Three-dimensional automated choroidal volume assessment on standard spectral-domain optical coherence tomography and correlation with the level of diabetic macular edema

Abstract

Purpose: To measure choroidal thickness on spectraldomain optical coherence tomography (SD OCT) images using automated algorithms and to correlate choroidal pathology with retinal changes attributable to diabetic macular edema (DME). Design: Post hoc analysis of multicenter clinical trial baseline data. Methods: SD OCT raster scans/fluorescein angiograms were obtained from 284 treatment-na?ve eyes of 142 patients with clinically significant DME and from 20 controls. Three-dimensional (3D) SD OCT images were evaluated by a certified independent reading center analyzing retinal changes associated with diabetic retinopathy. Choroidal thicknesses were analyzed using a fully automated algorithm. Angiograms were assessed manually. Multiple endpoint correction according to Bonferroni-Holm was applied. Main outcome measures were average retinal/choroidal thickness on foveacentered or peak of edema (thickest point of edema)- centered Early Treatment Diabetic Retinopathy Study grid, maximum area of leakage, and the correlation between retinal and choroidal thicknesses. Conclusion: Automated algorithms can be used to reliably assess choroidal thickness in eyes with DME. Choroidal thickness was generally reduced in patients with diabetes ifDME is present in 1 eye; however, no correlation was found between choroidal/retinal pathologies, suggesting different pathogenetic pathways. Results: Total choroidal thickness is significantly reduced inDME(175±23mm;P=.0016) and nonedematous fellow eyes (177 ± 20 mm; P = .009) of patients compared with healthy control eyes (190 ± 23 mm). Retinal/choroidal thickness values showed no significant correlation (1-mm: P = .27, r2 = 0.01; 3-mm: P = .96, r2 < 0.0001; 6-mm: P = .42, r2 = 0.006). No significant difference was found in the 1- or 3-mm circle of a retinal peak of edema-centered grid. All other measurements of choroidal/retinal thickness(DMEvs healthy, DME vs peak of edema-centered, DME vs fellow, healthy vs fellow, peak of edema-centered vs healthy, peak of edema-centered vs fellow eyes) were compared but no statistically significant correlation was found. By tendency a thinner choroid correlates with larger retinal leakage areas.