Aims This study examined the diagnostic value of the perimacular ganglion cell-inner plexiform layer (GCIPL) thickness in the detection of glaucoma according to the optic disc area.

Methods The participants underwent reliable standard automated perimetry tests and Cirrus optical coherence tomography. The area under the receiver operating characteristic curve (AUC) was used to determine the diagnostic ability of the GCIPL, total macular thickness, retinal nerve fibre layer (RNFL) and optic nerve head parameters. Subsequently, optic disc areas of ≤1.9, ≤2.4 and >2.4 mm² were chosen arbitrarily, and the AUCs and sensitivities at fixed specificities were compared for each.

Results 87 normal subjects and 96 glaucoma patients were enrolled. The mean GCIPL thickness and RNFL showed similar ability to diagnose glaucoma (p=0.911). The mean GCIPL thickness had higher diagnostic ability than the central retinal subfield thickness (p=0.001), comparable with that of the retinal cube volume (p=0.840) and mean retinal cube thickness (p=0.840). The mean RNFL (0.866), the minimum GCIPL (0.840) and the inferior and inferotemporal (0.853) disc had the highest AUCs for small, medium and large discs, respectively.

Conclusions The macular GCIPL thickness, total macular cube thickness, circumpapillary RNFL thickness and disc rim area showed similar performance in diagnosing glaucoma, irrespective of the optic disc size.