The macula is a tiny circle in the middle of the retina, a light-sensitive membrane that lines the inside of the back of the eye. In older people, it sometimes begins to deteriorate or degenerate for unknown reasons. Macular degeneration is the leading cause of legal blindness in Canada. However, macular degeneration rarely leaves you totally unable to see.
There are two types of this disease:
- Dry macular degeneration accounts for about 85% of cases. The tissue of the retina shrinks and pigments accumulate inside of it. Dry macular degeneration can progress to the wet form.
- In wet macular degeneration, new blood vessels grow around and behind the macula. There's sometimes bleeding in or behind the macula. Material seeps into the retina and settles in the macula. This is called an exudate. Eventually the exudate disappears, but a scar takes its place. All people who have wet macular degeneration had dry macular degeneration first.