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.