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Lappin JS, Bell HH. Form and Function in Information for Visual Perception. Iperception 2022; 12:20416695211053352. [PMID: 35003612 PMCID: PMC8728782 DOI: 10.1177/20416695211053352] [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: 05/04/2021] [Revised: 07/19/2021] [Accepted: 09/27/2021] [Indexed: 11/16/2022] Open
Abstract
Visual perception involves spatially and temporally coordinated variations in diverse
physical systems: environmental surfaces and symbols, optical images, electro-chemical
activity in neural networks, muscles, and bodily movements—each with a distinctly
different material structure and energy. The fundamental problem in the theory of
perception is to characterize the information that enables both perceptual awareness and
real-time dynamic coordination of these diverse physical systems. Gibson's psychophysical
and ecological conception of this problem differed from that of mainstream science both
then and now. The present article aims to incorporate Gibson's ideas within a general
conception of information for visual perception. We emphasize the essential role of
spatiotemporal form, in contrast with symbolic information. We consider contemporary
understanding of surface structure, optical images, and optic flow. Finally, we consider
recent evidence about capacity limitations on the rate of visual perception and
implications for the ecology of vision.
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Sheppard WEA, Dickerson P, Baraas RC, Mon-Williams M, Barrett BT, Wilkie RM, Coats RO. Exploring the effects of degraded vision on sensorimotor performance. PLoS One 2021; 16:e0258678. [PMID: 34748569 PMCID: PMC8575268 DOI: 10.1371/journal.pone.0258678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 10/02/2021] [Indexed: 11/19/2022] Open
Abstract
PURPOSE Many people experience unilateral degraded vision, usually owing to a developmental or age-related disorder. There are unresolved questions regarding the extent to which such unilateral visual deficits impact on sensorimotor performance; an important issue as sensorimotor limitations can constrain quality of life by restricting 'activities of daily living'. Examination of the relationship between visual deficit and sensorimotor performance is essential for determining the functional implications of ophthalmic conditions. This study attempts to explore the effect of unilaterally degraded vision on sensorimotor performance. METHODS In Experiment 1 we simulated visual deficits in 30 participants using unilateral and bilateral Bangerter filters to explore whether motor performance was affected in water pouring, peg placing, and aiming tasks. Experiment 2 (n = 74) tested the hypothesis that kinematic measures are associated with visuomotor deficits by measuring the impact of small visual sensitivity decrements created by monocular viewing on sensorimotor interactions with targets presented on a planar surface in aiming, tracking and steering tasks. RESULTS In Experiment 1, the filters caused decreased task performance-confirming that unilateral (and bilateral) visual loss has functional implications. In Experiment 2, kinematic measures were affected by monocular viewing in two of three tasks requiring rapid online visual feedback (aiming and steering). CONCLUSIONS Unilateral visual loss has a measurable impact on sensorimotor performance. The benefits of binocular vision may be particularly important for some groups (e.g. older adults) where an inability to complete sensorimotor tasks may necessitate assisted living. There is an urgent need to develop rigorous kinematic approaches to the quantification of the functional impact of unilaterally degraded vision and of the benefits associated with treatments for unilateral ophthalmic conditions to enable informed decisions around treatment.
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Affiliation(s)
| | - Polly Dickerson
- Department of Ophthalmology, York Teaching Hospital NHS Foundation Trust, North Yorkshire, United Kingdom
| | - Rigmor C. Baraas
- Department of Optometry, Radiography and Lighting Design, National Centre for Optics, Vision and Eye Care, University of South-Eastern Norway, Kongsberg, Norway
| | - Mark Mon-Williams
- School of Psychology, University of Leeds, Leeds, West Yorkshire, United Kingdom
- Department of Optometry, Radiography and Lighting Design, National Centre for Optics, Vision and Eye Care, University of South-Eastern Norway, Kongsberg, Norway
- Bradford Institute of Health Research, Bradford Teaching Hospital NHS Foundation Trust, West Yorkshire, United Kingdom
| | - Brendan T. Barrett
- Faculty of Life Sciences, School of Optometry & Vision Science, University of Bradford, West Yorkshire, United Kingdom
| | - Richard M. Wilkie
- School of Psychology, University of Leeds, Leeds, West Yorkshire, United Kingdom
| | - Rachel O. Coats
- School of Psychology, University of Leeds, Leeds, West Yorkshire, United Kingdom
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Abstract
Stereovision is the ability to perceive fine depth variations from small differences in the two eyes' images. Using adaptive optics, we show that even minute optical aberrations that are not clinically correctable, and go unnoticed in everyday vision, can affect stereo acuity. Hence, the human binocular system is capable of using fine details that are not experienced in everyday vision. Interestingly, stereo acuity varied considerably across individuals even when they were provided identical perfect optics. We also found that individuals' stereo acuity is better when viewing with their habitual optics rather than someone else's (better) optics. Together, these findings suggest that the visual system compensates for habitual optical aberrations through neural adaptation and thereby optimizes stereovision uniquely for each individual. Thus, stereovision is limited by small optical aberrations and by neural adaptation to one's own optics.
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Human Eye Optics within a Non-Euclidian Geometrical Approach and Some Implications in Vision Prosthetics Design. Biomolecules 2021; 11:biom11020215. [PMID: 33557081 PMCID: PMC7913825 DOI: 10.3390/biom11020215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 11/25/2022] Open
Abstract
An analogy with our previously published theory on the ionospheric auroral gyroscope provides a new perspective in human eye optics. Based on cone cells’ real distribution, we model the human eye macula as a pseudospherical surface. This allows the rigorous description of the photoreceptor cell densities in the parafoveal zones modeled further by an optimized paving method. The hexagonal photoreceptors’ distribution has been optimally projected on the elliptical pseudosphere, thus designing a prosthetic array counting almost 7000 pixel points. Thanks to the high morphological similarities to a normal human retina, the visual prosthesis performance in camera-free systems might be significantly improved.
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Wang Y, Wang X, Shi H, Xia L, Dong J, Nguchu BA, Uwisengeyimana JDD, Liu Y, Zhang D, Feng L, Qiu B. Microstructural properties of major white matter tracts in constant exotropia before and after strabismus surgery. Br J Ophthalmol 2021; 106:870-877. [PMID: 33468491 DOI: 10.1136/bjophthalmol-2020-317948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/08/2020] [Accepted: 01/04/2021] [Indexed: 11/04/2022]
Abstract
AIMS The purpose of this study was to explore the microstructural properties of the major white matter (WM) tracts in constant exotropia (XT) before and after strabismus surgery, and further investigate the association between microstructural alterations and the ocular dominance (OD). METHODS We collected diffusion tensor imaging data of patients with XT before (n=19) and after (n=15) strabismus surgery and 20 healthy controls and evaluated OD and stereopsis. The probabilistic streamline tractography of the 24 major WM tracts was reconstructed by using the automated fibre quantification package. Fractional anisotropy and mean diffusivity (MD) along each tract were estimated, and their differences between the groups were examined. Furthermore, we evaluated the relationship between OD and the absolute value of altered microstructural parameters. RESULTS While all postoperative XT patients restored normal stereopsis, most of their OD remained aberrant (9 out of 11). Compared with that of preoperation, the MD of postoperative patients decreased significantly along left anterior thalamic radiation (ATR), left arcuate fasciculus (AF), left corticospinal tract (CST), left cingulum cingulate (CGC) and left inferior fronto-occipital fasciculus. Moreover, OD was negatively correlated with the absolute value of MD changes in left ATR, left AF, left CST and left CGC. CONCLUSION Microstructural alterations after surgery in the visuospatial network tracts may contribute to the stereopsis restoration. Additionally, the results of the correlation analysis may signify that the balanced binocular input may be more conducive for the restoration and improvement of binocular visual function, including stereopsis. Thus, restoring normal ocular balance after surgical correction may be necessary to achieve more substantial improvements.
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Affiliation(s)
- Yanming Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and the Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiaoxiao Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and the Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Hongmei Shi
- Department of Ophthalmology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.,Department of Ophthalmology, The People's Hospital of Bozhou, Bozhou, Anhui, China
| | - Lin Xia
- Department of Ophthalmology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Jiong Dong
- Department of Ophthalmology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Benedictor Alexander Nguchu
- Hefei National Laboratory for Physical Sciences at the Microscale and the Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Jean De Dieu Uwisengeyimana
- Hefei National Laboratory for Physical Sciences at the Microscale and the Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Yanpeng Liu
- Hefei National Laboratory for Physical Sciences at the Microscale and the Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Du Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and the Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Lixia Feng
- Department of Ophthalmology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Bensheng Qiu
- Hefei National Laboratory for Physical Sciences at the Microscale and the Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
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Feldstein IT, Kölsch FM, Konrad R. Egocentric Distance Perception: A Comparative Study Investigating Differences Between Real and Virtual Environments. Perception 2020; 49:940-967. [PMID: 33002392 DOI: 10.1177/0301006620951997] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Virtual reality systems are a popular tool in behavioral sciences. The participants' behavior is, however, a response to cognitively processed stimuli. Consequently, researchers must ensure that virtually perceived stimuli resemble those present in the real world to ensure the ecological validity of collected findings. Our article provides a literature review relating to distance perception in virtual reality. Furthermore, we present a new study that compares verbal distance estimates within real and virtual environments. The virtual space-a replica of a real outdoor area-was displayed using a state-of-the-art head-mounted display. Investigated distances ranged from 8 to 13 m. Overall, the results show no significant difference between egocentric distance estimates in real and virtual environments. However, a more in-depth analysis suggests that the order in which participants were exposed to the two environments may affect the outcome. Furthermore, the study suggests that a rising experience of immersion leads to an alignment of the estimated virtual distances with the real ones. The results also show that the discrepancy between estimates of real and virtual distances increases with the incongruity between virtual and actual eye heights, demonstrating the importance of an accurately set virtual eye height.
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Affiliation(s)
- Ilja T Feldstein
- Harvard Medical School, Department of Ophthalmology, United States
| | - Felix M Kölsch
- Technical University of Munich, Department of Mechanical Engineering, Germany
| | - Robert Konrad
- Stanford University, Department of Electrical Engineering, United States
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Feldstein IT. Impending Collision Judgment from an Egocentric Perspective in Real and Virtual Environments: A Review. Perception 2019; 48:769-795. [DOI: 10.1177/0301006619861892] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The human egocentric perception of approaching objects and the related perceptual processes have been of interest to researchers for several decades. This article gives a literature review on numerous studies that investigated the phenomenon when an object approaches an observer (or the other way around) with the goal to single out factors that influence the perceptual process. A taxonomy of metrics is followed by a breakdown of different experimental measurement methods. Thereinafter, potential factors affecting the judgment of approaching objects are compiled and debated while divided into human factors (e.g., gender, age, and driving experience), compositional factors (e.g., approaching velocity, spatial distance, and observation time), and technical factors (e.g., field of view, stereoscopy, and display contrast). Experimental findings are collated, juxtaposed, and critically discussed. With virtual-reality devices having taken a tremendous developmental leap forward in the past few years, they have been able to gain ground in experimental research. Therefore, special attention in this article is also given to the perception of approaching objects in virtual environments and put in contrast to the perception in reality.
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Affiliation(s)
- Ilja T. Feldstein
- Harvard Medical School, Department of Ophthalmology, Boston, MA, USA; Technical University of Munich, Department of Mechanical Engineering, Garching, Germany
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