Some global aspects of blindness
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BjΓΆrn Thylefors
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Article
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1982
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Springer Netherlands
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English
β 625 KB
The number of blind in the world is not known, but estimates have been made based on the differing definitions of blindness used by various authorities -a fact that complicates the analysis of available data. There are also possible sources of error, such as unreliable population figures and a frequ