The pathophysiology of cigarette smoking and age-related macular degeneration.

Age-related macular degeneration (AMD) is the most common form of visual impairment, in people over 65, in the Western world. AMD is a multifactorial disease with genetic and environmental factors influencing disease progression. Cigarette smoking is the most significant environmental influence with an estimated increase in risk of 2- to 4-fold. Smoke-induced damage in AMD is mediated through direct oxidation, depletion of antioxidant protection, immune system activation and atherosclerotic vascular changes. Moreover, cigarette smoke induces angiogenesis promoting choroidal neovascularisation and progression to neovascular AMD. Further investigation into the effects of cigarette smoke through in vitro and in vivo experimentation will provide a greater insight into the pathogenesis of age-related macular degeneration.