A Scoping Review of Assistance and Therapy with Head-Mounted Displays for People Who Are Visually Impaired
Yifan Li, Kangsoo Kim, Austin Erickson, Nahal Norouzi, Jonathan Jules, Gerd Bruder, Gregory F. Welch · 2022 · ACM Transactions on Accessible Computing · doi:10.1145/3522693
Summary
This scoping review systematically examines how Head-Mounted Displays (HMDs) have been used for visual assistance and therapy for people with visual impairments. The authors searched six databases (IEEE, ACM, Springer, ScienceDirect, Web of Science, PubMed) and screened 1,251 articles down to 61 research articles and 8 survey papers for detailed analysis. The review develops a comprehensive classification framework across multiple dimensions: objectives (assistive technology to help users cope with limitations vs. therapeutic technology to improve or prevent vision loss), visualization approaches (virtual environments, augmented overlays, or modified/enhanced real-world imagery), HMD types (immersive VR blocking real world, optical see-through like HoloLens, or video see-through combining camera feeds with virtual content), and targeted visual conditions (central vision loss, visual field deficits, stereopsis disorders, and color vision deficiency). The authors trace the evolution of HMD use in this domain from early 1990s Low Vision Aids (LVAs) through modern consumer devices. While early head-mounted LVAs were bulky, expensive, and performed worse than conventional magnifiers, the 2010s brought a resurgence with affordable consumer HMDs and commercial products like eSight, IrisVision, and SightPlus demonstrating clinical viability.
Key findings
The quantitative analysis reveals distinct patterns in how HMDs are deployed for different purposes. Two-thirds of articles (41 of 61) focused on assistive technology, with the remaining 20 on therapeutic applications. AR approaches are predominantly used for assistance (11 of 12 augmented approach articles), while VR is mainly therapeutic (18 of 19 virtual approach articles). The "modified" approach—enhancing real-world imagery through magnification, contrast enhancement, or edge detection—was most common (32 articles). Visual conditions showed striking patterns: all 32 articles addressing central vision loss (age-related macular degeneration, retinitis pigmentosa) were assistive, since these conditions are currently incurable. All 16 stereopsis articles (amblyopia, strabismus) were therapeutic, leveraging HMDs' ability to present different images to each eye for dichoptic training. All 6 color vision deficiency articles were assistive, using color remapping algorithms. Research volume has increased dramatically since 2016, coinciding with consumer HMD availability (Oculus Rift, HTC Vive, HoloLens). However, user study rigor varies considerably—over half of articles had no user study or fewer than 10 participants, though multi-session longitudinal studies are emerging for therapeutic applications.
Relevance
This review provides an essential landscape map for researchers and practitioners interested in HMD-based visual accessibility solutions. The classification framework helps identify where different technologies and approaches are most applicable—AR for real-world assistance, VR for controlled therapeutic environments. For practitioners, the review highlights promising commercial products (eSight for low vision magnification, Vivid Vision for amblyopia therapy) and research prototypes addressing specific needs like stair navigation, wayfinding, and reading assistance. The finding that modified approaches dominate assistive applications suggests practical value in image processing techniques (magnification, contrast enhancement, edge highlighting) over purely virtual or augmented solutions. Key gaps identified include: limited field studies of daily life use, insufficient attention to simulator sickness in VR therapy, small sample sizes in user evaluations, and lack of research on non-visual HMD affordances (audio, haptic) for people who cannot benefit from visual enhancement. The review also notes the potential for extending vision-support HMD technologies to non-disabled users in challenging visual environments like first-responder scenarios.
Tags: low vision · visual impairment · head-mounted display · virtual reality · augmented reality · assistive technology · vision therapy · scoping review