Public Health Aspects of Ophthalmic Disease: Introduction

Visually disabling diseases are particularly topical as we grapple with new ways to deliver health services, recognize the imperative of functional status and its impact on quality of life, and seek new opportunities for prevention. It is also timely. Rigorous population-based studies in the U.S. and elsewhere are, for the first time, revealing the magnitude, causes, and impact of disabling ocular disease. The impacts of visual impairment and blindness were emphasized by the World Bank's landmark publication, World Development Report 1993: Investing in Health (26). It introduced the Disability Adjusted Life Year (DALY) as a basis for quantifying the global burden of disease and the relative costeffectiveness of alternative interventions. The most cost-effective is $1 per DALY gained from vitamin A distribution to prevent blindness. In the United States and other developed countries, a considerable proportion of visual impairment can be corrected with appropriate spectacles. Blindness, at either the U S . (20/200 or worse) or WHO (worse than 20/400) definitions, inevitably represents established pathology (23). Prevalence rates of blindness increase with age, particularly among the elderly (9,23), secondary to a small number of chronic degenerative conditions: cataract, age-related macular degeneration (AMD), primary open angle glaucoma, and diabetic retinopathy (15). Blindness rates among nursing home patients are 15 times as common as among age-matched noninstitutionalized subjects (21). Cataract, an entirely remedial condition, is paradoxically the commonest single cause of blindness around the world, from India, Nepal, and Cairo, to East Baltimore (13). It accounts for roughly half the 40 million blind people in the world. Cataract surgery, almost inevitably combined (in wealthy countries) with implantation of an intraocular lens, is extraordinarily safe and highly effective, providing complete rehabilitation. It led the movement to safe, costeffective outpatient surgery that has dramatically reduced costs per case, com-