Clinical meaning
Age-related macular degeneration (AMD) is a progressive degenerative disease of the macula, the central portion of the retina responsible for sharp, detailed central vision. It is the leading cause of legal blindness in adults over 50 in developed countries. AMD affects central vision while peripheral vision is typically preserved, meaning patients can navigate and move around but cannot read, recognise faces, drive, or see fine detail. The macula is only 5.5 mm in diameter but contains the highest concentration of cone photoreceptors, making it essential for colour vision, reading, facial recognition, and driving. Beneath the photoreceptors lies the retinal pigment epithelium (RPE), a single cell layer that performs critical support functions: absorbing excess light, phagocytosing shed photoreceptor outer segments, transporting nutrients from the choroidal blood supply, and recycling visual pigments. With ageing, the RPE becomes less efficient at clearing metabolic waste products. Lipofuscin (an indigestible yellowish pigment) accumulates within RPE cells. Extracellular debris deposits called drusen form between the RPE and Bruch membrane (the basement membrane separating the RPE from the choroidal blood supply). Drusen are the hallmark of early...