Investigations are used only for the wet form of macular degeneration or if there has been a sudden change in the central area of vision.

Fluorescein Angiography is the key investigation to detect leakage or blockage of blood vessels in the retina. A small amount of orange fluorescein dye is injected into a blood vessel of the forearm. It travels in the bloodstream and reaches the eye 10 seconds later, when a sequence of flash photographs is taken over the next five minutes. The pictures identify areas of the retina where blood vessels may be leaking or blocked and help decide if treatment will help.

Optical Coherence Tomography (OCT) sometimes replaces Fluorescein Angiography because it is free from risk and requires no injection. A special camera produces a detailed cross-sectional image to show the various layers of the retina.