circumpapillary ganglion cell complex thickness to diagnose glaucoma: a pilot study

Purpose: The purpose of this study is to evaluate the applicability of a new optical coherence tomography parameter, the circumpapillary ganglion cell complex (cpGCC) thickness for glaucoma diagnostics. Subjects and Methods: The RS-3000 Advance SD-OCT (NIDEK, Aichi, Japan) was used to measure global and sector macular GCC (mGCC) thickness, circumpapillary retinal nerve fiber layer (cpRNFL) thickness, cpGCC, and circumpapillary total retina (cpTR) thickness in 1 eye of 48 preperimetric/early perimetric primary open-angle glaucoma patients and 28 healthy Japanese participants. Area under the receiver-operating characteristic (AUROC) curves were used for between-method comparisons. Results: All global and sector parameters except for the nasal sector differed significantly between the patient groups (P ≤ 0.009). The AUROC for global mGCC (0.917) was significantly higher (P < 0.01) than that for global cpRNFL (0.760), global cpGCC (0.828), and global cpTR (0.812). The AUROC values of global and temporal cpGCC were significantly higher than those of the corresponding cpRNFL parameters (P < 0.05). Correlation between the visual field means deviation and each of the global thickness parameters was similar (r: 0.418–0.473, P< 0.001). At >90% specificity, the cpGCC, cpTR, and cpRNFL were able to detect 4%, 10%, and 0% of glaucoma eyes that were not detected by the mGCC thickness. Conclusions: In Japanese eyes, the diagnostic accuracy of cpGCC is lower than that of mGCC but higher than that of cpRNFL. Our results suggest that the use of cpGCC may not improve glaucoma diagnostics when there is no macular disease but may be of benefit when macular diseases prevent successful mGCC measurements.