To evaluate the changes in central macular thickness (CMT) and incidence of macular edema (ME) after cataract surgery in diabetic patients compared with non-diabetic patients using optical coherence tomography (OCT).

The records of 138 diabetic patients and 34 non-diabetic patients who underwent cataract surgery were retrospectively reviewed. The diabetic group was divided into 5 groups according to severity of diabetic retinopathy. The diabetic group was also divided into 2 groups depending on prior panretinal photocoagulation history. The changes in CMT were examined using OCT before cataract surgery and 1 week, 1-, 2- and 6-months after surgery in diabetic and non-diabetic patients.

The incidence of ME in the diabetic group and non-diabetic group was 19.6% and 2.9% respectively. The increased amount of CMT (ΔCMT) was significantly greater in the diabetic group compared with the non-diabetic group during the observation period ( p < 0.05). The ΔCMT of eyes without a history of panretinal photocoagulation was statistically greater compared to the eyes with a history of panretinal photocoagulation at 1-, 2- and 6-months after cataract surgery ( p = 0.005, 0.002, 0.008, respectively).

The ΔCMT and incidence of ME were significantly greater in the diabetic group compared with the non-diabetic group. Additionally, the incidence of ME was significantly greater depending on severity of diabetic retinopathy in the diabetic group.