Age-related macular degeneration (AMD) is a progressive disease associated with aging that affects a section in the retina of the eye called the macula.The macula is responsible for fine, detailed central vision enabling us to do tasks such as reading, driving, watching TV or distinguishing faces.When the macula is affected, the central vision becomes blurred, distorted, and dim or there appears to be a black hole.There is usually a slow and painless progression over years and if not caught early, the disease may reach an advanced stage where irreversible damage has already occurred.Over 10 million North Americans have AMD, which is the leading cause of vision loss in adults over 50.
AMD is divided into two forms:the dry (nonexudative) form that affects 85-90% of people and the wet (exudative) form, which affects the remainder.The wet form is usually quite aggressive and is responsible for nearly 90% of those with severe vision loss.Most of the time AMD begins as the dry form, which is characterized by deposits in the macula called drusen.The dry form has three stages:early (small drusen), intermediate (large drusen) and late/geographic atrophy (pigment epithelial cells of the retina die affecting the macula).Some people have the early stage and never progress to later stages.However, dry AMD can progress and spontaneously become wet AMD characterized by an overgrowth of blood vessels in the macula (neovascularization).These vessels are weak and leak blood and other fluids into the macular region.
