Outcome of cataract surgery in eyes with diabetic retinopathy: a Swedish national cataract register report

Purpose: To analyse if patients with diabetic retinopathy (DR) subjected to cataract surgery differ in outcome compared to patients without DR with regard to best-corrected visual acuity (BCVA), deviation from target refraction, intraoperative difficulties and risk of complications. Methods: A register-based study from the Swedish National Cataract Register (NCR) during the years 2015–2017 including 358 040 cataract procedures. Patients with other ocular pathology than cataract and DR were omitted from outcome analyses. Results: Diabetic retinopathy was reported in 13 724 of all eyes (3.8%). Preoperative BCVA was significantly worse in DR patients than in patients without DR, 0.54 ± 0.33 compared to 0.40 ± 0.27 (logMAR, mean ± SD, p < 0.001). The same was evident for postoperative BCVA, 0.15 ± 0.25 for DR patients versus 0.06 ± 0.13 (p < 0.001). The improvement in BCVA was slightly better in DR than in non-DR, −0.40 ± 0.32 (logMAR; mean ± SD) versus −0.35 ± 0.27, p < 0.001. The absolute mean biometry prediction error was 0.42 ± 0.50 diopters (D) in DR and 0.43 ± 0.71 D in non-DR patients, p = 0.768. One or more intraoperative difficulties, including mechanical pupil dilation, capsular stain, hooks at capsulorhexis margin or capsular tension ring, had an adjusted odds ratio (OR) of 1.75 (95% confidence interval [CI] 1.61–1.90, p < 0.001) in DR versus non-DR cases and the rate of posterior capsular tears (PCR) had an adjusted OR of 1.76 (95% CI 1.40–2.20, p < 0.001). Conclusion: Eyes with DR have inferior pre- and postoperative BCVA compared to non-DR eyes. There is little difference in improvement of BCVA and no difference in absolute mean biometry prediction error. Importantly, intraoperative difficulties and PCRs are almost twice as common in DR patients, strongly indicating that these patients should be managed by experienced surgeons.