An interventional study of tDCS in Amblyopia, Amblyopia Strabismic and Visual Acuity, sponsored by Universidad de Murcia. Recruiting at 1 site in Spain. Open to participants aged 4 Years to 14 Years. Per ClinicalTrials.gov, last updated 2026-07-28.
Sponsored by Universidad de Murcia · Not applicable, Interventional, and Treatment
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.
Amblyopia is a neurodevelopmental visual disorder characterised by reduced visual performance despite optimal optical correction and the absence of ocular pathology. It affects up to 2-4% of children and is the leading cause of visual impairment in this population. Conventional treatment involves optical correction and patching of the contralateral (non-amblyopic) eye, which usually produces limited improvement, low therapeutic compliance and frequent relapses, highlighting the need for new approaches based on neuroplasticity.
Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique that can modify cortical excitability by regulating GABAergic inhibition in the primary visual cortex (V1). It has been safely used in children with attention deficit disorder, schizophrenia, epilepsy or cerebral palsy.
Preliminary data from our group show that after three sessions of tDCS on paediatric strabismic amblyopia, there are significant and sustained improvements in visual acuity, contrast sensitivity, and stereopsis at 3 months.
This project proposes a randomised, double-blind clinical trial to evaluate the efficacy, safety and optimal dosage regimen of tDCS in children aged 4 to 14 years with strabismic or anisometropic amblyopia classified as non-responsive to occlusion therapy, according to the criteria established by the Pediatric Eye Disease Investigation Group (PEDIG). Objective biomarkers will be included using electroencephalogram, visual evoked potentials (pattern) and functional magnetic resonance imaging to explore cortical functional and structural changes, together with biochemical assessment of GABA levels.
The expected outcome is to validate tDCS as an effective, rapid, and safe alternative or complementary therapy for amblyopia. Demonstrating sustained visual and cortical improvements would support its inclusion in paediatric clinical protocols and promote translational neuro-ophthalmological rehabilitation
189 studies on the registry are indexed under Amblyopia; 41 are open to participants now.
This study's planned enrollment of 100 is above the median of 60 across 137 interventional studies indexed under Amblyopia.
Browse Amblyopia studies →Universidad de Murcia is the lead sponsor of 79 studies on the registry; 17 are open to participants now.
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Exclusion Criteria:
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
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
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.
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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 3 months
Ran from May 2026 to primary completion in Jun 2026, 0 months.
Of 58 non-industry interventional studies with no phase under Amblyopia, half reached primary completion within 34 months of starting (the median), counting those still running; a quarter within 21 and three quarters within 72. This study's 0 months is below that.
Counting every sponsor, half of 71 studies reached it within 33 months; a quarter within 17 and three quarters within 47.
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