Macular and peripapillary choroidal thickness in diabetic patients.

PURPOSE: : To investigate macular and peripapillary choroidal thickness (CT) in diabetic patients with and without diabetic retinopathy (DR). METHODS: : One hundred and fifty subjects were enrolled: 102 diabetic patients (102 eyes) and 48 normals, as controls. Exclusion criteria were previously treated DR, refractive error higher than ±3 diopters, and treated or untreated glaucoma. All patients underwent full ophthalmic examination, stereoscopic color fundus photography, and spectral domain optical coherence tomography (RS-3000; Nidek). Spectral domain optical coherence tomography examination consisted of linear scans, 6 mm in length, centered onto the fovea, and circle scan positioned around the optic disk (3.46 mm in diameter). Choroidal thickness was measured manually at the fovea and at 1, 2, and 3 mm distance along all scans in the macula. Peripapillary CT was measured at eight points along the circle scan. All measurements were performed independently by 2 masked graders. RESULTS: : Mean age was not significantly different between patients with diabetes and controls. In the macular area, CT was significantly lower in the nasal quadrant versus all other quadrants (P < 0.0001), in both groups. In the peripapillary area, CT was significantly lower in the inferior quadrant versus all other quadrants (P < 0.05), in both groups. Mean macular and peripapillary CT progressively and significantly decreased with increasing level of DR (nonproliferative and proliferative DR vs. controls, P < 0.05). No significant CT difference was found between controls and diabetic eyes without detectable DR. Diabetic macular edema did not influence CT. Interobserver coefficient of repeatability was 28.8 (95% confidence interval, 24.8-32.8) for foveal measurements and 13.0 (95% confidence interval, 11.2-14.8) for peripapillary measurements. Pearson correlation coefficient was 0.99, and P