CORRELATION BETWEEN OUTER RETINAL LAYERS THICKNESS AND VISUAL ACUITY IN DIABETIC MACULAR EDEMA

Abstract

Purpose. To investigate the correlation between the outer retinal layers (ORL) thickness and visual acuity (VA) in patients with diabetic macular edema (DME). Design. Prospective, observational, cross-sectional and case control. Methods. Consecutive DME patients seen at the ophthalmic out-patient clinic of Ain Shams University Hospital were recruited for OCT assessment. The ORL thickness was defined as the distance between external limiting membrane (ELM) and retinal pigment epithelium (RPE) at the foveal center. The correlation between total retinal thickness, ORL thickness, and vision was calculated. Results. 30 eyes of 30 patients with DME and 30 fellow eyes of 15 healthy persons without DME were recruited. The mean age of DME group was 52.9 years (±9.5 years) and their mean visual acuity measured with Snellen chart was 0.60 (±0.12). The correlation coefficient between total retinal thickness and visual acuity was 0.31 (P = 0.02) whereas the correlation coefficient was 0.56 between ORL thickness and visual acuity (P = 0.001). Conclusion. ORL thickness correlates better with vision than the total retinal thickness. It is a novel OCT parameter in the evaluation of DME. Moreover, it could be a potential long term visual prognostic factor for patients with DME.