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Cataract surgery outcomes in the developing world

2011; Wiley; Volume: 39; Issue: 2 Linguagem: Inglês

10.1111/j.1442-9071.2010.02494.x

1442-9071

Robert J. Casson,

Global Healthcare and Medical Tourism

Imagine a benevolent, human-like, ophthalmologist from the Vega system is visiting Earth and offering to help cure human eye diseases. Our alien friend (AL) has visual organs not unlike our own and is visiting an eye clinic to get some first-hand experience of human eye disease. You are excitedly showing AL some patients. A conversation between you and AL might go something like this: AL: (scanning a patient's eyes with an unfamiliar device) So, this man has severely reduced photoreceptor function in both maculae. YOU: Yes, he has a disease called geographic age-related macular degeneration. AL: We have something similar. I'll show you how to fix that. YOU: This next patient has a condition called primary open-angle glaucoma. It is an intraocular pressure-sensitive optic neuropathy. AL: (applying the scanner) Ah, I know what you mean. We call it Zod's disease. You do know in this case that it has nothing to do with his intraocular pressure. YOU: Well, he has a type of glaucoma we call normal tension glaucoma, and we know that lowering the intraocular pressure helps. AL: How do you know that? YOU: We did a study on it. AL: And it showed that lowering the intraocular pressure helped. YOU: Well, yes. Sort of. AL: Might want to look at that again. Anyway, let me show you how to fix it. YOU: Thanks AL. AL: By the way, what is the main cause of blindness on your planet? YOU: It's a condition where the lens opacifies; we call it cataract. AL: Oh, we have an operation for that where we remove the cataract from the eye and replace it with an artificial lens. It's very successful. YOU: (sheepishly) We have that already. AL: (confused) Then why is it the main cause of blindness? There is no rational answer to AL's question. It is a sobering indictment of humanity that cataract accounts for half the world's blindness. I remain optimistic that the solution is within reach of humans at their best. But goodwill alone is not enough. Goodwill must be combined with a critical-thinking approach and the determination to succeed. Critical-thinking, engineering-type approaches to the problem of cataract blindness remain surprisingly limited. For example, although we have robust epidemiological evidence that cataract is a serious public health problem in the developing world, and we have some understanding of the barriers to cataract surgery,1–4 there are still relatively few data about the outcomes of cataract surgery, with most robust data coming from population-based studies. It is clearly important to know how well (or not) a cataract surgery programme is performing. An increase in cataract surgery per se is not evidence that visual impairment is being prevented and cured. In a large population-based study from northwest India, the presenting visual acuity (VA) in the better eye of approximately one-third of individuals was <6/60 after cataract surgery,5 and in southern China 52% of operated eyes were still blind <6/60.6 In Fiji, this same poor outcome occurs in approximately 20% of operated eyes.7 In contrast, in a long-term Australian study, 77% of operated eyes had a VA ≥ 6/12.8 In general, strategies to reduce the burden of cataract-induced visual impairment in the developing world involve raising the quality and quantity of surgery in a sustainable manner. This involves understanding the region-specific needs, barriers and microeconomics coupled with a programme of collaboration, training, provision of infrastructure, and includes a move to accurate intraocular lens implantation and auditing of results. In this issue, Yuen et al. report on the outcomes of cataract surgery in four rural districts in Vietnam.9 After cataract surgery approximately 40% of eyes had a presenting VA < 6/18, and 20% were <6/60. Interestingly, they report that nearly 90% were satisfied with surgery and 95% would recommend surgery to others. One-third of patients paid ≥$US50 for surgery. The nexus of epidemiology and programme delivery is an exciting emerging field of research that aims to apply some critical thinking to the cataract problem. Outcome data after an intervention programme are extremely scarce. Recent high-quality data from southern China have demonstrated the effectiveness of surgical training in improving the quantity and quality of cataract surgery outcomes.10 More data about cataract surgical outcomes are needed in developing regions, particularly in the context of an interventional study. These data are not only necessary for quality control purposes, but also serves as important data for increasingly astute philanthropists, who (quite rightly) insist on knowing what their gift is achieving.