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Active, not recruitingNCT05393739Updated Jul 20, 2026

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

An interventional study of Theta burst transcranial magnetic stimulation (TBS) procedure in Amblyopia, sponsored by National Taiwan University Hospital. Active, not recruiting at 1 site in Taiwan. Open to participants aged 20 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-07-20.

Sponsored by National Taiwan University Hospital · Not applicable, Interventional, and Health services research

Phase
Not applicable
Study type
Interventional
Enrollment
30
Allocation
Randomized
Ages
20 Years to 50 Years
Sex
All
01

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.

02

Conditions studied

  • Amblyopia

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Keywords

  • Transcranial magnetic stimulation
  • Amblyopia
  • Neuroplasticity
03

In context

Amblyopia

189 studies on the registry are indexed under Amblyopia; 41 are open to participants now.

This study's planned enrollment of 30 is below the median of 60 across 137 interventional studies indexed under Amblyopia.

Browse Amblyopia studies →

Lead sponsor

National Taiwan University Hospital is the lead sponsor of 2,615 studies on the registry; 576 are open to participants now.

Of its 11 completed or terminated interventional studies of FDA-regulated products, 2 (18%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
20 Years to 50 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Adult amblyopia participants, aged 20-50 years old.
  2. Based on inclusion criteria, there was a minimum of 2 lines difference in BCVA between the 2 eyes.
  3. An amblyogenic factor and history of amblyopia treatment was recorded

Exclusion criteria

Exclusion Criteria:

  1. Unstable vital sign
  2. History of brain injury and/or head trauma
  3. Neurological and psychiatric disease
  4. Seizures or family history of seizure
  5. Pregnancy
  6. Uncontrolled migraine or the presence of metallic implants or shunt in the head or torso
  7. Wide region of ischemic cicatrix, multiple sclerosis, taking tricycle antidepressants,
  8. Analgesics or any drugs may decrease the threshold for inducing seizure
  9. Experienced sleep disorders during the rTMS treatment
  10. Severe alcoholism or taking seizure drugs
  11. Severe heart diseases or uncontrollable migraine caused by high intracranial pressure
05

Study design

Phase
Not applicable
Primary purpose
Health services research
Allocation
Randomized
Intervention model
Crossover assignment
Masking
Single (Participant)
Enrollment
30 participants (estimated)

Study arms

  • Experimental
    Intermittent theta burst

    The total TBS time is about 1 to 3 minutes and the subjects have to look at at a visual stimulus on a computer monitor while receiving TBS and continue the visual training until 20 minutes after the treatment. In iTBS group, the subjects look at the visual stimulus with amblyopic eye while in cTBS group, subjects look at visual stimulus with non-amblyopic eye. The subjects will receive three times of stimulations in one week. The visual function evaluation includes BCVA, contrast sensitivity and stereoacuity. Visual functions will be evaluated right after TBS session (t1). Participant will receive same type of treatment for another 2 times within one week followed by visual function tests (t2). To evaluate the long-term effect, participants will be followed for another visual function tests (t3) after 2 weeks.

    Device: Theta burst transcranial magnetic stimulation (TBS) procedure

  • Experimental
    Continuous theta burst

    The total TBS time is about 1 to 3 minutes and the subjects have to look at at a visual stimulus on a computer monitor while receiving TBS and continue the visual training until 20 minutes after the treatment. In iTBS group, the subjects look at the visual stimulus with amblyopic eye while in cTBS group, subjects look at visual stimulus with non-amblyopic eye. The subjects will receive three times of stimulations in one week. The visual function evaluation includes BCVA, contrast sensitivity and stereoacuity. Visual functions will be evaluated right after TBS session (t1). Participant will receive same type of treatment for another 2 times within one week followed by visual function tests (t2). To evaluate the long-term effect, participants will be followed for another visual function tests (t3) after 2 weeks.

    Device: Theta burst transcranial magnetic stimulation (TBS) procedure

  • Sham comparator
    Sham theta burst

    The stimulus intensity in sham group is about half of that in iTBS/cTBS groups, and the subjects receive a placebo stimulation with the coil orientation tilted to 90°. The visual function evaluation includes BCVA, contrast sensitivity and stereoacuity. Visual functions will be evaluated right after TBS session (t1). Participant will receive same type of treatment for another 2 times within one week followed by visual function tests (t2). To evaluate the long-term effect, participants will be followed for another visual function tests (t3) after 2 weeks.

    Device: Theta burst transcranial magnetic stimulation (TBS) procedure

Interventions

  • DeviceTheta 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.

06

What researchers measure

Primary outcomes

  1. Objective

    Change from baseline best corrected visual acuity: distance visual acuity measured for each eye at a distance of 6 m. Visual acuity scored letter-by-letter instead and lonarithm of the minimum angle of resolution (logMAR) scores were recored.

    Time frame: 1 month for each participant

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Study locations

1 site
08

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 20, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT05393739
Responsible party
Sponsor
First posted
May 26, 2022
Start date
Jan 5, 2023
Primary completion
Oct 17, 2025
Completion
Dec 31, 2027 (estimated)
Last update
Jul 20, 2026

Study contacts

Tzu-Hsun Tsai
principal investigator · National Taiwan University Hospital

Oversight

FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is active, not recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.

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