AMD is present in approximately 10 percent of the population over the age of 52 and in up to 33 percent of individuals older than 75. The earliest clinical manifestation of AMD are drusen and macular pigmentary atrophy. However, it serves as precursor, warning that there is the potential for progression and visual loss. AMD is bilateral in 55 percent of cases. The visual symptoms associated with AMD depend on its severity and type.
Some patients complain of color distortion.
Visual loss produced by wet AMD is often rapidly progressive. While the mechanisms and processes are poorly understood, some postulate these changes are initiated by isolated regions of choriocapillaris vascular failure. These proceedings cause the RPE to degenerate, resulting in photoreceptor loss. As the photoreceptors disintegrate, the inner nuclear layer collapses and contacts Bruch's membrane, initializing the degeneration of the outer retinal layers. Some theorize that the mechanism of damage may be through ultraviolet radiation-induced oxidation and free radical formation within these structures.