18 April 2012 – Using the most up-to-date studies, WHO estimates that the number of people with visual impairment (presenting vision) is 285 million (65% of whom are aged over 50 years). Of these, 246 million have low vision (63% over 50) and 39 million are estimated to be blind (82% over 50).
These estimates were based on 50 national and subnational studies from 38 countries, published and unpublished, conducted since 2004 and on previous studies that were still representative; the majority of the 50 surveys were rapid assessments for the population 50 years and older.
Regional estimates were calculated with a model taking into account, among other factors, the country's economic development status, after having verified the fit between data on visual impairment and development indicators.
The top three causes of visual impairment are uncorrected refractive errors, cataract and glaucoma. The top three causes of blindness in the 2010 estimate were cataract, glaucoma and age-related macular degeneration.
Given that the methodology to estimate the prevalence of visual impairment and blindness is different from the one used in previous studies, it is not possible to make a direct comparison of the magnitude and causes of visual impairment and blindness with earlier estimates.
There is a global and regional reduction in visual impairment and blindness, which is demonstrated in those countries where repeat surveys over time were conducted. This is considered to be largely attributable to socioeconomic development in many countries, but also to the investment and work of governments and international partners in improving quality and quantity of eye care services and in developing the national eye health system.
It is now important to increase the delivery of eye care services in all country in need. The Action plan for the prevention of avoidable blindness and visual impairment provides the roadmap for countries, WHO and international partners to secure achievements and continue to deliver services worldwide.
