Cataract is the leading cause of blindness and visual impairment worldwide. In developing countries, the relatively simple, low-cost surgical excision of cataract is not widely available, and the social burden is high. In developed countries, cataract surgery is available; more than half of people aged 80 years and older in the United States have had cataract surgery.1 Cataract surgery and related medical costs in the United States are estimated to be $6.8 billion per year2 and are likely to increase because of increasing rates of cataract surgery and the aging of the population. Lens opacities, which develop before surgery is indicated, can make seeing more difficult, especially under dim light and under conditions of glare, such as when driving at night.