Visual Influences on Vestibular Adaptation

NCT07380256 | Recruiting FDA Device

• 1 other identifier: 2025P012555
• Study Type: interventional
• Target: 100
• Locations: 1 country
• Sites: 2

Brief Summary

The goal of this study is to learn whether a balance-training exercise called incremental vestibulo-ocular reflex adaptation (IVA) is safe and effective for adults with vision impairments, with or without additional vestibular (inner-ear balance) problems. The main questions it aims to answer are:

• Does IVA cause only mild, temporary symptoms and no serious adverse events?
• Does IVA improve eye-movement reflexes, balance, and walking, and do these improvements differ between people with vision problems alone and those with both vision and vestibular impairments? Researchers will compare adults with vision impairment only to adults who have both vision and vestibular impairments to see whether the groups respond differently to IVA. Participants will:
• Complete symptom ratings before and after IVA
• Undergo tests of vestibular reflexes (e.g., VOR gain)
• Complete balance and walking assessments

Conditions

Vestibular Hypofunction; Reduced Vision; Binocular Vision Abnormalities

Keywords

vestibulo-ocular reflex; incremental vestibulo-ocular reflex adaptation; abnormal uncorrected static visual acuity; Gait Disorientation Test; video head impulse test; vertical and torsional alignment nulling; dynamic visual acuity test; modified Clinical Test of Sensory Interaction in Balance

Outcome Measures

Primary Outcomes (1)

• Change in Vestibulo-Ocular Reflex (VOR) Gain

  VOR gain will be measured using the video head impulse test (vHIT). Gain is calculated as eye velocity divided by head velocity during high-acceleration, moderate velocity, small amplitude head rotations in the plane of the semicircular canals. This outcome quantifies the strength of the vestibulo-ocular reflex, with higher gain values indicating stronger VOR responses, with normal gain = 0.8 to 1.2. The change in VOR gain from before to after training will be used to assess VOR adaptation. IVA: Incremental Vestibulo-Ocular Reflex Adaptation

  Baseline (visit 1) (before and after after IVA intervention), Visit 2 (2-10 days from baseline) (before and after IVA intervention)

Secondary Outcomes (3)

• Change in Modified Clinical Test of Sensory Interaction in Balance (mCTSIB)

  Baseline (visit 1) (before and after after IVA intervention), Visit 2 (2-10 days from baseline) (before and after IVA intervention)

• Change in Gait Disorientation Test (GDT)

  Baseline (visit 1) (before and after after IVA intervention), Visit 2 (2-10 days from baseline) (before and after IVA intervention)

• Symptom Severity During IVA (Verbal Analog Scales)

  Baseline (visit 1) (before and after after IVA intervention), Visit 2 (2-10 days from baseline) (before and after IVA intervention)

Study Arms (4)

Group 1: Abnormal Uncorrected Static Visual Acuity (No Vestibular Hypofunction)

EXPERIMENTAL

Adults with abnormal uncorrected distance visual acuity and normal vestibular function. This group will be part of Experiment 1. This experiment studies people whose main visual problem is reduced uncorrected distance visual acuity (i.e., blurry vision without glasses/contacts). Experiment 1 tests the effect of blurry vision on VOR adaptation

Device: StableEyes: Incremental Vestibulo-Ocular Reflex Adaptation (IVA)

Group 2: Abnormal Uncorrected Static Visual Acuity + Vestibular Hypofunction

EXPERIMENTAL

Adults with abnormal uncorrected distance visual acuity and unilateral vestibular hypofunction. This group will be part of Experiment 1. This experiment studies people whose main visual problem is reduced uncorrected distance visual acuity (i.e., blurry vision without glasses/contacts). Experiment 1 tests the effect of blurry vision on VOR adaptation

Device: StableEyes: Incremental Vestibulo-Ocular Reflex Adaptation (IVA)

Group 3: Binocular Vision Abnormalities (No Vestibular Hypofunction)

EXPERIMENTAL

Adults with binocular vision abnormalities (e.g., convergence insufficiency, ocular misalignment) and normal vestibular function. This group will be part of Experiment 2. This experiment studies people whose main visual problem is how the two eyes work together (e.g., convergence insufficiency, ocular misalignment). Experiment 2 tests the effect of binocular vision dysfunction on VOR adaptation

Device: StableEyes: Incremental Vestibulo-Ocular Reflex Adaptation (IVA)

Group 4: Binocular Vision Abnormalities + Vestibular Hypofunction

EXPERIMENTAL

Adults with binocular vision abnormalities and unilateral vestibular hypofunction. This group will be part of Experiment 2. This experiment studies people whose main visual problem is how the two eyes work together (e.g., convergence insufficiency, ocular misalignment). Experiment 2 tests the effect of binocular vision dysfunction on VOR adaptation

Device: StableEyes: Incremental Vestibulo-Ocular Reflex Adaptation (IVA)

Interventions

StableEyes: Incremental Vestibulo-Ocular Reflex Adaptation (IVA) DEVICE

IVA is delivered using the StableEyes device, which includes a lightweight head-mounted unit with inertial sensors and a micromirror that controls the position of a low-power laser target projected onto a wall. The device adjusts the target's movement based on the participant's head velocity to create a controlled visual error signal that induces vestibulo-ocular reflex (VOR) adaptation. During each session, participants sit about one meter from a blank wall and perform rapid, self-generated head impulses while visually tracking the moving laser target. The target appears at neutral, moves at a fraction of head velocity during each impulse, and briefly disappears before reappearing at center. Each session lasts 15 minutes and includes roughly 150 head impulses in the horizontal or vertical plane. The procedure has been well-tolerated in prior studies with no reported adverse events.

Group 1: Abnormal Uncorrected Static Visual Acuity (No Vestibular Hypofunction); Group 2: Abnormal Uncorrected Static Visual Acuity + Vestibular Hypofunction; Group 3: Binocular Vision Abnormalities (No Vestibular Hypofunction); Group 4: Binocular Vision Abnormalities + Vestibular Hypofunction

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• For All Participants (All Groups)
• Age 18 to 60 years
• Able to provide informed consent
• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Emory University: lead

Study Sites (2)

Emory Ophthalmology Clinics

Atlanta, Georgia, 30322, United States

NOT YET RECRUITING

Dizziness and Balance Center

Atlanta, Georgia, 30329, United States

RECRUITING

MeSH Terms

Conditions

Vision, Low

Condition Hierarchy (Ancestors)

Vision Disorders; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Eye Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Colin Grove, PT, DPT, PhD

  Emory University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Colin R Grove, PT,DPT,PhD

CONTACT

(404) 712-8685; colin.riess.grove@emory.edu

Hannah M Morris

CONTACT

hannah.m.morris@emory.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Model Details: Participants will be randomized for the vision condition (with or without correction) in which they will perform IVA during the first study visit. At the second study visit, all participants will cross over to perform IVA in the opposite vision condition

Study Record Dates

• First Submitted: January 20, 2026
• First Posted: February 2, 2026
• Study Start: February 4, 2026
• Primary Completion (Estimated): December 1, 2029
• Study Completion (Estimated): December 1, 2029
• Last Updated: April 17, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: 12 months after the primary outcome is published; indefinitely
• Access Criteria: Mechanism: Through the Open Science Framework or Emroy Dataverse

Locations

US (2)