogenesis which causes severe, and potentially rapid, visual deterioration. Laser treatment may be recommended if neovascularization exists.

Incidence and Risks

Incidence: In the US, it is estimated that between the ages of 43 to 86, approximately 1.2% of this population are affected by wet AMD, as opposed to 15.6% for dry AMD. (Source: Beaver Dam Eye Study). Based on this statistic, over 200,000 new cases of wet AMD, occur each year in North America.

Risks: Many studies have been done to identify risk factors for AMD.
Age: Wet AMD usually shows itself to individuals over the age of 50
Genetics: A hereditary link has been identified, and as such, the American Academy of Ophthalmology (AAO) recommends patients who have blood relatives with AMD undergo a retinal exam every two years.
Race/Gender: In general, the incidence of AMD is most prevalent in white women (over age 60).
Smoking: Studies have also shown definite associations between cigarette smoking and increased risk of both wet and dry macular degeneration. Hypertension: Furthermore, patients with dry AMD, who are on antihypertensive drug therapy coupled with high serum cholesterol levels, and low serum carotenoid are at a greater risk for developing choroidal neovascularization
Menopause: postmenopausal women who do not undergo estrogen therapy are also at a greater risk of developing neovascularization.
The role of vitamins, minerals, and antioxidants in the prevention of macular degeneration has been the source of controversy and conflicting information. High serum levels of vitamins E, A, and C, as well as zinc, may be beneficial, but currently their efficacy is unproven. The National Eye Institute is currently sponsoring a study called AREDS (The Age Related Eye Disease Study). The study is testing the use of antioxidants and zinc on the progression of AMD. The study should provide a more definitive answer regarding the use of these supplements.