Effects of Treatment with Citicoline Plus Nicotinamide Oral Solution on Retinal Ganglion Cells and Visual Pathways in Glaucomatous Impairment

Objectives: To evaluate the retinal ganglion cell (RGC) function and neural conduction along the visual pathways after treatment with Citicoline plus Nicotinamide oral solution in patients with open angle glaucoma (OAG). Methods: Thirty OAG patients (mean age ± standard deviation: 62.588 ± 6.022 years, IOP < 18 mmHg with medical therapy) were enrolled. Of these, 20 OAG patients (providing 20 eyes) were treated with Citicoline plus Nicotinamide oral solution (Kron^®, Omikron Italia) (Citicoline plus Nicotinamide group), and 10 OAG patients (providing 10 eyes) were treated with an oral placebo (Placebo group). In all participants, Humphrey 24-2 visual field (HFA 24-2), pattern electroretinogram (PERG), visual evoked potentials (VEP) and retinal nerve fiber layer thickness (RNFL-T) were assessed at baseline and at the end of the 3-month period of treatment. Results: PERG and VEP data obtained from 28 patients were included in the final analysis, while all the patients were included in the visual field and RNFL-T analyses. At baseline, both groups showed HFA 24-2 mean deviation (MD), PERG, VEP and RNFL-T values not statistically (ANOVA, p > 0.05) different. After 3 months of Citicoline plus Nicotinamide oral solution treatment, a significant (p < 0.05) increase in PERG P50-N95 and VEP N75-P100 amplitudes, and a significant (p < 0.05) shortening of VEP P100 implicit times were found. The shortening of VEP P100 implicit times was not significantly correlated (p > 0.01) with the increase in PERG P50-N95 amplitude. Conversely, in the Placebo group, no significant changes in PERG and VEP values were found. The HFA MD and RNFL-T changes were not significantly different (p > 0.05) between groups. Conclusions: In OAG patients, treatment with Citicoline plus Nicotinamide oral solution for three months induces RGC functional enhancement (increase in PERG amplitude) and improves the neural conduction along the visual pathways (shortening of VEP implicit time and increased amplitude), without significant changes in visual field or RNFL-T.