Cataracts are opacities of the ocular lens. General symptoms of cataracts include blurry vision, glare, and changes in refractive error. Worldwide, cataracts are the single most common cause of blindness.
Cataracts cause an estimated 51% of blindness worldwide, followed by glaucoma 8%, age-related macular degeneration (AMD) 5%, childhood causes 4%, and corneal opacities 4% (21% of blindness is from undetermined causes). Cataracts are also a leading cause of visual impairment worldwide (33%, behind refractive errors at 42%). Within the US, an estimated 30.1 million people are projected to have cataracts in 2020.
Controlling medical conditions such as diabetes can help slow the growth of cataract formation. Some studies have also shown that taking antioxidant supplements decreases the rate of cataract formation; however, other studies have shown no benefit (AREDS 2).