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Effect of Transcranial Magnetic Stimulation on Visual Functions of Adult Amblyopia: a Preliminary Study

NCT05393739 · Status: RECRUITING · Phase: NA · Type: INTERVENTIONAL · Enrollment: 30

Last updated 2025-06-22

No results posted yet for this study

Summary

Amblyopia, with a prevalence rates of 3% in adult population, is a common cause of vision impairment. It is characterized by impaired vision in one or both eyes because of disruption of normal visual stimuli and underdevelopment of the visual cortex, leads to lifelong visual deficits affecting both monocular and binocular visual function. Common causes of amblyopia include refraction error, anisometropia, strabismus and visual deprivation arising from ptosis or congenital cataract. Our previous studies had shed light on the relationship between abnormal early visual experience, and development of later amblyopia and possible neural developmental disorders. Functional recovery is difficult when neuroplasticity slows down at the end of the critical period. To date, there is no established effective treatment for adult amblyopia.

Repetitive transcranial magnetic stimulation (rTMS) is one of the non-invasive stimulations had been used widely as a research tool to understand the brain functions and an established treatment modality in neuropsychiatric diseases. Theta burst stimulation (TBS) is a newer form of rTMS protocol which have a major advantage over traditional rTMS in their reduced administration duration and allowing stimulation at significantly lower intensities to attain comparable effects. TBS had been demonstrated to able to improve functions in participants with visual disorders. However, studies of its use on adult amblyopia are scarce. Due to lack of efficient treatment at present, it is of scientific significance to conduct placebo-controlled experiments on this topic. Investigators will evaluate the effect of three regimens of TBS (intermittent, continuous and sham), after one session and accumulative sessions, on visual functions of amblyopia adults shortly after treatment and 2 weeks later (lasting effect), in order to evaluate its potential role in amblyopia and find out the best paradigm for amblyopia treatment.

Conditions

  • Amblyopia

Interventions

DEVICE

Theta burst transcranial magnetic stimulation (TBS) procedure

The procedure includes determining the specific occipital point at which place the stimulation coil; this corresponds to the area where magnetic stimulation is most capable of inducing phosphenes or transient visual phenomena. The phosphenes are directly induced by stimulation of the visual cortex and their presence indicates that the magnetic stimulation is in the correct location. The subjects would wear a personalized swimming cap with the determined area for stimulation marked on it. The major differences between iTBS and cTBS are the frequency and interval of stimulus.

Sponsors & Collaborators

  • National Taiwan University Hospital

    lead OTHER

Principal Investigators

  • Tzu-Hsun Tsai · National Taiwan University Hospital

Study Design

Allocation
RANDOMIZED
Purpose
HEALTH_SERVICES_RESEARCH
Masking
SINGLE
Model
CROSSOVER

Eligibility

Min Age
20 Years
Max Age
50 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2023-01-05
Primary Completion
2025-12-31
Completion
2025-12-31

Countries

  • Taiwan

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT05393739 on ClinicalTrials.gov