Ability of Head-Mounted Display Technology to Improve Mobility in People With Low Vision: A Systematic Review

Perspective on Wearable Systems for Human Underwater Perceptual Enhancement

Underwater areas have harsh environments with poor light, limited visibility, and high levels of noise. Humans have a weak perception of position, surroundings, and exterior information when staying underwater, which makes it difficult for humans to carry out complex underwater tasks, such as rescue, observation, and construction. Wearable devices have shown good results in enhancing human sensory function on land, thus they could potentially play a role in enhancing human underwater perception ability. This perspective aims to analyze the state-of-the-art of underwater wearable systems for human perception enhancement. This work discusses the core technology and challenges of human underwater perceptual enhancement, including wearable underwater navigation, underwater environment reconstruction, and underwater sensorial information delivery. Future research could focus on designing waterproof flexible human-machine interfaces for sensing and feedback, exploiting advanced sensors and fusion algorithms for wearable underwater positioning, and studying multimodal information interaction strategies of wearable systems.

Aligning Visual Prosthetic Development With Implantee Needs

Purpose

Visual prosthetics are a promising assistive technology for vision loss, yet research often overlooks the human aspects of this technology. While previous studies focus on the perceptual experiences or attitudes of implant recipients (implantees), a systematic account of how current implants are being used in everyday life is still lacking.

Methods

We interviewed six recipients of the most widely used visual implants (Argus II and Orion) and six leading researchers in the field. Through thematic analyses, we explored the daily usage of these implants by implantees and compared their responses to the expectations of researchers. We also sought implantees' input on desired features for future versions, aiming to inform the development of the next generation of implants.

Results

Although implants are designed to facilitate various daily activities, we found that implantees use them less frequently than researchers expect. This discrepancy primarily stems from issues with usability and reliability, with implantees finding alternative methods to accomplish tasks, reducing the need to rely on the implant. For future implants, implantees emphasized the desire for improved vision, smart integration, and increased independence.

Conclusions

Our study reveals a significant gap between researcher expectations and implantee experiences with visual prostheses. Although limited by access to a small population of implantees, this study highlights the importance of focusing future research on usability and real-world applications.

Translational Relevance

This retrospective qualitative study advocates for a better alignment between technology development and implantee needs to enhance clinical relevance and practical utility of visual prosthetics.

Aligning visual prosthetic development with implantee needs

Purpose

Visual prosthetics are a promising assistive technology for vision loss, yet research often overlooks the human aspects of this technology. While previous studies focus on the perceptual experiences or attitudes of implant recipients (implantees) , a systematic account of how current implants are being used in everyday life is still lacking.

Methods

We interviewed six recipients of the most widely used visual implants (Argus II and Orion) and six leading researchers in the field. Through thematic analyses, we explored the daily usage of these implants by implantees and compared their responses to the expectations of researchers. We also sought implantees' input on desired features for future versions, aiming to inform the development of the next generation of implants.

Results

Although implants are designed to facilitate various daily activities, we found that implantees use them less frequently than researchers expect. This discrepancy primarily stems from issues with usability and reliability, with implantees finding alternative methods to accomplish tasks, reducing the need to rely on the implant. For future implants, implantees emphasized the desire for improved vision, smart integration, and increased independence.

Conclusions

Our study reveals a significant gap between researcher expectations and implantee experiences with visual prostheses. Although limited by access to a small population of implantees, this study highlights the importance of focusing future research on usability and real-world applications.

Translational relevance

This retrospective qualitative study advocates for a better alignment between technology development and implantee needs to enhance clinical relevance and practical utility of visual prosthetics.

Evaluation of a Retinal Projection Laser Eyeware in Patients with Visual Impairment Caused by Corneal Diseases in a Randomized Trial

PURPOSE

Patients with incurable corneal diseases experience visual impairment (VI) despite having a healthy retina and optic pathway. Low-vision aids (LVAs) can optimize the use of remaining vision through magnification and contrast enhancement, but do not harness the full visual capacity because they rely on the optic media. Therefore, we investigated a novel laser eyewear (LEW) technology that bypasses the anterior segment of the eye. Images captured by an integrated camera are projected directly onto the retina using a low-energy laser. The patient is able to view a full-color video, realized as augmented reality. We aimed to evaluate the efficacy of the LEW to enhance the vision of individuals with corneal diseases.

DESIGN

Prospective, randomized, crossover clinical trial.

PARTICIPANTS

We examined the retinal projection glasses in 21 patients (25-69 years) with VI (0.7 logarithm of the minimum angle of resolution [logMAR] or worse) resulting from corneal diseases. Patients with comorbidities that impact vision, such as retinal disorders, were excluded.

METHODS

Standardized measurements of visual acuity (VA) for near vision (NV) and distance vision (DV) were conducted using ETDRS charts with the respective best correction (BC) and then with LEW. In addition reading speed, vision-related quality of life (QoL) and capacity to carry out daily tasks were assessed at an initial visit and at 2 subsequent visits after a home phase with and without the device. Six weeks after last use of the LEW, an ophthalmologic examination including spectral-domain-OCT or full-field-electroretinography was conducted and compared with baseline findings to evaluate the safety of the device. Four patients participated and completed a subsequent 12-month follow-up phase.

MAIN OUTCOME MEASURES

Improvement of VA using the LEW. Secondary objectives included safety, reading speed, QoL, and usability in daily activities.

RESULTS

The mean VA in patients with VI was improved by 0.43 logMAR in DV using the LEW compared with BC (P < 0.0001). Using the ×2 magnification mode of the LEW resulted in an average improvement of 0.66 logMAR compared with BC (P < 0.0001). In NV, an increase of 0.47 logMAR was achieved compared with BC (P < 0.0001). Although only 4 of 21 participants were able to read with BC, 17 of 21 participants were able to read with the LEW. Quality of life significantly improved in the 17 participants who completed all visits.

CONCLUSIONS

We demonstrated that the retinal projection glasses resulted in enhanced VA for all participants by directly projecting images onto the intact retina. In future, the LEW could represent a new option as an LVA for patients with corneal diseases. No pathological alterations were observed in the safety assessments.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Impact of Apps as Assistive Devices for Visually Impaired Persons

The pervasiveness of mobile devices and other associated technologies has affected all aspects of our daily lives. People with visual impairments are no exception, as they increasingly tend to rely on mobile apps for assistance with various visual tasks in daily life. Compared to dedicated visual aids, mobile apps offer advantages such as affordability, versatility, portability, and ubiquity. We have surveyed hundreds of mobile apps of potential interest to people with vision impairments, either released as special assistive apps claiming to help in tasks such as text or object recognition (n = 68), digital accessibility (n = 84), navigation (n = 44), and remote sighted service (n = 4), among others, or marketed as general camera magnification apps that can be used for visual assistance (n = 77). While assistive apps as a whole received positive feedback from visually impaired users, as reported in various studies, evaluations of the usability of every app were typically limited to user reviews, which are often not scientifically informative. Rigorous evaluation studies on the effect of vision assistance apps on daily task performance and quality of life are relatively rare. Moreover, evaluation criteria are difficult to establish, given the heterogeneity of the visual tasks and visual needs of the users. In addition to surveying literature on vision assistance apps, this review discusses the feasibility and necessity of conducting scientific research to understand visual needs and methods to evaluate real-world benefits.

Are wearable electronic vision enhancement systems (wEVES) beneficial for people with age-related macular degeneration? A scoping review

INTRODUCTION

Age-related macular degeneration (AMD) is the most common cause of irreversible visual impairment in the United Kingdom. It has a wide-ranging detrimental impact on daily living, including impairment of functional ability and quality of life. Assistive technology designed to overcome this impairment includes wearable electronic vision enhancement systems (wEVES). This scoping review assesses the usefulness of these systems for people with AMD.

METHODS

Four databases (Cumulative Index to Nursing and Allied Health Literature, PubMed, Web of Science and Cochrane CENTRAL) were searched to identify papers that investigated image enhancement with a head-mounted electronic device on a sample population that included people with AMD.

RESULTS

Thirty-two papers were included: 18 studied the clinical and functional benefits of wEVES, 11 investigated use and usability and 3 discussed sickness and adverse effects.

CONCLUSIONS

Wearable electronic vision enhancement systems provide hands-free magnification and image enhancement producing significant improvements in acuity, contrast sensitivity and aspects of laboratory-simulated daily activity. Adverse effects were infrequent, minor and spontaneously resolved with the removal of the device. However, when symptoms arose, they sometimes persisted with continued device usage. There are multi-factorial influences and a diversity of user opinions on promotors to successful device use. These factors are not exclusively driven by visual improvement and incorporate other issues including device weight, ease of use and inconspicuous design. There is insufficient evidence of any cost-benefit analysis for wEVES. However, it has been shown that a user's decision to make a purchase evolves over time, with their estimates of cost falling below the retail price of the devices. Additional research is needed to understand the specific and distinct benefits of wEVES for people with AMD. Further patient-centred research should assess the benefits of wEVES in user-led activities when directly compared with alternative coping strategies, allowing professionals and users to make better prescribing and purchasing decisions.

A holistic understanding of challenges faced by people with low vision

Prior research on visual impairments has documented specific challenges that people with low vision face such as reading and mobility. Yet, much less focus has been given to the relationships between seemingly separate challenges such as mobility and social interactions; limiting the potential of services and assistive technologies for people with low vision. To address this gap, we conducted semi-structured interviews with 30 low vision participants and examined the relationships between challenges and coping strategies overarching three facets of life - functional, psychological, and social. We found that challenges in a specific area of life commonly interacted and impacted other facets of life and provide a conceptual map of these relationship. For example, challenges in mobility reduced social interactions, which in turn affected the psychological well-being. Moreover, participants repeatedly described how a seemingly specific functional challenge (i.e., seeing under different lighting conditions) influenced a wide range of activities, from mobility (e.g., seeing obstacles) to social interactions (e.g., seeing faces and interpreting non-verbal cues). Our results highlight the importance of considering the interrelationships between different facets of life for assistive technology development and evaluation.

A systematic review of extended reality (XR) for understanding and augmenting vision loss

Over the past decade, extended reality (XR) has emerged as an assistive technology not only to augment residual vision of people losing their sight but also to study the rudimentary vision restored to blind people by a visual neuroprosthesis. A defining quality of these XR technologies is their ability to update the stimulus based on the user's eye, head, or body movements. To make the best use of these emerging technologies, it is valuable and timely to understand the state of this research and identify any shortcomings that are present. Here we present a systematic literature review of 227 publications from 106 different venues assessing the potential of XR technology to further visual accessibility. In contrast to other reviews, we sample studies from multiple scientific disciplines, focus on technology that augments a person's residual vision, and require studies to feature a quantitative evaluation with appropriate end users. We summarize prominent findings from different XR research areas, show how the landscape has changed over the past decade, and identify scientific gaps in the literature. Specifically, we highlight the need for real-world validation, the broadening of end-user participation, and a more nuanced understanding of the usability of different XR-based accessibility aids.

The use of augmented reality and virtual reality for visual field expansion and visual acuity improvement in low vision rehabilitation: a systematic review

INTRODUCTION

Developments in image processing techniques and display technology have led to the emergence of augmented reality (AR) and virtual reality (VR)-based low vision devices (LVDs). However, their promise and limitations in low vision rehabilitation are poorly understood. The objective of this systematic review is to appraise the application of AR/VR LVDs aimed at visual field expansion and visual acuity improvement in low vision rehabilitation.

METHODS

A systematic search of the literature was performed using MEDLINE, Embase, PsychInfo, HealthStar, and National Library of Medicine (PubMed) from inception to March 6, 2022. Articles were eligible if they included an AR or VR LVD tested on a sample of individuals with low vision and provided visual outcomes such as visual acuity, visual fields, and object recognition.

RESULTS

Of the 652 articles identified, 16 studies comprising 382 individuals with a mean age of 52.17 (SD = 18.30) years, and with heterogeneous low vision etiologies (i.e., glaucoma, age-related macular degeneration, retinitis pigmentosa) were included in this systematic review. Most articles used AR (53%), VR (40%), and one article used both AR and VR. The main visual outcomes evaluated were visual fields (67%), visual acuity (65%), and contrast sensitivity (27%). Various visual enhancement techniques were employed including variable magnification using digital zoom (67%), contrast enhancements (53%), and minification (27%). AR LVDs were reported to expand the visual field from threefold to ninefold. On average, individuals using AR/VR LVDs experienced an improved in visual acuity from 0.9 to 0.2 logMAR. Ten articles were classified as high or moderate risk of bias.

CONCLUSION

AR/VR LVDs were found to afford visual field expansion and visual acuity improvement in low vision populations. Even though the results of this review are promising, the lack of controlled studies with well-defined populations, use of small, convenience samples, and incomplete reporting of inclusion and exclusion criteria among included studies makes it challenging to judge the true impact of these devices. Future studies should address these limitations and compare various AR/LVDs to determine what is the ideal LVD type and vision enhancement combination based on the user's level of visual ability and lifestyle.

Towards aSmart Bionic Eye: AI-powered artificial vision for the treatment of incurable blindness

Objective.How can we return a functional form of sight to people who are living with incurable blindness? Despite recent advances in the development of visual neuroprostheses, the quality of current prosthetic vision is still rudimentary and does not differ much across different device technologies.Approach.Rather than aiming to represent the visual scene as naturally as possible, aSmart Bionic Eyecould provide visual augmentations through the means of artificial intelligence-based scene understanding, tailored to specific real-world tasks that are known to affect the quality of life of people who are blind, such as face recognition, outdoor navigation, and self-care.Main results.Complementary to existing research aiming to restore natural vision, we propose a patient-centered approach to incorporate deep learning-based visual augmentations into the next generation of devices.Significance.The ability of a visual prosthesis to support everyday tasks might make the difference between abandoned technology and a widely adopted next-generation neuroprosthetic device.

Design of Smart Head–Mounted Display Technology: A Convergent Mixed-Methods Study

Introduction: The purpose of this study was to characterize functional impairments and human factor considerations that affect perceptions and preferences for head-mounted display (HMD) technology for adults with low vision and chronic eye disease. Methods: Through a convergent mixed-methods design, participants with visual impairments (age-related macular degeneration, diabetic retinopathy, glaucoma, or retinitis pigmentosa) were recruited. Participants completed the Impact of Vision Impairment (IVI) questionnaire, used commercially available HMDs (eSight, NuEyes, and Epson Moverio), and were interviewed. The IVI was used to identify groups with low, moderate, and high vision–related quality of life (VRQOL). Transcribed interviews were analyzed using a thematic approach. The survey and qualitative findings were integrated using mixed-methods joint display analysis. Results: Twenty-one participants were enrolled (mean age of 58.2 years, 57% male, median Snellen acuity of 20/40 [range: 20/20–hand movement]). An equal number ( n = 9) expressed a preference for eSight and NuEyes, while ( n = 3) preferred the Moverio. Participants emphasized ease of use, including HMD controls and screen, as common reasons for preference. Those with lower IVI well-being scores preferred eSight due to vision improvement. Those with moderate IVI well-being scores preferred NuEyes due to comfort and size. Those with high IVI well-being scores cited usability as the most important feature. Discussion: User preferences for HMD features were associated with VRQOL. A mixed-methods approach explained how varying degrees of visual impairment and HMD preferences were qualitatively related to usability at the individual level. Implications for Practitioners: To increase acceptance, new HMD development for low vision should focus on performance, usability, and human factors engineering. Although HMD technology can benefit individuals with low vision, device features and functions vary in meaningful ways based on vision parameters. Practitioners should be aware of how patient and device variations influence preferences when they recommend wearable systems and optimize training to harness these systems.

Application of Spatial Cues and Optical Distortions as Augmentations during Virtual Reality (VR) Gaming: The Multifaceted Effects of Assistance for Eccentric Viewing Training

The present study investigates the effects of peripheral spatial cues and optically distorting augmentations over eccentric vision mechanisms in normally sighted participants with simulated scotoma. Five different augmentations were tested inside a virtual reality (VR)-gaming environment. Three were monocular spatial cues, and two were binocular optical distortions. Each was divided into three conditions: baseline with normal viewing, augmentation with one of the assistance methods positioned around the scotoma, and one with only the simulated central scotoma. The study found that the gaming scenario induced eccentric viewing for the cued augmentation groups, even when the peripheral assistance was removed, while for the optical distortions group, the eccentric behavior disappeared after the augmentation removal. Additionally, an upwards directionality of gaze relative to target during regular gaming was found. The bias was maintained and implemented during and after the cued augmentations but not after the distorted ones. The results suggest that monocular peripheral cues could be better candidates for implementing eccentric viewing training in patients. At the same time, it showed that optical distortions might disrupt such behavior. Such results are noteworthy since distortions such as zoom are known to help patients with macular degeneration see targets of interest.

Beyond the Cane: Describing Urban Scenes to Blind People for Mobility Tasks

Blind people face difficulties with independent mobility, impacting employment prospects, social inclusion, and quality of life. Given the advancements in computer vision, with more efficient and effective automated information extraction from visual scenes, it is important to determine what information is worth conveying to blind travelers, especially since people have a limited capacity to receive and process sensory information. We aimed to investigate which objects in a street scene are useful to describe and how those objects should be described. Thirteen cane-using participants, five of whom were early blind, took part in two urban walking experiments. In the first experiment, participants were asked to voice their information needs in the form of questions to the experimenter. In the second experiment, participants were asked to score scene descriptions and navigation instructions, provided by the experimenter, in terms of their usefulness. The descriptions included a variety of objects with various annotations per object. Additionally, we asked participants to rank order the objects and the different descriptions per object in terms of priority and explain why the provided information is or is not useful to them. The results reveal differences between early and late blind participants. Late blind participants requested information more frequently and prioritized information about objects’ locations. Our results illustrate how different factors, such as the level of detail, relative position, and what type of information is provided when describing an object, affected the usefulness of scene descriptions. Participants explained how they (indirectly) used information, but they were frequently unable to explain their ratings. The results distinguish between various types of travel information, underscore the importance of featuring these types at multiple levels of abstraction, and highlight gaps in current understanding of travel information needs. Elucidating the information needs of blind travelers is critical for the development of more useful assistive technologies.

Home-Use Evaluation of a Wearable Collision Warning Device for Individuals With Severe Vision Impairments: A Randomized Clinical Trial

IMPORTANCE

There is scant rigorous evidence about the real-world mobility benefit of electronic mobility aids.

OBJECTIVE

To evaluate the effect of a collision warning device on the number of contacts experienced by blind and visually impaired people in their daily mobility.

DESIGN, SETTING, AND PARTICIPANTS

In this double-masked randomized clinical trial, participants used a collision warning device during their daily mobility over a period of 4 weeks. A volunteer sample of 31 independently mobile individuals with severe visual impairments, including total blindness and peripheral visual field restrictions, who used a long cane or guide dog as their habitual mobility aid completed the study. The study was conducted from January 2018 to December 2019.

INTERVENTIONS

The device automatically detected collision hazards using a chest-mounted video camera. It randomly switched between 2 modes: active mode (intervention condition), where it provided alerts for detected collision threats via 2 vibrotactile wristbands, and silent mode (control condition), where the device still detected collisions but did not provide any warnings to the user. Scene videos along with the collision warning information were recorded by the device. Potential collisions detected by the device were reviewed and scored, including contacts with the hazards, by 2 independent reviewers. Participants and reviewers were masked to the device operation mode.

MAIN OUTCOMES AND MEASURES

Rate of contacts per 100 hazards per hour, compared between the 2 device modes within each participant. Modified intention-to-treat analysis was used.

RESULTS

Of the 31 included participants, 18 (58%) were male, and the median (range) age was 61 (25-73) years. A total of 19 participants (61%) had a visual acuity (VA) of light perception or worse, and 28 (90%) reported a long cane as their habitual mobility aid. The median (interquartile range) number of contacts was lower in the active mode compared with silent mode (9.3 [6.6-14.9] vs 13.8 [6.9-24.3]; difference, 4.5; 95% CI, 1.5-10.7; P < .001). Controlling for demographic characteristics, presence of VA better than light perception, and fall history, the rate of contacts significantly reduced in the active mode compared with the silent mode (β = 0.63; 95% CI, 0.54-0.73; P < .001).

CONCLUSIONS AND RELEVANCE

In this study involving 31 visually impaired participants, the collision warnings were associated with a reduced rate of contacts with obstacles in daily mobility, indicating the potential of the device to augment habitual mobility aids.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03057496.