In the 1990s, patients were waiting a year or more for cataract surgery. Resources limited the number of NHS surgeries permitted, with more stringent restrictions on second eye surgery due to uncertainty regarding its benefits. A randomised controlled trial undertaken at Bristol provided the first clear evidence that patients benefitted from the surgery.

The collaborative trial was led by eye surgeon John Sparrow, Honorary Professor in the School of Social and Community Medicine, and was undertaken at the Bristol Eye Hospital between 1993 and 1998. The study recruited and randomly expedited second eye surgery for half of the 208 participating patients who had previously undergone a successful first eye cataract operation. Six months later, the visual function and patient-reported quality of life benefits were assessed for the patients who had had surgery and compared them with the control group who were still awaiting second eye surgery.

Evidence of patient benefits influences policy

There were significant visual function and vision-related quality of life benefits for those patients who had received second eye surgery. Patients had better visual function overall, especially for depth perception (stereo-acuity) when assessed with both eyes open and importantly, patients reported that activities such as reading and seeing faces had improved significantly after second eye cataract surgery. This remains the only randomised trial of its kind and provided clear evidence of the benefits of restoring vision in both eyes.

These findings, published in 1998 in The Lancet, fed into the policy document 'Action on Cataracts' released in 2000 by the Department of Health. The policy outlined a fundamental shift in the approach to cataract surgery, recommending second eye surgery as good practice. As a result, the percentage of second eye surgeries steadily increased; they constituted only 25 per cent of cataract operations in the mid 1990s, but by 2010 accounted for nearly 35 per cent of the 232,000 cataract operations in the UK.

Estimating the backlog

The University of Bristol collaborated with the Bristol Eye Hospital on a second critical study to estimate what the population requirements for cataract surgery were in England during the late 1990s. Because the number of cataract surgeries had been limited prior to the release of the 2000 policy, the number of people in need of surgery far outweighed the number of available operations, creating a backlog.

The Bristol team considered the eligibility of over 1,000 participants aged 65 and older for cataract surgery using applied epidemiological approaches; detailed clinical and quality of life data from the patients were put into a model to determine their surgical need. They then used this representative sample to estimate that the backlog of cataract surgery for visually significant cataract in England was around half a million operations.

Reducing waiting times

This robust estimate allowed the NHS to implement strategies to cope with the surgical backlog and make significant inroads over the next decade into the unmet need for cataract surgery across England. A 65 per cent increase in the frequency of cataract surgery resulted, increasing from 201,682 operations in 1998-1999 to 332,625 operations in 2009-2010. This reduced waiting times in England from over a year to below 18 weeks between referral to surgery for more than 90 per cent of NHS patients.

'For older people in particular, long waiting times can have substantial implications,' explained Sparrow. 'Living with poor vision can lead to reduced confidence and higher functional dependence.'

Improving vision in patients can also have downstream benefits such as reducing their vulnerability to falls and the associated operative and rehabilitative care required after such an incident. At worst, falls may lead to potentially fatal consequences.

This research remains relevant to policy decisions as the NHS continues to operate under constrained expenditure.