Epidemiology of cataract: accomplishments over 25 years and future directions.

The purpose of this review is to highlight the advances made by epidemiologic research into cataract. Considerable progress has been made in characterizing phenotypes, determining the prevalence and incidence in various population groups, and understanding risk factors for cataract. Cataract surgery research has documented functional improvements following surgery and has identified aspects of surgery delivery that could be made. Cataract is an independent marker of early mortality, providing a possible system for studying the aging process. Promising future work in cataract epidemiology is highlighted. Despite the availability of cataract surgery, cataract is still the leading cause of blindness worldwide. From a public health standpoint, research that can identify ways to delay onset or progression, or achieve the holy grail of prevention of cataract, should remain a leading priority.