Effectiveness of tDCS in Paediatric Amblyopia.

NCT07547670 | Not Yet Recruiting

• 1 other identifier: T-TDCS-PJY
• Study Type: interventional
• Target: 100
• Locations: 0 countries
• Sites: N/A

Brief Summary

The goal of this randomized, double-blind clinical trial is to determine whether transcranial direct current stimulation (tDCS) can effectively and safely improve vision in children aged 4-14 years with strabismic or anisometropic amblyopia that has not responded to conventional patching therapy. The main questions it aims to answer are: Does tDCS produce significant and sustained improvements in visual acuity, contrast sensitivity, and stereopsis in children with amblyopia? Is tDCS a safe, well-tolerated, and faster alternative or complementary treatment compared with standard occlusion therapy? Does tDCS induce functional and structural changes in the visual cortex associated with increased neuroplasticity, including modulation of GABAergic activity? If there is a comparison group: Researchers will compare active tDCS with sham (placebo) stimulation to see if active treatment leads to greater visual recovery and cortical changes than placebo. Participants will: Receive several sessions of active or sham tDCS using low-intensity electrical stimulation applied to visual brain areas. Undergo standard visual assessments, including visual acuity, contrast sensitivity, and stereopsis. Complete neurophysiological and neuroimaging evaluations (EEG, pattern visual evoked potentials, and functional MRI). Provide biochemical measures related to GABA levels. This study aims to validate tDCS as a non-invasive, child-friendly, and effective therapy that may overcome the limitations of patching and support its inclusion in paediatric clinical practice.

Conditions

Amblyopia; Amblyopia Strabismic; Visual Acuity; Stereoscopic Vision

Keywords

tDCS; Ambyopia

Outcome Measures

Primary Outcomes (4)

• Visual Acuity

  Visual acuity measurements were performed by the same examiner, using a calibrated optotype at a distance of six meters, before starting treatment, after each session, one month after treatment, and three months after treatment.

  3 months

• Stereoscopic visual acuity

  Stereoscopic visual acuity was measured using TNO test (with the butterfly plate corresponding to 1300" and the circular plate to 1200"), the subject places the test 40 cm away and must identify calibrated figures.

  3 months

• Contrast sensitivity

  Contrast sensitivity was measured using CSV-1000 test (3, 6, 12, and 18 cycles per degree). The patient must identify scratched circles whose frequency is decreasing.

  3 months

• Eye Fixation

  Eye fixation was evaluated using the Topcon Macular Integrity Assessment (MAIA) microperimeter (Topcon corporation, Tokyo, Japan), which delineates two distinct regions using 1° (P1) and 2° (P2) circles.

  3 months

Study Arms (2)

Group tDCS

EXPERIMENTAL

Children aged 4 to 14 with amblyopia treated at one of the collaborating hospitals and centers, with visual acuity in the amblyopic eye between 20/32 and 20/200. They will undergo tests of visual acuity, stereoscopic visual acuity, fixation, and contrast sensitivity. The direct current will be gradually increased over 34 seconds to 2 mA, held constant for 15 minutes, and then gradually reduced to zero using NIC2® v2.1.2.0 software (Neuroelectrics®, Barcelona, Spain). The stimulating current is applied using two rubber electrodes housed in circular sponge pockets (8 cm² each) soaked in saline solution. The electrodes are placed at Oz (active/stimulating electrode, located in the visual cortex) and Cz (reference electrode).

Device: tDCS

Group Sham

SHAM COMPARATOR

The sham group is equipped with the same electrostimulation helmet, but the intensity protocol is set to 0 at all times. The same measurements are taken and exactly the same procedure is followed as with the experimental group.

Device: tDCS

Interventions

tDCS DEVICE

The direct current is gradually increased over 34 seconds until it reaches 2 mA, remains constant for 15 minutes, and then is gradually reduced to zero using NIC2® v2.1.2.0 software (Neuroelectrics®, Barcelona, Spain). The stimulating current is applied using two rubber electrodes housed in circular sponge pockets (8 cm² each) soaked in saline solution. The electrodes are placed at Oz (active/stimulating electrode, located in the visual cortex) and Cz (reference electrode). This includes a total of 3 sessions of 15 minutes and 34 seconds separated by 48 hours.

Group Sham; Group tDCS

Eligibility Criteria

• Age: 4 Years - 14 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17)

You may qualify if:

• Children aged 4-14 years.
• Strabismic amblyopia resistant to patching (PEDIG criteria).
• Anisometropic amblyopia resistant to patching (PEDIG criteria).

You may not qualify if:

• Ocular pathology.
• Nystagmus.
• Mental disability.
• Cognitive delay.
• Neurological problems incompatible with treatment.
• Pacemakers.
• Intracranial electrodes.
• Implanted defibrillators.
• Cranial pathologies.
• Cranial lesions.
• Withdrawal will occur upon adverse events, protocol deviation, refusal, or loss to follow-up.

Sponsors & Collaborators

• Universidad de Murcia: lead
• Hospital Universitario Virgen de la Arrixaca: collaborator
• Hospital Universitario Reina Sofia de Cordoba: collaborator
• Hospital General Universitario Morales Meseguer: collaborator

MeSH Terms

Conditions

Amblyopia

Interventions

Transcranial Direct Current Stimulation

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

Intervention Hierarchy (Ancestors)

Electric Stimulation Therapy; Therapeutics; Convulsive Therapy; Psychiatric Somatic Therapies; Behavioral Disciplines and Activities; Electroshock; Psychological Techniques

Central Study Contacts

Dr. Francisco Javier Valiente Soriano, Optics and Optometry

CONTACT

+34 670 25 58 48; fjvaliente@um.es

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: During months 1 to 6, preparatory activities will include obtaining ethical approvals, installing equipment, and selecting participants. From months 6 to 24, the main intervention phase will take place, comprising tDCS stimulation, optometric and microperimetric assessments, and clinical follow-up (study 1), together with neurophysiological recordings (VEP and EEG) under the same experimental conditions (study 2). This period will also include a six-month booster stimulation phase to assess the persistence of treatment effects. At the same time, data curation and preliminary analyses of studies 1 and 2 will be carried out. Starting in month 24, study 3 will focus on neurofunctional and neurochemical assessments using functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS). Between months 30 and 36, data from the three studies will be integrated, followed by final statistical analyses, interpretation, and preparation of scientific reports and manuscripts.

Study Record Dates

• First Submitted: April 16, 2026
• First Posted: April 23, 2026
• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): August 31, 2029
• Last Updated: April 29, 2026

Record last verified: 2026-01