Outcomes of vitrectomy for advanced diabetic retinopathy at Groote Schuur Hospital, Cape Town, South Africa
Background. Present limitations in primary and secondary prevention of diabetic retinopathy mean that many patients with diabetes present with advanced retinal complications, often requiring surgery (vitrectomy).
Objectives. To determine the outcomes of vitrectomy for advanced diabetic retinopathy and to examine context-specific risk factors that may influence outcomes and decisions affecting resource allocation.
Methods. This was a retrospective cohort study of 124 vitrectomies with up to 6 months’ follow-up.
Results. Visual acuity was 6/60 or worse in the better eye in 23.4% of patients at presentation. The mean visual acuity of the listed eye was 2/60. The fellow eye was considered inoperable in 20.2% of cases. Visual function declined significantly in 26.2% of patients while awaiting surgery. The average waiting time until surgery was 2.9 months (range 1 day - 9 months). Epiretinal membranes were present in 93.6% of cases, and posterior iatrogenic breaks occurred in 49.2%. Silicone oil was used in 24.2%. Visual acuity improved in 54.9%, was unchanged in 30.1%, and worsened in 14.0% of cases at 6 months. Patients with poorer vision at surgery were more likely to improve (odds ratio 2.15; p=0.048). Factors associated with a worse visual outcome were increased age at surgery (p=0.042) and posterior iatrogenic retinal breaks (p=0.007). Renal dysfunction was not associated with worse visual outcomes.
Conclusion. Vitrectomy improved or stabilised vision in 85.0% of cases, although outcomes were unpredictable. A long waiting time to surgery contributed to patient morbidity. The presence of renal dysfunction did not predict poorer visual outcomes.