There are two types of AMD:
The dry variant of macular degeneration is a gerontological process associated with metabolic disorders that impair the removal of retinal waste products (lipofuscins). This leads to the formation of hyaline deposits (drusen) that accumulate in a layer of the retina, called Bruch’s membrane, and slowly destroy retinal photoreceptor cells (cones). This age-related process advances gradually and cannot be reversed.
In the wet type of macular degeneration, abnormal blood vessels grow under the retina and macula (known as choroidal neovascularisation). The new blood vessels tend to leak (subretinal haemorrhage), causing retinal detachment. Unlike dry macular degeneration, the wet type can be treated with special injection therapies (Lucentis(ranibizumab) injections).
As the disease progresses, their reading ability, visual acuity and contrast sensitivity deteriorate significantly. Patients also experience gradual loss of colour vision and increased light and glare sensitivity. The most common early symptom of macular degeneration is that straight lines appear distorted (metamorphopsia); this can be checked with the Amsler grid test.
Magnifying visual aids can help patients largely retain their reading ability, while blue blocking filters are ideal to reduce glare.
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