Highlights of the First World Glaucoma Congress: Glaucoma Worldwide
In the Opening Session, Professor Gullapallin Rao, from the L V Prasad Eye Institute, Hyderabad, who is President of the International Agency for the Prevention of Blindness (IAPB), outlined the origins of the IAPB in 1975. Recognizing the serious public health problem posed by global visual disability and blindness, a number of nongovernment organizations came together to collaborate with the World Health Organization. Their major thrust currently is the Vision2020 project, which aims to eliminate all avoidable blindness by that deadline -- and indeed, the numbers of blind persons are already down from original forecasts. The older blinding diseases were cataract, trachoma, and onchocerciasis, while the newer threats include cataract, glaucoma, and, increasingly, diabetic retinopathy. Glaucoma is second only to cataract in causing blindness.
Professor Rao outlined a pyramidal care structure that is being developed in the developing world in order to further the goals of Vision2020. He stated that there should be a primary eye care center per 50,000 individuals, secondary eye care center per 500,000, tertiary per 5 million, and advanced tertiary per 50 million people. It is the advanced tertiary eye care centers that train the trainers who filter down through the structure to provide the necessary services and to teach other health and eye care workers.
Professor Harry Quigley, of Johns Hopkins University, Baltimore, Maryland, detailed the extent of glaucoma as a worldwide health problem, noting that it accounts for 10 of the estimated 83 million bilaterally blind people -- but that figure is dependent on where you come from. Blindness is 10 times higher in the developing than in the developed world, and the risk of dying is 4 times higher in blind Africans than in other blind individuals. Updating his previously published figures, Professor Quigley estimated that of the 65 million people affected by glaucoma (44 million with open-angle, 21 million with angle-closure), 10 million are bilaterally blind. Whereas about 10% of the open-angle glaucoma patients are bilaterally blind, the figure for angle-closure is about 25%. Hence, more people are blind from angle closure, even though it is far less common.
Asia accounts for a disproportionate amount of the glaucoma burden: 60% overall and 80% of angle-closure. The reasons for this disparity are unclear, although angle closure can be partly explained by anatomic features: shallow anterior chamber, narrow angle, smaller eye (hence more females than males) and older age (larger crystalline lens increasing anterior segment crowding). But these factors do not explain why Chinese individuals have a 5 times greater risk compared with white individuals. Angle closure is historically difficult to diagnose. Worldwide, 85% of glaucoma is undiagnosed, but when it is diagnosed, it is primarily open-angle -- of every 5 patients being treated, 2 have open-angle glaucoma and 3 have ocular hypertension. Professor Quigley argued that physiologic factors must be involved in angle closure, and that physiologic testing should therefore be explored as a means for diagnosing angle closure.
Expanding on the discussion of public health issues posed by glaucoma, Professor Ivan Goldberg, from the University of Sydney, Australia, demonstrated that with the increase in population superimposed on the exponential increases in both population aging and glaucoma prevalence with increasing age, the challenges in detecting and managing both main types of glaucoma are rising dramatically. Educational strategies using guidelines, such as those published over the past few years by the American Academy of Ophthalmology, European Glaucoma Society, and the South East Asia Glaucoma Interest Group, are ever more relevant and important.
