Age-related macular degeneration (AMD) is the term applied to ageing changes without any obvious cause that occur in the central area of the retina (macula) in people aged 50 years and above. In the early stages lipid material accumulates as deposits beneath the retinal pigment epithelium (RPE) and within Bruch’s membrane. When focal collections of lipid material are present these are referred to as drusen and can be seen as pale yellow spots on a clinical examination of the retina. The retinal pigment epithelium also undergoes morphological alteration and clinically this is evident as areas of hyperpigmentation and hypopigmentation. Generally drusen and RPE irregularities are not associated with disturbances of central visual function. A proportion of people with these early changes will progress to severe central vision loss. When vision loss occurs it is usually due to the development of geographic atrophy and/or exudative disease。
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