Introduction

The global demand for cost effective, timely, and high quality cataract surgery has never been greater, driven by an ageing population with high expectations and an ever increasing unmet need, particularly in developing countries. It is well-established that the leading cause of blindness and visual impairment in much of the world today is cataract.

The need for cataract surgery

We believe that, fundamentally, it should be possible to eliminate cataract blindness – there is an effective and reliable way to identify cases and a sight restoring treatment is available. Developed health systems such as those in Western Europe, North America and Australia have greatly reduced the prevalence of cataract by establishing an adequate cataract surgical rate (CSR). This term refers to the number of cataract operations performed per million population per year. It can be calculated from the number of surgical procedures and the population under consideration. In order to eliminate cataract blindness the CSR needs to equal the incidence (number of new cases) of cataract blindness – estimated at approximately 2000–3000 cases per million per year. If the CSR is less than 2000, the surgery rate will not keep up with the incidence, some people who become blind due to cataract will remain untreated and will remain blind until they die, and the backlog will continue to increase. This is the situation in much of the developing world.

If the CSR is 2000–3000, or more people who become blind due to cataract will be treated, the backlog will be abolished over a period of approximately 5 years. This applies if a visual acuity of <6/60 is used as the indication for surgery; a higher visual acuity cut-off will increase the required CSR. Figure 4.1 shows the CSR in WHO defined regions; only four regions have an adequate rate and millions of people have minimal or no access to surgery1.

Fig. 4.1 Estimates of global cataract surgical rates.

Reproduced with permission from Foster A. Cataract:Epidemiology and Service Delivery. Chapter 3. Survey of Ophthalmology 45, Supplement 1:S32 –44, 2000.

Cataract surgery outcomes

The solution to the world’s unmet need would seem to be increasing the number of operations but it is not sufficient to simply perform more surgery; the visual result of the procedure must be of the highest possible standard. Cataract surgery is a potentially sight restoring operation and our aim as surgeons must be to deliver the best possible visual outcomes with the lowest possible complication rate. Continuous monitoring of both individual and national outcomes is well-established practice in all modern eye units. Unfortunately this practice is not always a priority in developing countries where resources are scarce and a culture of audit and accountability is not necessarily well established. Yorston et al.2 have established the role of prospective monitoring in improving surgical outcomes.

The World Health Organization (WHO) has defined standards for the outcomes of cataract surgery (Fig. 4.2