Missing X and Y: a review of participant ages in population-based eye studies

Ophthalmic population-based studies have been used to establish the frequency of eye disease and the associated environmental and genetic factors that cause vision impairment and blindness. Most of these studies have concentrated on the diseases of ageing: cataract, age-related macular degeneration, glaucoma and diabetic retinopathy. Other studies have identified eye diseases in children but few studies of young adult eye disease exist. We conducted a systematic review of the ophthalmic literature to identify potential population-based eye studies and then note the age of participants in the studies. We then summarized the disease specific to young adults to show there is a need for further research to identify eye disease in this important and often-neglected group in the community. Eighty-four large population-based studies have been conducted worldwide: 9 in North America, 2 in South America, 17 in Africa, 35 in Asia, 11 in Australia and the Pacific, 6 in Europe, 4 in the Middle East and 1 that covered 3 continents. No studies specifically examined young adults. Twenty-six per cent of studies included young adults as part of all ages examined but none of these examined a large number of young adults.