Comparative study of macular ganglion cell complex thickness measured by spectral-domain optical coherence tomography in healthy eyes, eyes with preperimetric glaucoma, and eyes with early glaucoma.

Purpose: To evaluate the diagnostic accuracy of Topcon 3D spectral-domain optical coherence tomography (SD-OCT) for measuring the macular inner retinal layers and the circumpapillary retinal nerve fiber layer (cpRNFL) in order to detect preperimetric glaucoma.
Methods: Two hundred four eyes, including 64 healthy eyes, 68 eyes with preperimetric glaucoma, and 72 eyes with early glaucoma were analyzed. Patients had a comprehensive ocular examination including visual field testing and SD-OCT imaging (3D OCT-2000; Topcon Corporation, Tokyo, Japan) in the macular and peripapillary regions. OCT macular scans were segmented into the macular nerve fiber layer (mNFL), ganglion cell layer with the inner plexiform layer (GCIP), and ganglion cell complex (GCC) (composed of the mNFL and GCIP). Ability to discriminate preperimetric glaucoma was assessed using the area under the receiver operating curve for all macular parameters and the cpRNFL.
Results: The median visual field MD was -0.78 ± 1.19 dB for the healthy group, -1.02 ± 1.29 dB for the preperimetric glaucoma group, and -3.08 ± 1.61 dB for the early glaucoma group. There were significant differences between the preperimetric and healthy groups for GCIP and GCC and for almost all cpRNFL thickness parameters (P < 0.05), except for the mNFL and cpRNFL (nasal, 3, 4, 8, 9, and 10 o'clock sectors). The comparisons among the AUCs of the cpRNFL parameters (0.772), the GCIP parameters (0.727) and the GCC parameters (0.720) showed no significant differences in their abilities to detect preperimetric glaucoma.
Conclusions: The capacity of Topcon 3D-OCT macular intraretinal parameters (GCIP and GCC measurements, not mNFL measurements) to diagnose preperimetric glaucoma is similar to that of the cpRNFL.