Cataract is the leading cause of blindness, accounting for 50% of blindness worldwide. Although significant progress has been made toward identifying risk factors for cataract, there is no proven primary prevention or medical treatment. Surgical removal of cataract remains the only therapy. In this paper, we reviewed (a) the prevalence and incidence data of cataract, (b) the findings on risk factors for cataract, and (c) health service utilization and outcome of cataract surgery in both developed and developing countries.