About this trial
As a neurodevelopmental visual disorder, amblyopia, especially monocular form-deprivation amblyopia, can lead to severe visual developmental impairments. Due to reduced neural plasticity in the visual cortex after the critical period of visual development, older children and adults with amblyopia show poor responses to conventional treatments, lacking effective therapeutic options. Recent basic and clinical research has shown that transcranial direct current stimulation can effectively treat adult amblyopia by altering cortical excitability, enhancing synaptic plasticity, and affecting the excitatory/inhibitory balance in the cortex to reboot adult visual cortex plasticity. This proposed study aims to conduct a large-scale prospective randomized controlled trial to objectively assess the efficacy and safety of transcranial direct current stimulation in treating amblyopia in older adolescents and adults. By comparing changes in best-corrected visual acuity, visual evoked potentials(VEPs), contrast sensitivity, and functional connectivity between the visual cortex and other cortical areas using fMRI, the study seeks to provide robust clinical evidence, clarify the treatment effects of transcranial direct current stimulation in adult amblyopia, elucidate potential mechanisms of enhancing adult visual cortex plasticity with transcranial direct current stimulation, and potentially offer a safe and effective treatment modality for adult amblyopia.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Children and their legal guardians have obtained consent in writing.
Participants aged 10-30, of any gender.
Participants must meet the diagnostic criteria for amblyopia: unilateral amblyopia with a difference of two lines or more in visual acuity between the eyes, or bilateral amblyopia with best-corrected visual acuity worse than 20/30 (or worse than 0.2 logMAR). The visual acuity charts to be used are LEA SYMBOLS® (Good-Lite Co., Elgin, IL) or HOTV visual acuity chart.
Disqualifiers
Participants who may have eye diseases affecting vision or refractive errors (such as cataracts, crystalline lens damage, glaucoma, macular degeneration, corneal disorders, retinitis pigmentosa, retinal detachment, severe vitreous opacities, etc
History of eye trauma or intraocular surgery
Inability to cooperate with examinations
Presence of concomitant systemic diseases (such as epilepsy)
Trial design
Parallel
Treatments tested in this trial
tDCS Stimulation
Procedure/SurgeryAnode tDCS or sham stimulation for amblyopia of Adolescents
Anodal tDCS
DeviceAnodal tDCS
Sham tDCS
DeviceSham tDCS
Treatment groups
Trial outcomes
Primary outcomes
Improvement in Best Corrected Visual Acuity (BCVA)
quantified by the number of lines gained on a standard visual acuity chart(HOTV chart). This measure will be assessed at baseline, 3 months, and 6 months post-intervention. A line gain is defined as the ability to correctly read an additional row of optotypes compared to baseline measurements. The improvement will be evaluated separately for each eye and averaged to assess overall treatment efficacy.
Secondary outcomes
Changes in Visual Evoked Potential (VEP)
changes in Visual Evoked Potential (VEP) metrics, specifically amplitude and latency, at 15 minutes and 1-degree visual angle stimulations. These measures will be used to assess the functional responsiveness of the visual pathways and cortical processing efficiency. Baseline, 3-month, and 6-month assessments will provide comparative data to evaluate the neurophysiological effects of the intervention.
Improvements in contrast sensitivity at different spatial frequencies
Contrast sensitivity will be evaluated using a contrast sensitivity test with CSV-1000E(Vector vision, US), which measures the ability to detect differences in luminance across varying spatial frequencies (low 3 c/d, medium 6c/d、12 c/d, and high 18 c/d). Assessments will be conducted at baseline, 3 months, and 6 months post-intervention. The degree of improvement will be compared across groups to determine the impact of tDCS on visual function beyond acuity.
Sponsors and contacts
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