Effects of Impaired Visual Acuity and Binocular Control Abnormalities (VABC) on Vestibulo-ocular Reflex (VOR) Adaptation in Adults With and Without Vestibular Hypofunction
Emory University
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
Description
Impairment of vestibular pathways can lead to deficits in balance, gait, and gaze stability. Gaze-stability exercises are a central component of vestibular rehabilitation and have been shown to improve vision during head movement as well as functional mobility in individuals with peripheral or central vestibular dysfunction. Improvements in gaze stability may occur through vestibulo-ocular reflex (VOR) adaptation or through compensatory saccadic eye movements. However, many adults with vestibular hypofunction also present with uncorrected visual acuity deficits or binocular vision abnormalitie…
Eligibility
- Age range
- 18–60 years
- Sex
- All
- Healthy volunteers
- No
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,…
Interventions
- DeviceStableEyes: Incremental Vestibulo-Ocular Reflex Adaptation (IVA)
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.
Locations (2)
- Emory Ophthalmology ClinicsAtlanta, Georgia
- Dizziness and Balance CenterAtlanta, Georgia