AMDWhat is AMD?AMD or Macular degeneration or age-related macular degeneration is the disease of the eye which will affect central vision. Central vision is very important to everyone to see objects clearly and sharply and helps to do things like reading, driving and sewing. It is the leading cause of central visual loss among individuals 65 years of age and older in developed countries.The part of the eye which is responsible for central vision is called the macula. It is the macula that allows humans to see 20 20. This macular area is about two-tenths of an inch (5 millimeters) in diameter at the center of the retina. The cause of this disease remains unknown despite the extensive AMD research regarding its prevention and treatments
AMD typesClassification of AMD will depend mainly in the presence of choroidal neovascularization.It can be classified into:
1- Dry AMDFor more information about Dry AMD click here2-Wet or neovascular AMDFor more information about Wet AMD click here80% of AMD cases are dry AMD while more than 80% of cases with severe visual disabilities are caused by wet AMD. The severe form of dry AMD is called geographical atrophy which is responsible for the remaining 20% of cases with severe visual disabilities. EpidemiologyThis is the disease of old age. After the age of 50, the incidence will increase.The incidence of the disease is slightly more significant in female than male especially the moderate to severe form.AMD is a bilateral disease in which both eyes are affected but one eye is affected more than the other.Pathogenesis:It is characterized by one or more of the following findings:Drusens formation, atrophy of photoreceptors, retinal pigment epithelial (RPE) and choriocapillaris, and neovascular formation. The initial site of change is the retinal pigment epithelium (RPE) layer which is a single layer of cells located just behind the photoreceptors layer. Drusens are lipids deposition underneath the RPEs and they considered as precursor lesions for AMD. Drusens are extremely common and more than 80% of populations over the age 30 have at least one of them which usually increase with age. They are clinically insignificant when they are outside the macular area and when they are alone. The risk of AMD will increase when the number and size of Drusens increase and when the consistency of them changed in which soft drusens are more clinically significant than hard drusens.
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