Relationship between Optical Coherence Tomography Retinal Parameters and Visual Acuity in Diabetic Macular Edema

Purpose: To investigate the relationship between optical coherence tomography (OCT)-derived measurements of retinal morphology and visual acuity in patients with diabetic macular edema. Design: Retrospective cross-sectional study. Participants: A total of 67 consecutive patients (67 eyes) with diabetic macular edema (DME) who underwent Stratus OCT imaging (Carl Zeiss Meditec, Inc., Dublin, CA). Methods: Best-corrected Snellen visual acuity was recorded for each patient. Raw exported Stratus OCT images for each patient were analyzed using custom software entitled OCTOR, which allows the precise positioning of prespecified boundaries on individual B-scans. Thickness, volume, and intensity were calculated for neurosensory retina and subretinal fluid. In addition, photoreceptor outer segment (POS) thickness was quantified. Main Outcome Measures: Optical coherence tomography-derived measurements of retinal morphology and visual acuity. Results: The Spearman coefficient values (r) of the correlation between OCTOR-derived measurements of central subfield thickness, intensity, subretinal fluid volume, and POS thickness and the logarithm of the minimum angle of resolution visual acuities were 0.3428 (P = 0.005), -0.2658 (P = 0.03), -0.2683 (P = 0.38), and -0.3703 (P = 0.002), respectively. Multivariate models with stepwise selection revealed a cumulative R-2 of 0.4305 in the total study population, with R-2 of 0.4999 and 0.7628 in the untreated and prior focal laser groups, respectively. Conclusions: Subanalysis and quantification of OCT features in eyes with DME seem to be of value. In particular, POS thickness seems to be an important predictor of function and visual acuity in patients with DME.