RE-PERG as a Diagnostic Tool for Neuroenhancement Studies in Primary Open Angle Glaucoma: A Pilot Study

Purpose: To evaluate the ability of RE-PERG to detect metabolic variations of the retinal ganglion cells (RGC) after administration of a commercially available fixed oral combination of Citicoline and Homotaurine (C+H, Neuprozin®) in primary open-angle glaucoma (POAG). Methods: Longitudinal, interventional case-control study on 36 eyes of 36 POAG patients controlled with topical treatment and stable visual field (deteriorating by <1 dB/year). Patients were randomly divided into two groups after the first ophthalmic evaluation (T0): 18 NP (patients continued topical therapy and took the fixed combination C+H for 4 months) and 18 age and gender-matched GLA (patients continued only the current topical treatment). Four months later, a second follow-up examination (T1) was scheduled for the two groups. The effects of taking C+H were assessed through the RE-PERG, of which the amplitude, the phase standard deviation (SD Ph) and circular phase standard deviation (cSD°) of the second harmonic were calculated, along with PMI (Phase Magnitude Index). As a secondary outcome, three visual field parameters, MD, pattern standard deviation (PSD) and Visual Field Index (VFI), were also evaluated. Results: As for RE-PERG, no variations were found in the GLA group. In the NP group, no significant amplitude variations were observed; at T1, the SDPh, and the cSD° were significantly reduced compared to T0 (0.22±0.05 vs 0.32±0.07, p=0.0002; 12.61±2.69 vs 18.30±4.36, p=0.0002, respectively), and PMI was significantly increased (0.81±0.37 vs 0.31±0.31, p=0.0003). No significant variation in the visual field parameters was observed. Conclusion: RE-PERG can detect variations in the metabolic status of the RGCs in glaucomatous patients after oral intake of a fixed combination of C+H in addition to topical treatment. RE-PERG can be a valid tool in neuroenhancement studies, representing a biological marker of neuronal performance.