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

NCT ID: NCT05016830

Last Updated: 2021-08-23

Basic Information

• Recruitment Status: TERMINATED
• Clinical Phase: NA
• Total Enrollment: 12 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-11-05
• Study Completion Date: 2020-01-31

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.

Detailed Description

Theoretical Framework: Ocular occlusion treatment has been used classically and with excellent results for the treatment of amblyopia in those under 14 years of age, since in this period it has been seen that there is greater neuroplasticity, leaving little to do in the period of lower neuroplasticity, in young and adult patients with later diagnoses. Transcranial Direct Current Stimulation therapy is an emergent technique used in neurological diseases to increase neuroplasticity, by changing the resting potential of neurons. Our hypothesis is that the combination of tDCS and visual occlusion therapy is capable of increasing visual acuity, contrast sensitivity, and depth perception, in young people over 18 years of age.

Methodology: The application of a double-blind, randomized clinical trial is proposed to evaluate the application of 2 different therapies: Occlusion with bilateral tDCS, and Occlusion with tDCS sham (sham). The study subjects will be randomly assigned to a group, and one session of stimulation will be performed. Data will be analyzed using Student's t test, or Mann-Whitney test, according to the normal or non-normal distribution of the sample, respectively. Also, the change over time of the variables will be measured using the Conditional Change Model.

Expected Results: The investigators expect that visual acuity, contrast vision, and dichoptic vision in the Occlusion therapy group with bilateral tDCS will be significantly higher than the Occlusion therapy group with tDCS sham (sham).

Conditions

Amblyopia

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

Sham bilateral transcranial direct current stimulation

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.

Group Type: SHAM_COMPARATOR

Bilateral transcranial direct current stimulation

Intervention Type: 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

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.

Group Type: EXPERIMENTAL

Bilateral transcranial direct current stimulation

Intervention Type: 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.

Interventions

Bilateral transcranial direct current stimulation

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.

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

• Prior diagnosis of Amblyopia

Exclusion Criteria

• 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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Chile

OTHER

Sponsor Role: lead

Responsible Party

Romulo Antonio Fuentes Flores

Assistant Professor at Department of Neuroscience, and Director of Research at the Faculty of Medicine of University of Chile

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Romulo A Fuentes Flores, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Chile

Locations

Faculty of Medicine of University of Chile

Santiago, Santiago Metropolitan, Chile

Countries

Chile

Other Identifiers

CECI-HCUCH Nº44-2019

Identifier Type: -

Identifier Source: org_study_id