Brain Stimulation for Convergence Insufficiency

(NIBSCI Trial)

Overseen By Adrienne C Quan, OD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: Midwestern University

Must not be taking: Antipsychotics, Antiepileptics, Opioids

Disqualifiers: Amblyopia, Strabismus, Neurological disorders, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Approved in 2 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 14

Duration: 8 weeks

150 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether non-invasive brain stimulation, such as Anodal-Transcranial Direct Current Stimulation, can help treat convergence insufficiency. This condition causes the eyes to struggle when focusing on nearby objects, often leading to eye strain or headaches. Researchers aim to determine if this brain stimulation can accelerate or even replace traditional therapy. Participants will try different combinations of brain stimulation and therapy to identify the most effective approach. Those who have struggled with convergence insufficiency without prior treatment might be suitable candidates for this trial. As an unphased trial, this study offers a unique opportunity to explore innovative treatments that could potentially improve the condition.

Will I have to stop taking my current medications?

The trial requires that participants not take medications that can affect normal neurological function, such as antipsychotics, antiepileptics, and opioids. If you are taking these medications, you may need to stop them to participate.

What prior data suggests that non-invasive brain stimulation is safe for treating convergence insufficiency?

Research has shown that non-invasive brain stimulation, such as transcranial direct current stimulation (tDCS), is generally well-tolerated. Some studies report mild side effects like tingling, headaches, or skin irritation, which typically resolve on their own without medical intervention.

Reviews have examined the safety of office-based vergence/accommodative therapy, another treatment option in the study, for treating convergence insufficiency in children and young adults. This therapy is generally considered safe and effective, with no major risks reported.

These findings suggest that both non-invasive brain stimulation and vergence/accommodative therapy are safe options for prospective trial participants. However, discussing any concerns with a healthcare provider before participating in a clinical trial is always advisable. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about these treatments for convergence insufficiency because they explore non-invasive brain stimulation as a novel approach. Unlike traditional treatments that primarily rely on vision therapy exercises to improve eye coordination, these new methods integrate brain stimulation, potentially enhancing the effectiveness and speed of treatment. One arm combines non-invasive brain stimulation with vergence/accommodative therapy, offering a dual approach that might provide faster or more robust improvements. Another arm focuses solely on brain stimulation, which could offer a more streamlined and accessible option for patients. This innovative direction could lead to more effective and convenient treatment options for those struggling with convergence insufficiency.

What evidence suggests that this trial's treatments could be effective for convergence insufficiency?

This trial will compare different treatments for convergence insufficiency. Studies have shown that office-based vergence/accommodative therapy, which participants in this trial may receive, effectively treats convergence insufficiency, a condition where the eyes struggle to work together when focusing on nearby objects. Research strongly supports that this therapy improves eye coordination. Meanwhile, non-invasive brain stimulation, another treatment option in this trial, has proven effective for other issues like migraines and movement problems. Scientists believe it might also help with convergence insufficiency by possibly reducing treatment time or being as effective as traditional therapy. However, specific evidence linking brain stimulation to better outcomes for this eye condition is still being developed. ^{5 6 7 8 9}

Are You a Good Fit for This Trial?

Adults with symptomatic convergence insufficiency, specifically those who have a receded near point of convergence, insufficient positive fusional vergence at near, and a certain score on the CISS test. Participants must not have had previous treatments for this condition, no history of constant strabismus or surgery for it, and should not be affected by systemic diseases that impact eye function.

Inclusion Criteria

Insufficient positive fusional vergence at near (< 15∆ base-out blur or break)

Best-corrected visual acuity of > 20/25 in each eye at distance and near

Exophoria at near at least 4∆ greater than at far

Exclusion Criteria

Developmental disability, attention deficit hyperactivity disorder (ADHD), learning disability or cognitive dysfunction that would interfere with treatment

I have a permanent eye misalignment.

I have had surgery for crossed eyes.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive non-invasive brain stimulation and/or office-based vergence/accommodative therapy

8 weeks

8 sessions

Follow-up

Participants are monitored for safety and effectiveness after treatment

12 months

Assessments at 6 months and 12 months post-treatment

What Are the Treatments Tested in This Trial?

Interventions

• Anodal-Transcranial Direct Current Stimulation
• Office-Based Vergence/Accommodative Therapy
• Sham Transcranial Direct Current Stimulation

Trial Overview

The trial is testing if non-invasive brain stimulation can reduce treatment time from 12 to 8 weeks when combined with office-based therapy for eye disorders or if it's as effective alone. It involves comparing three groups: one receiving both therapies, one with sham stimulation plus therapy, and one with only the brain stimulation.

How Is the Trial Designed?

Group I: NIBS-OBVAT Active Control 2 Interventions

8 sessions of non-invasive brain stimulation with 8 weeks of office-based vergence/accommodative therapy.

Group II: NIBS Active Control 1 Intervention

8 sessions of non-invasive brain stimulation only.

Group III: OBVAT Placebo Group 2 Interventions

8 sessions of sham stimulation with 8 weeks of office-based vergence/accommodative therapy.

Office-Based Vergence/Accommodative Therapy is already approved in United States, European Union for the following indications:

Approved in United States as Vergence/Accommodative Therapy for:

• Symptomatic Convergence Insufficiency

Approved in European Union as Vergence/Accommodative Therapy for:

• Symptomatic Convergence Insufficiency

Who Is Running the Clinical Trial?

Midwestern University

Lead Sponsor

Trials

24

Recruited

3,500+

New Jersey Institute of Technology

Collaborator

Trials

11

Recruited

1,100+

University of Waterloo School of Optometry and Vision Science

Collaborator

Trials

1

Recruited

150+

Pennsylvania College of Optometry

Industry Sponsor

Trials

4

Recruited

310+

Southern California College of Optometry at Marshall B. Ketchum University

Collaborator

Trials

24

Recruited

1,400+

Published Research Related to This Trial

A retrospective study of 43 prepresbyopic patients using an automated home computer vision therapy program (HTS) showed significant reductions in asthenopic symptoms, with scores improving from an average of 32.8 to 20.6 after treatment.

The therapy also led to clinically significant improvements in convergence and divergence amplitudes, indicating that HTS can effectively address accommodative and vergence disorders, especially when in-office therapy is not feasible.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Reduction of symptoms in binocular anomalies using computerized home therapy-HTS. Cooper, J., Feldman, J.[2022]

Vergence-accommodative therapy significantly alters brain activation patterns in adults with convergence insufficiency (CI), as shown by fMRI scans, indicating its effectiveness in treatment.

After 12 weeks of therapy, there was a notable decrease in activation in brain areas related to attention and an increase in activation in the occipital lobe, suggesting improved processing of visual information and reduced conscious effort needed for convergence.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Post-therapy Functional Magnetic Resonance Imaging in Adults with Symptomatic Convergence Insufficiency. Widmer, DE., Oechslin, TS., Limbachia, C., et al.[2019]

Office-Based Vergence/Accommodative Therapy (OBVAT) effectively treats convergence insufficiency (CI), improving symptoms in about 75% of patients, as shown in a study with 25 symptomatic CI patients who underwent 12 hours of therapy.

Post-therapy assessments revealed significant improvements in near point of convergence, positive fusional vergence, and reduced symptoms, alongside increased functional brain activity in areas related to eye movement control, indicating that OBVAT not only enhances visual function but also engages neural mechanisms involved in rehabilitation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Clinical and Functional Imaging Changes Induced from Vision Therapy in Patients with Convergence Insufficiency. Alvarez, TL., Scheiman, M., Santos, EM., et al.[2020]

In a study involving 50 young adults with convergence insufficiency, office-based vergence/accommodative therapy significantly improved the near point of convergence by an average of 6.0 cm compared to only 3.1 cm in the placebo group, indicating its effectiveness in treating this condition.

The therapy also led to a greater increase in positive fusional vergence (17.3Δ) compared to placebo (7.4Δ), but both groups reported similar reductions in symptoms, suggesting the need to revise the Convergence Insufficiency Symptom Survey for future studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Convergence Insufficiency Neuro-mechanism in Adult Population Study Randomized Clinical Trial: Clinical Outcome Results. Alvarez, TL., Scheiman, M., Santos, EM., et al.[2022]

Office-based vergence/accommodative therapy with home reinforcement (OBVAT) significantly reduced symptoms of convergence insufficiency in children, achieving a mean score of 15.1 on the Convergence Insufficiency Symptom Survey after 12 weeks, compared to higher scores in other treatment groups.

OBVAT also led to better clinical outcomes, with 73% of patients showing improvement, and demonstrated significant enhancements in near point of convergence and positive fusional vergence compared to home-based therapies and office-based placebo treatments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Randomized clinical trial of treatments for symptomatic convergence insufficiency in children. [2022]

Office-based vergence and accommodative therapies have been shown to improve motor outcomes in children with convergence insufficiency (CI), supported by level I evidence from two randomized controlled trials.

However, the effectiveness of these therapies in relieving symptoms of CI is inconsistent, and there is insufficient evidence to determine the efficacy of home-based therapies compared to placebo.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Home- and Office-Based Vergence and Accommodative Therapies for Treatment of Convergence Insufficiency in Children and Young Adults: A Report by the American Academy of Ophthalmology. Chang, MY., Morrison, DG., Binenbaum, G., et al.[2021]

Office-based vergence/accommodative therapy significantly improved accommodative amplitude by an average of 8.6 diopters in children with convergence insufficiency, compared to a 5.2 diopter improvement in the placebo group, indicating a meaningful therapeutic effect.

The therapy also enhanced accommodative facility, with an average increase of 13.5 cycles per minute in the treatment group versus 7.6 in the placebo group, and a higher percentage of participants achieving normal function (85% vs. 49%), demonstrating its efficacy in addressing these visual dysfunctions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effectiveness of vergence/accommodative therapy for accommodative dysfunction in children with convergence insufficiency. Chen, AM., Roberts, TL., Cotter, SA., et al.[2023]

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