Quantitative assessment of retinal thickness in diabetic patients with and without clinically significant macular edema using optical coherence tomography

Abstract

Purpose: To assess patients with diabetic macular edema quantitatively using optical coherence tomography (OCT). Methods: OCT was performed in 14 eyes with diabetic retinopathy and ophthalmoscopic evidence of clinically significant macular edema (CSME) and in 19 diabetic eyes without CSME. Retinal thickness was computed from the tomograms at fovea and other 36 locations throughout the macula. Results: The mean±standard deviation foveal thickness was 255.6±138.9 μm in eyes with CSME, and 174.6±38.2 μm in eyes without CSME (p=0.051). Within 2000 μm of the center of the macula, eyes with CSME had significantly thicker retina in the inferior quadrant than those without CSME (p<0.01). The foveal thickness was correlated with logMAR visual acuity (γ=0.68, p<0.01). OCT identified sponge-like retinal swelling and/or cystoid macular edema in 11 (58%) eyes without CSME, and in 12 (86%) eyes with CSME. Conclusions: Criteria of CSME seem to be insufficient in really identifying macular edema. OCT may be more sensitive than a clinical examination in assessing diabetic macular edema and is a quantitative tool for documenting changes in macular thickening.