With the tremendous progress in fundus imaging and histopathology over the past decade, the understanding of age-related macular degeneration (AMD) has taken a qualitative leap. AMD is defined as a progressive neurodegenerative disease of photoreceptors and retinal pigment epithelium (RPE) characterized by extracellular deposits under RPE and the retina, including drusen, basal laminar and linear deposits, and subretinal drusenoid deposits, that can evolve to atrophy of the retina, RPE and choroid and neovascularization in the choroid and/or retina. It is the leading cause of blindness and visual impairment in older populations, despite recent advances in treatments. AMD is a multifactorial disease with genetic and environmental factors including advanced age, smoking, high-fat diet, and cardiovascular disorder to enhance the disease susceptibility. The physiopathologic mechanism includes inflammatory processes (complement pathway dysregulation, inflammasome activation), intrinsic (e.g., photo-oxidation) and extrinsic oxidative insult to the retina, age-related metabolic impairment (mitochondrial, autophagic and endoplasmic reticulum stress). Autophagy dysfunction and local inflammation in aged RPE specially result in the extracellular deposits, cell death and AMD. Further investigation of the pathogenesis of AMD will provide with new therapeutic targets and strategy for prevention and treatment of the disease in the early stages.
