Effectiveness of tDCS in Paediatric Amblyopia.

Condition(s) studied

Investigational drug(s) / intervention(s)

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.

Study 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.

Eligibility

Primary outcome measure(s)

• Visual Acuity — 3 months
  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.
• Stereoscopic visual acuity — 3 months
  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.
• Contrast sensitivity — 3 months
  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.
• Eye Fixation — 3 months
  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.

Trial sites (1)

More Universidad de Murcia trials in Spain