Treatment of patients with optic nerve damage with electrical stimulation: a home stimulation study

The overall aim of the current project is to investigate the efficacy and safety of long-term treatment of glaucoma by transorbital alternating current stimulation with a home-stimulation device (SASm). We hypothesize that tACS home-stimulation significantly improves vision and associated biomarkers compared to sham-controls. Our secondary aim is exploratory, namely to investigate possible mechanisms of action. The current study will be a double blind, parallel group interventional study. Participants (N=45) will be randomized to one of two intervention arms following a 2:1 scheme: (1) arm 1 - intervention group receiving tACS; (2) arm 2 - placebo group receiving sham (no tACS, only phosphene threshold measured at study entry). The primary endpoint of this clinical investigation is improved near-threshold Humphrey Visual Field Index of the worse eye/solely available eye following active tACS stimulation compared to sham, as indicated by relative change over baseline at end of treatment.

According to our goal of investigating the long-term tACS efficiency, participants will undergo 30 stimulation sessions. Endpoints will be assessed before, immediately after and 2 and 6 months after the end of treatment. To our knowledge, this would be the longest stimulation duration and follow-up period investigating the effect of tACS. It would allow us not only to collect information on long-term effects, but also to compare it with short-term interventions (i.e., 10 days). The study will be considered completed after the last follow-up measurement of the last patient.

To examine the retinal blood vessel dynamics, we want to use a CE-approved "Dynamic Vessel Analyzer" in an additional "open label" feasibility study on a sample of patients (N=20) from an outpatient care center to determine the effect of electrical stimulation on the blood supply. These patients will undergo 10 electrostimulation sessions using a device which is equivalent to the devices used for the other two-arms. As part of our study we will have two measurement points to investigate the effect of the electrical stimulation on the blood supply, namely before and after therapy.