Charles Wright and colleagues1 reported highlights of the RESIO study, including information about patients undergoing cataract surgery. The comprehensive report of that study2 states that 10% of the patients had preoperative vision better than 20/50 and therefore might not have met the cataract surgical guidelines. Wright and colleagues have suggested that these patients might have undergone unnecessary surgery.1 In fact, the policy manual of the College of Physicians and Surgeons of British Columbia states that patients with vision better than 20/50 but significant functional visual impairment are suitable candidates for cataract surgery.3 For example, bus drivers, police officers and airline pilots need vision that is considerably better than the 20/50 level to function in their jobs.
Wright and colleagues claimed that the outcome of cataract surgery was poor.1 In the RESIO study, the average visual function score before cataract surgery was 79 out of 100, and this score rose to 88 after the surgery.2 I suspect that the 9-point improvement in patient- reported visual function was interpreted as a very small improvement and therefore a poor outcome. However, given that 100 represents absolutely no visual disability, a score of 88 is in fact an excellent outcome, and this score was higher than the postoperative scores for any of the other surgical procedures in the study.
In the routine cataract assessment program at the University of British Columbia, 94% of the patients have better visual acuity, 3% have the same visual acuity, and 3% have worse visual acuity after cataract surgery.4 The RESIO study measured objective visual acuity before but not after surgery. It would have been helpful to have objective postoperative data to determine why, if only 3% had worse vision, 26% scored worse on their visual function form. We are currently re-examining the RESIO data to try to answer some of these questions.
Duncan P. Anderson President, Canadian Ophthalmological Society Ottawa, Ont.