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Liu Y, Liu L, Liu M, Wang X, Jin C, Ni B, Ke B. Change in three-dimensional choroidal vessel network after AR device assisted 1-hour visual task in 2D/3D mode in young healthy subjects. Acta Ophthalmol 2024; 102:e117-e125. [PMID: 37088997 DOI: 10.1111/aos.15671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/07/2023] [Accepted: 03/27/2023] [Indexed: 04/25/2023]
Abstract
PURPOSE The purpose of the study was to investigate the changes of choroidal blood perfusion in different layers and quadrants and its possible related factors after 1 h visual task by augmented reality (AR) device in two-dimensional (2D) and three-dimensional (3D) mode, respectively. METHODS Thirty healthy subjects aged 22-37 years watched the same video source in 2D and 3D mode separately using AR glasses for 1 h with a one-week interval. Swept-source optical coherence tomography angiography (SS-OCTA) was performed before and immediately after watching to acquire choroidal thickness (ChT), three-dimensional choroidal vascularity index (CVI) of large- and middle-sized choroidal vessels and choriocapillaris flow voids (FV%) at macular and peripapillary area. Near point of accommodation (NPA) and accommodative facility (AF) were examined to evaluate the accommodative ability. Pupil diameters by infrared-automated pupillometer under scotopic, mesopic and photopic condition were also obtained. RESULTS Compared with pre-visual task, the subfoveal CVI decreased from 0.406 ± 0.097 to 0.360 ± 0.102 after 2D watching (p < 0.001) and to 0.368 ± 0.102 after 3D watching (p = 0.002). Pupil sizes under different illuminance conditions became smaller after both 2D and 3D watching (all p < 0.001). AF increased after both 2D and 3D watching (both p < 0.05). NPA receded in post-3D watching (p = 0.017) while a not significant tendency was observed in post-2D. CONCLUSION A reduction in subfoveal choroidal blood flow accompanied with pupil constriction was observed immediately after 1 h visual task using AR glasses in 2D and 3D mode. Accommodative facility improved after 2D and 3D watching with AR glasses, whereas decrease in the maximum accommodation power was only found in 3D mode.
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Affiliation(s)
- Yuying Liu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photo Medicine, Shanghai, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Lu Liu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photo Medicine, Shanghai, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Mingming Liu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photo Medicine, Shanghai, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Xuetong Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photo Medicine, Shanghai, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Chengcheng Jin
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photo Medicine, Shanghai, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
| | - Bingbing Ni
- Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Bilian Ke
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photo Medicine, Shanghai, China
- Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
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2
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Lin CJ, Canny S. Effects of virtual target size, position, and parallax on vergence-accommodation conflict as estimated by actual gaze. Sci Rep 2022; 12:20100. [PMID: 36418905 PMCID: PMC9684416 DOI: 10.1038/s41598-022-24450-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 11/15/2022] [Indexed: 11/24/2022] Open
Abstract
Due to the increased utilization of stereoscopic displays, the scope of the vergence-accommodation conflict has been studied extensively to reveal how the human visual system operates. The purpose of this work was to study the phenomenon of vergence-accommodation conflict by comparing the theoretical eye vergence angle (vergence response) and gaze-based eye vergence angle (vergence stimulus) based on eye tracker gaze data. The results indicated that the gaze-based eye vergence angle was largest at the greatest parallax. The result also revealed that the eye vergence angle accuracy was significantly highest at the nearest parallax. Generally, accuracy improves when virtual objects are put in the middle and close to participants' positions. Moreover, the signed error decreases significantly when the virtual object is in the middle. Based on the results of this study, we can gain a greater understanding of the vergence-accommodation conflict in the stereoscopic environment.
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Affiliation(s)
- Chiuhsiang Joe Lin
- grid.45907.3f0000 0000 9744 5137Department of Industrial Management, National Taiwan University of Science and Technology, Taipei, 10607 Taiwan, ROC
| | - Susmitha Canny
- grid.45907.3f0000 0000 9744 5137Department of Industrial Management, National Taiwan University of Science and Technology, Taipei, 10607 Taiwan, ROC
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Lin CH, Lin HC, Chen CY, Lih CC. Variations in intraocular pressure and visual parameters before and after using mobile virtual reality glasses and their effects on the eyes. Sci Rep 2022; 12:3176. [PMID: 35210496 PMCID: PMC8873506 DOI: 10.1038/s41598-022-07090-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 02/11/2022] [Indexed: 11/11/2022] Open
Abstract
We examined the effects of using mobile devices with immersive virtual reality for a short period on the physiological parameters of both eyes. The average age of the 50 participants (23 men and 27 women) was 17.72 ± 1.48 years, and refractive error ranged from 0 D to − 5.00 D. All the participants wore + 3.00 D glasses and underwent a 5-min relaxation adjustment through the atomization method. The participants wore immersive virtual reality (VR) glasses to watch a movie on a roller coaster for 10 min. Their relevant physiological parameters of the eyes were measured both before and after using VR glasses. Compared with before VR use, no significant difference (P > 0.05) was observed in the near-horizontal vergence and refractive error but a significant difference (P < 0.05) was observed in the amplitude of accommodation, intraocular pressure, divergence/convergence, and stereopsis after VR use. The corneal elastic coefficient was > 0.2 MPa, and we used Friedenwald’s eye rigidity relationship to obtain the K value (0.065–0.09). Approximately 10% of the participants experienced cybersickness symptoms such as nausea and dizziness. The use of VR to watch three-dimensional movies reduced intraocular pressure, which may help prevent or treat glaucoma. Moreover, the binocular convergence was higher when viewing near-field objects in VR than in the real world. Therefore, individuals with convergence excess may experience symptoms. Binocular parallax is the most likely cause of cybersickness symptoms. Thus, mobile VR devices with higher quality and comfort are necessary.
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Affiliation(s)
- Ching-Huang Lin
- Department of Electronic Engineering, National Yunlin University of Science and Technology, Yunlin, Taiwan, 640
| | - Hsien-Chang Lin
- Graduate School of Engineering Science and Technology, National Yunlin University of Science and Technology, Yunlin, Taiwan, 640
| | - Chien-Yu Chen
- Graduate Institute of Color and Illumination Technology, National Taiwan University of Science and Technology, Taipei, Taiwan, 106
| | - Chong-Chung Lih
- Department of Optometry, Jenteh Junior College of Medicine, Nursing and Management, Miaoli, Taiwan, 35664.
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4
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Lee SH, Kim M, Kim H, Park CY. Visual fatigue induced by watching virtual reality device and the effect of anisometropia. ERGONOMICS 2021; 64:1522-1531. [PMID: 34270388 DOI: 10.1080/00140139.2021.1957158] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
The effect of small anisometropia on visual fatigue when using virtual reality (VR) devices was investigated. Participants (n = 34) visited three times. In the first visit, VR exposure (10 min) was conducted with the full correction of the refractive error of both eyes. Experimental anisometropia was induced by adding a + 1.0 dioptre spherical lens either on the dominant eyes in the second visit or on the non-dominant eyes in the third visit. At each visit, the participants played a predetermined video game using a head-mounted display VR for 10 min. Visual fatigue was assessed before and after playing VR game using the Virtual Reality Symptom Questionnaire (VRSQ) and high-frequency component of accommodative microfluctuation. Results showed that watching VR induced significant increase of VRSQ score, significant decrease in the maximum accommodation power and objective increase in visual fatigue. Experimental anisometropia induction either on the dominant or non-dominant eyes did not aggravate visual fatigue. Practitioner summary: Mild differences in refractive error (up to 1.0 dioptre) between both eyes do not significantly increase ocular fatigue by viewing virtual reality device (10 min). The impact of small anisometropia may be limited in developing a virtual reality device. Abbreviations: VR: virtual reality; VRSQ: virtual reality symptom questionnaire; HMD: head-mounted display; HFC: high-frequency component.
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Affiliation(s)
- Sang Hyeok Lee
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Martha Kim
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Hyosun Kim
- Samsung Display, Display R&D center, Suwon, South Korea
| | - Choul Yong Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
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Lyu J, Ng CJ, Bang SP, Yoon G. Binocular accommodative response with extended depth of focus under controlled convergences. J Vis 2021; 21:21. [PMID: 34415998 PMCID: PMC8383898 DOI: 10.1167/jov.21.8.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Vergence and accommodation can be mismatched under virtual reality viewing conditions, and this mismatch has been thought to be one of the main causes of visual discomfort. The goal of this study was to investigate how optical conditions of the eyes affect accommodative responses to different convergence. Specifically, we hypothesized that extending the depth of focus (DoF) could weaken the control of the screen on accommodation, so that accommodation could be induced by convergence. To test this hypothesis, we extended the DoF using Zernike spherical aberrations (fourth and sixth orders) induced by a binocular adaptive optics (AO) vision simulator. Nine normal subjects between the ages of 21 and 34 (26 ± 5) years were recruited. Three optical conditions were generated: AO condition (aberration-free), monovision condition, and extended depth of focus (EDoF) condition. Binocular accommodative responses, along with binocular visual acuity and stereoacuity, were measured under all three optical conditions with varied binocular vergence levels. At 3 diopters of binocular convergence, the EDoF condition was the most efficient in inducing excessive accommodative response compared with the monovision condition and the AO condition. Visual acuity was impaired with EDoF as compared with the other two conditions. The average stereoscopic thresholds (at 0 vergence) under the EDoF condition were degraded compared with the AO condition but were superior to those of the monovision condition. Therefore, despite some compromise to visual performance, extending the DoF could allow for a more natural vergence–accommodation relationship, providing the potential for alleviating the vergence–accommodation conflict and associated visual fatigue symptoms in virtual reality.
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Affiliation(s)
- Jiakai Lyu
- Institute of Optics, Flaum Eye Institute, Center for Vision Science, University of Rochester, Rochester, NY, USA.,
| | - Cherlyn J Ng
- Flaum Eye Institute, Center for Vision Science, University of Rochester, Rochester, NY, USA.,
| | - Seung Pil Bang
- Department of Biomedical Engineering, Flaum Eye Institute, Center for Vision Science, University of Rochester, Rochester, NY, USA.,
| | - Geunyoung Yoon
- Flaum Eye Institute, Center for Vision Science, University of Rochester, Rochester, NY, USA.,
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6
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Chen CY, Lin HC, Wu PJ, Chuang CH, Lin BS, Lin CH. Reducing the discomfort in viewing 3D video with a prism device modified eye convergence. Heliyon 2021; 7:e06877. [PMID: 33981906 PMCID: PMC8085701 DOI: 10.1016/j.heliyon.2021.e06877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/21/2020] [Accepted: 04/16/2021] [Indexed: 11/30/2022] Open
Abstract
A prism device is utilized in this study for modifying the eye convergence to reduce eye accommodation and enhance the comfort in viewing 3D video. Without changing the contents of 3D films, it aims to apply the myosis, convergence, and accommodation visual triad of eyeballs viewing near distance to not change the eyeball pupillary distance when viewing 3D films. Without convergence, the discomfort caused by intraocular muscle contraction when viewing near distance is reduced. Such an effect of a small prism lens is also proven in this study. When viewing 3D films with 1.0△ lenses, the physiological accommodation reaction of eyes would reduce (the right eye decreases 65% and the left eye decreases 70%), revealing the decreasing tension of intraocular muscle. The subjective psychological evaluation result also shows that viewing 3D images with small prism lenses could enhance the comfort. The evaluation of optical simulation, physiological reaction, and mental fatigue proves that the small prism lens proposed in this study could actually improve the comfort in viewing 3D films.
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Affiliation(s)
- Chien-Yu Chen
- Graduate Institute of Color and Illumination Technology, National Taiwan University of Science & Technology, 10607 Taipei, Taiwan
| | - Hsien-Chang Lin
- Graduate School of Engineering Science and Technology, National Yunlin University of Science & Technology, 64002 Yunlin, Taiwan
| | - Pei-Jung Wu
- College of Information and Distribution Science, National Taichung University of Science & Technology, 40401 Taichung, Taiwan
| | - Chih-Hao Chuang
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, 10607 Taipei, Taiwan
| | - Bor-Shyh Lin
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, Tainan, 71150, Taiwan
| | - Ching-Huang Lin
- Department of Electronic Engineering, National Yunlin University of Science & Technology, 64002 Yunlin, Taiwan
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7
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Aghasi A, Heshmat B, Wei L, Tian M. Optimal allocation of quantized human eye depth perception for multi-focal 3D display design. OPTICS EXPRESS 2021; 29:9878-9896. [PMID: 33820153 DOI: 10.1364/oe.412373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Creating immersive 3D stereoscopic, autostereoscopic, and lightfield experiences are becoming the center point of optical design of future head mounted displays and lightfield displays. However, despite the advancement in 3D and light field displays, there is no consensus on what are the necessary quantized depth levels for such emerging displays at stereoscopic or monocular modalities. Here we start from psychophysical theories and work toward defining and prioritizing quantized levels of depth that would saturate the human depth perception. We propose a general optimization framework, which locates the depth levels in a globally optimal way for band limited displays. While the original problem is computationally intractable, we manage to find a tractable reformulation as maximally covering a region of interest with a selection of hypographs corresponding to the monocular depth of field profiles. The results indicate that on average 1731 stereoscopic and 7 monocular depth levels (distributed optimally from 25 cm to infinity) would saturate the visual depth perception. Such that adding further depth levels adds negligible improvement. Also the first 3 depth levels should be allocated at (148), then (83, 170), then (53, 90, 170) distances respectively from the face plane to minimize the monocular error in the entire population. The study further discusses the 3D spatial profile of the quantized stereoscopic and monocular depth levels. The study provides fundamental guidelines for designing optimal near eye displays, light-field monitors, and 3D screens.
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8
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Haar S, Sundar G, Faisal AA. Embodied virtual reality for the study of real-world motor learning. PLoS One 2021; 16:e0245717. [PMID: 33503022 PMCID: PMC7840008 DOI: 10.1371/journal.pone.0245717] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 01/06/2021] [Indexed: 02/07/2023] Open
Abstract
Motor-learning literature focuses on simple laboratory-tasks due to their controlled manner and the ease to apply manipulations to induce learning and adaptation. Recently, we introduced a billiards paradigm and demonstrated the feasibility of real-world-neuroscience using wearables for naturalistic full-body motion-tracking and mobile-brain-imaging. Here we developed an embodied virtual-reality (VR) environment to our real-world billiards paradigm, which allows to control the visual feedback for this complex real-world task, while maintaining sense of embodiment. The setup was validated by comparing real-world ball trajectories with the trajectories of the virtual balls, calculated by the physics engine. We then ran our short-term motor learning protocol in the embodied VR. Subjects played billiard shots when they held the physical cue and hit a physical ball on the table while seeing it all in VR. We found comparable short-term motor learning trends in the embodied VR to those we previously reported in the physical real-world task. Embodied VR can be used for learning real-world tasks in a highly controlled environment which enables applying visual manipulations, common in laboratory-tasks and rehabilitation, to a real-world full-body task. Embodied VR enables to manipulate feedback and apply perturbations to isolate and assess interactions between specific motor-learning components, thus enabling addressing the current questions of motor-learning in real-world tasks. Such a setup can potentially be used for rehabilitation, where VR is gaining popularity but the transfer to the real-world is currently limited, presumably, due to the lack of embodiment.
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Affiliation(s)
- Shlomi Haar
- Brain and Behaviour Lab, Dept. of Bioengineering, Imperial College London, London, United Kingdom
- * E-mail: (SH); (AAF)
| | - Guhan Sundar
- Brain and Behaviour Lab, Dept. of Bioengineering, Imperial College London, London, United Kingdom
| | - A. Aldo Faisal
- Brain and Behaviour Lab, Dept. of Bioengineering, Imperial College London, London, United Kingdom
- Dept. of Computing, Imperial College London, London, United Kingdom
- UKRI Centre for Doctoral Training in AI for Healthcare, Imperial College London, London, United Kingdom
- MRC London Institute of Medical Sciences, Imperial College London, London, United Kingdom
- * E-mail: (SH); (AAF)
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9
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Virtual reality head-mounted goggles increase the body sway of young adults during standing posture. Neurosci Lett 2020; 737:135333. [DOI: 10.1016/j.neulet.2020.135333] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 07/22/2020] [Accepted: 08/26/2020] [Indexed: 11/30/2022]
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10
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Park S, Lee G. Full-immersion virtual reality: Adverse effects related to static balance. Neurosci Lett 2020; 733:134974. [PMID: 32294492 DOI: 10.1016/j.neulet.2020.134974] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 03/29/2020] [Accepted: 04/07/2020] [Indexed: 10/24/2022]
Abstract
The use of virtual reality (VR) is associated with several adverse effects including dizziness, headache, and motion sickness. This study investigates how full-immersion VR games cause changes in static balance with associated adverse effects, and whether a fixed or a changing game background is more likely to contribute to such problems. Static balance and adverse effects (eye fatigue and dizziness) were measured in 15 healthy adults under three conditions: baseline; after a full-immersion virtual reality game (PlayStation 4 Pro and PlayStation® VR headset) with a fixed background (15 min); and after a full-immersion virtual reality game with a unfixed background (15 min). Static balance was measured with an AMTI force plate, while eye fatigue and dizziness were measured with the Virtual Reality Symptom Questionnaire (VRSQ) and the Simulator Sickness Questionnaire (SSQ). It was determined that playing a full-immersion VR game had a negative effect on static balance and produced several adverse effects including eye fatigue and dizziness. Moreover, sway velocity and sway length increased significantly in the game with a moving background compared to both the baseline and the game with a fixed background (p < 0.05); VRSQ and SSQ were also significantly higher in this case. It is thus preferable from the perspective of reducing adverse effects that only fixed-background full-immersion VR games be used in rehabilitative interventions.
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Affiliation(s)
- SoHu Park
- Department of Physical Therapy, Graduate School of Kyungnam University, 7 Kyungnamdaehak-ro, Masanhappo-gu, Changwon, Gyeongsangnam-do 51767, Republic of Korea
| | - GyuChang Lee
- Department of Physical Therapy, Kyungnam University, 7 Kyungnamdaehak-ro, Masanhappo-gu, Changwon, Gyeongsangnam-do 51767, Republic of Korea.
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11
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Poffa R, Joos R. The influence of vergence facility on binocular eye movements during reading. J Eye Mov Res 2019; 12. [PMID: 33828738 PMCID: PMC7880129 DOI: 10.16910/jemr.12.4.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Optometrists regularly use binocular measurements in patients with asthenopic complaints when performing close-up work. The focus of this work was therefore on the correlation of optometric parameters and objective fixation disparity (FD) measured by an eye tracker. In our investigation, 20 participants (6 male, 14 female) were subjected to a classical optometric procedure. Subsequently, these subjects read various sentences on a screen and eye movements were registered by using a RED500 eye tracker. The experiment was performed under two reading distance conditions. In order to be comparable with previous work, the present study was conducted under dark illumination conditions [12]. FD values were deduced from objective eye tracking data during reading. Data analysis was done using linear mixed-effects models. FD was found to depend on vergence facility (t=3.3, p=0.004). Subjects with a low vergence facility showed more eso fixation disparity than subjects with a normal vergence facility. If studies of binocular coordination using eye tracking methods are performed under dark illumination conditions, vergence facility is an important parameter and should be accounted for. Neglecting this parameter may mask other important parameters. Vergence facility in context of reading difficulties may be important.
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Affiliation(s)
- Remo Poffa
- University of Applied Sciences and Arts Northwestern Switzerland School of Engineering, Institute of optometry
| | - Roland Joos
- University of Applied Sciences and Arts Northwestern Switzerland School of Engineering, Institute of optometry
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12
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Lam HH, Tsang PWM, Poon TC. Ensemble convolutional neural network for classifying holograms of deformable objects. OPTICS EXPRESS 2019; 27:34050-34055. [PMID: 31878461 DOI: 10.1364/oe.27.034050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
Recently, a method known as "ensemble deep learning invariant hologram classification" (EDL-IHC) for classifying of holograms of deformable objects with deep learning network (DLN) has been demonstrated. However DL-IHC requires substantial computational resources to attain near perfect success rate (≥99%). In practice, it is always desirable to have higher success rate with a low complexity DLN. In this paper we propose a low complexity DLN known as "ensemble deep learning invariant hologram classification" (EDL-IHC). In comparison with DL-IHC, our proposed hologram classifier has promoted the success rate by 2.86% in the classification of holograms of handwritten numerals.
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13
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Abstract
Recent applications of eye tracking for diagnosis, prognosis and follow-up of therapy in age-related neurological or psychological deficits have been reviewed. The review is focused on active aging, neurodegeneration and cognitive impairments. The potential impacts and current limitations of using characterizing features of eye movements and pupillary responses (oculometrics) as objective biomarkers in the context of aging are discussed. A closer look into the findings, especially with respect to cognitive impairments, suggests that eye tracking is an invaluable technique to study hidden aspects of aging that have not been revealed using any other noninvasive tool. Future research should involve a wider variety of oculometrics, in addition to saccadic metrics and pupillary responses, including nonlinear and combinatorial features as well as blink- and fixation-related metrics to develop biomarkers to trace age-related irregularities associated with cognitive and neural deficits.
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Affiliation(s)
- Ramtin Z Marandi
- Department of Health Science & Technology, Aalborg University, Aalborg E 9220, Denmark
| | - Parisa Gazerani
- Department of Health Science & Technology, Aalborg University, Aalborg E 9220, Denmark
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14
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Iskander J, Hossny M, Nahavandi S. Using biomechanics to investigate the effect of VR on eye vergence system. APPLIED ERGONOMICS 2019; 81:102883. [PMID: 31422246 DOI: 10.1016/j.apergo.2019.102883] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 02/05/2019] [Accepted: 06/23/2019] [Indexed: 06/10/2023]
Abstract
Vergence-accommodation conflict (VAC) is the main contributor to visual fatigue during immersion in virtual environments. Many studies have investigated the effects of VAC using 3D displays and expensive complex apparatus and setup to create natural and conflicting viewing conditions. However, a limited number of studies targeted virtual environments simulated using modern consumer-grade VR headsets. Our main objective, in this work, is to test how the modern VR headsets (VR simulated depth) could affect our vergence system, in addition to investigating the effect of the simulated depth on the eye-gaze performance. The virtual scenario used included a common virtual object (a cube) in a simple virtual environment with no constraints placed on the head and neck movement of the subjects. We used ocular biomechanics and eye tracking to compare between vergence angles in matching (ideal) and conflicting (real) viewing conditions. Real vergence angle during immersion was significantly higher than ideal vergence angle and exhibited higher variability which leads to incorrect depth cues that affects depth perception and also leads to visual fatigue for prolonged virtual experiences. Additionally, we found that as the simulated depth increases, the ability of users to manipulate virtual objects with their eyes decreases, thus, decreasing the possibilities of interaction through eye gaze. The biomechanics model used here can be further extended to study muscular activity of eye muscles during immersion. It presents an efficient and flexible assessment tool for virtual environments.
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Affiliation(s)
- Julie Iskander
- Institute for Intelligent Systems Research and Innovation (IISRI), Deakin University, Australia.
| | - Mohammed Hossny
- Institute for Intelligent Systems Research and Innovation (IISRI), Deakin University, Australia
| | - Saeid Nahavandi
- Institute for Intelligent Systems Research and Innovation (IISRI), Deakin University, Australia
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15
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Vienne C, Plantier J, Neveu P, Priot AE. (Disparity-Driven) Accommodation Response Contributes to Perceived Depth. Front Neurosci 2018; 12:973. [PMID: 30618592 PMCID: PMC6305428 DOI: 10.3389/fnins.2018.00973] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/05/2018] [Indexed: 11/23/2022] Open
Abstract
When looking at objects at various distances in the physical space, the accommodation and vergence systems adjust their parameters to provide a single and clear vision of the world. Subtended muscle activity provides oculomotor cues that can contribute to the perception of depth and distance. While several studies have outlined the role of vergence in distance perception, little is known about the contribution of its concommitant accommodation component. It is possible to unravel the role of each of these physiological systems by placing observers in a situation where there is a conflict between accommodation and vergence distances. We thus sought to determine the contribution of each response system to perceived depth by simultaneously measuring vergence and accommodation while participants judged the depth of 3D stimuli. The distance conflict decreased depth constancy for stimulus displayed with negative disparity steps (divergence). Although vergence was unaffected by the stimulus distance, accommodation responses were significantly reduced when the stimulus was displayed with negative disparities. Our results show that biases in perceived depth follow undershoots in the disparity-driven accommodation response. These findings suggest that accommodation responses (i.e., from oculomotor information) can contribute to perceived depth.
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Affiliation(s)
- Cyril Vienne
- Institut de Recherche Biomédicale des Armées, Bretigny sur Orge, France
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16
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Turnbull PRK, Phillips JR. Ocular effects of virtual reality headset wear in young adults. Sci Rep 2017; 7:16172. [PMID: 29170432 PMCID: PMC5701049 DOI: 10.1038/s41598-017-16320-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 11/02/2017] [Indexed: 11/10/2022] Open
Abstract
Virtual Reality (VR) headsets create immersion by displaying images on screens placed very close to the eyes, which are viewed through high powered lenses. Here we investigate whether this viewing arrangement alters the binocular status of the eyes, and whether it is likely to provide a stimulus for myopia development. We compared binocular status after 40-minute trials in indoor and outdoor environments, in both real and virtual worlds. We also measured the change in thickness of the ocular choroid, to assess the likely presence of signals for ocular growth and myopia development. We found that changes in binocular posture at distance and near, gaze stability, amplitude of accommodation and stereopsis were not different after exposure to each of the 4 environments. Thus, we found no evidence that the VR optical arrangement had an adverse effect on the binocular status of the eyes in the short term. Choroidal thickness did not change after either real world trial, but there was a significant thickening (≈10 microns) after each VR trial (p < 0.001). The choroidal thickening which we observed suggest that a VR headset may not be a myopiagenic stimulus, despite the very close viewing distances involved.
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Affiliation(s)
- Philip R K Turnbull
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand.
| | - John R Phillips
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand.,Department of Optometry, Asia University, Taichung, Taiwan
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17
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Maiello G, Kerber KL, Thorn F, Bex PJ, Vera-Diaz FA. Vergence driven accommodation with simulated disparity in myopia and emmetropia. Exp Eye Res 2017; 166:96-105. [PMID: 29051012 DOI: 10.1016/j.exer.2017.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 08/25/2017] [Accepted: 10/08/2017] [Indexed: 11/24/2022]
Abstract
The formation of focused and corresponding foveal images requires a close synergy between the accommodation and vergence systems. This linkage is usually decoupled in virtual reality systems and may be dysfunctional in people who are at risk of developing myopia. We study how refractive error affects vergence-accommodation interactions in stereoscopic displays. Vergence and accommodative responses were measured in 21 young healthy adults (n=9 myopes, 22-31 years) while subjects viewed naturalistic stimuli on a 3D display. In Step 1, vergence was driven behind the monitor using a blurred, non-accommodative, uncrossed disparity target. In Step 2, vergence and accommodation were driven back to the monitor plane using naturalistic images that contained structured depth and focus information from size, blur and/or disparity. In Step 1, both refractive groups converged towards the stereoscopic target depth plane, but the vergence-driven accommodative change was smaller in emmetropes than in myopes (F1,19=5.13, p=0.036). In Step 2, there was little effect of peripheral depth cues on accommodation or vergence in either refractive group. However, vergence responses were significantly slower (F1,19=4.55, p=0.046) and accommodation variability was higher (F1,19=12.9, p=0.0019) in myopes. Vergence and accommodation responses are disrupted in virtual reality displays in both refractive groups. Accommodation responses are less stable in myopes, perhaps due to a lower sensitivity to dioptric blur. Such inaccuracies of accommodation may cause long-term blur on the retina, which has been associated with a failure of emmetropization.
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Affiliation(s)
- Guido Maiello
- UCL Institute of Ophthalmology, University College London, London, UK; Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
| | - Kristen L Kerber
- New England College of Optometry, 424 Beacon Street, Boston, MA 02115, USA
| | - Frank Thorn
- New England College of Optometry, 424 Beacon Street, Boston, MA 02115, USA
| | - Peter J Bex
- Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA
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18
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Kang MK, Cho H, Park HM, Jun SC, Yoon KJ. A wellness platform for stereoscopic 3D video systems using EEG-based visual discomfort evaluation technology. APPLIED ERGONOMICS 2017; 62:158-167. [PMID: 28411726 DOI: 10.1016/j.apergo.2017.02.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 12/07/2016] [Accepted: 02/28/2017] [Indexed: 05/16/2023]
Abstract
Recent advances in three-dimensional (3D) video technology have extended the range of our experience while providing various 3D applications to our everyday life. Nevertheless, the so-called visual discomfort (VD) problem inevitably degrades the quality of experience in stereoscopic 3D (S3D) displays. Meanwhile, electroencephalography (EEG) has been regarded as one of the most promising brain imaging modalities in the field of cognitive neuroscience. In an effort to facilitate comfort with S3D displays, we propose a new wellness platform using EEG. We first reveal features in EEG signals that are applicable to practical S3D video systems as an index for VD perception. We then develop a framework that can automatically determine severe perception of VD based on the EEG features during S3D video viewing by capitalizing on machine-learning-based braincomputer interface technology. The proposed platform can cooperate with advanced S3D video systems whose stereo baseline is adjustable. Thus, the optimal S3D content can be reconstructed according to a viewer's sensation of VD. Applications of the proposed platform to various S3D industries are suggested, and further technical challenges are discussed for follow-up research.
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Affiliation(s)
- Min-Koo Kang
- Imaging Media Research Center, Korea Institute of Science and Technology, Seoul, 136-791, South Korea.
| | - Hohyun Cho
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Seoul, 136-791, South Korea.
| | - Han-Mu Park
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Seoul, 136-791, South Korea.
| | - Sung Chan Jun
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Seoul, 136-791, South Korea.
| | - Kuk-Jin Yoon
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, Seoul, 136-791, South Korea.
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Vienne C, Plantier J, Neveu P, Priot AE. The Role of Vertical Disparity in Distance and Depth Perception as Revealed by Different Stereo-Camera Configurations. Iperception 2016; 7:2041669516681308. [PMID: 27994843 PMCID: PMC5154397 DOI: 10.1177/2041669516681308] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vertical binocular disparity is a source of distance information allowing the portrayal of the layout and 3D metrics of the visual space. The role of vertical disparity in the perception of depth, size, curvature, or slant of surfaces was revealed in several previous studies using cue conflict paradigms. In this study, we varied the configuration of stereo-cameras to investigate how changes in the horizontal and vertical disparity fields, conflicting with the vergence cue, affect perceived distance and depth. In four experiments, observers judged the distance of a cylinder displayed in front of a large fronto-parallel surface. Experiment 1 revealed that the presence of a background surface decreases the uncertainty in judgments of distance, suggesting that observers use the relative horizontal disparity between the target and the background as a cue to distance. Two other experiments showed that manipulating the pattern of vertical disparity affected both distance and depth perception. When vertical disparity specified a nearer distance than vergence (convergent cameras), perceived distance and depth were underestimated as compared with the condition where vertical disparity was congruent with vergence cues (parallel cameras). When vertical disparity specified a further distance than vergence, namely an infinite distance, distance and depth were overestimated. The removal of the vertical distortion lessened the effect on perceived distance. Overall, the results suggest that the vertical disparity introduced by the specific camera configuration is mainly responsible for the effect. These findings outline the role of vertical disparity in distance and depth perception and support the use of parallel cameras for designing stereograms.
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Affiliation(s)
- Cyril Vienne
- Institut de recherche biomédicale des armées, Brétigny-sur-Orge, France
| | - Justin Plantier
- Institut de recherche biomédicale des armées, Brétigny-sur-Orge, France
| | - Pascaline Neveu
- Institut de recherche biomédicale des armées, Brétigny-sur-Orge, France
| | - Anne-Emmanuelle Priot
- Institut de recherche biomédicale des armées, Brétigny-sur-Orge, France INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center Bron, France
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