Wearable Warning Device Reduces Collisions for the Blind and Visually Impaired

Wearable Warning Device Reduces Collisions for the Blind and Visually Impaired

(Reuters Health) – A wearable computerized vision device may reduce collisions among blind and visually impaired people who use a long cane and/or guide dog, a new study suggests.

In a monthlong trial involving 31 adults with severe visual impairment, the electronic collision-avoidance device reduced contacts with hazards by 37%, according to the report in JAMA Ophthalmology.

“The study shows that the wearable collision warning device helped individuals with severe vision impairments or those who are blind in avoiding contacts with obstacles while walking,” said the study’s lead author, Shrinivas Pundlik, an instructor of ophthalmology at the Harvard Medical School and an investigator at the Schepens Eye Research Institute of Mass Eye and Ear in Boston. “More importantly, the trial was done in naturalistic settings, which is somewhat rare in the context of evaluating vision/mobility aids,” he noted.

“Blind individuals typically rely on a long cane or on guide dogs for mobility,” Pundlik said in an email. “However, there might be certain hazards in everyday situations, such as overhanging objects or dynamic obstacles like pedestrians, that may be missed by the habitual mobility aids. The device is designed to work with the users’ habitual mobility aids and therefore can act as an additional alerting method to hazards that may be missed by a long cane.”

The device used in the experiment consists of a processor and recorder carried in a sling backpack, a wide-angle camera mounted at chest level on the backpack’s strap and two Bluetooth-connected wristbands worn by the user. The processing unit analyzes images from the camera and determines collision risk based on the relative movement of incoming and surrounding objects in the camera’s field of view.

If an imminent collision is detected on the left or right side, the corresponding wristband vibrates; a head-on collision causes both wristbands to vibrate. Unlike other devices that simply warn of nearby objects whether or not a user is moving toward the objects, this device analyzes relative motion, warning only of approaching obstacles that pose a collision risk, and ignoring objects not on a collision course.

Study participants were aged 18 or older and had visual acuity worse than 20/200 OU or restricted visual field (tunnel vision less than 40 degrees diameter remaining field) and were independently mobile using a mobility aid without a sighted guide.

After being trained to use the device, the study participants used it for about a month at home in conjunction with their typical mobility aids. In the double-masked randomized trial, the intervention condition with the device activated to give warnings and the control condition with the device monitoring hazards but in silent mode were alternated randomly.

The effectiveness of the device was evaluated by comparing collision incidents that occurred during active and silent modes.

Pundlik and another study author disclosed that they are listed as inventors on a patent related to the device used in the study, and the work was supported by the U.S. Army Medical Research and Materiel Command.

“The study is a great proof of concept,” said Dr. Gareth Lema, a retinal surgeon at the New York Eye and Ear Infirmary at Mount Sinai and site director for quality, safety, and patient experience for the department of ophthalmology at Mount Sinai Hospital in New York City. “It seems to be the first of its kind done in a real-world situation. It was conducted among participants in their daily environments.”

“In terms of a proof of concept, it’s an incredible success,” said Dr. Lema, who wasn’t involved in the research. “Is it the last word on wearable devices, probably not. But wearable devices like this will only improve as they are able to be evaluated in real-world situations.”

“I can see a day when someone has a camera mounted on sunglasses,” Dr. Lema said. “The promise of this study is excellent. The most important thing is what it indicates for the future of our patients with visual disabilities and their ability to navigate independently.”

SOURCE: https://bit.ly/3zyWVfD and https://bit.ly/3rI7uud JAMA Ophthalmology, online July 22, 2021.

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