Published: 20 November 2013 at 13:54
Report finds large geographical differences in cases of cataracts and macular degeneration
The largest ever analysis of worldwide vision impairment and blindness data has been published in The Lancet Global Health journal.
Led by Professor Rupert Bourne of the Vision and Eye Research Unit at Anglia Ruskin University, the study examines the main causes of blindness and vision impairment worldwide and by geographical region, including analysis of trends over time.
The study used a vast range of published and unpublished data on vision impairment and blindness to produce figures for 1990 and 2010.
The number of people affected by blindness caused by cataracts decreased between 1990 and 2010 from 12.3million to 10.8million, and for MSVI (moderate and severe vision impairment) it fell from 44.0million to 35.2million
Causes of blindness differed substantially by region, with the prevalence of cataracts being lowest and macular degeneration being greatest in the highest-income regions.
In 2010, the proportion of blindness caused by cataracts ranged from less than 15% in high-income regions, to more than 40% in south and southeast Asia, and Oceania.
The proportion of blindness caused by macular degeneration (the loss of central vision) was higher in regions with older, higher-income populations, such as Europe and North America. In these areas more than 15% of blindness was caused by macular degeneration, whereas the proportion was much lower in regions such as south Asia (2.6%).
In all regions, the proportion of blindness and MSVI caused by cataract and macular degeneration was higher in women than in men.
Cataract or uncorrected refractive error, both easily treatable, led to 54% of blindness cases and 71% of MSVI cases in 2010. Of the 31.8million people who were blind in 1990, 68% had preventable or treatable causes. By 2010, the proportion had decreased to 65% of the 32.4million who were blind.
Professor Bourne said: