The Royal College of Ophthalmologists' National Ophthalmology Database Study of Vitreoretinal Surgery: Report 6, Diabetic Vitrectomy.

Importance: Patients and clinicians need to accurately assess the risks and benefits of pars plana vitrectomy for proliferative diabetic retinopathy, but clinical trial data may not reflect real-world experience.
Objective: To prospectively audit the complications of vitrectomy for proliferative diabetic retinopathy and help establish benchmarks.
Design, Setting, and Participants: Royal College of Ophthalmologists' National Ophthalmology Database study of 939 eyes of 834 patients undergoing primary vitrectomy for proliferative diabetic retinopathy at 16 different vitreoretinal units in the United Kingdom. Data were obtained for the period from January 2001 to November 2010.
Interventions: Pars plana vitrectomy with or without delamination/segmentation.
Main Outcomes and Measures: Descriptions of the primary procedures performed, intraoperative complication rate, and proportion of eyes undergoing further surgery. An exploratory analysis of visual outcome was undertaken, with visual success and visual loss defined as a gain or reduction of 0.3 logMAR or more, respectively (approximately 2 Snellen lines), 6 to 12 months after surgery.
Results: Of 420 eyes (among 408 patients) that underwent vitrectomy without delamination, the intraoperative complication rate was 13.1% (95% CI, 10.2%-16.7% [55 of 420 eyes]), with 126 eyes (30.0%) requiring an intravitreal tamponade and 49 eyes (11.7%) undergoing further vitrectomy (median follow-up, 6.9 months); 17.9% of 127 phakic eyes developed cataracts within a year, with 63.6% achieving visual success and 8.2% visual loss. Of 519 eyes (among 463 patients) that underwent vitrectomy with delamination, the intraoperative complication rate was 30.4% (95% CI, 26.6%-34.5% [158 of 519 eyes]), with 299 eyes (57.6%) requiring an intravitreal tamponade and 78 eyes (15.0%) undergoing further vitrectomy (median follow-up, 7.1 months); 21.2% of 126 phakic eyes developed cataracts within a year, with 62.8% achieving visual success and 14.9% visual loss.
Conclusions and Relevance: Diabetic vitrectomy has an appreciable complication rate, particularly if delamination or segmentation are required. Nonetheless, the data available on visual acuity suggest that a majority of patients achieve clinically meaningful gains in vision.