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Cataract surgery
  1. R P Wormald1,
  2. A Foster2
  1. 1Moorfields Eye Hospital, City Road, London EC1 2PD, UK
  2. 2London School of Hygiene and Tropical Medicine, UK
  1. Correspondence to: R P Wormald Moorfields Eye Hospital, City Road, London EC1 2PD, UK; r.wormalducl.ac.uk

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The times they are a changing

Are our cataract surgical outcomes as good as they can get? If the answer is that there is still room for improvement, then how?

The outcome of cataract surgery is determined by the patient, the technique, and the surgeon: the patient where there is coexisting morbidity; modern techniques (most notably the implantation of an intraocular lens and probably small incision methods) have transformed the quality of visual rehabilitation; and—dare we say—the “better” the surgeon the “better” the results. There is often little we can do to influence co-morbidity. As for technique, we have countless papers, posters, presentations, and videos promoting new techniques claiming excellent results (but rarely of sufficient study design quality to justify the claims). But what of the surgeon? Can the surgeon improve and if so how?

Habib et al’s paper in this issue of BJO (p 643) describes the association between higher volume and lower complication rates which has been noted in other spheres of surgery but not so far in ophthalmology. The message is—the more you do, the fewer the complications. This is just an association, and one cannot tell from this kind of study which way the cause and effect works. It could be that “better” surgeons do more surgery because they have fewer complications or is it, as the old adage states, “practice makes perfect” and that doing more makes you better?

If, as seems plausible, practice does make perfect and increasing one’s surgical experience improves results, then what is the optimum number of cataract surgeries per week? Habib et al suggest that the complication rate is lower in those who perform more than 400 operations per year (8–10 per week) than in those who perform fewer. Given there are not a limitless number of cataracts to be extracted each year, what is the optimum number of cataract surgeons for the population operating at an optimum rate? We know that in the Americas and western Europe there are too many ophthalmologists for most of them to perform regular cataract surgery. So are more cataract surgeons actually required in the United Kingdom to reduce time on the waiting lists?

The cataract surgical rate (CSR, cataract operations per million population per year) in the United Kingdom is probably between 4000 and 4500. This is about 100 operations per working week per million population. If a rate of 8–10 cataract operations per week is associated with a lower complication rate then 10–12 “cataract surgeons” are needed per million population. (Of course it may be that doing 12–14 per week gives even lower complication rates.) At present the United Kingdom has approximately 14 ophthalmologists per million population (all specialties). Australia has a CSR of around 6500, or 150 cataract operations per week per million population. If the United Kingdom wish to have a CSR like Australia (currently the highest worldwide) then it would require 75% of UK ophthalmologists performing 14 cataracts per week (approximately 7 hours operating), 44 weeks per year. It would therefore seem that the number of “cataract surgeons” is not the main limiting factor in reducing cataract waiting times, and one could argue that if too many people are performing cataract surgery, the complication rate may be more than optimal.

Change in the way cataract services are provided may be difficult to accept but, if well planned, could become a rewarding challenge for the profession with significant societal benefits

In order to reduce time on waiting lists there is a need to increase volume (CSR); a point made in an editorial several years ago in response to Minassian et al’s modelling of cataract backlog in the United Kingdom.1,2 The government, in order to reduce cataract waiting time, has introduced “treatment centres” as they are now termed. This move has not been welcomed by many consultants and there is a concern about training the next generation of eye surgeons. The use of surgical teams from outside the United Kingdom has further aggravated the situation and does not provide the basis for a sustainable cataract service for the United Kingdom which can meet the growing needs of an ageing population.

On the other hand, successful implementation of high quality, high volume units within the NHS can be achieved and be a positive experience. Some exemplary units, including the one reporting in this issue, were used as examples of best practice to form policies in the “Action on cataract” document. These units show that despite many barriers, progress can and has been made within the National Health Service. It is puzzling why more effort has not been made to disseminate and implement these examples of best practice.

There is a separate point to consider from Habib and colleagues’ article. The authors were able to review complication rates from a database of nearly 17 000 cases. Over time the complication rates fell for those performing fewer than 400 operations per year as well as for those performing more than 400. Yorston et al have shown that prospective monitoring of complications and visual outcome leads to an improvement in results over time.3 This strategy of routine monitoring every 100 cases is now being encouraged as part of the “Vision 2020—right to sight” strategy to improve the results of cataract surgery worldwide. High volume, high quality, and low cost units have been pioneered in many parts of south Asia and are now emerging in Africa. Increasingly, these centres are monitoring the visual outcome in order to give objective real time feedback of the results to the surgeon. This is not to compare one surgeon with another, but rather for each surgeon to monitor his own results over time.

Ophthalmology has pioneered and embraced many changes in technology—cataract extraction is just one example. A growing elderly population with a greater expectation of good vision, means that high volume, high quality cataract services are required. Change in the way cataract services are provided may be difficult to accept, but, if well planned, could become a rewarding challenge for the profession with significant societal benefits. Efficient use of an ophthalmologist’s time making best use of surgical skills in a way which optimises those skills seems a sensible part of planning a sustainable cataract service for the NHS.

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The times they are a changing

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