Diagnostic Ability of Macular Ganglion Cell–Inner Plexiform Layer Thickness in Chinese Glaucoma Suspects

Abstract

Purpose : It is challenging to identify real glaucoma from glaucoma suspects including ocular hypertension (OHT) and eyes with enlarged vertical cup-to-disc ratio (C/D). We assessed the diagnostic ability for early glaucoma of macular ganglion cell–inner plexiform layer (GCIPL) thickness in a Chinese population which included glaucoma suspects, and compared it with that of peripapillary retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) parameters.

Methods : �A total of 367 patients with glaucoma (168 early glaucoma, 78 moderate glaucoma and 121 advanced glaucoma), 52 patients with OHT, 59 patients with enlarged C/D, and 225 normal subjects were enrolled. One randomly selected eye of each participant were examined using Cirrus high-definition optical coherence tomography (HD-OCT). GCIPL (average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal) thickness, RNFL (average, superior, temporal, nasal, and inferior) thickness and ONH parameters (rim area, cup area and cup-to-disc ratio) were measured and compared. The diagnostic ability of OCT parameters was assessed by area under receiver operating characteristic curve (AUROC) in three distinguishing groups: normal subjects and patients with early glaucoma (Group 1), normal subjects and patients with glaucoma regardless of disease stage (Group 2), and nonglaucomatous subjects (normal subjects, subjects with OHT and enlarged C/D) and patients with early glaucoma (Group 3).

Results : Glaucoma patients showed a significant reduction in GCIPL thickness compared to nonglaucomatous subjects. In all three distinguishing groups, minimum GCIPL thickness (expressed in AUROC, 0.899, 0.952 and 0.900, respectively), average RNFL thickness (0.904, 0.953 and 0.892) and rim area (0.861, 0.925 and 0.824) were parameters with the highest diagnostic power in GCIPL thickness, RNFL thickness and ONH parameters, respectively. There was no statistical significance of AUROC between minimum GCIPL thickness, average RNFL thickness and rim area (all P >0.05).

Conclusions : GCIPL thickness was able to discriminate early glaucoma from normal and glaucoma suspects. The glaucoma diagnostic ability of GCIPL thickness was comparable to that of RNFL thickness and ONH parameters.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

The proportion of three distinguishing groups in which the diagnostic ability of OCT parameters was assessed. Sample size was marked in each color bar.