Obstacle Negotiation in Older People With and Without Vision Impairment

NCT ID: NCT05888441

Last Updated: 2025-11-13

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 200 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-04-14
• Study Completion Date: 2028-12-31

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.

Conditions

Low Vision

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: NONE

Study Groups

Low Vision Group

At a single study visit, the group of low vision participants will be asked to perform a series of short walking trials. During each trial they will walk at a self-selected speed along a walkway (6 meters in length) that may or may not contain an obstacle to step over. The trials will be randomly varied with regard to an obstacle's presence, height, and contrast from the walkway surface. Repeated trials of each condition variation will be performed during the visit.

Group Type: EXPERIMENTAL

Obstacle characteristics

Intervention Type: OTHER

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.

Control Group

At a single study visit, the group of age-matched participants without low vision will be asked to perform a series of short walking trials. During each trial they will walk at a self-selected speed along a walkway (6 meters in length) that may or may not contain an obstacle to step over. The trials will be randomly varied with regard to an obstacle's presence, height, and contrast from the walkway surface. Repeated trials of each condition variation will be performed during the visit.

Group Type: ACTIVE_COMPARATOR

Obstacle characteristics

Intervention Type: OTHER

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.

Interventions

Obstacle 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.

Intervention Type: OTHER

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Indiana University

OTHER

Sponsor Role: lead

Responsible Party

Shirin E. Hassan

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Indiana University

Bloomington, Indiana, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Kierstyn A Napier-Dovorany, OD

Role: CONTACT

Phone: 8128554426

Email: knapier@iu.edu

Facility Contacts

Kierstyn A Napier-Dovorany, OD

Role: primary

Other Identifiers

16447

Identifier Type: -

Identifier Source: org_study_id