Wet AMD (exudative macular degeneration) accounts for around 10% of all AMD cases. It is caused by the growth of abnormal blood vessels in the retina. These new blood vessels leak fluid into the retina and cause rapid onset of distorted vision and scarring at the back of the eye. If left untreated this results in retinal tissue in the area being destroyed, leaving a large central blind spot. Macular degeneration cannot be reversed once this has occurred.

Most AMD patients start with the dry form with 10% of people developing the wet form. Although the wet type is less common it tends to be more aggressive, causing greater and more rapid visual loss.