Collision Warning Device for Blind and Visually Impaired

Not Applicable

Completed

Conditions: Hemianopia
Blindness
Retinitis Pigmentosa
Peripheral Visual Field Defect
Glaucoma
Hemianopsia

Brief Summary: This study evaluates a novel collision warning device to help people with severe vision impairment or blindness avoid collisions with obstacles. The main hypothesis to be tested is that the device reduces the number of collisions with obstacles in everyday activities.

Detailed Description: Participants with blindness or severe visual field loss (hemianopia or tunnel vision) will be trained to use a collision warning device that alerts them to impending collisions. Participants will use the device at home during everyday mobility for about 1 month. The device is designed to supplement existing mobility devices, such as a long cane or dog guide. The device will provide warnings about potential collisions with mid- or high-level obstacles (which are typically not detected by a long cane).

Recruitment & Eligibility

Inclusion Criteria

Blindness (or very limited vision with visual acuity no better than "counting fingers"),
Or severe peripheral field loss / tunnel vision (≤ 40° remaining visual field) with visual acuity of at least 20/200,
Or homonymous hemianopia with visual acuity of at least 20/200;
Able to walk independently either with or without mobility aids such as a long cane or guide dog (but without the aid of a sighted guide);
Reports at least minor bumps or collisions within the last 3 months;

Exclusion Criteria

Currently participating in a mobility training program
Diagnosed dementia
Significant cognitive decline
Participants with hemianopia will be excluded if they have hemianopia for less than 3 months and/or have spatial neglect

Arm && Interventions

Group	Intervention	Description
Intervention	Collision warning device	Participants will use the collision warning device as much as possible for about one month during everyday activities, when walking indoors and outdoors.

Primary Outcome Measures

Name	Time	Method
Number of Collision Incidents (All Contacts)	During the one-month period of device use	Collision incidents recorded by the device in everyday use, including long cane contacts and body contacts with surrounding objects in the environment.

Secondary Outcome Measures

Name	Time	Method
Number of Body Contacts	During the one-month period of device use	Collision incidents with body contacts recorded by the device
Device Questionnaire	During the one-month period of device use	Questionnaire addressing participants' experiences of using the device. Scores were on a 5-point rating scale (1 to 5) with higher scores representing a better score. Questions were grouped into four main categories: i) overall satisfaction, ii) comfort, iii) mobility benefit, and iv) ease of operation. An average score was computed for questions within each category.