Ganglion cell-inner plexiform layer thickness of high definition optical coherence tomography in perimetric and preperimetric glaucoma

Abstract

Purpose: We determined the diagnostic performance of ganglion cell-inner plexiform layer (GCIPL) parameters of high definition optical coherence tomography (HD-OCT) in perimetric and preperimetric glaucoma, and compared it to optic nerve head (ONH) and peripapillary retinal nerve fiber layer (RNFL) parameters.

Methods: In a cross-sectional study, 53 eyes of normal subjects and 83 eyes of glaucoma patients (62 perimetric and 21 preperimetric) from the Longitudinal Glaucoma Evaluation Study (LOGES) underwent HD-OCT imaging with Optic Disc and Macular Cube protocols. Diagnostic abilities of GCIPL, ONH, and RNFL parameters were determined using area under receiver operating characteristic curves (AUC) and likelihood ratios (LR).

Results: The AUCs of GCIPL parameters to diagnose perimetric glaucoma ranged from 0.84 to 0.90. The same of ONH and RNFL parameters ranged from 0.88 to 0.97 and 0.56 to 0.94, respectively. The AUCs of GCIPL, ONH, and RNFL parameters to diagnose preperimetric glaucoma ranged from 0.55 to 0.63, 0.77 to 0.92, and 0.39 to 0.80, respectively. For diagnosing preperimetric glaucoma, AUCs of all GCIPL parameters were significantly lower (P < 0.05) than those of the global ONH (vertical cup-to-disc ratio [CDR]; AUC, 0.92) and RNFL (average RNFL; AUC, 0.79) parameters. Outside normal limits category of GCIPL parameters also were associated with significantly smaller effects on the posttest probability of perimetric and preperimetric glaucoma.

Conclusions: The diagnostic ability of GCIPL parameters was similar to that of ONH and peripapillary RNFL parameters in perimetric glaucoma. However, in preperimetric glaucoma, the diagnostic ability of GCIPL parameters was significantly lower than that of ONH and RNFL parameters.

Keywords: glaucoma, high definition optical coherence tomography, ganglion cell; inner plexiform layer.