Prevalence and Causes of Vision Impairment and Blindness: The Global Burden of Disease
Few studies have investigated the prevalence of refractive error (RE) in older adults in China, and most have focused on East China.
The data required to provide the evidence to plan eye care services have been provided from an extensive meta-analysis conducted by the Global Burden of Disease Vision Loss Expert Group.
The meta-analysis provides data on changes in the prevalence and causes of vision loss from 1990 to 2010.
The number of people with moderate and severe vision impairment (MSVI, <6/18–3/60) was 172 million in 1990 which had increased to 191 million by 2010.
The increase in the number blind quite similar with 31.8 million in 1990 and 32.4 million in 2010.
The global prevalence of blindness had reduced from 3.0% to 1.9% and MSVI from 14.3% to 10.4% in people aged ≥50 years; the greatest changes were seen in African and southern Asian regions, but the rates in low-income countries were 25 times greater than in high-income countries.
Both cataract and trachoma have reduced significantly as causes of blindness and MSVI over the two decades, whilst there has been no significant change in the prevalence of uncorrected refractive errors.
There has been a small but not significant increase in the prevalence of MSVI due to macular degeneration, glaucoma and diabetic retinopathy but small decreases in the prevalence of blindness of these causes of vision loss.
The increases have been mainly in the low-resource countries of Africa, southern Asia and Oceania.
Given the increase in both the size and the age of the global population between 1990 and 2010, the increase in the number of people with vision loss is lower than projected reflecting the lower prevalence, but avoidable causes are still the most common causes.
The longer life expectancy over the last two decades has resulted in an increase in the number of years lived with disability.