Myopic Macular Degeneration |
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Myopia and macula |
The macula is the central part of the retina. It is responsible for detailed vision: for reading, seeing faces, watching TV etc. Myopia is discussed here. Essentially myopia is an optical condition caused by having an extra-long eyeball, so the eye may be 28 mm long instead of the normal 22.3mm, for example. Because the eyeball is extra long the retina becomes very thin and may become damaged. If the macula is damaged (the central area of the retina), central vision will be affected. There may be distortion with bendy lines, or there may be a patch in the centre with no vision. |
In myopia the eye is extra long, and the
retina extra thin. See |
Myopic macular degeneration ...atrophy |
The main type of macula change in myopia is thinning of the retina in the macula area. This is not treatable, and gets worse slowly with age. Central vision is affected, and reading, TV, crossing roads, seeing bus numbers, become difficult. Low visual aids and help from the low vision team can be very helpful indeed. Everyone keeps their side vision, and no one becomes completely blind. Generally the worst outcome is partial sight. More severe thinning (atrophy) may occur after CNV (immediately below). Myopic retinal changes may progress 2010 thin atrophic patches |
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Myopic CNV |
In this type of myopic macula disease, new vessels grow in the macula area. 5% of highly myopic eyes (more than -6.00d) develop CNV. This is similar to wet ARMD, but in myopia it may occur in much younger people. However, it is much commoner in older people with myopia. These new vessels are called 'CNV'...choroidal new vessels or choroidal neoovascularisation, as the blood vessels originate in the choroid and grow under the retina. The CNV cause retinal leakage and swelling. The condition progresses to cause a scar in the macular area. If the scar is small, sight is reasonable; if large, the sight can be very poor. The long term prognosis is not good: most eyes develop less than <6/60 vision. Younger patients have a better prognosis..the CNV get walled off. All types of wet ARMD (CNV) will progress 4 times faster in smokers, a 400% increase. In addition to smoking, high blood pressure, poor diet, lack of exercise increase the likelihood of progression and progression rate. |
New vessels growing under the central retina in myopia (similar anatomically to regular CNV) enlarge photo photo Myopic CNV Arevalo , Ruiz-Moreno, Avastin, Chan 2008 Wakabayashi 09 Some CNV are related to newly developed areas of lacquer cracks Eye 2011. |
Treatment of myopic CNV |
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| The address of this site ('org' changing to 'nhs') is changing from http://www.goodhope.org.uk/departments/eyedept/ to http://www.goodhope.nhs.uk/departments/eyedept/ |
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