Purpose: Vision impairment is a leading and largely preventable cause of disability worldwide. However, no study of global and regional trends in the prevalence of vision impairment has been carried out. We estimated the prevalence of vision impairment and its changes worldwide for the past 20 years. Design: Systematic review. Participants: A systematic review of published and unpublished population-based data on vision impairment and blindness from 1980 through 2012. Methods: Hierarchical models were fitted fitted to estimate the prevalence of moderate and severe vision impairment (MSVI; defined as presenting visual acuity <6/18 but ≥3/60) and the prevalence of blindness (presenting visual acuity <3/60) by age, country, and year. Main Outcome Measures: Trends in the prevalence of MSVI and blindness for the period 1990 through 2010. Results: Globally, 32.4 million people (95% confidence interval [CI], 29.4-36.5 million people; 60% women) were blind in 2010, and 191 million people (95% CI, 174-230 million people; 57% women) had MSVI. The age-standardized prevalence of blindness in older adults (≥50 years) was more than 4% in Western Sub-Saharan Africa (6.0%; 95% CI, 4.6%-7.1%), Eastern Sub-Saharan Africa (5.7%; 95% CI, 4.4%-6.9%), South Asia (4.4%; 95% CI, 3.5%-5.1%), and North Africa and the Middle East (4.6%; 95% CI, 3.5%-5.8%), in contrast to high-income regions with blindness prevalences of ≤0.4% or less. The MSVI prevalence in older adults was highest in South Asia (23.6%; 95% CI, 19.4%-29.4%), Oceania (18.9%; 95% CI, 11.8%-23.7%), and Eastern and Western Sub-Saharan Africa and North Africa and the Middle East (95% CI, 15.9%-16.8%). The MSVI prevalence was less than 5% in all 4 high-income regions. The global age-standardized prevalence of blindness and MSVI for older adults decreased from 3.0% (95% CI, 2.7%-3.4%) worldwide in 1990 to 1.9% (95% CI, 1.7%-2.2%) in 2010 and from 14.3% (95% CI, 12.1%-16.2%) worldwide to 10.4% (95% CI, 9.5%-12.3%), respectively. When controlling for age, women's prevalence of blindness was greater than men's in all world regions. Because the global population has increased and aged between 1990 and 2010, the number of blind has increased by 0.6 million people (95% CI, -5.2 to 5.3 million people). The number with MSVI may have increased by 19 million people (95% CI, -8 to 72 million people) from 172 million people (95% CI, 142-198 million people) in 1990. Conclusions: The age-standardized prevalence of blindness and MSVI has decreased in the past 20 years. However, because of population growth and the relative increase in older adults, the blind population has been stable and the population with MSVI may have increased. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.