Bilateral Transcranial Direct Current Stimulation and Ocular Occlusion for Adults With Amblyopia

NCT05016830 | Terminated

• 1 other identifier: CECI-HCUCH Nº44-2019
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

A prospective interventional study is expected to be conducted, to test a possible new treatment for amblyopia (lazy eye syndrome). Bilateral transcranial direct current stimulation (tDCS) is a type of noninvasive brain stimulation, which may help in visual function recovery of adult patients with amblyopia. This pilot study will test the feasibility of said therapy, along with the short term effects of bilateral tDCS in visual function.

Conditions

Amblyopia

Keywords

Lazy eye syndrome; Transcranial direct current stimulation; Ocular occlusion; Amblyopia

Outcome Measures

Primary Outcomes (4)

• Visual Acuity

  Clarity or Sharpness in vision, measured in LogMar

  1-2 hours

• Visual Sensitivity

  The ability to perceive differences between an object and its background, measured in percentage of contrast sensitivity.

  1-2 hours

• Stereopsis

  the perception of depth produced by the reception in the brain of visual stimuli from both eyes in combination. Measured in degrees of arc.

  1-2 hours

• Visual evoked potentials

  The electroencephalographic response from the primary visual cortex to a stimuli. Measured in millivolts (mV).

  1-2 hours

Study Arms (2)

Sham bilateral transcranial direct current stimulation

SHAM COMPARATOR

Sham bilateral transcranial direct current stimulation consisted of 2 milliamperes (mA) of current from the anodal electrode in the amblyopic primary visual cortex to the cathodal electrode located in the fellow primary visual cortex, but the stimulation was turned off after 30 seconds. On Sham Stimulation onset, the participant's fellow eye was occluded and the participant performed a reading task for 20 minutes.

Device: Bilateral transcranial direct current stimulation

Bilateral transcranial direct current stimulation

EXPERIMENTAL

Bilateral transcranial direct current stimulation consisted of 2 mA of current from the anodal electrode in the amblyopic primary visual cortex to the cathodal electrode located in the fellow primary visual cortex and the stimulation was on for 20 minutes. On stimulation onset, the participant's fellow eye was occluded and the participant performed a reading task for 20 minutes.

Device: Bilateral transcranial direct current stimulation

Interventions

Bilateral transcranial direct current stimulation DEVICE

A direct current is applied with two electrodes (cathode and anode) in specific parts of the skull. In this case the anode was over the occipital area to target the amblyopic cortex, while the cathode was over the contralateral side, targeting the fellow cortex.

Bilateral transcranial direct current stimulation; Sham bilateral transcranial direct current stimulation

Eligibility Criteria

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

You may qualify if:

• Prior diagnosis of Amblyopia

You may not qualify if:

• Ophthalmologic disease other than amblyopia
• Chronic pharmacological therapy
• Implanted medical device
• Neurologic disease or surgery history
• History of an adverse reaction to tDCS
• Pregnancy
• Not able to give informed consent

Sponsors & Collaborators

• University of Chile: lead

Study Sites (1)

Faculty of Medicine of University of Chile

Santiago, Santiago Metropolitan, 8380453, Chile

Location

MeSH Terms

Conditions

Amblyopia

Condition Hierarchy (Ancestors)

Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vision Disorders; Sensation Disorders; Neurologic Manifestations; Eye Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Romulo A Fuentes Flores, PhD

  University of Chile

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, OUTCOMES ASSESSOR
• Masking Details: Both sham and bilateral transcranial direct current stimulation were applied with the same electrode configuration, but the functioning of the stimulation device was blinded to the patient, the care provider, and the researcher performing measurements. The operator of the stimulation device selected the stimulation protocol. Sham stimulation protocol consisted of current ramp and delivery of current for 30 seconds and 19 minutes and 30 seconds with no current delivery. Actual stimulation consisted of a current ramp and 20 minutes of current delivery. There were no visual cues allowing to differentiate sham and stimulation protocols.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor at Department of Neuroscience, and Director of Research at the Faculty of Medicine of University of Chile

Model Details: A randomized, controlled pilot trial, that consists in two groups: a control group that receives sham stimulation and ocular occlusion, and a second group that receives bilateral transcranial direct current stimulation and ocular occlusion.

Study Record Dates

• First Submitted: August 13, 2021
• First Posted: August 23, 2021
• Study Start: November 5, 2019
• Primary Completion: January 31, 2020
• Study Completion: January 31, 2020
• Last Updated: August 23, 2021

Record last verified: 2021-08

Data Sharing

• IPD Sharing: Will not share

Locations

CL (1)