Optical Coherence Tomographic Assessment of Diabetic Macular Edema: Comparison with Fluorescein Angiographic and Clinical Findings

Abstract

Purpose: To compare the optical coherence tomographic (OCT) features with clinical and fluorescein angiographic (FA) findings in patients with diabetic retinopathy. Methods: In a retrospective study ophthalmologic examination together with FA and OCT images were obtained from 195 eyes of 110 patients with different stages of diabetic retinopathy and OCT images were obtained from 40 eyes of 20 control subjects. Fluorescein leakage characteristics were organized into five groups: no leakage (1), focal (2), diffuse (3), combined focal + diffuse leakage (4) and cystoid (5). The Pearson correlation test was used to test the correlation between visual acuity and central foveal thickness and ANOVA was used for the statistical comparison between the groups. Results: The OCT images demonstrated retinal swelling in 66.1% of eyes, cystoid macular edema (CME) in 11.8% of eyes, serous foveal detachment + swelling in 6.2% of eyes, serous foveal detachment + swelling + CME in 3.6% of eyes and normal foveal structure in 12.3% of eyes. The best-corrected visual acuity was significantly correlated with central foveal thickness (r: –0.528, p < 0.01). There was 77% agreement between clinical examination and OCT results. CME was detected with OCT in 15.4% of eyes in our study, 40% of which was not detected with slit-lamp biomicroscopy and 63.3% of which was not evident in FA. None of the serous foveal detachments could be detected during slit-lamp biomicroscopy or FA. Conclusions: OCT-3 provided objective documentation of foveal structural changes in eyes with diabetic retinopathy. Best-corrected visual acuity provided a significant correlation with the retinal thickness at the central fovea. These results indicate that OCT can facilitate deciding on the treatment protocol (surgical or medical) and follow-up of diabetic patients, which is especially important in the early stages of diabetic maculopathy when the structural changes are not yet evident with slit-lamp biomicroscopy or angiographically.