DOI: 10.4103/odjo.odjo_22_26 ISSN: 2949-9607

Comparative analysis of retinal ganglion cell complex thickness in primary open-angle, normal-tension and primary angle-closure glaucoma using spectral-domain optical coherence tomography

Praggya Mishra, Mamta Singh
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Abstract

Purpose:

The purpose of this study was to compare macular ganglion cell complex (GCC) thickness among primary open-angle glaucoma (POAG), normal-tension glaucoma (NTG), and primary angle-closure glaucoma (PACG) using spectral-domain optical coherence tomography (SD-OCT), and assess its association with visual field mean deviation (MD).

Materials and Methods:

This single-center cross-sectional study enrolled 125 patients with POAG, NTG, or PACG. One eye per participant was analyzed; when both were eligible, the eye with milder functional severity was selected. After visual-field/optical coherence tomography (OCT) quality exclusions, 106 eyes remained (36 POAG, 28 NTG and 42 PACG). Humphrey 24-2 perimetry and SD-OCT GCC measurements were evaluated using intergroup comparisons with effect sizes, structure-function correlation, regional asymmetry, and exploratory receiver-operating characteristic (ROC) analysis.

Results:

Demographic characteristics were comparable across groups. Average GCC thickness was 75.17 ± 4.81 μm in POAG, 76.49 ± 3.95 μm in NTG, and 75.28 ± 4.26 μm in PACG ( P = 0.421; η 2 = 0.017). Other GCC parameters also showed no significant differences and small effects (η 2 = 0.001-0.037). Average GCC correlated strongly with MD overall ( r = 0.716, P < 0.001) and within each subtype. Inferior GCC was thinner than superior GCC in all groups, with the greatest asymmetry in NTG. In exploratory ROC analysis, average GCC (area under the curve [AUC] 0.866) and inferior GCC (AUC 0.858) showed good discrimination between early and moderate functional severity.

Conclusion:

In this early-to-moderate glaucoma cohort, macular GCC thickness did not differ significantly among POAG, NTG, and PACG. GCC thickness nevertheless correlated strongly with visual field MD, and inferior GCC thinning was seen consistently across subtypes, with the greatest superior–inferior difference in NTG. GCC analysis therefore appears to be a useful structural adjunct to perimetry and optic disc assessment in routine glaucoma care.

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