Comparison of diagnostic capability of macular ganglion cell complex vs retinal fiber layer thickness in primary open angle glaucoma patients of Indian origin.

Abstract

Comparison of diagnostic capability of macular ganglion cell complex thickness vs. retinal nerve fiber layer (RNFL) thickness in patients of primary open-angle glaucoma (POAG). This cross-sectional observational study was carried out between June 2021 and October 2022 at a tertiary care hospital in North India. A total of 118 eyes were included in the study with 30 control and the rest 88 eyes with POAG were divided into three groups based on visual field loss Group 1 (30 eyes): early field loss with mean deviation (MD) < -6 dB; Group 2 (30 eyes): moderate field loss with MD -6 to -12 dB; and Group 3 (28 eyes): severe field loss with MD > -12 dB. Optical coherence tomography (OCT) scans to measure RNFL loss and ganglion cell inferior plexiform layer (GCIPL) loss were taken for each patient. Categorical variables were analyzed using either the Chi-square test or Fisher's exact test. A receiver operating characteristics analysis was calculated to determine optimal cut-off values of superior, inferior, and average GCIPL and RNFL for determining the severity of field loss as compared to controls (30 normal eyes). In the mild field loss group the sensitivity of superior, inferior, and average GCIPL was 86.7, 96.7, and 96.7%, respectively. Similarly, the specificity was 96.7, 93.3, and 100%, respectively. In the same group, the sensitivity of superior, inferior, and average RNFL was 70, 93, and 66%, respectively. Similarly, the specificity was 46.7, 83.3, and 70%, respectively. In the moderate and severe groups, the results were comparable. The sensitivity and specificity of GCIPL loss are significantly better than that of RNFL parameters in the mild field loss group.