Combined Non-Invasive Brain and Visual Stimulation for Vision Improvement

NCT07486323 | Not Yet Recruiting

• 1 other identifier: HSEARS20251208001
• Study Type: interventional
• Target: 56
• Locations: 1 country
• Sites: 1

Brief Summary

Glaucoma is a complex disease that can result in progressive vision loss. It is the second leading cause of blindness, accounting for 23% of permanent blindness in Hong Kong. There are no treatments that restore vision lost to glaucoma. This study will examine the effect of transcranial direct current stimulation (NIBS) on improving quality of life, visual function and functional performance in patients with peripheral field loss due to glaucoma.

Conditions

Glaucoma Open-Angle

Keywords

tDCS; transcranial electrical stimulation; visual tetanic stimulation; alpha frequency stimulation

Outcome Measures

Primary Outcomes (4)

• Visual field test

  Visual field test is measured monocularly using the 24-2 Swedish interactive threshold algorithm (SITA) standard tests by Humphrey visual field analyzer (HFA, Carl Zeiss Meditec Inc., California). The mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI) are recorded, and the MD of the 24-2 visual field test will be used as the primary outcome of intervention effect.

  Baseline (before the first intervention session), and immediately before and after each intervention block (5 session of intervention)

• Electroencephalography (EEG)

  Electrophysiological function is assessed using a 64-channel high-resolution electroencephalography (EEG) system. EEG outcome measures include spectral power in the delta, theta, alpha, beta, and gamma frequency bands, with particular focus on alpha-band activity, as well as functional connectivity measures derived from scalp EEG recordings, including coherence, phase-based connectivity, and related network indices. Pattern-reversal visual evoked potentials (PR-VEP) are recorded during presentation of a high-contrast checkerboard stimulus to the central 20-degree visual field under monocular viewing conditions. Stimuli are presented at 0.5 Hz and 1.5 Hz with 40 reversals. PR-VEP outcome measures include N75 latency, P100 latency, N135 latency, and N75-P100 and/or P100-N135 amplitude.

  Baseline (before the first intervention session), and immediately before and after each intervention block (5 session of intervention)

• Optical Coherence Tomography (OCT)

  Retinal nerve fiber layer is measured using spectral-domain Optical Coherence Tomography (OCT). Peripapillary retinal nerve fiber layer thickness is obtained from a circular scan centered on the optic nerve head. Ganglion cell thickness is measure using macular OCT imaging

  Baseline (before the first intervention session), and immediately before and after each intervention block (5 session of intervention)

• Optical Coherence Tomography Angiography (OCT-A)

  Evaluation of retinal vascular function in glaucoma patients is measured. Detailed visualisation of microvasculature structure within the retina and optic nerve head is measured, change of ocular perfusion is shown.

  Baseline (before the first intervention session), and immediately before and after each intervention block (5 session of intervention)

Study Arms (4)

Visual Tetanic Stimulation (VTS)

EXPERIMENTAL

Participant will receive 5 training sessions with VTS: about 1 hour per session

Other: VTS

Transcranial direct current stimulation (NIBS)

ACTIVE COMPARATOR

Participant will receive 5 training sessions with NIBS: about 1 hour per session

Other: NIBS

Transcranial direct current stimulation+ Visual Tetanic Stimulation (NIBS+VTS)

EXPERIMENTAL

Participant will receive 5 training sessions with NIBS+VTS: about 1 hour per session

Other: NIBS+VTS

Sham

PLACEBO COMPARATOR

Participant will receive 5 training sessions with Sham: about 1 hour per session

Other: Sham

Interventions

NIBS OTHER

Around 1 hour

Transcranial direct current stimulation (NIBS)

VTS OTHER

Around 1 hour

Visual Tetanic Stimulation (VTS)

NIBS+VTS OTHER

Around 1 hour

Transcranial direct current stimulation+ Visual Tetanic Stimulation (NIBS+VTS)

Sham OTHER

Around 1 hour

Sham

Eligibility Criteria

• Age: 40 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age range from 18 to 80 years;
• Diagnosis of primary open angle or normal tension glaucoma with relative scotoma in both eyes;
• A relative scotoma defined as a Humphrey Field Analyser (HFA) threshold perimetry loss (mean deviation of -6dB) within the central 24 degree of the visual field for at least one eye;
• Best-corrected distance visual acuity of 6/12 or better (equivalent to 0.3 logMAR acuity or better to confirm that participant's central vision is preserved).
• Stable vision and visual field loss for at least 3 months;
• With a cognitive functional score of 22 or above in the Montreal Cognitive Assessment - Hong Kong version (HK-MoCA) (to confirm participant's intact cognitive function).

You may not qualify if:

• Ocular diseases other than glaucoma (e.g. age-related macular degeneration, diabetic retinopathy, moderate to severe cataract) or severe hearing impairment (to ensure that participant can hear the instructions clearly during assessments and training);
• Severe medical problems (e.g. stroke, Parkinson's disease) or self-reported neurological (e.g. brain surgery, brain tumor, peripheral neuropathy), or cognitive disorders (e.g. diagnosed dementia or cognitive impairment);
• Self-reported vestibular or cerebellar dysfunction, history of vertigo;
• Using any medications for any neurological conditions or psychiatric drugs (e.g. sedative, hypnotic) that might interfere motor control;
• Contraindications for non-invasive brain stimulation.

Sponsors & Collaborators

• The Hong Kong Polytechnic University: lead

Study Sites (1)

The Hong Kong Polytechnic University

Hong Kong, Hong Kong

Location

MeSH Terms

Conditions

Glaucoma, Open-Angle

Interventions

salicylhydroxamic acid

Condition Hierarchy (Ancestors)

Glaucoma; Ocular Hypertension; Eye Diseases

Central Study Contacts

Ming Yan Cheong, PhD

CONTACT

852-27666108; allen.my.cheong@polyu.edu.hk

Lok Hin Chan, BSc (Hons) in Optometry

CONTACT

852-34002309; lhinchan@polyu.edu.hk

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assoc. Head (Academic Programmes and Clinical Training), Prog. Leader [BSc (Hons) in Optometry; MSc in Vision Science and Innovation] & Professor

Study Record Dates

• First Submitted: March 10, 2026
• First Posted: March 20, 2026
• Study Start: April 20, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): July 10, 2027
• Last Updated: March 24, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR, ANALYTIC CODE
• Time Frame: De-identified individual participant data and supporting documents will be made available beginning within 6 months after publication of the primary study results and will remain available indefinitely on the Open Science Framework (OSF).
• Access Criteria: will be publicly available

Locations

HK (1)