Beyond the white cane

Image credit: AdobeStock/zlikovec

Technological advancements have revolutionized the way we travel and navigate the world. From getting directions to the closest coffee shop to ordering a rideshare back from the airport, technology has made travel more efficient, convenient, and less stressful. However, for someone with vision loss, navigating a route and doing it safely still has many challenges.

Challenges for people with a visual impairment may include reading a street sign, crossing a busy street, or avoiding an obstacle. Finding the restroom in an unknown indoor environment has been reported as the biggest challenge, followed by locating signage, stairs, and elevators.1 Consequences of these challenges often result in avoiding travel, social isolation,² or even injury.³ Outdoor head-level accidents requiring medical attention are not uncommon for people with vision loss.⁴

Early technologies, dating back to the 1960s, concentrated on protection from injury. Known as electronic travel aids, ultrasonic sensors were used to detect a potential hazard through haptics or sound.⁵ Although this technology is still in use today and is combined with other technologies, it is important to understand that limitations still exist, such as false positive feedback in crowded or urban environments.

One of the tools most associated with vision loss is the white cane. Although not meant to replace a cane, technologies can assist by providing additional information for orientation and mobility that extend beyond a cane. Orientation and mobility play a vital role in someone’s journey with declining vision. Knowing one’s orientation helps to define where someone is in their environment, such as knowing nearby landmarks or stores, whereas mobility is the ability to move safely within that environment, avoiding both static and dynamic obstacles. Although optometry plays an indirect role, providing best corrected vision, contrast, and telescopic or magnification solutions, we should also be aware of the digital technologies available, of which many are integrated right in our smartphones.

Accessible GPS

The Global Positioning System (GPS), initially developed for the military, is now used by millions of people every day, giving directions all over the world. GPS can be extremely helpful to someone with a visual impairment, as it is readily available on a smartphone and gives audible directions. However, the accuracy of GPS can be off by as much as 4.9 m or even more in urban areas.⁶ This now becomes a safety concern for turn-by-turn navigation, and a discrepancy often means that the user will only get close to their destination, complicating travel for those relying on accurate positioning cues to compensate for their vision loss. In addition, GPS cannot be used indoors and many applications heavily rely on a visual display. However, there are accessible GPS applications available that are designed and adapted for use by someone with vision loss. Two popular apps are Lazarillo and BlindSquare.

The Lazarillo and BlindSquare apps are specifically designed for travelers with low vision and blindness. They have similar features that provide audible information on current locations, intersections, nearby points of interest (POI), public transportation, and turn-by-turn walking directions.

A distinguishable difference in the Lazarillo app includes the ability to turn on or off nearby POI by category that the user wants to be notified about. The POI are organized by categories such as food, stores, banks, or health. It also allows an individual’s choice to be provided by their mode of transportation, either heard when walking or when riding in a vehicle. This can help users discover new places or assist in their orientation for recognizing known places along a route.

The BlindSquare application also searches and vocalizes POI, and although you can pick a specific category, if not specified, the app will speak out all POI. BlindSquare allows customization of the search radius ranging from 82 feet to 1.2 miles. This flexibility enables users to hear about POI within their specified area. Additionally, BlindSquare includes features such as Look Around, providing information about the environment in the direction that the user is facing within their set range, as well as the Around Me feature, giving a comprehensive 360° overview of the surrounding environment that extends beyond the set range. The feature can also enhance an individual’s orientation, helping them discover new areas.

In a review and study on assistive GPS application user experiences, Theodorou et al found that BlindSquare was favored due to its customization options.⁷ However, when they compared BlindSquare and the Lazarillo app with their external and more accurate GPS system, they found that people were willing to forgo personalization features for greater accuracy.

The choice of one application over the other comes down to preference and preferred operating system. The Lazarillo app is free and is available on both iOS and Android, whereas BlindSquare costs $39.99 and is only available on iOS. Both companies also provide other technology solutions for indoor navigation using sensor technologies that businesses can purchase.

Another assistive GPS, HapticNav, is optimized for on-foot travel and is unique, as it guides through haptic feedback on a smartphone. While providing turn-by-turn instructions, the app uses vibrations to alert the user to stay on course. If the person is walking in the correct direction, there is no vibration. The user can also choose to have a haptic pulse. You can think of it as a corridor, and if you veer off course or step out of the corridor, the app will notify you via vibrations. Navigating through haptics can be advantageous in noisy environments, which can drown out audio guidance, or for those with a hearing impairment. The company reports that in 2017, a runner who was blind was able to run 15 miles of the New York City Marathon without sighted assistance using their haptic feedback technology.⁸ It also reports that the app will soon work on the Apple Watch. HapticNav is free and is available on iOS and Android.

Although GPS-based apps and tools provide mapping and directional information, obstacle avoidance is still challenging and adds another layer of complexity. As previously mentioned, initial technologies concentrated on obstacle avoidance alone.

The premise of the WeWALK Smart Cane is to incorporate a blend of technologies with the traditional white cane. The WeWALK Smart Cane is a traditional folding cane with a plastic attachment on the handle housing an ultrasonic sensor, trackpad, and speaker. Unlike a conventional white cane, the ultrasonic sensor offers a 55° coverage area to detect obstacles above the chest, protecting users from head injury. The user is alerted to a potential hazard by haptic feedback. The speaker and trackpad also allow the user to receive audio feedback with a Bluetooth headphone option and to control the WeWALK app directly from the cane, eliminating the need to hold the phone in their hand.

The WeWALK GPS app provides location feedback, discovery of nearby POI, step-by-step navigation along with location and directions to public transportation, and updates on bus/train arrivals and can create an entire route to complete a journey, transitioning from foot travel to public transit and back again. WeWALK offers use of their app to anyone in a subscription model, but cane owners have access to the app at no additional cost. The application is available on both iOS and Android.

The WeWALK Smart Cane 2, with a design closer to the feel of a traditional white cane, is due out later this year. The company has also integrated artificial intelligence (AI) with this cane, providing the option of AI-assisted mobility training and the ability to connect to someone for sighted assistance.

Wearable assistive navigation technologies for obstacle avoidance

Although WeWALK integrates technology with the white cane, wearables by biped and Strap Tech allow hands-free obstacle avoidance. These devices use a combination of sensors and AI to provide analysis and feedback about the environment.

Bryan Wolynski, OD, FAAO, testing out the Ara device by Strap Tech at the Consumer Electronics Show. Image courtesy of Bryan Wolynski, OD, FAAO.

The Ara device by Strap Tech communicates the location and distance of obstacles through vibrations, alerting a user to low-lying, chest, and head-level obstacles while walking (Figure 1). This obstacle alert system is worn across the midtorso, weighs just over three-quarters of a pound, and encases advanced sensors, including LiDAR (light detection and ranging), ultrasonic sensors, an accelerometer, a gyroscope, and haptic actuators. When worn, Ara’s AI continuously processes the sensor’s data, prioritizing feedback based on size, speed, and proximity of a potential obstruction risk, providing that to the wearer through vibrational patterns. When used with a white cane or guide dog, the Ara features the White Cane Mode, which dampens low-level obstacle feedback, reducing any unnecessary alerts.⁹

Shannel Matos using a biped device alongside its company developer. Image courtesy of Bryan Wolynski, OD, FAAO.

Similar to how autonomous vehicles scan for risks on the road, biped—which is worn as a harness over the shoulders—uses specialized cameras to scan a 170° field of view and alerts the user to potential obstacles via spatial sounds through a bone conduction headset (Figure 2).¹⁰ With a detection range of up to 15 feet, its algorithm warns the user of the most significant potential risk, scanning the environment for stationary and moving targets such as cars and people. For example, it can predict a potential head-level collision with a tree branch that the user is advancing upon while filtering out other objects that pose no threat and gives audio feedback to avoid it.¹⁰ biped also incorporates AI scene description (photo-to-text generative AI) and GPS instructions to provide more comprehensive information about a route.

A new, noteworthy wearable technology is SideSight, developed by Ocutech. SideSight helps people with hemianopsia avoid obstacles on their blind side. Attached to the user’s glasses, ultrasonic sensors (in which range and angle can be customized by the optometrist) detect an obstacle and provide proximity information through vibrations to the individual.

References

1. Başgöze Z, Gualtieri J, Sachs MT, Cooper EA. Navigational aid use by individuals with visual impairments. J Technol Pers Disabil. 2020;8:22-39.

2. Curriero FC, Pinchoff J, van Landingham SW, Ferrucci L, Friedman DS, Ramulu PY. Alteration of travel patterns with vision loss from glaucoma and macular degeneration. JAMA Ophthalmol. 2013;131(11):1420-1426. doi:10.1001/jamaophthalmol.2013.4471

3. Ireland - Clear Our Paths campaign. EBU. Accessed June 21, 2024. https://www.euroblind.org/newsletter/2023/september/en/ireland-clear-our-paths-campaign

4. Manduchi R, Kurniawan S. Mobility-related accidents experienced by people with visual impairment. Insight (Lawrence). 2011;4(2):44-54.

5. Real S, Araujo A. Navigation systems for the blind and visually impaired: past work, challenges, and open problems. Sensors (Basel). 2019;19(15):3404. doi:10.3390/s19153404

6. van Diggelen F, Enge P. The world’s first GPS MOOC and worldwide laboratory using smartphones. In: Proceedings of the 28th International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GNSS+ 2015). The Institute of Navigation; 2015:361-369.

7. Theodorou P, Tsiligkos K, Meliones A. Multi-sensor data fusion solutions for blind and visually impaired: research and commercial navigation applications for indoor and outdoor spaces. Sensors (Basel). 2023;23(12):5411. doi:10.3390/s23125411

8. About. Haptic. Accessed June 30, 2024. https://haptic.works/about-1

9. How it works. Strap Tech. Accessed June 30, 2024. https://www.strap.tech/the-device

10. biped AI. Accessed June 30, 2024. https://biped.ai/