Abstract
Purpose :
In recent years, non-invasive brain stimulation (NIBS) is emerging as a vision rehabilitation tool. Our study was aimed to assess which NIBS protocol at visual cortical region was optimal for improving visual function, maximizing the rehabilitation of peripheral vision loss in glaucoma patients.
Methods :
Using a double-blind, placebo-controlled, within-subjects design, we compared 3 different protocols of NIBS (anodal transcranial direct current stimulation (a-tDCS), transcranial random noise stimulation (tRNS), transcranial alternating current stimulation (tACS) against sham. Thirty-six glaucoma patients (age: 62.0 ± 7.9 years, mean deviation (MD) of 30-2 Humphrey visual field: -12.85 ± 5.75 db) attended 4 stimulation sessions (active a-tDCS, active tRNS, active tACS, and sham) in a random order with at least 48-hours between visits. Each visit involved 20-mins of stimulation with an anodal electrode over occipital zone (Oz) and a cathodal electrode at cheek. High resolution perimetry (HRP) and multifocal visual evoked potential (mfVEP) measurements were made before and immediately after stimulation. Pre-post changes in HRP detection accuracy and mfVEP signal-to-noise ratio (SNR) in the central 20 degrees were analyzed by linear mixed models, with stimulation type as the fixed effect, MD as the covariate, and subjects as a random effect.
Results :
Compared to sham, detection accuracy (b=0.032, SE=0.013, t=2.37, p=0.02) and SNR (b=0.015, SE=0.006, t=2.58, p< 0.01) were significantly improved after a-tDCS, but not after any other active NIBS protocols.
Conclusions :
A single session of a-tDCS enhances perceptual and electrophysiological measures of vision loss in patients with glaucoma. Future work will determine the longevity of these effects and the effect of repeated stimulation sessions.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.