Application of electronic head-mounted display aids in low vision rehabilitation / 中华实验眼科杂志

As society ages and the number of people with low vision grows, the need for low vision rehabilitation for patients is increasing.The electronic head-mounted display (HMD) aids is a new type of low vision aids, which can be divided into different types such as monocular, binocular, virtual reality (VR) and augmented reality (AR). The performance of electronic HMD visual aids is important in their development and evaluation, including improved illumination, contrast ratio, resolution, and expanded vision field.VR devices have higher resolution and richer image modes, which can effectively improve central vision acuity and contrast sensitivity, and are more suitable for static applications.AR devices do not block the patients' habitual field of vision and do not destroy stereoscopic vision, which are more suitable for dynamic applications.With the development of VR and AR display technology in recent years, electronic HMD aids have made great progress in functionality, portability and aesthetics.In most of the research, the application population of electronic HMD aids are patients with low central vision.Electronic HMD aids can improve their visual acuity, contrast sensitivity and reading ability by enlarging pictures, improving illumination and contrast ratio and enhancing contour.For patients with peripheral visual field defects, electronic HMD aids, especially AR devices, can significantly expand their peripheral visual field without blocking original visual field.However, the improvement of electronic HMD aids on daily activities, especially athletic ability, needs further research.This article summarized the types, performance and application progress of electronic HMD aids in patients with low vision.

The Effect Of Virtual Reality - Head-Mounted Display In Autism Spectrum Disorder -A Systematic Review

Background: Virtual reality has been a focus of evidence-based studies in educating autistic children for more than a couple of decades. It is suggested that the evolving technology creates a real-world that targets social and life skills training in a very safe, controllable, and repeatable scenario. The development of affordable head-mount displays leads a pivotal role in its wide range acceptability. The paper aims to discuss these concerns in detail. Design/methodology/ approach: Focused on the empirical studies that used VR among children with Autism, a systematic search of the electronic document was done. The literature review identified limited studies in this area characterized byFindings: types of application, individual differences of participants, and the technology implemented. Research limitations/implications: It is essential to have more studies in the educational settings with the use of technology to substantiate the recommendations that could be made on its implementation, results, and reliability.

Relationship between Ocular Fatigue and Use of a Virtual Reality Device

PURPOSE: To investigate ocular fatigue after the use of a head-mounted display (HMD)-type virtual reality device.METHODS: Healthy adult volunteers were examined for ocular fatigue before and after watching videos for 10 min with an HMD-type virtual reality device. Subjective ocular fatigue was measured using a questionnaire. Objective fatigue was measured using the critical flicker fusion frequency (CFF), high frequency component of accommodative microfluctuation, and accommodation amplitude. The accommodation amplitude was measured using the push-up method and the dynamic measurement mode of the autorefractometer. Changes in the spherical equivalent were also measured.RESULTS: The questionnaire-based subjective ocular fatigue increased (p = 0.020) after use of the HMD device. In the dominant eye, the high frequency component of accommodative microfluctuation increased (p < 0.05). The accommodation amplitude using the push-up method was decreased in the nondominant eye (p = 0.007), and temporary myopia was observed (p < 0.05). However, there was no increase in ocular fatigue in the CFF or the accommodation amplitude using the dynamic measurement mode, which showed no significant difference before and after using the HMD device (p > 0.05).CONCLUSIONS: A subjective test and some objective tests suggested that use of the HMD-type virtual reality display increased ocular fatigue. However, no increase in ocular fatigue was measured using CFF nor in the accommodation amplitude using the dynamic measurement mode which was a limitation of the study. More studies with the aim to alleviate ocular fatigue after using HMD-type virtual reality devices are therefore needed.

Joint Attention Virtual Classroom: A Preliminary Study

OBJECTIVE: Previous studies have suggested that a virtual classroom is immersive and ecologically valid neuropsychological assessment, but those studies have limited components for social attentions. Therefore, the objective in the current study is the development of a joint attention virtual reality (JA-VR) classroom to incorporate social attentions between a participant and a virtual avatar teacher. METHODS: Fifty-eight participants were recruited for current study (25 for pilot and 33 for main studies; 32.8% female, n=19; age: M=24.5, SD=4.0). We suggested a JA-VR classroom, and compared it with previous methods including a VR classroom without JA components. We conducted attention experiments with AX-version of continuous performance tasks. RESULTS: Our results suggest that the new JA-VR classroom had convergent validity with previous methods, and that the JA-VR classroom promoted attentional processing among participants better than both old VR and non-VR measures. CONCLUSION: We add an important social attention concept to the virtual classroom, and believe that this work is an methodological foundation for the study of social attention in school life. We hope it ultimately help people with mental handicaps in social attention.

Spatial Learning and Memory Using a Radial Arm Maze with a Head-Mounted Display

OBJECTIVE: A radial arm maze (RAM) is an essential tool for assessing spatial learning and memory. Although this tool is widely used to study deficits in spatial memory in animal models, it has several restrictions that prevent its adaptation to human research and training. Therefore, we developed a head-mounted-display RAM (HMD-RAM) program for humans and verified its validity by comparing it to the results obtained by previous RAM studies. We also compared the HMD and a flat monitor as experimental devices. METHODS: Forty participants were recruited for the current study (Study 1: 20 participants with the HMD device; Study 2: 20 participants with the flat monitor). They navigated a virtual room as a first-person viewer and used environmental landmarks to remember their spatial position and orientation. The main dependent measures were working memory error, reference memory error, detection time, travel distance, and participant’s head movements. To validate the program, participants also conducted neuropsychological assessments and self-reported measures. RESULTS: The results for HMD-RAM tasks were consistent with the results of previous research conducted on animals, and the HMD elicited a higher sense of presence, immersion, and simulator sickness than the flat monitor. According to post-experiment questions on navigation strategy, creating landmarks was important when people were discovering locations in their environment, and an HMD was beneficial for better navigation strategy. CONCLUSION: These results suggest that the HMD-RAM is valuable for estimating spatial learning and memory in humans and may be a useful tool for early diagnosis of deficits in spatial learning and memory, including amnestic mild cognitive impairment and Alzheimer’s disease.

Augmented reality assisted surgery: A urologic training tool / 亚洲男科学杂志(英文版)

Augmented reality is widely used in aeronautics and is a developing concept within surgery. In this pilot study, we developed an application for use on Google Glass ® optical head-mounted display to train urology residents in how to place an inflatable penile prosthesis. We use the phrase Augmented Reality Assisted Surgery to describe this novel application of augmented reality in the setting of surgery. The application demonstrates the steps of the surgical procedure of inflatable penile prosthesis placement. It also contains software that allows for detection of interest points using a camera feed from the optical head-mounted display to enable faculty to interact with residents during placement of the penile prosthesis. Urology trainees and faculty who volunteered to take part in the study were given time to experience the technology in the operative or perioperative setting and asked to complete a feedback survey. From 30 total participants using a 10-point scale, educational usefulness was rated 8.6, ease of navigation was rated 7.6, likelihood to use was rated 7.4, and distraction in operating room was rated 4.9. When stratified between trainees and faculty, trainees found the technology more educationally useful, and less distracting. Overall, 81% of the participants want this technology in their residency program, and 93% see this technology in the operating room in the future. Further development of this technology is warranted before full release, and further studies are necessary to better characterize the effectiveness of Augmented Reality Assisted Surgery in urologic surgical training.

Visual Evoked Potential Using Head-Mounted Display Versus Cathode Ray Tube: A Pilot Study

OBJECTIVE: To present a new stimulation method based on the use of a head-mounted display (HMD) during pattern reversal visual evoked potential (PR-VEP) testing and to compare variables of HMD to those of conventional cathode ray tube (CRT). METHODS: Twenty-three normal subjects without visual problems were recruited. PR-VEPs were generated using CRT or HMD stimuli. VEP outcome measures included latencies (N75, P100, and N145) and peak-to-peak amplitudes (N75-P100 and P100-N145). Subjective discomfort associated with HMD was determined using a self-administered questionnaire. RESULTS: PR-VEPs generated by HMD stimuli showed typical triphasic waveforms, the components of which were found to be correlated with those obtained using conventional CRT stimuli. Self-administered discomfort questionnaires revealed that HMD was more comfortable in some aspects. It allowed subjects to concentrate better than CRT. CONCLUSION: The described HMD stimulation can be used as an alternative to the standard CRT stimulation for PR-VEPs. PR-VEP testing using HMD has potential applications in clinical practice and visual system research because HMD can be used on a wider range of subjects compared to CRT.

Usefulness of Computerized Objective Visual Acuity Test System Using Suppression Method

PURPOSE: The objective visual acuity test is mandatory in certain cases, such as infants, nonverbal subjects, and subjects who need legal assistance. We designed an objective system for visual acuity test (SOVAT) consisting of three components: stimuli applied via a suppression method, display and evaluation and made a suppression method as stimuli component for SOVAT. Usefulness of the SOVAT was evaluated. METHODS: The visual stimuli were presented on a high-resolution head-mounted display (HMD). An eye movement tracking program and gaze monitoring device allowed us to monitor the patient's fixation status during the test. The suppression method, in addition to a conventional induction method, was developed to use with the SOVAT and its accuracy and confidence level were evaluated. RESULTS: On the basis of clinical data, we present the reference values for the SOVAT as below. For the induction method, objective visual acuity (smallest pixel size), the presumed subjective visual acuity was 3: 0.35-0.6, 7: 0.05-0.25, 12: below 0.05 and for the suppression method it was 1: 0.6-1.0, 1.5: 0.4-0.7, 3: 0.15-0.4, 5: 0.1-0.2. CONCLUSIONS: SOVAT using this suppression method to assess objective visual acuity proved to be more useful than that with a conventional induction method, especially in the range of high visual acuity.

The Effect of Using Head Mounted Display on Human Eyes

In order to investigate the effect of head mounted display (HMD) on the human eye, the authors performed ophthalmologic examination on normal persons, dry eye patients and strabismus patients before and after use of Glastron, i-glasses, LGHMD(PT),LGHMD10 for two hours once or for five consecutive days, respectively. There were no substantial changes in visual acuity, color vision, intraocu-lar pressure, and tear secretion before and after use of HMD. There were transient changes in terms of corneal curvature, refraction, stereopsis, the angle of strabismus, and accommodation. There existed no difference according to the kinds of HMD. In conclusion, there was no permanent ocular changes with use of four kinds of HMD for two hours once or for five consecutive days.