Purpose: To determine whether measurement of ganglion cell complex (GCC) thickness over a wide area (8-mm diameter) can improve the glaucoma-discriminating ability of spectral-domain optical coherence tomography (SD-OCT) compared to that in the standard macular area (6-mm diameter).
Methods: Ninety-three subjects were enrolled, including 46 healthy eyes of 46 volunteers and 47 eyes of 47 glaucoma patients (23 eyes with preperimetric glaucoma [PPG] and 24 eyes with early glaucoma [EG]). All patients underwent SD-OCT raster scanning over a 9 mm × 9 mm square area centered on the fovea. Areas under the receiver operating characteristic curves (AROCs) were compared between wide sector (1-8-mm ring) and standard-size sector (1-6-mm ring) charts.
Results: AROCs for average GCC thickness in the wide chart were significantly greater than those of the standard chart in eyes with PPG (0.928 vs. 0.891; P = 0.038), EG (0.912 vs. 0.861; P = 0.003), and both (0.920 vs. 0.876; P = 0.004). Overall, the AROCs of regional GCC thicknesses were nearly comparable between the middle ring (4-6 mm) and outer ring (6-8 mm). Coefficients of variation were 0.68% and 0.97% in the standard and wide sector charts, respectively, in eyes with PPG, and 0.45% and 0.72% in the standard and wide sector charts, respectively, in eyes with EG.
Conclusions: Addition of the GCC thickness outside the macula to the standard macular GCC thickness significantly increased the glaucoma-discriminating ability of SD-OCT.