Randomised trial of effectiveness of second eye cataract surgery

Background The effectiveness of cataract surgery on one eye is well established; but concerns over healthcare expenditure have called into question the value of cataract surgery on the second eye. We examined the effects of second eye surgery in terms of patient perceptions as well as through visual acuity, contrast sensitivity, and stereoacuity tests. Methods 208 otherwise healthy patients awaiting second eye cataract surgery were recruited into our randomised trial. At randomisation participants were allocated expedited surgery (planned to take place within 6 weeks) or routine surgery (routine waiting time, 7-12 months). Assessments were made at randomisation and again at review after about 6 months. Eight primary trial outcomes consisted of four questionnaire items and four visual function tests, done with bath eyes open. Findings Traditional clinical tests of success in cataract surgery (visual acuity and contrast sensitivity) showed only slight differences in binocular vision in favour of the expedited-surgery group. There were major benefits for the expedited-surgery group in terms of reported visual symptoms and effects on quality of life. At review, differences in self-reported vision related difficulties between the two groups ranged from 11% (95% CI 4.4-17%, activities) to 30% (19-41%, reading). Stereoacuity was better in the expedited surgery group, the difference between the groups for the proportions with stereoacuity of 3000 s of are or worse was 58% (47-69%). Interpretation This trial has shown that there is a clear benefit from second eye cataract surgery.