Who gets age-related macular degeneration?
ARMD is the most common form of macular degeneration and develops in older people. (There are other rare types of macular degeneration which occur in younger people.) ARMD can affect anyone. It is the most common cause of severe sight problems ('visual impairment') in the UK. It becomes more common with increasing age. If you develop ARMD in one eye, you have a high chance that it will also develop in the other eye.
About 1 in 100 people aged 65-75, and about 1 in 8 people aged over 85 have ARMD severe enough to cause serious visual loss. About twice as many women over the age of 75 have ARMD compared to men of the same age.
The two types of age-related macular degeneration
Dry age-related macular degeneration (dry-ARMD)
This is the most common form and occurs in 9 in 10 cases. In this type the cells in the retinal pigment epithelium of the macula gradually become thin (they 'atrophy') and degenerate. This layer of cells is crucial for the function of the rods and cones (the 'seeing cells') which then also degenerate and die. Typically, dry ARMD is a very gradual process as the number of cells affected increases. It usually takes several years for vision to become seriously affected. Many people with dry-ARMD do not totally lose their reading vision.
Wet age-related macular degeneration (wet-ARMD)
This occurs in about 1 in 10 cases. However, it is likely to cause severe visual loss over quite a short time - sometimes just months. In this type of ARMD, in addition to the retinal pigment cells degenerating, new tiny blood vessels grow from the tiny blood vessels in the choroid. (This is called 'choroidal neovascularisation'.) The new vessels break through Bruch's membrane and into the macular part of the retina. These vessels are not 'normal'. They are fragile and tend to leak blood and fluid. This can damage the rods and cones, and cause scarring in the macula.
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