Author Affiliations: Dana Center for Preventive Ophthalmology, Johns Hopkins University Schools of Medicine and Public Health, Baltimore, Md (Drs Congdon and Friedman); and Proctor Foundation, University of California San Francisco School of Medicine, San Francisco (Dr Lietman).
Contempo Updates Section Editor: Sarah Pressman
Lovinger, MD, Fishbein Fellow.
Visual impairment, which may be defined as blindness (best vision of
≤20/200 in the better eye in the United States and <20/400 by the World
Health Organization [WHO] definition) or low vision (<20/40 in the United
States and <20/60 according to WHO), is one of the most common disabilities:
an estimated 40 million people worldwide were blind nearly a decade ago, the
time of the last accurate assessment, and 110 million people had low vision.1 Among persons older than 40 years in the United States,
937 000 people were blind and 2.4 million people had low vision in 2002.
Figures for the developing world, where approximately 90% of world blindness
exists, and the developed world are expected to increase significantly during
the next decades as the world's population ages.2
Congdon NG, Friedman DS, Lietman T. Important Causes of Visual Impairment in the World Today. JAMA. 2003;290(15):2057-2060. doi:10.1001/jama.290.15.2057