Amblyopia
Conditions
Keywords
Amblyopia, Non-invasive Brain Stimulation, Transcranial Random Noise Stimulation, Visual Perception, Visual Evoked Potentials
Brief summary
The goal of this randomized controlled trial is to investigate the effectiveness of non-invasive brain stimulation in treating adults with amblyopia. The main questions it aims to answer are: 1. What are the effects of non-invasive brain stimulation on neuronal plasticity in the visual cortex of adults with amblyopia, and does it produce lasting changes? 2. Do cumulative sessions of non-invasive brain stimulation influence neural plasticity and higher-order visual functions in adults with amblyopia? The investigators hypothesize that non-invasive brain stimulation will show a positive cumulative effect after five (5) consecutive days of stimulation on visual perception and function in adults with amblyopia. Participants will be randomized into one of two treatment groups: 1. High-frequency transcranial random noise stimulation (hf-tRNS). 2. Sham stimulation. Researchers will compare baseline measurements of crowded visual acuity, contrast sensitivity, stereoacuity, phosphene thresholds, global motion perception, form pattern recognition and pattern-reversal visual evoked potentials (VEPs) to post-treatment measurements for each group.
Interventions
DEVICESham Transcranial Random Noise Stimulation
Sham transcranial random noise stimulation will be applied over the primary visual cortex (area V1) with the current ramping up for 20 seconds before ramping down for 20 seconds. The 2.0 milliamp current stimulation will occur for only a few seconds at the start and at the end of the 40 minutes.
DEVICEHigh Frequency Transcranial Random Noise Stimulation
Non-invasive brain stimulation will involve the use of high-frequency transcranial random noise stimulation (100-640 Hz) to apply a 2.0 milliamp current over the primary visual cortex (area V1) for approximately 40 minutes with a ramp up to the maximum programmed current and ramp down of 20 seconds.
Sponsors
Midwestern University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 55 Years
Healthy volunteers
Yes
Inclusion criteria
* Adults between 18 and 55 years of age * Formal diagnosis of amblyopia in one or both eyes of any etiology
Exclusion criteria
* History of optic nerve disease, including glaucoma and optic neuritis * History of neurological conditions, including demyelinating disease or stroke * Presence of metal or electronic implants in or on the body, including pacemakers * Taking medications that can affect normal neurological function, including antipsychotics, antiepileptics, and opioids
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Crowded Visual Acuity | Pre- and post-treatment (Days 1-5); 24-hour follow-up (Day 6); 72-hour follow-up (Day 8); and 10-day follow-up (Day 15). | A change in crowded visual acuity is measured in LogMAR from baseline. |
| Stereo Acuity | Pre- and post-treatment (Days 1-5); 24-hour follow-up (Day 6); 72-hour follow-up (Day 8); and 10-day follow-up (Day 15). | A change in stereo acuity is measured in arc seconds from baseline. |
| Phosphene Threshold | Pre- and post-treatment (Days 1-5); 24-hour follow-up (Day 6); 72-hour follow-up (Day 8); and 10-day follow-up (Day 15). | A change in phosphene threshold (%) from baseline. |
| Global Motion Perception | Pre- and post-treatment (Days 1-5); 24-hour follow-up (Day 6); 72-hour follow-up (Day 8); and 10-day follow-up (Day 15). | A change in global motion perception coherence threshold (%) from baseline. |
| Form Pattern Recognition | Pre- and post-treatment (Days 1-5); 24-hour follow-up (Day 6); 72-hour follow-up (Day 8); and 10-day follow-up (Day 15). | A change in form pattern recognition coherence threshold (%) from baseline. |
| Pattern-reversal Visual Evoked Potentials (pVEP) | Pre-treatment (Day 1); post-treatment (Day 5); 24-hour follow-up (Day 6); 72-hour follow-up (Day 8); and 10-day follow-up (Day 15). | A change in N75-P100 amplitudes and P100 latencies from baseline. |
Countries
United States
Contacts
Primary ContactArijit Chakraborty, PhD
Backup ContactAdrienne C Quan, OD
Outcome results
None listed