作者: Nathan G Congdon , David S Friedman , Thomas Lietman
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摘要: VISUAL IMPAIRMENT, WHICH may be defined as blindness (best vision of 20/200 in the better eye United States and 20/400 by World Health Organization [WHO] definition) or low ( 20/40 20/60 according to WHO), is one most common disabilities: an estimated 40 million people worldwide were blind nearly a decade ago, time last accurate assessment, 110 had vision. Among persons older than years States, 937000 2.4 2002. Figures for developing world, where approximately 90% world exists, developed are expected increase significantly during next decades world’s population ages.