Evaluation of Changes of Macular Thickness in Diabetic Retinopathy after Cataract Surgery

PURPOSE To assess the macular thickness changes after cataract surgery in diabetic patients using optical coherence tomography (OCT). METHODS We retrospectively reviewed the records of 104 diabetic patients who underwent cataract surgery. We examined the changes of macular thickness using OCT before cataract surgery and 1 week, 1-, 2- and 6-months after surgery. The central subfield mean thickness (CSMT) was used to evaluate macular edema which was defined as an increase of CSMT (ΔCSMT) > 30% from the baseline. The association between prior laser treatment or severity of diabetic retinopathy and macular thickness were also analyzed. RESULTS Macular edema occurred in 19 eyes (18%) from the diabetic group and 63% of macular edema developed at 1 month after surgery. Thirteen (68%) out of 19 eyes with macular edema showed the resolution of macular edema by 6 months after surgery without treatment. ΔCSMT of eyes without a history of laser treatment was statistically greater compared to eyes with a history of laser treatment in at 1- and 2-months after surgery, but was not different than eyes who had laser treatment at 6-months after surgery. The severity of diabetic retinopathy was not significantly correlated to macular edema, but there was statistical difference when patients who had a history of prior laser treatment were excluded. CONCLUSIONS The incidence of macular edema after cataract surgery in diabetic patients was 18%. Its peak incidence was at 1 month post surgery and it resolved spontaneously in 68% of patients by 6 months post surgery. Prior laser treatment might prevent postoperative macular edema until 2 months after cataract surgery in diabetic patients. However, macular edema did not affect the severity of diabetic retinopathy.