Brien Holden Vision Institute.

Brien Holden Vision Institute.

Summary Background To contribute to the WHO initiative, VISION 2020: The Right to Sight, an assessment of global vision impairment in 2020 and temporal change is needed. We aimed to extensively update estimates of global vision loss burden, presenting estimates for 2020, temporal change over three decades between 1990–2020, and forecasts for 2050. Methods We did a systematic review and meta-analysis of population-based surveys of eye disease from January, 1980, to October, 2018. Only studies with samples representative of the population and with clearly defined visual acuity testing protocols were included. We fitted hierarchical models to estimate 2020 prevalence (with 95% uncertainty intervals [UIs]) of mild vision impairment (presenting visual acuity ≥6/18 and <6/12), moderate and severe vision impairment (<6/18 to 3/60), and blindness (<3/60 or less than 10° visual field around central fixation); and vision impairment from uncorrected presbyopia (presenting near vision

PURPOSE.To estimate prevalence and number of people visually impaired or blind due to cataract. METHODS.Based on the Global Burden of Diseases Study 2010 and ongoing literature research, we examined how many people were affected by moderate to severe vision impairment (MSVI; presenting visual acuity <6/18, ‡3/60) and blindness (presenting visual acuity <3/60) due to cataract. RESULTS.In 2010, of overall 32.4 million blind and 191 million vision impaired, 10.8 million people were blind and 35.1 million were visually impaired due to cataract. Cataract caused worldwide 33.4% of all blindness in 2010, and 18.4% of all MSVI. These figures were lower in the high-income regions (<15%) and higher (>40%) in South and Southeast Asia and Oceania. From 1990 to 2010, the number of blind or visually impaired due to cataract decreased by 11.4% and by 20.2%, respectively; the age-standardized global prevalence of cataract-related blindness and MSVI reduced by 46% and 50%, respectively, and the worldwide crude prevalence of cataract-related blindness and MSVI reduced by 32% and 39%, respectively. The percentage of global blindness and MSVI caused by cataract decreased from 38.6% to 33.4%, and from 25.6% to 18.4%, respectively. This decrease took place in almost all world regions, except East Sub-Saharan Africa.CONCLUSIONS. In 2010, one in three blind people was blind due to cataract, and one of six visually impaired people was visually impaired due to cataract. Despite major improvements in terms of reduction of prevalence, cataract remains a major public health problem.Keywords: cataract, epidemiology, blindness, visual impairment A lthough cataract is relatively easily, safely, and costefficiently treatable, and in spite of the increasing rates of cataract surgery, 1 cataract is still the leading cause of blindness and visual impairment worldwide, especially in developing countries. 2,3 Population-based studies and previous meta-analyses performed in different regions worldwide have reported that cataract is responsible for 47.8% to 51% of all global blindness. 2,4-9 However, these studies did not report data on the change during the past 2 decades in terms of prevalence and number of people blind or visually impaired due to cataract.The purpose of the current study was to determine, in a meta-analysis of all available population-based studies performed worldwide within the past 2 decades, prevalence and number of people affected by blindness and visual impairment due to cataract, to assess changes during the period from 1990 to 2010, and to examine regional differences in the prevalence of cataract-related blindness and visual impairment.