Evaluation of Macular and Retinal Ganglion Cell Count Estimates for Detecting and Staging Glaucoma

Purpose: To investigate the clinical significance of macular estimated retinal ganglion cell (mRGC) and estimated retinal ganglion cell (eRGC) in the diagnosis and staging of glaucoma.Methods: This is a cross-section study. All enrolled subjects underwent standard automated perimetry (SAP) and optical coherence tomography (OCT) examination. Swedish Interactive Threshold Algorithm (SITA)-FAST detection strategy and 24-2, 10-2 detection programs were employed in SAP assessment. The visual-field parameters and OCT parameters were calculated according to three formulas to obtain the eRGC and mRGC1 or mRGC2. The efficiency of eRGC, mRGC1, and mRGC2 estimates for the staging of glaucoma was compared. The sensitivity and specificity of each parameter for diagnosis of glaucoma were analyzed using the receiver operating characteristic (ROC) curve.Results: A total of 119 eyes were included in the analysis. Compared with the healthy controls, eRGC, mRGC1, and mRGC2 estimates were significantly decreased in patients with glaucoma. As glaucoma progressed, eRGC, mRGC1, and mRGC2 estimates were gradually reduced. In preperimetric glaucoma, mRGC1, mRGC2, and eRGC were reduced by 13.2, 14.5, and 18%, respectively. In the mild stage of glaucoma, mRGC1, mRGC2, and eRGC were reduced by 28, 34, and 38%, respectively. In the advanced stage of glaucoma, mRGC1, mRGC2, and eRGC were reduced by 81, 85, and 92% respectively. The proportion of retinal ganglion cell (RGC) loss in the macula was close to that outside the macula. The specificity at 95% gave a sensitivity of 95.51, 86.52, and 87.64% for eRGC, mRGC1, and mRGC2, respectively. The sensitivity of structural parameters macular ganglion cell complex thickness and retinal nerve fiber layer (RNFL) were 98.88 and 95.51%, respectively. The sensitivity of functional parameters mean deviation (24-2) and visual field index (VFI) were 80.90 and 73.03%, respectively. The area under ROC curve of mRGC1, mRGC2, and eRGC were 0.982, 0.972, and 0.995 (P < 0.0001), respectively.Conclusion: Estimated retinal ganglion cell, mRGC1, and mRGC2 provide value to the staging of glaucoma and better diagnostic performance. Macular RGC estimatesthat integration of both structural and functional damages in macular may serve as a sensitive indicator for assessing macular damage in glaucoma and are of importance for the diagnosis and progression management of glaucoma.