Age related macular degeneration (AMD) is the leading cause of severe vision loss among the elderly in the United States, Europe, and Australia. However, the cause of this blinding disease remains a topic of active investigation. Most agree the pathogenesis of AMD is multifactorial and that it results from the interaction of genetic, environmental and ageing effects. Evidence from population based studies has supported a role for heredity in the pathogenesis of AMD. Recent studies have identified a polymorphism in the gene for complement factor H which may be present in up to half of all white AMD patients.^1–4 However, polymorphisms in this gene are also frequently found in Japanese⁵ and Chinese⁶ populations, where AMD infrequently causes vision loss. Clearly, development of AMD depends on the interaction of genetic background with other, presumably environmental, factors.

With the goal of preventing vision loss from this disease, it is important to identify modifiable risk factors that may be targets for intervention. Some, but not all, epidemiological studies have identified an association between cardiovascular disease risk and AMD.⁷ Cigarette smoking, a well recognised risk factor for cardiovascular disease, is the most consistently demonstrated modifiable risk factor contributing to AMD,⁸ and its role in complement activation has been considered supportive evidence …