How vision affects a brief balance training that strengthens eye movement reflexes

Effects of Impaired Visual Acuity and Binocular Control Abnormalities (VABC) on Vestibulo-ocular Reflex (VOR) Adaptation in Adults With and Without Vestibular Hypofunction

This study will see if a 15-minute balance exercise called incremental vestibulo-ocular reflex adaptation (IVA) is safe and helps adults with vision impairment, with or without inner-ear balance problems.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 100 (estimated)
• Ages: 18 Years to 60 Years
• Sex: All
• Sponsor: Emory University (Academic / other)
• Locations: 2 sites (Atlanta, Georgia and 1 other locations)
• Trial ID: NCT07380256 on ClinicalTrials.gov

What this trial studies

Researchers will use a 15-minute incremental vestibulo-ocular reflex adaptation (IVA) protocol that presents a moving visual target programmed to the participant's head movement to induce increases in VOR gain. Adults (18–60) with abnormal uncorrected visual acuity or binocular vision problems will be enrolled and grouped by whether they also have peripheral vestibular hypofunction. Participants will complete symptom ratings before and after IVA, undergo vestibular reflex testing (including VOR gain measures and video head impulse testing), and perform balance and walking assessments such as the Gait Disorientation Test. The trial compares responses between vision-only and vision-plus-vestibular-impairment groups to determine safety and differential effects on gaze stability and mobility.

Who should consider this trial

Good fit: Adults aged 18–60 with abnormal uncorrected static visual acuity or binocular vision abnormalities, with or without peripheral vestibular hypofunction, who can provide informed consent are eligible.

Not a fit: People outside the 18–60 age range, those without visual impairment, or individuals who cannot tolerate head movement or have conditions that prevent accurate vestibular testing may not receive benefit from this approach.

Why it matters

Potential benefit: If successful, IVA could improve gaze stability and walking ability and reduce dizziness for adults with vision impairments, potentially lowering fall risk.

How similar studies have performed: IVA has been studied extensively in adults with vestibular hypofunction and has produced immediate increases in VOR gain, but its effectiveness in people with impaired visual acuity or binocular vision is largely untested.

Eligibility criteria

Inclusion Criteria:

For All Participants (All Groups)

* Age 18 to 60 years
* Able to provide informed consent

Group-Specific Inclusion Criteria:

* Group 1: Abnormal Uncorrected Static Visual Acuity (No Vestibular Hypofunction) Normal peripheral vestibular function
* Group 2: Abnormal Uncorrected Static Visual Acuity + peripheral Vestibular Hypofunction
* Group 3: Binocular Vision Abnormalities (No Vestibular Hypofunction) Normal peripheral vestibular function
* Group 4: Binocular Vision Abnormalities + peripheral Vestibular Hypofunction

Individuals who have abnormal static visual acuity, a binocular vision abnormality (ocular misalignment, convergence insufficiency), and vestibular loss will be assigned to Group 4.

The following definitions will be used when determining group placement:

* Abnormal Static Visual Acuity: Uncorrected visual acuity (head is still) ≥0.30 logMAR in both eyes.
* Unilateral Vestibular Hypofunction: 60 ms VOR gain \<0.80 unilaterally for the lateral semicircular canal.
* Bilateral Vestibular Hypofunction: 60 ms VOR gain \<0.80 bilaterally for the lateral semicircular canals.
* Normal Vestibular Function: 60 ms VOR gain of 0.80 to 1.20 bilaterally for the lateral semicircular canals.
* Convergence Insufficiency: ≥6 cm near point of convergence.
* Ocular Misalignment: ≥4 prism diopters of manifest deviation of the eyes (tropia) on cover/uncover testing.

Exclusion Criteria:

* Diagnosis of fluctuating vestibular disorders (e.g., benign paroxysmal positional vertigo)
* Neurologic conditions (e.g., multiple sclerosis), dementia,
* Alcohol or drug abuse,
* A major psychiatric disorder (e.g., schizophrenia),
* Pain that limits cervical spine range of motion by \>50% or that results in an -altered gait pattern.

Where this trial is running

Atlanta, Georgia and 1 other locations

• Emory Ophthalmology Clinics — Atlanta, Georgia, United States (Not_yet_recruiting)
• Dizziness and Balance Center — Atlanta, Georgia, United States (Recruiting)

Study contacts

• Principal investigator: Colin Grove, PT, DPT, PhD — Emory University
• Study coordinator: Colin R Grove, PT,DPT,PhD

Conditions Vestibular Hypofunction; Binocular Vision Abnormalities; Reduced Vision; vestibulo-ocular reflex; incremental vestibulo-ocular reflex adaptation; abnormal uncorrected static visual acuity; Gait Disorientation Test; video head impulse test