Augmented reality has potential in obstacle navigation for people with low vision

Despite barriers in technology and design, there is a future for the use of augmented reality as assistive technology in individuals with low vision, according to a study published in Optics Express.

In addition, data revealed that 3D world-locked augmented reality (AR) visual cues were more beneficial than directional heads-up cues when navigating obstacles.

“[The study] definitely validates that there is a future for this kind of assistive technology,” Dylan R. Fox, MIMS, UX designer at the University of California, Berkeley, told Healio. “The results affirmed the potential to improve people’s quality of life.”

Utilizing a HoloLens 2 headset and a Unity engine, Fox and colleagues developed a prototype AR application with visual navigation cues and a low-intensity 15-meter-long obstacle course to assess the effectiveness of AR visual cues in 20 individuals (average age, 46 years; 30% women) with moderate visual impairment.

The visual cues included 3D world-locked cues that highlighted obstacles when a user was within 5 meters, as well as directional heads-up cues that identified obstacles with virtual indicator bars.

Researchers noted obstacle course navigation errors, including hesitations, object contacts, stumbles, high stepping, corrections, experimenter interventions and behavior modifications, to gather quantitative data on the application’s effectiveness in detecting and avoiding obstacles.

Study participants were asked to rate their experiences with the AR visual cues on a scale of –3 to 3 (0 representing the control, no headset) after completing the obstacle course to provide qualitative user experience results about multiple aspects of the application’s effectiveness. The subjective user experience ratings were grouped by confidence, obstacle location, obstacle size and awareness.

Fox and colleagues found that 3D world-locked visual cues were preferred by participants and less disruptive to walking speed compared with directional heads-up cues.

In the post-study user experience survey, world-locked cues received median ratings of 2 for confidence, 2 for obstacle location, 2.5 for obstacle size and 1 for awareness. Conversely, heads-up cues received median ratings of 0 for confidence, 1 for obstacle location, 0 for obstacle size and 0 for awareness.

In addition, 60% of participants said they preferred world-locked visual cues at the end of the experiment.

“AR vision enhancement systems have great potential to support people with visual impairments that cannot be corrected by conventional glasses,” Fox and colleagues wrote in the study. “However, research into the technical requirements and visual design of these systems is still in its infancy.”

The co-authors added, “Fruitful avenues for future research on AR support for obstacle avoidance include examinations of visual cues for moving obstacles, comparisons of different environmental scanning technology, assessments of eye tracking and gaze-mediated interactions, explorations of different kinds of environments, and combining visual cues with other forms of feedback such as haptics and sound.”

The utilization of AR systems has drastically increased in the last couple of years as the technology has become more readily available. AR systems can boost visibility of objects in an environment and, as such, the researchers hypothesized that AR may assist individuals with low vision. 

 Video game design and technology was applied in a way that could be used by individuals with low vision. Two strategies, world-locked and heads-up were studied. World-locked cues highlight existing objects in the environment, and heads-up cues alert individuals of the direction and proximity of obstacles. 

 While the concept of AR systems in low vision has significant potential to impact a wide variety of the visually impaired patients seen in clinical practice, there are still several limitations that need to be addressed to make the technology fully usable.

First, the study participants had difficulties utilizing the AR headset, and it sometimes worsened mobility. Additionally, using both the world-locked and heads-up strategies together proved overwhelming. Most significantly, the processing speeds were too slow for the amount of incoming data to be used in real time.

As such, while the idea of AR in clinical practice is exciting, this study exemplified the substantial technological advancements needed to bring this concept to reality.