Paraorbital-Occipital Alternating Current Stimulation Therapy for Optic Neuropathy (MCT_optnerve)

Transorbital alternating current stimulation (tACS) is applied with a multi-channel device with paraorbital montage of 4 stimulation electrodes generating weak current pulses in predetermined firing bursts of 8 to 14 pulses. The amplitude of each current pulse was below 1000 microA. Current intensity was individually adjusted according to how well patients perceived phosphenes, i.e. any sensation of flickering light in response to the rtACS stimulation.

tACS is applied with the same device with equal electrodes set-up procedures but only one of four channels actually delivers current. The current intensity of this channel is individually adjusted (preselected on the side of lesioned eye) according with patient able to clearly perceive single phosphenes or any skin irritation phenomena (like weak sense of needles or vibration) whenever a single pulse is applied. The amplitude of pulses is always below 1000 microA. Current pulses are given as 1 pulse per minute during 25-35 min of session time. Session duration is equal for verum and sham patients. The perception of the single pulses leaves sham patients at the impression that they might receive the verum intervention, but total number of pulses is less than 0,5% of verum tACS.