Age-related macular degeneration (AMD) is the leading cause of legal, irreversible blindness among people 50 years of age and older.

Dry (ARMD) macular degeneration (atrophic AMD) is the most common form of macular degeneration and can progress to cause severe central vision loss. This disease progresses slowly and most people usually maintain some central vision in at least one eye.

"Wet" macular degeneration (exudative or neovascular AMD) is caused by blood vessels growing under the retina in the macula. "Wet" AMD always arises from pre-existing "dry" AMD. These blood vessels leak fluid, protein, lipid and blood. Eventually, if untreated scar tissue forms under the macula and central vision is destroyed. Current treatments approved for "wet" macular degeneration include thermal laser therapy (TTT) and photodynamic therapy (PDT) with Visudyne®.

The most common symptom of dry AMD is slightly blurred or fuzzy vision requiring greater illumination to see greater details. Also, an inability to recognize faces at a distance may develop. Symptoms of wet AMD may be that straight lines, such as sentences on a page, appear wavy; rapid loss of central vision; and a blurred or blind spot in the center of vision.