Obstacle Negotiation Training for Low Vision

Overseen By Kierstyn A Napier-Dovorany, OD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Indiana University

Disqualifiers: Vestibular disorder, Deafness, Cognitive limitations, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 1

200 Participants Needed

Trial Summary

What is the purpose of this trial?

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.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

What data supports the effectiveness of the treatment Obstacle characteristics for low vision?

The standardized obstacle course study shows that training with obstacle courses can improve mobility function, as participants demonstrated changes in walking speed and error rates after training. This suggests that obstacle negotiation training could be effective for people with low vision by enhancing their ability to navigate environments safely. ^{1 2 3 4 5}

Is obstacle negotiation training for low vision safe for humans?

The research suggests that obstacle negotiation training, including virtual reality-based training, is generally safe for individuals with low vision. Studies have shown improvements in safety during street crossing after training, indicating that the training methods do not pose significant safety risks. ^{3 6 7 8 9}

How does Obstacle Negotiation Training for Low Vision differ from other treatments for low vision?

Obstacle Negotiation Training for Low Vision is unique because it focuses on improving mobility by training individuals to better detect and navigate around obstacles, rather than relying solely on traditional aids like canes. This approach may enhance personal independence by presenting the visual environment in a way that makes it easier to identify obstacles, which is different from other treatments that may not address obstacle negotiation directly. ^{3 7 10 11 12}

Eligibility Criteria

This trial is for adults over 18 who can walk on their own. It's for those with normal vision or impaired vision, defined as having a visual acuity of 20/25 or worse, possibly with central scotoma, or a restricted field of view. People not allowed include those advised against moderate exercise by doctors, have vestibular disorders or deafness, conditions affecting long walks, cognitive issues (scoring below 24 out of 30 on the Mini Mental State Exam), gait abnormalities from injuries or diseases like Parkinson's, and non-English speakers.

Inclusion Criteria

I can walk on my own without help.

I am 18 years old or older.

You can see normally, or you have impaired vision, meaning your eyesight is 20/25 or worse with or without a central blind spot, and your field of vision is limited to an average of 100 degrees or less.

Exclusion Criteria

I have a history of balance issues or deafness.

I can walk for up to 2 hours with breaks without feeling dizzy, chest pain, or shortness of breath.

I am not cleared for moderate exercise by a doctor.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Intervention

Participants perform a series of short walking trials with obstacles of varying height and contrast

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after the intervention

2-4 weeks

Treatment Details

Interventions

• Obstacle characteristics

Trial Overview The study tests how adults with vision impairment adjust their walking when they encounter obstacles that differ in height and contrast to the ground. The goal is to understand how these individuals use their gaze and change their gait to navigate safely and potentially reduce fall risks.

Participant Groups

Group I: Low Vision Group Experimental Treatment 1 Intervention

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 II: Control Group Active Control 1 Intervention

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.

Who Is Running the Clinical Trial?

Indiana University

Lead Sponsor

Trials

1,063

Recruited

1,182,000+

Findings from Research

A study involving 316 low-vision patients and 38 clinicians found that clinicians' predictions of the success of low-vision rehabilitation (LVR) did not correlate with the actual self-reported outcomes of patients, indicating a disconnect between clinician expectations and patient experiences.

Clinicians' predictions were influenced by patients' cognitive functioning and a combination of visual acuity and functional ability, but these predictions were not reliable, as they showed no better agreement with patient outcomes than chance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Comparison of clinician-predicted to measured low vision outcomes. Chan, TL., Goldstein, JE., Massof, RW.[2021]

The LOVIT II trial is a multicenter randomized controlled trial involving 330 patients with macular disease, aiming to compare the effectiveness of low vision rehabilitation (LVR) with basic low vision (LV) services.

Preliminary results show that LVR, which includes therapy sessions to teach effective use of vision aids, may lead to better improvements in visual reading ability compared to basic LV, where devices are simply dispensed without additional training.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

VA LOVIT II: a protocol to compare low vision rehabilitation and basic low vision. Stelmack, JA., Tang, XC., Reda, DJ., et al.[2015]

A standardized indoor course was developed to effectively evaluate obstacle avoidance in individuals with ultralow vision, involving 36 blind participants and 6 sighted controls across multiple trials.

The course proved to be a feasible and cost-effective method for testing mobility function, showing significant differences in performance metrics like percent error and preferred walking speed across different course iterations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A standardized obstacle course for assessment of visual function in ultra low vision and artificial vision. Nau, AC., Pintar, C., Fisher, C., et al.[2021]

The NEI VFQ-25 questionnaire effectively measures changes in visual abilities after low-vision rehabilitation in veterans, with significant improvements noted in both the Blind Rehabilitation Center and Visual Impairment Center programs.

After rehabilitation, certain tasks like reading ordinary and small print became easier for veterans, indicating that low-vision aids and training contributed to improved functional abilities, although only 7 out of 34 items on the questionnaire showed sensitivity to these changes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Measuring low-vision rehabilitation outcomes with the NEI VFQ-25. Stelmack, JA., Stelmack, TR., Massof, RW.[2022]

Participants with low vision (LV) showed significant mobility challenges when their visual field was less than 1.2 steradians (sr), indicating that practitioners should monitor mobility difficulties at this threshold.

Visual fields constricted to between 0.23 and 0.63 sr (31 to 52° diameter) signal a need for mobility rehabilitation, while critical mobility issues arise when the visual field is reduced to 0.05 sr (15° diameter).

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Visual field size criteria for mobility rehabilitation referral. Lovie-Kitchin, JE., Soong, GP., Hassan, SE., et al.[2022]

This systematic review identified a wide variety of outcome measures used to assess orientation and mobility (O&M) performance in adults with vision impairment, highlighting the complexity of measuring O&M due to the diverse aspects such as efficiency, obstacle avoidance, and social interaction.

Nearly half of the identified outcome measures demonstrated strong validity, reliability, and feasibility, suggesting they can be effectively implemented in clinical practice to provide a comprehensive assessment of O&M abilities in individuals with low vision or blindness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Orientation and mobility outcome measures. Chang, KJ., Dillon, LL., Deverell, L., et al.[2021]

The Bristol Mobility Aid (BMA) did not improve mobility performance for visually impaired individuals, as evidenced by reduced preferred walking speeds and increased errors during navigation in an indoor course.

Both low-vision and sighted subjects experienced challenges when using the BMA, indicating that modifications are needed to enhance its effectiveness as a mobility aid.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Mobility performance of low-vision adults using an electronic mobility aid. Jones, T., Troscianko, T.[2015]

Training individuals with low vision using virtual reality can effectively teach them safe street crossing skills, as demonstrated by a study involving 12 participants who improved their timing for crossing streets after training.

Both virtual and real street training resulted in significant safety improvements, with 90% of participants' 'GO' calls occurring in the safer early half of the pedestrian phase after training, indicating that virtual reality can be a viable alternative to traditional training methods.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Individuals with severely impaired vision can learn useful orientation and mobility skills in virtual streets and can use them to improve real street safety. Bowman, EL., Liu, L.[2022]

A wearable device that projects a laser line onto curbs significantly enhances curb recognition for individuals with visual impairments, improving accuracy from 33% to 95% in identifying low-contrast curbs at a distance of five feet.

The effectiveness of the laser line as a visual cue is highly dependent on its angle relative to the user's walking path, indicating that proper alignment is crucial for maximizing safety and mobility for people with visual impairments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Structured Laser Light Improves Tripping Hazard Recognition for People with Visual Impairments. Stahl, M., Peli, E.[2021]

In a study with 48 normally sighted participants using acuity-reducing goggles, it was found that the visibility of ramps and steps is significantly affected by viewing distance, with performance declining at larger distances but improving at closer ranges.

Interestingly, the study revealed that steps going up were more visible than steps going down, highlighting the importance of edge contours and height cues in enhancing visual accessibility for individuals with low vision.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Visual accessibility of ramps and steps. Legge, GE., Yu, D., Kallie, CS., et al.[2021]

Visually impaired individuals can learn to operate mobility scooters effectively, demonstrating sufficient driving skills despite their visual challenges, as shown in a study involving 48 visually impaired participants and 37 sighted controls.

Participants with visual field defects and low visual acuity faced more difficulties, particularly with skills like reverse driving and stopping, indicating that tailored training and individual assessments are essential for improving their mobility scooter driving abilities.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Mobility scooter driving ability in visually impaired individuals. Cordes, C., Heutink, J., Brookhuis, KA., et al.[2018]

The study developed 'residual vision glasses' (RVGs) that help visually impaired individuals detect obstacles by presenting distance information through brightness, leading to improved mobility performance, especially for those with the most severe impairments.

While participants were able to navigate obstacle courses using the RVGs, they experienced slower walking speeds and increased hesitations, indicating that while the technology shows promise, further research is needed to address these challenges.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Improving Mobility Performance in Low Vision With a Distance-Based Representation of the Visual Scene. van Rheede, JJ., Wilson, IR., Qian, RI., et al.[2022]

References

1. United States pubmed.ncbi.nlm.nih.gov

Comparison of clinician-predicted to measured low vision outcomes. [2021]

2. England pubmed.ncbi.nlm.nih.gov

VA LOVIT II: a protocol to compare low vision rehabilitation and basic low vision. [2015]

3. United States pubmed.ncbi.nlm.nih.gov

A standardized obstacle course for assessment of visual function in ultra low vision and artificial vision. [2021]

4. United States pubmed.ncbi.nlm.nih.gov

Measuring low-vision rehabilitation outcomes with the NEI VFQ-25. [2022]

5. United States pubmed.ncbi.nlm.nih.gov

Visual field size criteria for mobility rehabilitation referral. [2022]

6. United States pubmed.ncbi.nlm.nih.gov

Orientation and mobility outcome measures. [2021]

7. United States pubmed.ncbi.nlm.nih.gov

Mobility performance of low-vision adults using an electronic mobility aid. [2015]

8. United States pubmed.ncbi.nlm.nih.gov

Individuals with severely impaired vision can learn useful orientation and mobility skills in virtual streets and can use them to improve real street safety. [2022]

9. United States pubmed.ncbi.nlm.nih.gov

Structured Laser Light Improves Tripping Hazard Recognition for People with Visual Impairments. [2021]

10. United States pubmed.ncbi.nlm.nih.gov

Visual accessibility of ramps and steps. [2021]

11. England pubmed.ncbi.nlm.nih.gov

Mobility scooter driving ability in visually impaired individuals. [2018]

12. United States pubmed.ncbi.nlm.nih.gov

Improving Mobility Performance in Low Vision With a Distance-Based Representation of the Visual Scene. [2022]