Glaucoma Rehabilitation Using ElectricAI Transcranial Stimulation (GREAT)-Optimizing Stimulation Protocol for Vision...

Area of Science:

• Neuroscience
• Ophthalmology
• Medical Engineering

Background:

• Glaucoma is a leading cause of irreversible blindness worldwide.
• Current treatments aim to slow disease progression but do not restore lost vision.
• Non-invasive brain stimulation techniques offer potential novel therapeutic avenues.

Purpose of the Study:

• To investigate the effects of three transcranial electrical stimulation (tES) protocols on visual function in glaucoma patients.
• To compare anodal transcranial direct current stimulation (a-tDCS), transcranial alternating current stimulation (tACS), and transcranial random noise stimulation (tRNS) against sham stimulation.

Main Methods:

• A double-masked, placebo-controlled study involving 35 glaucoma patients.
• Four randomized stimulation sessions: a-tDCS, tACS, tRNS, and sham, with at least 48 hours between sessions.
• Assessment of visual function using high-resolution perimetry (HRP) and multifocal visual evoked potential (mfVEP) before and after each 20-minute stimulation session.

Main Results:

• a-tDCS significantly improved HRP detection accuracy in both central and peripheral visual fields compared to sham.
• a-tDCS also significantly increased mfVEP signal-to-noise ratio (SNR) and reduced latency in the central visual field.
• A trend for improved peripheral mfVEP SNR was observed with a-tDCS, but did not reach statistical significance.

Conclusions:

• A single session of a-tDCS demonstrates potential for enhancing visual perceptual and electrophysiological measures in glaucoma patients.
• The observed improvements, while statistically significant, were of a small magnitude and may not yet be clinically meaningful.
• Further research is warranted to assess long-term effects and clinical relevance using validated perimetric measures.