Low Vision
Conditions
Brief summary
Falls are common among people with vision impairment and can lead to devastating health consequences. Understanding the functions of vision and how the visual characteristics of obstacles in the walking path impact the gait of people with vision impairment is necessary to create strategies to prevent falls in this population. The purpose of this study is to determine how adults with vision impairment change their gait behavior when stepping over obstacles that vary in height and contrast to the ground. We will then determine the mechanisms of gaze behavior that correlate to the gait behavior.
Interventions
OTHERObstacle characteristics
In the walking trials, when an obstacle is present, the obstacle height and obstacle contrast level will be varied across the trial repetitions. Each participant will be exposed to obstacles of two heights: the first will be 1 centimeter in height, and the second will be approximately 20% of the subject's leg length (ranging in physical height between 15 - 22 centimeters to cover a range of leg lengths in the population). Obstacles (of both heights) will also be painted such that their measured luminance (or contrast) level against the floor luminance is varied. High contrast obstacles will have ≥80% Michelson contrast and low contrast obstacles will have ≤30% Michelson contrast.
Sponsors
Indiana University
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Age 18 or over * Able to walk independently * Either have normal vision, or impaired vision. * Impaired vision is defined as binocular visual acuity of 20/25 or worse with or without a central scotoma; and/or binocular visual field that is restricted to an average of 100 degrees in diameter or less * Control subjects will have visual acuity of 20/40 or better.
Exclusion criteria
* Not cleared by a medical provider for moderate physical activity * Self-report or have a history of: vestibular disorder or deafness * Medical history of any condition that affects the ability to walk for up to 2 hours with breaks, such as feeling dizzy or faint, chest pain, palpitations, pain or numbness in the legs, shortness of breath, * Cognitive limitations either by self-report or a score on the Mini Mental State Exam below 24 (out of 30) * Walking or gait abnormalities, such as those caused from an injury, surgery, severe arthritis, or neurological condition such as Parkinson's disease * Unable to walk without any walking aids such as a walker, cane, guide dog, or oxygen tank. * Does not speak English
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Vertical foot clearance, lead limb | During a single intervention visit (Study Visit 2), up to 2-3 hours in duration. | Distance from lowest point of foot (heel or toe) to top of obstacle |
| Foot placement variability | During a single intervention visit (Study Visit 2), up to 2-3 hours in duration. | Standard deviation of position of toe to obstacle over 2-4 steps before the obstacle |
| Obstacle crossing speed | During a single intervention visit (Study Visit 2), up to 2-3 hours in duration. | Speed from lead toe off immediately before the obstacle to trail heel down immediately after the obstacle. |
| Gaze sequencing | During a single intervention visit (Study Visit 2), up to 2-3 hours in duration. | Sequence of fixations from start of trial to end of trial, normalized to the total duration and divided into 100 equal segments |
Countries
United States
Contacts
Primary ContactKierstyn A Napier-Dovorany, OD
Outcome results
None listed