Learning Study: Improving Vision in Adults With Macular Degeneration

NCT04762368 | Recruiting

• 1 other identifier: VSBrainStim2
• Study Type: interventional
• Target: 30
• Locations: 2 countries
• Sites: 2

Brief Summary

The purpose of this study is to test whether a kind of brain stimulation called anodal transcranial direct current stimulation (a-tDCS) can be combined with perceptual learning to improve the ability of people with age-related macular degeneration (AMD) or juvenile macular degeneration (JMD) to read words presented to them on a computer screen better than if perceptual learning alone were used. In addition, secondary measures of visual acuity will also be examined to determine whether brain stimulation can allow patients to resolve finer details of an image. The proposed treatment is the application of a-tDCS onto the participant's head, with brain stimulation aimed at Primary Visual Cortex toward the occipital pole, while patients undergo six separate sessions of training. The investigators will test the ability of participants to read words before the start of the training sessions (pre test) and after the completion of all training sessions (post test). This is a between-subjects design, and half of the participants will receive true stimulation, and the other half will receive sham stimulation. The difference between the pre and post tests when receiving active stimulation will be compared to the difference when receiving sham stimulation, because the sham stimulation is not expected to influence reading beyond a placebo. The aim of the study is to examine the potential of concurrent brain stimulation and perceptual learning as an effective treatment for macular degeneration that may be used in conjunction with more traditional eye-based interventions. The investigators hypothesize that the brain stimulation will enable higher performance in the reading task after and secondary measures after perceptual training due to an increase in the cortical excitability of the stimulated brain cells.

Conditions

Macular Degeneration

Keywords

Macular Degeneration; Brain Stimulation; Psychophysics; Reading; tDCS; RSVP; Visual Acuity; Uncrowded Visual Acuity; Crowded Visual Acuity; Contrast Sensitivity

Outcome Measures

Primary Outcomes (2)

• Change in Rapid Serial Visual Presentation (RSVP) Reading performance before and right after training.

  Behavioral Measure - Participants will verbally read words presented on a computer. A variety of speeds and sizes will be presented, so that an accurate measure of the maximum reading speed, and the smallest text size readable at the maximum reading speed can be calculated. The maximum reading speed and smallest text size will be measured before and after training. The outcome measures are the change in these reading measurements from pre test to post test.

  The pre test and post test will take roughly 1 hour to complete, and they will be roughly 4-7 weeks apart.

• Change in Rapid Serial Visual Presentation (RSVP) Reading performance 30 days after training

  Behavioral Measure - Participants will verbally read words presented on a computer. A variety of speeds and sizes will be presented, so that an accurate measure of the maximum reading speed, and the smallest text size readable at the maximum reading speed can be calculated. The maximum reading speed and smallest text size will be measured before and after training. The outcome measures are the change in these reading measurements from pre test to the 30 day follow up.

  The test will take roughly 1 hour to complete, and they will be roughly 7-10 weeks apart.

Secondary Outcomes (8)

• Change in Uncrowded Visual Acuity before and just after training

  The pre test and post test will take roughly 5 minutes to complete, and they will be roughly 4-7 weeks apart.

• Change in Uncrowded Visual Acuity before and 30 days after training

  The pre test and post test will take roughly 5 minutes to complete, and they will be roughly 7 to 10 weeks apart.

• Change in Crowded Visual Acuity before and just after training

  The tests will take roughly 5 minutes to complete, and they will be roughly 4 - 7 weeks apart.

• Change in Crowded Visual Acuity before and 30 days after training

  The tests will take roughly 5 minutes to complete, and they will be roughly 7 - 10 weeks apart.

• Change in Contrast Sensitivity before and just after training

  The tests will take roughly 5 minutes to complete, and they will be roughly 4 - 7 weeks apart.

Study Arms (2)

Active + Training

ACTIVE COMPARATOR

Participants in this arm will be exposed to active stimulation for the first 25 minutes of a roughly hour - long perceptual training procedure in which participants must verbally read sentences presented at various speeds and sizes.

Device: Active anodal tDCS

Sham + Training

SHAM COMPARATOR

Participants in this arm will be exposed to sham stimulation for the first 25 minutes of a roughly hour - long perceptual training procedure in which participants must verbally read sentences presented at various speeds and sizes.

Device: Sham anodal tDCS

Interventions

Active anodal tDCS DEVICE

a weak electric current is applied to the head through electrodes to affect the cortical excitability of the targeted cells in the brain.

Active + Training

Sham anodal tDCS DEVICE

The tDCS machine will be used as in active stimulation, except the electrical current will not be applied.

Sham + Training

Eligibility Criteria

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

You may qualify if:

• Diagnosis of AMD (age 60+) or JMD (current age 18+).
• Visual acuity (VA); between 6/9-6/96 in the better eye
• Best-corrected near visual acuity of 4.0M at 40 cm or better in the better eye
• Stable vision in previous 3 months (patient report)
• Central vision loss

You may not qualify if:

• Diagnosed dementia.
• Not fluent in reading English (Waterloo) or Chinese characters (Hong Kong).
• Any ocular surgery (including anti-vegF injections) within the duration of the study, except for: A. Chronic and continuous injections for at least 1 year. B. Injections stopped at least 2 months before participation. C. Injections in the untested eye
• Ocular pathology other than JMD or AMD that can significantly reduce central vision. Example: mild cataract of grade 2 or below is acceptable
• Severe hearing impairment.
• Contraindications for brain stimulation

Sponsors & Collaborators

• University of Waterloo: lead
• The Hong Kong Polytechnic University: collaborator

Study Sites (2)

University of Waterloo

Waterloo, Ontario, N2L 3G1, Canada

RECRUITING

The Hong Kong Polytechnic University

Hung Hom, Kowloon, Hong Kong

RECRUITING

MeSH Terms

Conditions

Macular Degeneration

Condition Hierarchy (Ancestors)

Retinal Degeneration; Retinal Diseases; Eye Diseases

Study Officials

• Ben Thompson, PhD

  University of Waterloo

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Ben Thompson, PhD

CONTACT

15198884567; ben.thompson@uwaterloo.ca

Andrew E Silva, PhD

CONTACT

a8silva@uwaterloo.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: The participant and the researcher will be blind to which group any given participant is assigned to.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor; Associate Director for Research

Model Details: Group A: 6 training sessions with active brain stimulation and perceptual training Group B: 6 training sessions with sham brain stimulation and perceptual training

Study Record Dates

• First Submitted: February 13, 2021
• First Posted: February 21, 2021
• Study Start: February 13, 2021
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: January 22, 2026

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will share
• Shared Documents: ANALYTIC CODE
• Time Frame: IDP will be available upon a publication, and no more than 9 months after the publication.
• Access Criteria: IDP will be shared to researchers who provide a methodologically sound proposal.

Locations

CA (1); HK (1)