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Wang Y, Wong J, Duncan JL, Roorda A, Tuten WS. Enhanced S-Cone Syndrome: Elevated Cone Counts Confer Supernormal Visual Acuity in the S-Cone Pathway. Invest Ophthalmol Vis Sci 2023; 64:17. [PMID: 37459066 PMCID: PMC10362924 DOI: 10.1167/iovs.64.10.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023] Open
Abstract
Purpose To measure photoreceptor packing density and S-cone spatial resolution as a function of retinal eccentricity in patients with enhanced S-cone syndrome (ESCS) and to discuss the possible mechanisms supporting their supernormal S-cone acuity. Methods We used an adaptive optics scanning laser ophthalmoscope (AOSLO) to characterize photoreceptor packing. A custom non-AO display channel was used to measure L/M- and S-cone-mediated visual acuity during AOSLO imaging. Acuity measurements were obtained using a four-alternative, forced-choice, tumbling E paradigm along the temporal meridian between the fovea and 4° eccentricity in five of six patients and in seven control subjects. L/M acuity was tested by presenting long-pass-filtered optotypes on a black background, excluding wavelengths to which S-cones are sensitive. S-cone isolation was achieved using a two-color, blue-on-yellow chromatic adaptation method that was validated on three control subjects. Results Inter-cone spacing measurements revealed a near-uniform cone density profile (ranging from 0.9-1.5 arcmin spacing) throughout the macula in ESCS. For comparison, normal cone density decreases by a factor of 14 from the fovea to 6°. Cone spacing of ESCS subjects was higher than normal in the fovea and subnormal beyond 2°. Compared to the control subjects (n = 7), S-cone-mediated acuities in patients with ESCS were normal near the fovea and became increasingly supernormal with retinal eccentricity. Beyond 2°, S-cone acuities were superior to L/M-cone-mediated acuity in the ESCS cohort, a reversal of the trend observed in normal retinas. Conclusions Higher than normal parafoveal cone densities (presumably dominated by S-cones) confer better than normal S-cone-mediated acuity in ESCS subjects.
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Affiliation(s)
- Yiyi Wang
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, California, United States
| | - Jessica Wong
- Department of Ophthalmology, University of California, San Francisco, California, United States
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, California, United States
| | - Austin Roorda
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, California, United States
| | - William S Tuten
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, California, United States
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Wang Y, Wong J, Duncan JL, Roorda A, Tuten WS. Enhanced S-cone Syndrome, a Mini-review. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:189-194. [PMID: 37440033 DOI: 10.1007/978-3-031-27681-1_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Enhanced S-cone Syndrome (ESCS) is an autosomal recessive inherited retinal disease mostly associated with disease-causing variants in the NR2E3 gene. During retinal development in ESCS, rod photoreceptor precursors are misdirected to form photoreceptors similar to short-wavelength cones, or S-cones. Compared to a normal human retina, patients with ESCS have no rods and significantly increased numbers of S-cones. Night blindness is the main visual symptom, and visual acuity and color vision can be normal at early disease stages. Histology of donor eyes and adaptive optics imaging revealed increased S-cone density outside of the fovea compared to normal. Visual function testing reveals absent rod function and abnormally enhanced sensitivity to short-wavelength light. Unlike most retinal degenerative diseases, ESCS results in a gain in S-cone photoreceptor function. Research involving ESCS could improve understanding of this rare retinal condition and also shed light on the role of NR2E3 expression in photoreceptor survival.
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Affiliation(s)
- Yiyi Wang
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA.
| | - Jessica Wong
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Austin Roorda
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA
| | - William S Tuten
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA
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Stapley V, Anderson RS, Saunders K, Mulholland PJ. Examining the concordance of retinal ganglion cell counts generated using measures of structure and function. Ophthalmic Physiol Opt 2022; 42:1338-1352. [PMID: 36065739 PMCID: PMC9826349 DOI: 10.1111/opo.13041] [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: 03/23/2022] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 01/11/2023]
Abstract
PURPOSE There are several indirect methods used to estimate retinal ganglion cell (RGC) count in an individual eye, but there is limited information as to the agreement between these methods. In this work, RGC receptive field (RGC-RF) count underlying a spot stimulus (0.43°, Goldmann III) was calculated and compared using three different methods. METHODS RGC-RF count was calculated at a retinal eccentricity of 2.32 mm for 44 healthy adult participants (aged 18-58 years, refractive error -9.75 DS to +1.75 DS) using: (i) functional measures of achromatic peripheral grating resolution acuity (PGRA), (ii) structural measures of RGC-layer thickness (OCT-model, based on the method outlined by Raza and Hood) and (iii) scaling published histology density data to simulate a global expansion in myopia (Histology-Balloon). RESULTS Whilst average RGC-RF counts from the OCT-model (median 105.3, IQR 99.6-111.0) and the Histology-Balloon model (median 107.5, IQR 97.7-114.6) were similar, PGRA estimates were approximately 65% lower (median 37.7, IQR 33.8-46.0). However, there was poor agreement between all three methods (Bland-Altman 95% limits of agreement; PGRA/OCT: 55.4; PGRA/Histology-Balloon 59.3; OCT/Histology-Balloon: 52.4). High intersubject variability in RGC-RF count was evident using all three methods. CONCLUSIONS The lower PGRA RGC-RF counts may be the result of targeting only a specific subset of functional RGCs, as opposed to the coarser approach of the OCT-model and Histology-Balloon, which include all RGCs, and also likely displaced amacrine cells. In the absence of a 'ground truth', direct measure of RGC-RF count, it is not possible to determine which method is most accurate, and each has limitations. However, what is clear is the poor agreement found between the methods prevents direct comparison of RGC-RF counts between studies utilising different methodologies and highlights the need to utilise the same method in longitudinal work.
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Affiliation(s)
- Victoria Stapley
- Centre for Optometry & Vision Science, Biomedical Sciences Research InstituteUlster UniversityColeraineUK
| | - Roger S. Anderson
- Centre for Optometry & Vision Science, Biomedical Sciences Research InstituteUlster UniversityColeraineUK,National Institute for Health Research (NIHR)Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of OphthalmologyLondonUK
| | - Kathryn Saunders
- Centre for Optometry & Vision Science, Biomedical Sciences Research InstituteUlster UniversityColeraineUK
| | - Pádraig J. Mulholland
- Centre for Optometry & Vision Science, Biomedical Sciences Research InstituteUlster UniversityColeraineUK,National Institute for Health Research (NIHR)Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of OphthalmologyLondonUK
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Shamsi F, Liu R, Owsley C, Kwon M. Identifying the Retinal Layers Linked to Human Contrast Sensitivity Via Deep Learning. Invest Ophthalmol Vis Sci 2022; 63:27. [PMID: 35179554 PMCID: PMC8859491 DOI: 10.1167/iovs.63.2.27] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose Luminance contrast is the fundamental building block of human spatial vision. Therefore contrast sensitivity, the reciprocal of contrast threshold required for target detection, has been a barometer of human visual function. Although retinal ganglion cells (RGCs) are known to be involved in contrast coding, it still remains unknown whether the retinal layers containing RGCs are linked to a person's contrast sensitivity (e.g., Pelli-Robson contrast sensitivity) and, if so, to what extent the retinal layers are related to behavioral contrast sensitivity. Thus the current study aims to identify the retinal layers and features critical for predicting a person's contrast sensitivity via deep learning. Methods Data were collected from 225 subjects including individuals with either glaucoma, age-related macular degeneration, or normal vision. A deep convolutional neural network trained to predict a person's Pelli-Robson contrast sensitivity from structural retinal images measured with optical coherence tomography was used. Then, activation maps that represent the critical features learned by the network for the output prediction were computed. Results The thickness of both ganglion cell and inner plexiform layers, reflecting RGC counts, were found to be significantly correlated with contrast sensitivity (r = 0.26 ∼ 0.58,Ps < 0.001 for different eccentricities). Importantly, the results showed that retinal layers containing RGCs were the critical features the network uses to predict a person's contrast sensitivity (an average R2 = 0.36 ± 0.10). Conclusions The findings confirmed the structure and function relationship for contrast sensitivity while highlighting the role of RGC density for human contrast sensitivity.
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Affiliation(s)
- Foroogh Shamsi
- Department of Psychology, Northeastern University, Boston, Massachusetts, United States
| | - Rong Liu
- Department of Psychology, Northeastern University, Boston, Massachusetts, United States.,Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States.,Department of life science and medicine, University of Science and Technology of China, Hefei, China
| | - Cynthia Owsley
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - MiYoung Kwon
- Department of Psychology, Northeastern University, Boston, Massachusetts, United States.,Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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Zlatkova MB, Racheva K, Totev T, Mihaylova M, Hristov I, Anderson RS. Resolution acuity and spatial summation of chromatic mechanisms in the peripheral retina. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2021; 38:1003-1014. [PMID: 34263756 DOI: 10.1364/josaa.418073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 05/28/2021] [Indexed: 06/13/2023]
Abstract
Green stimuli are more difficult to detect than red stimuli in the retinal periphery, as reported previously. We examined the spatial characteristics of chromatic mechanisms using stimuli, modulated from an achromatic background to each pole of the "red-green" cardinal axis in DKL space at 20 deg eccentricity. The "blue-yellow" cardinal axis was also studied for comparison. By measuring both grating discrimination at the resolution limit (resolution acuity) and spatial summation, assessed by the Michaelis-Menten function, we demonstrated a marked "red-green" asymmetry. The resolution acuity was worse and spatial summation more extended for "green" compared to "red" stimuli, while showing significant individual variations. Ricco's area was also measured, but not determined for "green" spots because of the poor small stimuli detection. These results cannot be explained by differences in L- and M-cone numerosity and/or spatial arrangement, but rather have postreceptoral origin, probably at the cortical level.
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Haun AM. What is visible across the visual field? Neurosci Conscious 2021; 2021:niab006. [PMID: 34084558 PMCID: PMC8167368 DOI: 10.1093/nc/niab006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 11/09/2020] [Accepted: 01/08/2021] [Indexed: 12/22/2022] Open
Abstract
It is sometimes claimed that because the resolution and sensitivity of visual perception are better in the fovea than in the periphery, peripheral vision cannot support the same kinds of colour and sharpness percepts as foveal vision. The fact that a scene nevertheless seems colourful and sharp throughout the visual field then poses a puzzle. In this study, I use a detailed model of human spatial vision to estimate the visibility of certain properties of natural scenes, including aspects of colourfulness, sharpness, and blurriness, across the visual field. The model is constructed to reproduce basic aspects of human contrast and colour sensitivity over a range of retinal eccentricities. I apply the model to colourful, complex natural scene images, and estimate the degree to which colour and edge information are present in the model's representation of the scenes. I find that, aside from the intrinsic drift in the spatial scale of the representation, there are not large qualitative differences between foveal and peripheral representations of 'colourfulness' and 'sharpness'.
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Affiliation(s)
- Andrew M Haun
- Center for Sleep and Consciousness, Department of Psychiatry, University of Wisconsin-Madison, WI, USA
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Abstract
Purpose Peripheral resolution acuity depends on the orientation of the stimuli. However, it is uncertain if such a meridional effect also exists for peripheral detection tasks because they are affected by optical errors. Knowledge of the quantitative differences in acuity for different grating orientations is crucial for choosing the appropriate stimuli for evaluations of peripheral resolution and detection tasks. We assessed resolution and detection thresholds for different grating orientations in the peripheral visual field. Methods Resolution and detection thresholds were evaluated for gratings of four different orientations in eight different visual field meridians in the 20-deg visual field in white light. Detection measurements in monochromatic light (543 nm; bandwidth, 10 nm) were also performed to evaluate the effects of chromatic aberration on the meridional effect. A combination of trial lenses and adaptive optics system was used to correct the monochromatic lower- and higher-order aberrations. Results For both resolution and detection tasks, gratings parallel to the visual field meridian had better threshold compared with the perpendicular gratings, whereas the two oblique gratings had similar thresholds. The parallel and perpendicular grating acuity differences for resolution and detection tasks were 0.16 logMAR and 0.11 logMAD, respectively. Elimination of chromatic errors did not affect the meridional preference in detection acuity. Conclusions Similar to peripheral resolution, detection also shows a meridional effect that appears to have a neural origin. The threshold difference seen for parallel and perpendicular gratings suggests the use of two oblique gratings as stimuli in alternative forced-choice procedures for peripheral vision evaluation to reduce measurement variation.
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Coates DR, Chung STL. Crowding in the S-cone pathway. Vision Res 2016; 122:81-92. [PMID: 27063360 DOI: 10.1016/j.visres.2016.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 02/24/2016] [Accepted: 03/14/2016] [Indexed: 10/21/2022]
Abstract
The spatial extent of interference from nearby object or contours (the critical spacing of "crowding") has been thoroughly characterized across the visual field, typically using high contrast achromatic stimuli. However, attempts to link this measure with known properties of physiological pathways have been inconclusive. The S-cone pathway, with its ease of psychophysical isolation and known anatomical characteristics, offers a unique tool to gain additional insights into crowding. In this study, we measured the spatial extent of crowding in the S-cone pathway at several retinal locations using a chromatic adaptation paradigm. S-cone crowding was evident and extensive, but its spatial extent changed less markedly as a function of retinal eccentricity than the extent found using traditional achromatic stimuli. However, the spatial extent agreed with that of low contrast achromatic stimuli matched for isolated resolvability. This suggests that common cortical mechanisms mediate the crowding effect in the S-cone and achromatic pathway, but contrast is an important factor. The low contrast of S-cone stimuli makes S-cone vision more acuity-limited than crowding-limited.
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Affiliation(s)
- Daniel R Coates
- Vision Science Graduate Group, University of California, Berkeley, United States.
| | - Susana T L Chung
- Vision Science Graduate Group, University of California, Berkeley, United States; School of Optometry, University of California, Berkeley, United States
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Peripheral vision, perceptual asymmetries and visuospatial attention in young, young-old and oldest-old adults. Exp Gerontol 2016; 75:30-6. [DOI: 10.1016/j.exger.2015.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/06/2015] [Accepted: 12/10/2015] [Indexed: 11/23/2022]
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Peripheral vision and perceptual asymmetries in young and older martial arts athletes and nonathletes. Atten Percept Psychophys 2015; 76:2465-76. [PMID: 25005071 DOI: 10.3758/s13414-014-0719-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The present study investigated peripheral vision (PV) and perceptual asymmetries in young and older martial arts athletes (judo and karate athletes) and compared their performance with that of young and older nonathletes. Stimuli were dots presented at three different eccentricities along the horizontal, oblique, and vertical diameters and three interstimulus intervals. Experiment 1 showed that although the two athlete groups were faster in almost all conditions, karate athletes performed significantly better than nonathlete participants when stimuli were presented in the peripheral visual field. Experiment 2 showed that older participants who had practiced a martial art at a competitive level when they were young were significantly faster than sedentary older adults of the same age. The practiced sport (judo or karate) did not affect performance differentially, suggesting that it is the practice of martial arts that is the crucial factor, rather than the type of martial art. Importantly, older athletes lose their PV advantage, as compared with young athletes. Finally, we found that physical activity (young and older athletes) and age (young and older adults) did not alter the visual asymmetries that vary as a function of spatial location; all participants were faster for stimuli presented along the horizontal than for those presented along the vertical meridian and for those presented at the lower rather than at the upper locations within the vertical meridian. These results indicate that the practice of these martial arts is an effective way of counteracting the processing speed decline of visual stimuli appearing at any visual location and speed.
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The relationship between foveal short-wavelength-sensitive visual function and macular pigment optical density in the ageing age. Vision Res 2013; 86:81-6. [DOI: 10.1016/j.visres.2013.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 12/20/2012] [Accepted: 04/02/2013] [Indexed: 11/21/2022]
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Lewis P, Rosén R, Unsbo P, Gustafsson J. Resolution of static and dynamic stimuli in the peripheral visual field. Vision Res 2011; 51:1829-34. [DOI: 10.1016/j.visres.2011.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 05/31/2011] [Accepted: 06/10/2011] [Indexed: 10/18/2022]
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Comparing mfERGs with estimates of cone density from in vivo imaging of the photoreceptor mosaic using a modified Heidelberg retina tomograph. Vision Res 2010; 50:1462-8. [PMID: 20417226 DOI: 10.1016/j.visres.2010.04.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 04/01/2010] [Accepted: 04/18/2010] [Indexed: 11/21/2022]
Abstract
The spatial variation in central retinal function determined from mfERG was compared to co-localised measurements of cone density in two normal subjects. Individual cone cells in the parafoveal region of the retina were identified from 1 degrees x1 degrees images of the photoreceptor mosaic using a modified Heidelberg retina tomograph (HRT). The variation in cone density compared well with previous histology and retinal imaging studies and was strongly linearly correlated (r=0.98, p<0.001) with mfERG amplitude within the central retina. Retinal function determined from mfERG amplitude appears to directly reflect the density of the cone cells in this region.
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How does the short-wavelength-sensitive contrast sensitivity function for detection and resolution change with age in the periphery? Vision Res 2008; 48:1894-901. [DOI: 10.1016/j.visres.2008.05.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Revised: 05/16/2008] [Accepted: 05/19/2008] [Indexed: 11/22/2022]
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Wolsley CJ, Saunders KJ, Silvestri G, Anderson RS. Investigation of changes in the myopic retina using multifocal electroretinograms, optical coherence tomography and peripheral resolution acuity. Vision Res 2008; 48:1554-61. [DOI: 10.1016/j.visres.2008.04.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 04/09/2008] [Accepted: 04/16/2008] [Indexed: 11/28/2022]
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Zlatkova MB, Coulter EE, Anderson RS. The effect of simulated lens yellowing and opacification on blue-on-yellow acuity and contrast sensitivity. Vision Res 2006; 46:2432-42. [PMID: 16524612 DOI: 10.1016/j.visres.2006.01.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 01/17/2006] [Accepted: 01/26/2006] [Indexed: 10/24/2022]
Abstract
Short-wavelength-sensitive (SWS) resolution acuity has been reported to be limited by the density of the responding ganglion cells for people without appreciable age-related lenticular change. This study measured the robustness of SWS-cone acuity and contrast sensitivity (CS) to simulated lens yellowing and opacification. Resolution acuity at 8 deg eccentricity proved robust to significant amounts of yellowing and remained lower than detection acuity, indicating that the resolution continued to be limited by ganglion cell density. Both the detection and resolution CS functions were affected by simulated lens yellowing, except for resolution close to the CS cut-off. For simulated opacification, only dense opacity significantly affected performance. SWS resolution acuity and CS close to the resolution limit are resistant to moderate simulated age-related lens changes and continue to be mediated by the density of the responding ganglion cells, indicating important clinical potential to measure SWS neural losses of vision in older subjects.
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Affiliation(s)
- Margarita B Zlatkova
- Vision Science Research Group, School of Biomedical Sciences, University of Ulster at Coleraine, Coleraine, UK.
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Shupe JM, Kristan DM, Austad SN, Stenkamp DL. The eye of the laboratory mouse remains anatomically adapted for natural conditions. BRAIN, BEHAVIOR AND EVOLUTION 2005; 67:39-52. [PMID: 16219997 PMCID: PMC2582157 DOI: 10.1159/000088857] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Accepted: 06/27/2005] [Indexed: 11/19/2022]
Abstract
Evolutionary effects of domestication have been demonstrated for several body systems, including the eye, and for several vertebrate species, including the mouse. Given the importance of the laboratory mouse to vision science, we wished to determine whether the anatomical and histological features of the eyes of laboratory mice are distinct from those of their naturally adapted, wild counterparts. We measured dimensions and masses of whole eyes and lenses from a wild population plus three inbred strains (C57BL/6J, NZB/BINJ, and DBA/1J) of the house house, Mus musculus, as well as wild and outbred laboratory-domesticated stock of the deer mouse, Peromyscus maniculatus. Histological preparations from these eyes were used to determine outer nuclear layer thickness, linear density of the ganglion cell layer, and for indirect immunofluorescence evaluation of cone opsin expression. For all of these traits, no statistically significant differences were found between any laboratory strain and its wild counterpart. The evolutionary effects of domestication of mice therefore do not include changes to the eye in any variable measured, supporting the continued use of this animal as a model for a naturally adapted visual system.
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Affiliation(s)
- Jonathan M Shupe
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844-3015, USA
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Abstract
Perimetry of some kind remains an important tool in the detection, diagnosis and monitoring of glaucomatous damage to the visual pathway. However, recent studies have served to reinforce the suspicion that conventional perimetry does not possess the sensitivity to detect the earliest signs of functional loss resulting from glaucoma. The relationship between differential light threshold and ganglion cell loss is extremely weak and, in the early stages of glaucoma, non-existent. Alternative, more novel perimetric techniques seem to offer promise of better detectability for early loss by claiming to tap in to one or other of the separate parallel pathways of the visual system. While some of these tests show potential for better detection and monitoring of glaucoma, the reasons why this might be so are not always clearly formulated or represented. This leads to misunderstanding of what the test actually measures and of the glaucomatous disease process itself. This paper seeks to revisit and review the theory underlying psychophysical testing of visual function related to glaucoma and stresses the importance of developing tests that are based on a firm theoretical understanding of visual function and processing in order to both detect glaucoma at an earlier stage and better understand the mechanisms of loss from the disease process.
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Affiliation(s)
- Roger S Anderson
- Vision Science Research Group, School of Biomedical Sciences, University of Ulster at Coleraine, Co. Londonderry, Northern Ireland BT52 1SA, UK.
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Beirne RO, Zlatkova MB, Anderson RS. Changes in human short-wavelength-sensitive and achromatic resolution acuity with retinal eccentricity and meridian. Vis Neurosci 2005; 22:79-86. [PMID: 15842743 DOI: 10.1017/s0952523805221119] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Indexed: 11/06/2022]
Abstract
Psychophysical measurements using achromatic grating resolution acuity in peripheral vision show a prominent retinal asymmetry in acuity which is consistent with predicted values based on available estimates of midget ganglion cell density. Recent studies have shown that peripheral grating resolution acuity values for short-wavelength-sensitive (SWS) isolating gratings in normal observers are closely related to predicted values based on the underlying small bistratified ganglion cell density. By measuring SWS resolution acuity at different locations across the visual field, we wished to see if any significant acuity asymmetry exists for the short-wavelength system. In addition to this, we wanted to compare SWS and achromatic resolution acuity at different retinal locations of equal eccentricity. SWS and achromatic grating resolution acuity was measured in two observers at a number of different retinal meridians of 10- and 25-deg eccentricity from the fovea, and out to 35-deg eccentricity along the horizontal meridian. Achromatic resolution acuity was higher than SWS resolution acuity at all locations. At 10-deg eccentricity there was slight radial asymmetry in SWS and achromatic acuity, both displaying highest acuity along the horizontal meridian. At 25-deg eccentricity, SWS and achromatic acuity showed significant asymmetry with acuity being higher in the nasal retina compared to the temporal retina and with higher acuity in the superior retina compared to the inferior retina. At 35-deg eccentricity, the acuity asymmetry along the horizontal meridian was maintained with acuity for both significantly higher in the nasal retina. The SWS acuity changes with eccentricity and meridian were qualitatively similar to that found for achromatic acuity at the majority of retinal locations. Like achromatic acuity, SWS acuity shows significant asymmetry at different retinal locations of equal eccentricity. This suggests that both the midget and small bistratified ganglion cell population density changes significantly with retinal location and eccentricity. SWS acuity appears to change in parallel with achromatic acuity for the majority of retinal locations measured, although the amount of nasotemporal asymmetry appears to be slightly less for the SWS system at 25- and 35-deg eccentricity.
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Affiliation(s)
- Raymond O Beirne
- Vision Science Research Group, School of Biomedical Sciences, University of Ulster at Coleraine, Coleraine, Northern Ireland, UK.
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Popovic Z, Sjöstrand J. The relation between resolution measurements and numbers of retinal ganglion cells in the same human subjects. Vision Res 2005; 45:2331-8. [PMID: 15924946 DOI: 10.1016/j.visres.2005.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Revised: 02/15/2005] [Accepted: 02/16/2005] [Indexed: 11/29/2022]
Abstract
Limiting factors of resolution have previously only been investigated by using resolution data and retinal ganglion cell spacing data from different individuals. We report on our unique opportunity to study the intra-individual relationship in three human subjects between retinal ganglion cell separations and resolution thresholds, measured with high-pass resolution perimetry. Our data show that resolution is directly proportional to half the midget population, in accordance with the hypothesis that a dichotomous midget ON/OFF population mediates resolution.
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Affiliation(s)
- Zoran Popovic
- Institute of Clinical Neuroscience, Department of Ophthalmology, Sahlgrenska Academy, Göteborg University, SU/Mölndal, 431 80 Mölndal, Sweden.
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21
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Sally SL, Gurnsey R. Orientation discrimination across the visual field: matching perceived contrast near threshold. Vision Res 2004; 44:2719-27. [PMID: 15358066 DOI: 10.1016/j.visres.2004.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Revised: 05/26/2004] [Indexed: 10/26/2022]
Abstract
Performance can often be made equal across the visual field by scaling peripherally presented stimuli according to F=1+E/E2 where E2 is the eccentricity at which stimulus size must double to maintain foveal performance levels. Previous studies suggest that E2 for orientation discrimination is in the range of 1.5 degrees -2 degrees when stimuli are presented at contrasts well above detection threshold. Recent psychophysical and physiological evidence suggests spatial reorganization of receptive fields at near-threshold contrasts. Such contrast-dependent changes in receptive field structure might alter the amount of size scaling necessary to equate task performance across the visual field. To examine this question we measured orientation discrimination thresholds for a range of stimulus sizes and eccentricities (0 degrees -15 degrees ). We used the same procedure previously employed except that stimuli were presented at near-threshold contrasts. We controlled for the effects of perceptual contrast on thresholds through a matching procedure. A standard line of 3 degrees in length presented at fixation was set to 2 just noticeable differences above detection threshold. The perceived contrast of all other stimuli was adjusted by the subject to match this one. Orientation discrimination thresholds were then obtained at these matching contrasts for all stimulus sizes and eccentricities. E2 values of 3.42 degrees and 3.50 degrees were recovered for two subjects; these values were about a factor of two larger than E2 values previously found for this task when stimuli were presented at higher physical contrasts.
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Affiliation(s)
- Sharon L Sally
- Department of Psychology, Concordia University, 7141 Sherbrooke Street West, Montréal, Qué., Canada H4B 1R6
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22
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Vassilev A, Mihaylova MS, Racheva K, Zlatkova M, Anderson RS. Spatial summation of S-cone ON and OFF signals: effects of retinal eccentricity. Vision Res 2003; 43:2875-84. [PMID: 14568375 DOI: 10.1016/j.visres.2003.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We studied spatial summation for S-cone ON and OFF signals as a function of retinal eccentricity in human subjects. S-cone isolation was obtained by the two-colour threshold method of Stiles, modified by adding blue light to the yellow background. Test stimuli were blue light increments or decrements within a circular area of variable size. These were presented for 100 ms at 0 to 20 deg along the horizontal temporal retinal meridian. Ricco's area of complete spatial summation was measured from the threshold vs. area curves. This was nearly constant and approximately the same for both types of stimuli within the 0-5 deg range and increased beyond this range. The decremental area increased faster, suggesting that separate mechanisms, presumably ON and OFF, integrate S-cone increments and decrements. The results appear to provide new evidence for the existence of separate S-cone ON and OFF pathways. We compare the data with known morphology of primate retina and assume that, if S-cone decrements are detected via separate OFF cells, these should differ in density and dendritic field size from the S-cone ON cells, but only in the retinal periphery.
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Affiliation(s)
- Angel Vassilev
- Institute of Physiology, Bulgarian Academy of Sciences, Acad G Bonchev St Bl 23, Sofia 1113, Bulgaria.
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23
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Abstract
For over 30 years there has been a controversy over whether
color-defined motion can be perceived by the human visual system. Some
results suggest that there is no chromatic motion mechanism at all,
whereas others do find evidence for a purely chromatic motion
mechanism. Here we examine the chromatic input to global motion
processing for a range of color directions in the photopic luminance
range. We measure contrast thresholds for global motion identification
and simple detection using sparse random-dot kinematograms. The results
show a discrepancy between the two chromatic axes: whereas it is
possible for observers to perform the global motion task for stimuli
modulated along the red–green axis, we could not assess the
contrast threshold required for stimuli modulated along the
yellowish-violet axis. The contrast required for detection for both
axes, however, are well below the contrasts required for global motion
identification. We conclude that there is a significant red–green
input to global motion processing providing further evidence for the
involvement of the parvocellular pathway. The lack of S-cone input to
global motion processing suggests that the koniocellular pathway
mediates the detection but not the processing of complex motion for our
parameter range.
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Affiliation(s)
- Alexa I Ruppertsberg
- Eleanor Rathbone Building, Department of Psychology, University of Liverpool, Liverpool, L69 7ZA, UK.
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24
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Anderson RS, Coulter E, Zlatkova MB, Demirel S. Short-wavelength acuity: optical factors affecting detection and resolution of blue-yellow sinusoidal gratings in foveal and peripheral vision. Vision Res 2003; 43:101-7. [PMID: 12505609 DOI: 10.1016/s0042-6989(02)00410-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Previous studies have indicated that peripheral achromatic grating resolution is limited by the sampling density of the neural array (sampling limited), and largely unaffected by large amounts of optical defocus and significant changes in luminance. Under certain conditions, peripheral short-wavelength sensitive (SWS) grating acuity is also sampling limited. We wished to determine how the sampling-limited nature of SWS-driven grating resolution was affected by changing optical defocus and stimulus luminance. Using SWS-cone isolation techniques, detection and resolution acuity were measured for sinusoidal gratings under varying levels of stimulus mean luminance and optical defocus in the fovea and at 20 degrees eccentricity. From 1.4 down to 0.3 cd/m(2) peripheral detection acuity was superior to resolution acuity, accompanied by observations of aliasing: there was little change in resolution performance throughout this range. For defocus up to 3-4 dioptres, peripheral detection acuity was superior to resolution but fell steadily: resolution performance remained flat throughout the same range. Unlike achromatic acuity, foveal resolution performance displayed some robustness to defocus but to a lesser degree than the periphery. Peripheral SWS-driven resolution remains sampling limited for large changes in stimulus luminance and optical defocus, and should thus be useful as a clinical test of SWS-driven ganglion cell density.
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Affiliation(s)
- Roger S Anderson
- Vision Science Research Group, School of Biomedical Sciences, University of Ulster at Coleraine, Co Londonderry BT52 1SA, UK.
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25
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Zlatkova MB, Coulter E, Anderson RS. Short-wavelength acuity: blue-yellow and achromatic resolution loss with age. Vision Res 2003; 43:109-15. [PMID: 12505610 DOI: 10.1016/s0042-6989(02)00411-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Previous studies have indicated that peripheral resolution for achromatic gratings is sampling limited and directly related to the density of the underlying midget ganglion cell population. Previous studies by the authors have shown that peripheral resolution for blue-cone isolating gratings is also sampling limited, is robust to optical defocus and short-wavelength attenuation, and yields estimates of sampling density which correspond closely with the density of small bistratified ganglion cells. We measured peripheral resolution in a group of normal subjects ranging in age from 12 to 72 years, using both achromatic and blue-cone isolating gratings, to determine how performance (and hence ganglion cell density) changed with age for both systems. Resolution was higher for achromatic than blue-yellow gratings and performance was flat for both until the fifth decade. After this, performance declined for both at a rate of approximately 14%/decade with no significant difference between the two rates of decline. Individual measurements of lens density were not correlated with short-wavelength sensitive resolution performance in the older subjects, further indicating that the decline in resolution was not attributable to pre-retinal absorption.
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Affiliation(s)
- Margarita B Zlatkova
- Vision Science Research Group, School of Biomedical Sciences, University of Ulster at Coleraine, Co Londonderry BT52 1SA, UK
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26
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Anderson RS, Zlatkova MB, Beirne RO. The contrast sensitivity function for detection and resolution of blue-on-yellow gratings in foveal and peripheral vision. Ophthalmic Physiol Opt 2002; 22:420-6. [PMID: 12358313 DOI: 10.1046/j.1475-1313.2002.00068.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Previous studies using polychromatic gratings have shown that the peripheral grating contrast sensitivity function is significantly different when the task is resolution rather than detection. Specifically, in the middle frequency range, while resolution acuity drops suddenly to zero, detection performance continues up to much higher frequencies, accompanied by observations of aliasing. We wanted to determine if the same holds true for blue-cone isolating gratings in either foveal or peripheral vision. Contrast sensitivity function (CSFs) were measured at the fovea and 20 degrees eccentricity in the temporal retina under conditions of short-wavelength-sensitive (SWS)-cone pathway isolation using a two-alternative forced choice paradigm. The detection and resolution CSF were identical at the low frequency end but at higher frequencies resolution sensitivity falls abruptly while contrast detection remained possible till higher frequencies [cut-off frequencies: fovea detection 6.0 cycles (degree)(-1), resolution 4.6 cycles (degree)(-1); periphery detection 1.6 cycles (degree)(-1), resolution 1.05 cycles (degree)(-1)]. Aliasing was observable when spatial frequency exceeded the resolution limit. Medium/high contrast blue-cone-mediated resolution acuity is sampling limited in both the fovea and periphery. Previous studies of blue-cone contrast sensitivity which employed a detection task do not reflect the true resolution limit.
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Affiliation(s)
- R S Anderson
- Vision Science Research Group, School of Biomedical Sciences, University of Ulster at Coleraine, UK
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