Retinal and macular ganglion cell count estimated with optical coherence tomography RTVUE-100 as a candidate biomarker for glaucoma

PURPOSE: To evaluate the ability of total and macular estimated retinal ganglion cell (RGC) counts to discriminate between healthy and glaucomatous eyes. To determine threshold markers of the estimated RGCs taking into account age dependence. METHODS: This was a cross-sectional, observational study. The study group consisted of 176 eyes subdivided in three groups: 32 healthy, 91 preperimetric (PPG), and 53 primary open-angle glaucoma (POAG) eyes. The estimate of total and macular number of RGCs was obtained using a model described later. To account for the inverse correlation of RGC count with age, we considered two age subgroups (≤55 and >55 years) for both total and macular estimated RGC counts. We computed frequency distributions and receiver operating characteristic (ROC) curves to measure the discriminating ability and derive the cut-offs between two different conditions with their relative diagnostic parameters. RESULTS: The total and macular estimated RGC counts showed highly significant differences among the three groups (P < 0.0001). The estimated RGC counts performed fairly well in distinguishing healthy from glaucomatous (PPG+POAG) eyes (area under the curve [AUC] = 0.79-0.92) with no statistically significant difference between total and macular RGCs. The approach allowed a good discrimination also between PPG and POAG eyes (AUC = 0.86-0.92). Cutoffs for the older age bracket were found to be lower in all cases. CONCLUSIONS: Retinal ganglion cell counts estimated with empirical formulas with RTVue-100 could be used as a valid surrogate for neural losses in glaucoma.