Wet AMD occurs when abnormal blood vessels called choroidal neovascularisation (CNV) start to grow under the macula. These new blood vessels are very fragile and often leak blood and fluid. The blood and fluid lead to swelling of the macula, causing damage to the macula occur very rapidly.
An early symptom of wet AMD is that straight lines appear wavy. This will then progress to sudden deterioration of central vision.
The Dry AMD is more common than Wet AMD. However, the most common cause of severe visual loss in AMD is due to the development of CNV (Wet AMD).