Wearable Collision-Warning Device for Blind and Visually Impaired People

Article: Wearable Devices Can Reduce Collision Risk in Blind and Visually Impaired People
Source: Massachusetts Eye and Ear Infirmary, via ScienceDaily
Published: July 22, 2021

For individuals with visual impairment or blindness, collisions and falls are a common risk in independent daily life. The use of mobility aids such long canes and guide dogs can offer benefits, but also come with limitations. For example, a long cane primarily detects hazards on the ground, often missing hazards above ground level. The range of long cane sweeping is also limited and not always appropriate in busy settings with many pedestrians. Guide dogs are highly effective but can be cost-prohibitive, as training a guide dog typically costs $45,000-$60,000. Vision rehabilitation researchers at Harvard developed and tested a wearable collision-warning device as an added safety measure to reduce collisions, for use along with the conventional long cane. The device uses a chest-mounted wide-angle camera connected to a processing unit that records video and analyzes collision risk based on the relative movement of incoming and surrounding objects in the camera’s field of view. This information is relayed to two Bluetooth-connected wristbands worn by the user, which vibrate on either or both wrists depending on the location of the imminent object, with both wristbands vibrating to indicate an object directly ahead. Notably, this device analyzes relative motion, warning only of approaching obstacles that pose a collision risk and ignoring objects that are not on a collision course. The researchers then conducted a randomized-controlled trial involving 31 blind or severely visually impaired adults who, after training, were instructed to use the device at home for 4 weeks, in conjunction with their existing mobility aids. The device was randomized (double-masked) to switch between active and silent modes, with silent mode replicating the placebo condition, only recording but not alerting the user. The results showed that the collision frequency in active mode was 37% less than that in silent mode, demonstrating the potential benefit of the device, especially as a more affordable option than a guide dog. One of the authors adds that the video recordings from the device can also provide rich data about daily mobility life and challenges for people with visual impairment to improve mobility aid training. The researchers plan on ongoing technical improvements in device processing power and cosmesis.

My rating of this study: ⭐⭐🌸

Pundlik S, Baliutaviciute V, Moharrer M, et al. "Home-Use Evaluation of a Wearable Collision Warning Device for Individuals With Severe Vision Impairments: A Randomized Clinical Trial." JAMA Ophthalmology.  22 July 2021. https://doi.org/10.1001/jamaophthalmol.2021.2624