Cataract surgery in patients with diabetic retinopathy: visual outcome, progression of diabetic retinopathy, and incidence of diabetic macular oedema.

BACKGROUND: Compared to non-diabetic patients, outcome after cataract surgery was reported to be worse in diabetic patients--especially in those with diabetic retinopathy. This prospective study was planned to evaluate visual outcome, progression of diabetic retinopathy, and incidence of clinically significant macular oedema (CSME) in a homogenous group of patients with non-proliferative diabetic retinopathy (NPDR) without CSME at baseline 1 year after cataract surgery.
METHODS: Over a period of 18 months, all consecutive patients with mild-to-moderate diabetic retinopathy who had cataract surgery with phacoemulsification and posterior chamber lens implantation were prospectively followed up. Outcomes were assessed 1 year postoperatively and included visual acuity (VA), progression of retinopathy, and incidence of CSME. Progression of retinopathy and incidence of CSME were compared to the non-operated fellow eyes.
RESULTS: Of 50 patients included, 42 completed the 1-year follow-up. VA improved in 85% of patients, and was better than 0,5 in 71%. Progression of retinopathy occurred in 12% of eyes after cataract surgery and in 10.8% of non-operated fellow eyes. No patient developed proliferative diabetic retinopathy in the operated eye. CSME occurred in 13 operated eyes (31%), five of them with retinal ischemia, and in five non-operated eyes (13.5%). Patients with ischemic macular oedema had the worst prognosis regarding VA.
CONCLUSION: Modern cataract surgery seems to have no influence on the progression of diabetic retinopathy. A visual improvement is achieved in the majority of patients with NPDR, but poorer visual outcome is observed in patients developing macular oedema.