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Song J, Breitmeyer BG, Brown JM. Further Examination of the Pulsed- and Steady-Pedestal Paradigms under Hypothetical Parvocellular- and Magnocellular-Biased Conditions. Vision (Basel) 2024; 8:28. [PMID: 38804349 PMCID: PMC11130818 DOI: 10.3390/vision8020028] [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: 01/30/2024] [Revised: 04/12/2024] [Accepted: 04/25/2024] [Indexed: 05/29/2024] Open
Abstract
The pulsed- and steady-pedestal paradigms were designed to track increment thresholds (ΔC) as a function of pedestal contrast (C) for the parvocellular (P) and magnocellular (M) systems, respectively. These paradigms produce contrasting results: linear relationships between ΔC and C are observed in the pulsed-pedestal paradigm, indicative of the P system's processing, while the steady-pedestal paradigm reveals nonlinear functions, characteristic of the M system's response. However, we recently found the P model fits better than the M model for both paradigms, using Gabor stimuli biased towards the M or P systems based on their sensitivity to color and spatial frequency. Here, we used two-square pedestals under green vs. red light in the lower-left vs. upper-right visual fields to bias processing towards the M vs. P system, respectively. Based on our previous findings, we predicted the following: (1) steeper ΔC vs. C functions with the pulsed than the steady pedestal due to different task demands; (2) lower ΔCs in the upper-right vs. lower-left quadrant due to its bias towards P-system processing there; (3) no effect of color, since both paradigms track the P-system; and, most importantly (4) contrast gain should not be higher for the steady than for the pulsed pedestal. In general, our predictions were confirmed, replicating our previous findings and providing further evidence questioning the general validity of using the pulsed- and steady-pedestal paradigms to differentiate the P and M systems.
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Affiliation(s)
- Jaeseon Song
- Department of Psychology, University of Georgia, Athens, GA 30602, USA;
| | | | - James M. Brown
- Department of Psychology, University of Georgia, Athens, GA 30602, USA;
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Ye Q, Xu K, Chen Z, Liu Z, Fan Y, Liu P, Yu M, Yang Y. Early impairment of magnocellular visual pathways mediated by isolated-check visual evoked potentials in primary open-angle glaucoma: a cross-sectional study. BMJ Open Ophthalmol 2024; 9:e001463. [PMID: 38237934 PMCID: PMC10806665 DOI: 10.1136/bmjophth-2023-001463] [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: 08/16/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024] Open
Abstract
OBJECTIVE To explore different performances in the magnocellular (MC) and parvocellular (PC) visual pathways in patients with primary open-angle glaucoma (POAG) and to objectively assess impairment in early stage of POAG. METHODS AND ANALYSIS This is a cross-sectional study. MC and PC visual pathways were assessed using isolated-check visual evoked potential (ic-VEP). Visual acuity, intraocular pressure, fundus examination, optical coherence tomography and visual field were measured. Signal-to-noise ratios (SNRs), mediated by ic-VEP were recorded. The Spearman's correlation analysis was used to estimate the relationships between visual functions and structures. Receiver-operating-characteristic (ROC) curves were used to estimate the accuracy in detection of early POAG. RESULTS 60 participants (30 early POAG eyes and 30 age-matched control subjects) were recruited. MC visual pathway showed a non-linear response function, while PC visual pathway was a linear response function as contrast increased. Early POAG eyes exhibited significantly weaker initial contrast gains and lower maximum responses in the MC visual pathway (p=0.001, p=0.004, respectively). The SNRs at 8% and 32% depths of modulation (DOM) were significantly correlated with temporal-side retinal nerve fibre layer (RNFL) thickness in early POAG in MC-biased stimulation (p=0.017, p=0.020, respectively). The areas under ROC of 16% DOM were 0.780 (sensitivity 80.0%, specificity 63.3%) with the cut-off SNR of 2.07. CONCLUSIONS The MC visual pathway was damaged in the early stage of POAG. The SNRs at 8% and 32% DOM of MC-biased stimulation were significantly correlated with temporal-side RNFL thickness in early POAG, which helped in understanding the mechanisms of visual impairment in the early stage of POAG.
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Affiliation(s)
- Qiaona Ye
- Department of Glaucoma, State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Kezheng Xu
- Department of Glaucoma, State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zidong Chen
- Department of Glaucoma, State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zitian Liu
- Department of Glaucoma, State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yanmei Fan
- Department of Glaucoma, State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Pingping Liu
- Department of Glaucoma, State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Minbin Yu
- Department of Glaucoma, State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yangfan Yang
- Department of Glaucoma, State Key Laboratory of Ophthalmology, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, Guangdong, China
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Song J, Breitmeyer BG, Brown JM. Examining Increment thresholds as a function of pedestal contrast under hypothetical parvo- and magnocellular-biased conditions. Atten Percept Psychophys 2024; 86:213-220. [PMID: 38030820 DOI: 10.3758/s13414-023-02819-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2023] [Indexed: 12/01/2023]
Abstract
Theoretically, the pulsed- and steady-pedestal paradigms are thought to track contrast-increment thresholds (ΔC) as a function of pedestal contrast (C) for the parvocellular (P) and magnocellular (M) systems, respectively, yielding linear ΔC versus C functions for the pulsed- and nonlinear functions for the steady-pedestal paradigm. A recent study utilizing these paradigms to isolate the P and M systems reported no evidence of the M system being suppressed by red light, contrary to previous physiological and psychophysical findings. Curious as to why this may have occurred, we examined how ΔC varies with C for the P and M systems using the pulsed- and steady-pedestal paradigms and stimuli biased towards the P or M systems based on their sensitivity to spatial frequency (SF) and color. We found no effect of color and little influence of SF. To explain this lack of color effects, we used a quantitative model of ΔC (as it changes with C) to obtain Csat and contrast-gain values. The contrast-gain values (i) contradicted the hypothesis that the steady-pedestal paradigm tracks the M-system response, and (ii) our obtained Csat values indicated strongly that both pulsed- and steady-pedestal paradigms track primarily the P-system response.
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Affiliation(s)
- Jaeseon Song
- Department of Psychology, University of Georgia, Athens, GA, 30602-3013, USA.
| | - Bruno G Breitmeyer
- Department of Psychology, University of Houston, Houston, TX, 77204-5022, USA
| | - James M Brown
- Department of Psychology, University of Georgia, Athens, GA, 30602-3013, USA
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Soucy JR, Aguzzi EA, Cho J, Gilhooley MJ, Keuthan C, Luo Z, Monavarfeshani A, Saleem MA, Wang XW, Wohlschlegel J, Baranov P, Di Polo A, Fortune B, Gokoffski KK, Goldberg JL, Guido W, Kolodkin AL, Mason CA, Ou Y, Reh TA, Ross AG, Samuels BC, Welsbie D, Zack DJ, Johnson TV. Retinal ganglion cell repopulation for vision restoration in optic neuropathy: a roadmap from the RReSTORe Consortium. Mol Neurodegener 2023; 18:64. [PMID: 37735444 PMCID: PMC10514988 DOI: 10.1186/s13024-023-00655-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/07/2023] [Indexed: 09/23/2023] Open
Abstract
Retinal ganglion cell (RGC) death in glaucoma and other optic neuropathies results in irreversible vision loss due to the mammalian central nervous system's limited regenerative capacity. RGC repopulation is a promising therapeutic approach to reverse vision loss from optic neuropathies if the newly introduced neurons can reestablish functional retinal and thalamic circuits. In theory, RGCs might be repopulated through the transplantation of stem cell-derived neurons or via the induction of endogenous transdifferentiation. The RGC Repopulation, Stem Cell Transplantation, and Optic Nerve Regeneration (RReSTORe) Consortium was established to address the challenges associated with the therapeutic repair of the visual pathway in optic neuropathy. In 2022, the RReSTORe Consortium initiated ongoing international collaborative discussions to advance the RGC repopulation field and has identified five critical areas of focus: (1) RGC development and differentiation, (2) Transplantation methods and models, (3) RGC survival, maturation, and host interactions, (4) Inner retinal wiring, and (5) Eye-to-brain connectivity. Here, we discuss the most pertinent questions and challenges that exist on the path to clinical translation and suggest experimental directions to propel this work going forward. Using these five subtopic discussion groups (SDGs) as a framework, we suggest multidisciplinary approaches to restore the diseased visual pathway by leveraging groundbreaking insights from developmental neuroscience, stem cell biology, molecular biology, optical imaging, animal models of optic neuropathy, immunology & immunotolerance, neuropathology & neuroprotection, materials science & biomedical engineering, and regenerative neuroscience. While significant hurdles remain, the RReSTORe Consortium's efforts provide a comprehensive roadmap for advancing the RGC repopulation field and hold potential for transformative progress in restoring vision in patients suffering from optic neuropathies.
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Affiliation(s)
- Jonathan R Soucy
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Erika A Aguzzi
- The Institute of Ophthalmology, University College London, London, England, UK
| | - Julie Cho
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Michael James Gilhooley
- The Institute of Ophthalmology, University College London, London, England, UK
- Moorfields Eye Hospital, London, England, UK
| | - Casey Keuthan
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ziming Luo
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Aboozar Monavarfeshani
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
- Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA
| | - Meher A Saleem
- Bascom Palmer Eye Institute, University of Miami Health System, Miami, FL, USA
| | - Xue-Wei Wang
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Petr Baranov
- Department of Ophthalmology, Schepens Eye Research Institute of Mass. Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, QC, Canada
- University of Montreal Hospital Research Centre, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Health, Portland, OR, USA
| | - Kimberly K Gokoffski
- Department of Ophthalmology, Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Jeffrey L Goldberg
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - William Guido
- Department of Anatomical Sciences and Neurobiology, School of Medicine, University of Louisville, Louisville, KY, USA
| | - Alex L Kolodkin
- The Solomon H Snyder, Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carol A Mason
- Departments of Pathology and Cell Biology, Neuroscience, and Ophthalmology, College of Physicians and Surgeons, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Thomas A Reh
- Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Ahmara G Ross
- Departments of Ophthalmology and Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian C Samuels
- Department of Ophthalmology and Visual Sciences, Callahan Eye Hospital, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Derek Welsbie
- Shiley Eye Institute and Viterbi Family Department of Ophthalmology, University of California, San Diego, CA, USA
| | - Donald J Zack
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas V Johnson
- Departments of Neuroscience, Molecular Biology & Genetics, and Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Cellular & Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, 21287 MD, USA.
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Lee BB, Swanson WH. Detection and discrimination of achromatic contrast: A ganglion cell perspective. J Vis 2022; 22:11. [PMID: 35848903 PMCID: PMC9308016 DOI: 10.1167/jov.22.8.11] [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: 11/24/2022] Open
Abstract
The magnocellular (MC) pathway in the primate has much higher achromatic contrast sensitivity than the parvocellular (PC) pathway, and is implicated in luminance contrast detection. But MC pathway responses tend to saturate at lower achromatic contrast than do PC pathway responses. It has been proposed that the PC pathway plays a major role in discriminating suprathreshold achromatic contrast, because the MC pathway is in saturation. This has been termed the pulsed-pedestal protocol. To test this hypothesis, responses of MC and PC pathway ganglion cells have been examined under suprathreshold conditions with stimulus configurations similar to those in psychophysical tests. For MC cells, response saturation was much less for flashed or moving edges than for sinusoidal modulation, and MC cell thresholds predicted for these stimuli were similar to psychophysical discrimination (and detection) data. Results suggest the protocol is not effective in segregating MC and PC function.
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Affiliation(s)
- Barry B Lee
- Graduate Center for Vision Research, Department of Biological Sciences, SUNY College of Optometry, New York, NY, USA.,Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,
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Brooks CJ, Chan YM, Fielding J, White OB, Badcock DR, McKendrick AM. Visual contrast perception in visual snow syndrome reveals abnormal neural gain but not neural noise. Brain 2021; 145:1486-1498. [PMID: 34633444 DOI: 10.1093/brain/awab383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 09/17/2021] [Accepted: 09/21/2021] [Indexed: 11/14/2022] Open
Abstract
Visual snow syndrome is a neurological condition characterised by a persistent visual disturbance, visual snow, in conjunction with additional visual symptoms. Cortical hyperexcitability is a potential pathophysiological mechanism, which could be explained by increased gain in neural responses to visual input. Alternatively, neural noise in the visual pathway could be abnormally elevated. We assessed these two potential competing neural mechanisms in our studies of visual contrast perception. Cortical hyperexcitation also occurs in migraine, which commonly co-occurs with visual snow syndrome. Therefore, to determine whether the effect of visual snow syndrome can be distinguished from interictal migraine, we recruited four participant groups: controls, migraine alone, visual snow syndrome alone, visual snow syndrome with migraine. In the first experiment, we estimated internal noise in 20 controls, 21 migraine participants, 32 visual snow syndrome participants (16 with migraine) using a luminance increment detection task. In the second experiment, we estimated neural contrast gain in 21 controls, 22 migraine participants, 35 visual snow syndrome participants (16 with migraine) using tasks assessing sensitivity to changes in contrast from a reference. Contrast gain and sensitivity were measured for the putative parvocellular and ON and OFF magnocellular pathways, respectively. We found that luminance increment thresholds and internal noise estimates were normal in both visual snow syndrome and migraine. Contrast gain measures for putative parvocellular processing and contrast sensitivity for putative OFF magnocellular processing were abnormally increased in visual snow syndrome, regardless of migraine status. Therefore, our results indicate that visual snow syndrome is characterised by increased neural contrast gain but not abnormal neural noise within the targeted pathways.
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Affiliation(s)
- Cassandra J Brooks
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Australia
| | - Yu Man Chan
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Australia
| | - Joanne Fielding
- Department of Neurosciences, Central Clinical School, Monash University, Melbourne, Australia
| | - Owen B White
- Department of Neurosciences, Central Clinical School, Monash University, Melbourne, Australia
| | - David R Badcock
- School of Psychological Science, The University of Western Australia, Crawley, Western Australia
| | - Allison M McKendrick
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Australia
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7
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Huchzermeyer C, Horn F, Lämmer R, Mardin C, Kremers J. Summation of Temporal L-Cone- and M-Cone-Contrast in the Magno- and Parvocellular Retino-Geniculate Systems in Glaucoma. Invest Ophthalmol Vis Sci 2021; 62:17. [PMID: 33988692 PMCID: PMC8132014 DOI: 10.1167/iovs.62.6.17] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Purpose The purpose of this study was to characterize summation of temporal L- and M-cone contrasts in the parvo- (P-) and magnocellular (M-) pathways in glaucoma and the relationship between the respective temporal contrast sensitivities (tCS) and clinical parameters. Methods Perifoveal tCS to isolated or combined L- and M-cone contrasts (with different contrast ratios, and therefore different luminance and chromatic components) were measured at different temporal frequencies (at 1 or 2 Hz and at 20 Hz) using triple silent substitution in 73 subjects (13 healthy, 25 with glaucoma, and 35 with perimetric glaucoma). A vector summation model was used to analyze whether perception was driven by the P-pathway, the M-pathway, or both. Using this model, L- and M-cone input strengths (AL, AM) and phase differences between L- and M-cone inputs were estimated. Results Perception was always mediated by the P-pathway at low frequencies, as indicated by a median phase angle of 179.84 degrees (cone opponency) and a median AL/AM ratio of 1.04 (balanced L- and M-cone input strengths). In contrast, perception was exclusively mediated by the M-pathway at higher frequencies (input strength not balanced: AL/AM = 2.94, median phase angles = 130.17 degrees). Differences in phase were not significant between diagnosis groups (Kruskal-Wallis = 0.092 for P- and 0.35 for M-pathway). We found differences between groups only for the M-pathway (L-cone tCS deviations at 20 Hz were significantly lower in the patients with glaucoma P = 0.014, with a strong tendency in M-cones P = 0.049). L-cone driven tCS deviations at 20 Hz were linearly correlated with perimetric mean defect (MD) and quadratically correlated with retinal nerve fiber layer (RNFL) thickness. Conclusions Unaltered phase angles between L- and M-cone inputs in glaucoma indicated intact temporal processing. Only in the M-pathway, contrast sensitivity deviations were closely related to diagnosis group, MD, and RNFL thickness, indicating M-pathway involvement.
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Affiliation(s)
- Cord Huchzermeyer
- Department of Ophthalmology, University Hospital Erlangen, Germany.,Friedrich-Alexander-University Erlangen-Nürnberg, Germany
| | - Folkert Horn
- Department of Ophthalmology, University Hospital Erlangen, Germany.,Friedrich-Alexander-University Erlangen-Nürnberg, Germany
| | - Robert Lämmer
- Department of Ophthalmology, University Hospital Erlangen, Germany.,Friedrich-Alexander-University Erlangen-Nürnberg, Germany
| | - Christian Mardin
- Department of Ophthalmology, University Hospital Erlangen, Germany.,Friedrich-Alexander-University Erlangen-Nürnberg, Germany
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Germany.,Friedrich-Alexander-University Erlangen-Nürnberg, Germany
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Retinal ganglion cell dysfunction in mice following acute intraocular pressure is exacerbated by P2X7 receptor knockout. Sci Rep 2021; 11:4184. [PMID: 33603067 PMCID: PMC7893065 DOI: 10.1038/s41598-021-83669-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/22/2020] [Indexed: 12/21/2022] Open
Abstract
There is increasing evidence for the vulnerability of specific retinal ganglion cell (RGC) types in those with glaucoma and in animal models. In addition, the P2X7-receptor (P2X7-R) has been suggested to contribute to RGC death following stimulation and elevated IOP, though its role in RGC dysfunction prior to death has not been examined. Therefore, we examined the effect of an acute, non-ischemic intraocular pressure (IOP) insult (50 mmHg for 30 min) on RGC function in wildtype mice and P2X7-R knockout (P2X7-KO) mice. We examined retinal function using electroretinogram recordings and individual RGC responses using multielectrode arrays, 3 days following acute IOP elevation. Immunohistochemistry was used to examine RGC cell death and P2X7-R expression in several RGC types. Acute intraocular pressure elevation produced pronounced dysfunction in RGCs; whilst other retinal neuronal responses showed lesser changes. Dysfunction at 3 days post-injury was not associated with RGC loss or changes in receptive field size. However, in wildtype animals, OFF-RGCs showed reduced spontaneous and light-elicited activity. In the P2X7-KO, both ON- and OFF-RGC light-elicited responses were reduced. Expression of P2X7-R in wildtype ON-RGC dendrites was higher than in other RGC types. In conclusion, OFF-RGCs were vulnerable to acute IOP elevation and their dysfunction was not rescued by genetic ablation of P2X7-R. Indeed, knockout of P2X7-R also caused ON-RGC dysfunction. These findings aid our understanding of how pressure affects RGC function and suggest treatments targeting the P2X7-R need to be carefully considered.
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Kong AW, Della Santina L, Ou Y. Probing ON and OFF Retinal Pathways in Glaucoma Using Electroretinography. Transl Vis Sci Technol 2020; 9:14. [PMID: 33117606 PMCID: PMC7571283 DOI: 10.1167/tvst.9.11.14] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/14/2020] [Indexed: 12/31/2022] Open
Abstract
Glaucoma is a progressive neurodegenerative disease involving damage and eventually death of retinal ganglion cells (RGCs) that comprise the optic nerve. This review summarizes current understanding of specific RGC type vulnerability in glaucoma and how electroretinography (ERG) may provide an objective measure of these functional perturbations. There is building evidence to suggest that ON RGCs, which respond to light increments, may be more resilient to elevated intraocular pressure and glaucoma, whereas OFF RGCs, which respond to light decrements, may be more susceptible. ERG experiments in nonhuman primates and mice have also shown that the ON- and OFF-pathways can be separated using a variety of techniques such as pattern ERG and the photopic negative response. Another ERG paradigm of interest to separate the ON and OFF responses is a flicker stimulus at varying temporal frequencies. Response to lower temporal frequencies is associated with the ON-pathway, and ERG response to higher frequencies is associated with the OFF-pathway. In mice, experimental glaucoma models have shown greater decreases in ERG response at higher frequencies, suggesting that the OFF-pathway is more susceptible. We also summarize current clinical ERG protocols used for glaucoma and discuss innovations for developing new types of stimuli that can further separate the ON- and OFF-pathways. Applying these novel paradigms that distinguish ON- and OFF-pathways may ultimately improve glaucoma diagnostics and monitoring of glaucoma progression.
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Affiliation(s)
- Alan W Kong
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA
| | - Luca Della Santina
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA
| | - Yvonne Ou
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, USA
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10
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Yuan N, Li M, Chen X, Lu Y, Fang Y, Gong H, Qian L, Wu J, Zhang S, Shipp S, Andolina IM, Sun X, Wang W. Immediate Impact of Acute Elevation of Intraocular Pressure on Cortical Visual Motion Processing. Invest Ophthalmol Vis Sci 2020; 61:59. [PMID: 32462199 PMCID: PMC7405714 DOI: 10.1167/iovs.61.5.59] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Purpose To physiologically examine the impairment of cortical sensitivity to visual motion during acute elevation of intraocular pressure (IOP). Methods Motion processing in the cat brain is well characterized, its X and Y cell visual pathways being functionally analogous to parvocellular and magnocellular pathways in primates. Using this model, we performed ocular anterior chamber perfusion to reversibly elevate IOP over a range from 30 to 90 mm Hg while monitoring cortical activity with intrinsic signal optical imaging. Drifting random-dot fields and gratings were used to characterize cortical population responses to motion direction and orientation in early visual areas 17 and 18. Results We found that acute IOP elevations at 50 mm Hg and above, which is often observed in acute glaucoma, suppressed cortical motion direction responses. This suppression was more profound in area 17 than in area 18, and more profound in central than peripheral visual field (eccentricities 0°–4° vs. 4°–8°) within area 17. In addition, orientation responses were more suppressed than motion direction responses for the same IOP modulation. Conclusions In contrast to human chronic glaucoma that may cause greater dysfunction in large-cell magnocellular than in small-cell parvocellular visual pathways, our direct measurement of cortical processing networks implies that the small X-cell pathway shows greater vulnerability to acute IOP elevation than the large Y-cell pathway in visual motion processing. The results demonstrate that fine discrimination mechanisms for motion in the central visual field are particularly impacted by acute IOP attacks, suggesting a neural basis for immediate visual deficits in the fine motion perception of acute glaucoma patients.
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11
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Bham HA, Dewsbery SD, Denniss J. Unaltered Perception of Suprathreshold Contrast in Early Glaucoma Despite Sensitivity Loss. Invest Ophthalmol Vis Sci 2020; 61:23. [PMID: 32676636 PMCID: PMC7425759 DOI: 10.1167/iovs.61.8.23] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Glaucoma raises contrast detection thresholds, but our natural visual environment is dominated by high contrast that may remain suprathreshold in early to moderate glaucoma. This study investigates the effect of glaucoma on the apparent contrast of visible stimuli. Methods Twenty participants with glaucoma with partial visual field defects (mean age, 72 ± 7 years) and 20 age‐similar healthy controls (mean age, 70 ± 7 years) took part. Contrast detection thresholds for Gabor stimuli (SD, 0.75°) of four spatial frequencies (0.5, 1.0, 2.0, and 4.0 c/deg) were first measured at 10° eccentricity, both within and outside of visual field defects for participants with glaucoma. Subsequently, the contrast of a central Gabor was matched to that of a peripheral Gabor with contrast fixed at two times or four times the detection threshold. Data were analyzed by linear mixed modelling. Results Compared with controls, detection thresholds for participants with glaucoma were raised by 0.05 ± 0.025 (Michelson units, ± SE; P = 0.12) and by 0.141 ± 0.026 (P < 0.001) outside and within visual field defects, respectively. For reference stimuli at two times the detection contrast, matched contrast ratios (matched/reference contrast) were 0.16 ± 0.039 (P < 0.001) higher outside compared with within visual field defects in participants with glaucoma. Matched contrast ratios within visual field defects were similar to controls (mean 0.033 ± 0.066 lower; P = 0.87). For reference stimuli at four times the detection contrast, matched contrast ratios were similar across all three groups (P = 0.58). Spatial frequency had a minimal effect on matched contrast ratios. Conclusions Despite decreased contrast sensitivity, people with glaucoma perceive the contrast of visible suprathreshold stimuli similarly to healthy controls. These results suggest possible compensation for sensitivity loss in the visual system.
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Wang AY, Lee PY, Bui BV, Jobling AI, Greferath U, Brandli A, Dixon MA, Findlay Q, Fletcher EL, Vessey KA. Potential mechanisms of retinal ganglion cell type-specific vulnerability in glaucoma. Clin Exp Optom 2019; 103:562-571. [PMID: 31838755 DOI: 10.1111/cxo.13031] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/17/2019] [Accepted: 11/16/2019] [Indexed: 12/22/2022] Open
Abstract
Glaucoma is a neurodegenerative disease characterised by progressive damage to the retinal ganglion cells (RGCs), the output neurons of the retina. RGCs are a heterogenous class of retinal neurons which can be classified into multiple types based on morphological, functional and genetic characteristics. This review examines the body of evidence supporting type-specific vulnerability of RGCs in glaucoma and explores potential mechanisms by which this might come about. Studies of donor tissue from glaucoma patients have generally noted greater vulnerability of larger RGC types. Models of glaucoma induced in primates, cats and mice also show selective effects on RGC types - particularly OFF RGCs. Several mechanisms may contribute to type-specific vulnerability, including differences in the expression of calcium-permeable receptors (for example pannexin-1, P2X7, AMPA and transient receptor potential vanilloid receptors), the relative proximity of RGCs and their dendrites to blood supply in the inner plexiform layer, as well as differing metabolic requirements of RGC types. Such differences may make certain RGCs more sensitive to intraocular pressure elevation and its associated biomechanical and vascular stress. A greater understanding of selective RGC vulnerability and its underlying causes will likely reveal a rich area of investigation for potential treatment targets.
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Affiliation(s)
- Anna Ym Wang
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Pei Ying Lee
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Andrew I Jobling
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Ursula Greferath
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Alice Brandli
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Michael A Dixon
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Quan Findlay
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Erica L Fletcher
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
| | - Kirstan A Vessey
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Australia
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13
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Normal tension glaucoma-like degeneration of the visual system in aged marmosets. Sci Rep 2019; 9:14852. [PMID: 31619716 PMCID: PMC6795850 DOI: 10.1038/s41598-019-51281-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 09/27/2019] [Indexed: 01/25/2023] Open
Abstract
The common marmoset (Callithrix jacchus) is a non-human primate that provides valuable models for neuroscience and aging research due to its anatomical similarities to humans and relatively short lifespan. This study was carried out to examine whether aged marmosets develop glaucoma, as seen in humans. We found that 11% of the aged marmosets presented with glaucoma-like characteristics; this incident rate is very similar to that in humans. Magnetic resonance imaging showed a significant volume loss in the visual cortex, and histological analyses confirmed the degeneration of the lateral geniculate nuclei and visual cortex in the affected marmosets. These marmosets did not have elevated intraocular pressure, but showed an increased oxidative stress level, low cerebrospinal fluid (CSF) pressure, and low brain-derived neurotrophic factor (BDNF) and TrkB expression in the retina, optic nerve head and CSF. Our findings suggest that marmosets have potential to provide useful information for the research of eye and the visual system.
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14
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Bierings RAJM, Overkempe T, van Berkel CM, Kuiper M, Jansonius NM. Spatial contrast sensitivity from star- to sunlight in healthy subjects and patients with glaucoma. Vision Res 2019; 158:31-39. [PMID: 30721742 DOI: 10.1016/j.visres.2019.01.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 01/26/2019] [Accepted: 01/30/2019] [Indexed: 02/08/2023]
Abstract
Glaucoma is traditionally considered an asymptomatic disease until later stages. However, questionnaire studies revealed visual complaints related to various tasks, especially under extreme luminance conditions (such as outdoor at night on an unlit road or outside in the sun). We measured contrast sensitivity (CS) over a luminance range of 6 log units spanning the scotopic to photopic range and we aimed (1) to determine whether Weber's law also holds under extremely high luminance conditions and (2) to compare CS as a function of spatial frequency and luminance between glaucoma patients and healthy subjects. We included 22 glaucoma patients and 51 controls, all with normal visual acuity. For the second aim, we used a subgroup of 22 age-similar controls. Vertically oriented sine-wave gratings were generated with a projector-based setup (stimulus size 8x5 degrees). CS was measured monocularly at 1, 3, and 10 cycles per degree (cpd); mean luminance ranged from 0.0085 to 8500 cd/m2. ANOVA was used to analyze the effect of glaucoma, luminance, and spatial frequency on logCS. In controls, Weber's law held for 3 and 10 cpd; for 1 cpd, CS dropped above 1000 cd/m2 (P = 0.003). The logCS versus log luminance curves did not differ grossly between patients and controls (P = 0.14; typically 0-0.2 log units); the difference became larger with decreasing luminance (P = 0.003) but did not depend clearly on spatial frequency (P = 0.27). We conclude that differences between glaucoma and healthy were relatively modest for the spatially redundant, static stimulus as used in the current study.
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Affiliation(s)
- R A J M Bierings
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - T Overkempe
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - C M van Berkel
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - M Kuiper
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - N M Jansonius
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
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15
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Lek JJ, Nguyen BN, McKendrick AM, Vingrys AJ. An Electrophysiological Comparison of Contrast Response Functions in Younger and Older Adults, and Those With Glaucoma. Invest Ophthalmol Vis Sci 2019; 60:442-450. [PMID: 30703209 DOI: 10.1167/iovs.17-23522] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Aging and glaucoma both result in contrast processing deficits. However, it is unclear the extent to which these functional deficits arise from retinal or post-retinal neuronal changes. This study aims to disentangle the effects of healthy human aging and glaucoma on retinal and post-retinal contrast processing using visual electrophysiology. Methods Steady-state pattern electroretinograms (PERG) and pattern visual evoked potentials (PVEP) were simultaneously recorded across a range of contrasts (0%, 4%, 9%, 18%, 39%, 73%, 97%; 0.8° diameter checks, 31° diameter checkerboard) in 13 glaucoma patients (67 ± 6 years), 15 older (63 ± 8 years) and 14 younger adults (27 ± 3 years). PERG and PVEP contrast response functions were fit with a linear and saturating hyperbolic model, respectively. PERG and PVEP magnitude, timing (phase), and model fit parameters (slope, semi-saturation constant) were compared between groups. Results PERG responses were reduced and delayed in older adults relative to younger adults, and further reduced and delayed in glaucoma patients across all contrasts. PVEP signals were also reduced and delayed in glaucoma patients, relative to age-similar (older) controls. However, despite having reduced PERG magnitudes, older adults did not demonstrate reduced PVEP magnitudes. Conclusions Older adults with healthy vision demonstrate reduced magnitude and delayed timing in the PERG that is not reflected in the PVEP. In contrast, glaucoma produces functional deficits in both PERG and PVEP contrast response functions. Our results suggest that glaucomatous effects on contrast processing are not a simple extension of those that arise as part of the aging process.
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Affiliation(s)
- Jia Jia Lek
- Department of Optometry & Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Bao N Nguyen
- Department of Optometry & Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Allison M McKendrick
- Department of Optometry & Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Algis J Vingrys
- Department of Optometry & Vision Sciences, The University of Melbourne, Parkville, Victoria, Australia
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16
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Bierings RAJM, de Boer MH, Jansonius NM. Visual Performance as a Function of Luminance in Glaucoma: The De Vries-Rose, Weber's, and Ferry-Porter's Law. ACTA ACUST UNITED AC 2018; 59:3416-3423. [DOI: 10.1167/iovs.17-22497] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Ronald A. J. M. Bierings
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Marije H. de Boer
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Nomdo M. Jansonius
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
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17
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La Morgia C, Di Vito L, Carelli V, Carbonelli M. Patterns of Retinal Ganglion Cell Damage in Neurodegenerative Disorders: Parvocellular vs Magnocellular Degeneration in Optical Coherence Tomography Studies. Front Neurol 2017; 8:710. [PMID: 29312131 PMCID: PMC5744067 DOI: 10.3389/fneur.2017.00710] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/08/2017] [Indexed: 12/02/2022] Open
Abstract
Many neurodegenerative disorders, such as Parkinson’s disease (PD) and Alzheimer’s disease (AD), are characterized by loss of retinal ganglion cells (RGCs) as part of the neurodegenerative process. Optical coherence tomography (OCT) studies demonstrated variable degree of optic atrophy in these diseases. However, the pattern of degenerative changes affecting the optic nerve (ON) can be different. In particular, neurodegeneration is more evident for magnocellular RGCs in AD and multiple system atrophy with a pattern resembling glaucoma. Conversely, in PD and Huntington’s disease, the parvocellular RGCs are more vulnerable. This latter pattern closely resembles that of mitochondrial optic neuropathies, possibly pointing to similar pathogenic mechanisms. In this review, the currently available evidences on OCT findings in these neurodegenerative disorders are summarized with particular emphasis on the different pattern of RGC loss. The ON degeneration could become a validated biomarker of the disease, which may turn useful to follow natural history and possibly assess therapeutic efficacy.
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Affiliation(s)
- Chiara La Morgia
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Neurology Unit, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Lidia Di Vito
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
| | - Valerio Carelli
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Neurology Unit, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Michele Carbonelli
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy
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18
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Siah WF, O'Brien C, Loughman JJ. Macular pigment is associated with glare-affected visual function and central visual field loss in glaucoma. Br J Ophthalmol 2017; 102:929-935. [PMID: 28982957 DOI: 10.1136/bjophthalmol-2017-310215] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 09/03/2017] [Accepted: 09/21/2017] [Indexed: 11/03/2022]
Abstract
AIM To evaluate the relationship between macular pigment optical density (MPOD) and glare disability in open-angle glaucoma. METHODS A cross-sectional analysis of baseline data (88 subjects; median age, 67 (range 36-84) years) collected during the Macular Pigment and Glaucoma Trial (ISRCTN registry number: 56985060). MPOD at 0.25°, 0.5° and 1° of retinal eccentricity was measured using customised heterochromatic flicker photometry. Mesopic contrast sensitivity with glare (mCSg), photostress recovery time (PRT) and self-reported glare symptoms were evaluated. Fourier-domain optical coherence tomography was used to analyse ganglion cell complex (GCC) and identify foveal involvement. RESULTS Low spatial frequency (f) mCSg was significantly correlated with MPOD at 0.25°(3 cycles per degree (cpd): r=0.25, p=0.04) and 0.5° (3 cpd: r=0.23, p=0.04) of retinal eccentricity. Those with foveal GCC loss exhibited lower MPOD, had worse low spatial fmCSg (1.5 cpd and 3 cpd, p=0.02 each) and prolonged PRT (p=0.02) in comparison with those without foveal involvement. The depth of central 10° field loss was related to MPOD at all eccentricities (p<0.01 for all). Those who reported glare symptoms had a significantly lower MPOD at all retinal eccentricities (0.25° and 1°: p=0.05 each; 0.5°: p=0.04), including those with foveal involvement (0.25°: p=0.05; 0.5°: p<0.01; 1°: p=0.01). CONCLUSIONS Macular pigment level may be an important consideration among those experiencing disability glare in glaucoma, including those with foveal involvement. TRIAL REGISTRATION NUMBER ISRCTN56985060, Post-results.
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Affiliation(s)
- We Fong Siah
- Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Colm O'Brien
- Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland.,School of Medicine, University College Dublin, Dublin, Ireland
| | - James J Loughman
- School of Physics, Clinical and Optometric Sciences, College of Sciences and Health, Dublin Institute of Technology, Dublin, Ireland.,Faculty of Health Sciences, African Vision Research Institute, University of KwaZulu-Natal, Durban, South Africa
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19
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Accuracy of isolated-check visual evoked potential technique for diagnosing primary open-angle glaucoma. Doc Ophthalmol 2017; 135:107-119. [PMID: 28702796 DOI: 10.1007/s10633-017-9598-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 06/19/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE The aim of this study was to determine the diagnostic accuracy, sensitivity and specificity of isolated-check visual evoked potentials (icVEP) in primary open-angle glaucoma (POAG). METHODS Ninety POAG patients and sixty-six healthy controls were recruited consecutively. All subjects underwent icVEP and visual field testing. Swept icVEP response functions were obtained by increasing contrast in six stimulus steps, recording the electroencephalogram synchronized to the stimulus display's frame rate and calculating the corresponding signal-to-noise ratio (SNR) of the response at the fundamental frequency to evaluate visual function. Depth of modulation of the check luminance was increased as follows: 2, 4, 8, 14, 22 and 32%, about an equal level of standing contrast, so that the pattern appeared and disappeared at a frequency of 10.0 Hz. SNR above 0.85 was deemed to be significant at the 0.1 level and SNR above 1 significant at the 0.05 level. RESULTS The results show that SNR is contrast dependent. It significantly rose as contrast increased. The areas under receiver-operating-characteristic curves (AUCs) indicating classification accuracy for all POAG cases in comparison with normal subjects were 0.790 (sensitivity 91.1%, specificity 69.7%) with the cutoff SNR of 0.85, and 0.706 (sensitivity 95.6%, specificity 51.5%) with the cutoff SNR of 1. The AUC of early glaucoma cases (EG) in comparison with normal subjects was 0.801 (sensitivity 93.3%, specificity 69.7%) with the cutoff SNR of 0.85, and 0.717 (sensitivity 97.8%, specificity 51.5%) with the cutoff SNR of 1. CONCLUSION icVEP has good diagnostic accuracy (high sensitivity and moderate specificity) in distinguishing early POAG patients from healthy subjects. It might be a promising device to use in conjunction with complementary functional and structural measures for early POAG detection.
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20
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Lenoble Q, Lek JJ, McKendrick AM. Visual object categorisation in people with glaucoma. Br J Ophthalmol 2016; 100:1585-1590. [DOI: 10.1136/bjophthalmol-2015-308289] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 06/14/2016] [Accepted: 07/18/2016] [Indexed: 11/03/2022]
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21
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Denniss J, Astle AT. Central perimetric sensitivity estimates are directly influenced by the fixation target. Ophthalmic Physiol Opt 2016; 36:453-8. [DOI: 10.1111/opo.12304] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/18/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Jonathan Denniss
- Visual Neuroscience Group; School of Psychology; University of Nottingham; Nottingham UK
| | - Andrew T. Astle
- Visual Neuroscience Group; School of Psychology; University of Nottingham; Nottingham UK
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22
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Junoy Montolio FG, Meems W, Janssens MSA, Stam L, Jansonius NM. Lateral Inhibition in the Human Visual System in Patients with Glaucoma and Healthy Subjects: A Case-Control Study. PLoS One 2016; 11:e0151006. [PMID: 26953590 PMCID: PMC4783060 DOI: 10.1371/journal.pone.0151006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 02/21/2016] [Indexed: 11/18/2022] Open
Abstract
In glaucoma, the density of retinal ganglion cells is reduced. It is largely unknown how this influences retinal information processing. An increase in spatial summation and a decrease in contrast gain control and contrast adaptation have been reported. A decrease in lateral inhibition might also arise. This could result in a larger than expected response to some stimuli, which could mask ganglion cell loss on functional testing (structure-function discrepancy). The aim of this study was to compare lateral inhibition between glaucoma patients and healthy subjects; we used a case-control design. Cases (n = 18) were selected to have advanced visual field loss in combination with a normal visual acuity. Controls (n = 50) were not allowed to have symptoms or signs of any eye disease. Lateral inhibition was measured psychophysically on a computer screen, with (1) a modified illusory movement experiment and (2) a contrast sensitivity (CS) test. Illusory movement was quantified by nulling it with a real movement; measure of lateral inhibition was the amount of illusory movement. CS was measured at 1 and 4 cycles per degree (cpd); measure of lateral inhibition was the difference between log CS at 4 and 1 cpd. Both measures were compared between cases and controls; analyses were adjusted for age and gender. There was no difference between cases and controls for these two measures of lateral inhibition (p = 0.58 for illusory movement; p = 0.20 for CS). The movement threshold was higher in cases than in controls (p = 0.008) and log CS was lower, at both 1 (-0.20; p = 0.008) and 4 (-0.28; p = 0.001) cpd. Our results indicate that spatially antagonistic mechanisms are not specifically affected in glaucoma, at least not in the intact center of a severely damaged visual field. This suggests that the structure-function discrepancy in glaucoma is not related to a decrease in lateral inhibition.
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Affiliation(s)
- Francisco G. Junoy Montolio
- Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Wilma Meems
- Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Marieke S. A. Janssens
- Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Lucas Stam
- Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Nomdo M. Jansonius
- Dept. of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
- Dept. of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands
- * E-mail:
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23
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Abe RY, Gracitelli CPB, Diniz-Filho A, Zangwill LM, Weinreb RN, Medeiros FA. Frequency Doubling Technology Perimetry and Changes in Quality of Life of Glaucoma Patients: A Longitudinal Study. Am J Ophthalmol 2015; 160:114-122.e1. [PMID: 25868760 DOI: 10.1016/j.ajo.2015.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 04/03/2015] [Accepted: 04/06/2015] [Indexed: 11/17/2022]
Abstract
PURPOSE To evaluate the relationship between rates of change on frequency doubling technology (FDT) perimetry and longitudinal changes in quality of life (QoL) of glaucoma patients. DESIGN Prospective observational cohort study. METHODS One hundred fifty-two subjects (127 glaucoma and 25 healthy) were followed for an average of 3.2 ± 1.1 years. All subjects were evaluated with National Eye Institute Visual Function Questionnaire (NEI VFQ-25), FDT, and standard automated perimetry (SAP). Glaucoma patients had a median of 3 NEI VFQ-25, 8 FDT, and 8 SAP tests during follow-up. Mean sensitivities of the integrated binocular visual fields were estimated for FDT and SAP and used to calculate rates of change. A joint longitudinal multivariable mixed model was used to investigate the association between change in binocular mean sensitivities and change in NEI VFQ-25 Rasch-calibrated scores. RESULTS There was a statistically significant correlation between change in binocular mean sensitivity for FDT and change in NEI VFQ-25 scores during follow-up in the glaucoma group. In multivariable analysis with the confounding factors, each 1 dB/year change in binocular FDT mean sensitivity corresponded to a change of 0.8 units per year in the NEI VFQ-25 scores (P = .001). For binocular SAP mean sensitivity, each 1 dB/year change was associated with 2.4 units per year change in NEI VFQ-25 scores (P < .001). The multivariable model containing baseline and rate of change information from SAP had stronger ability to predict change in NEI VFQ-25 scores compared to the equivalent model for FDT (R(2) of 50% and 30%, respectively; P = .001). CONCLUSION SAP performed significantly better than FDT in predicting change in NEI VFQ-25 scores in our population, suggesting that it may still be the preferable perimetric technique for predicting risk of disability from the disease.
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Affiliation(s)
- Ricardo Y Abe
- Department of Ophthalmology, Visual Performance Laboratory and Hamilton Glaucoma Center, University of California, San Diego, La Jolla, California
| | - Carolina P B Gracitelli
- Department of Ophthalmology, Visual Performance Laboratory and Hamilton Glaucoma Center, University of California, San Diego, La Jolla, California
| | - Alberto Diniz-Filho
- Department of Ophthalmology, Visual Performance Laboratory and Hamilton Glaucoma Center, University of California, San Diego, La Jolla, California
| | - Linda M Zangwill
- Department of Ophthalmology, Visual Performance Laboratory and Hamilton Glaucoma Center, University of California, San Diego, La Jolla, California
| | - Robert N Weinreb
- Department of Ophthalmology, Visual Performance Laboratory and Hamilton Glaucoma Center, University of California, San Diego, La Jolla, California
| | - Felipe A Medeiros
- Department of Ophthalmology, Visual Performance Laboratory and Hamilton Glaucoma Center, University of California, San Diego, La Jolla, California.
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24
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Dul M, Ennis R, Radner S, Lee B, Zaidi Q. Retinal adaptation abnormalities in primary open-angle glaucoma. Invest Ophthalmol Vis Sci 2015; 56:1329-34. [PMID: 25613950 DOI: 10.1167/iovs.14-15725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Dynamic color and brightness adaptation are crucial for visual functioning. The effects of glaucoma on retinal ganglion cells (RGCs) could compromise these functions. We have previously used slow dynamic changes of light at moderate intensities to measure the speed and magnitude of subtractive adaptation in RGCs. We used the same procedure to test if RGC abnormalities cause slower and weaker adaptation for patients with glaucoma when compared to age-similar controls. We assessed adaptation deficits in specific classes of RGCs by testing along the three cardinal color axes that isolate konio, parvo, and magno RGCs. METHODS For one eye each of 10 primary open-angle glaucoma patients and their age-similar controls, we measured the speed and magnitude of adapting to 1/32 Hz color modulations along the three cardinal axes, at central fixation and 8° superior, inferior, nasal, and temporal to fixation. RESULTS In all 15 comparisons (5 locations × 3 color axes), average adaptation was slower and weaker for glaucoma patients than for controls. Adaptation developed slower at central targets than at 8° eccentricities for controls, but not for patients. Adaptation speed and magnitude differed between affected and control eyes even at retinal locations showing no visual field loss with clinical perimetry. CONCLUSIONS Neural adaptation is weaker in glaucoma patients for all three classes of RGCs. Since adaptation abnormalities are manifested even at retinal locations not exhibiting a visual field loss, this novel form of assessment may offer a functional insight into glaucoma and an early diagnosis tool.
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Affiliation(s)
- Mitchell Dul
- Department of Biological & Visual Sciences and Graduate Center for Vision Research, State University of New York College of Optometry, New York, New York, United States
| | - Robert Ennis
- Department of Biological & Visual Sciences and Graduate Center for Vision Research, State University of New York College of Optometry, New York, New York, United States
| | - Shira Radner
- Department of Biological & Visual Sciences and Graduate Center for Vision Research, State University of New York College of Optometry, New York, New York, United States
| | - Barry Lee
- Department of Biological & Visual Sciences and Graduate Center for Vision Research, State University of New York College of Optometry, New York, New York, United States
| | - Qasim Zaidi
- Department of Biological & Visual Sciences and Graduate Center for Vision Research, State University of New York College of Optometry, New York, New York, United States
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25
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Transcranial direct current stimulation can selectively affect different processing channels in human visual cortex. Exp Brain Res 2015; 233:1213-23. [DOI: 10.1007/s00221-015-4199-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 01/07/2015] [Indexed: 12/14/2022]
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26
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Danias J, Serle J. Can Visual Field Progression be Predicted by Confocal Scanning Laser Ophthalmoscopic Imaging of the Optic Nerve Head in Glaucoma? (An American Ophthalmological Society Thesis). TRANSACTIONS OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY 2015; 113:T4. [PMID: 26549913 PMCID: PMC4622448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
PURPOSE To determine whether confocal scanning laser ophthalmoscopic imaging (Heidelberg retinal tomography [HRT]) can predict visual field change in glaucoma. METHODS The study included 561 patients with glaucoma or ocular hypertension whose clinical course was followed at the Mount Sinai Faculty practice. Humphrey visual fields (HVFs) and HRT images were collected on one randomly selected eye per patient. Glaucoma progression was determined by the presence of two sequential statistically significant negative slopes in mean deviation (MD) or visual field index (VFI) at any point during the study period. Trend-based analysis on HRT parameters was used to determine progressive changes and whether these occurred before or after HVF change. Sensitivity and specificity of HRT to predict HVF change were calculated. HVF rate of change was correlated to the rate of change detected by HRT imaging. RESULTS Approximately 17% of patients progressed by either MD or VFI criteria. MD and VFI correlated highly and identified overlapping sets of patients as progressing. HRT global parameters had poor sensitivity (∼42%) and moderate specificity (∼67%) to predict HVF progression. Regional stereometric parameters were more sensitive (69%-78%) but significantly less specific (24%-27%). Sensitivity of global stereometric parameters in detecting HVF change was not significantly affected by the level of visual field damage (P=.3, Fisher exact test). HVF rate of change did not correlate with rate of change of HRT parameters. CONCLUSIONS Trend-based analysis of HRT parameters has poor sensitivity and specificity in predicting HVF change. This may be related specifically to HRT imaging or may reflect the fact that in some patients with glaucoma, functional changes precede structural alterations.
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Affiliation(s)
- John Danias
- Departments of Ophthalmology and Cell Biology, State University of New York (SUNY), Downstate Medical Center, Brooklyn, New York, and the SUNY Eye Institute
| | - Janet Serle
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York
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Lenoble Q, Boucart M, Rougier MB, Bordaberry P, Delord S. Does a yellow filter improve visual object categorization in normal aging? AGING NEUROPSYCHOLOGY AND COGNITION 2013; 21:325-45. [DOI: 10.1080/13825585.2013.823143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Legacy J, Hanea S, Theoret J, Smith PD. Granulocyte macrophage colony-stimulating factor promotes regeneration of retinal ganglion cells in vitro through a mammalian target of rapamycin-dependent mechanism. J Neurosci Res 2013; 91:771-9. [DOI: 10.1002/jnr.23205] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 11/22/2012] [Accepted: 12/21/2012] [Indexed: 01/18/2023]
Affiliation(s)
- Jacqueline Legacy
- Department of Neuroscience; Carleton University; Ottawa; Ontario; Canada
| | - Sonia Hanea
- Department of Neuroscience; Carleton University; Ottawa; Ontario; Canada
| | - Jennifer Theoret
- Department of Neuroscience; Carleton University; Ottawa; Ontario; Canada
| | - Patrice D. Smith
- Department of Neuroscience; Carleton University; Ottawa; Ontario; Canada
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Zhuang X, King A, McNamara P, Pokorny J, Cao D. Differential effects of alcohol on contrast processing mediated by the magnocellular and parvocellular pathways. J Vis 2012; 12:12.11.16. [PMID: 23090614 DOI: 10.1167/12.11.16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
This study investigated how acute alcohol intake affects contrast processing mediated by inferred magnocellular (MC) and parvocellular (PC) pathways. Achromatic contrast discrimination thresholds were measured in 16 young healthy participants using a steady-pedestal, pulsed-pedestal or pedestal-Δ-pedestal paradigm designed to favor the inferred MC or the PC pathway. Each participant completed two randomized sessions that included consumption of either 0.8 g/kg alcohol or a placebo beverage, with each session consisting of contrast discrimination measurements at baseline and at 60 min following beverage consumption. The results showed that, compared to placebo, alcohol significantly reduced MC contrast sensitivity and PC contrast gain but had no effect on PC contrast sensitivity for the majority of the participants; and did not alter MC contrast gain consistently across participants. The decrease in contrast gain in the PC pathway can be interpreted as a degradation of the postretinal signal-to-noise ratio, whereas the decrease of sensitivity in the MC pathway likely results from a change of cortical processing.
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Affiliation(s)
- Xiaohua Zhuang
- Department of Ophthalmology & Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA.
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30
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Goodbourn PT, Bosten JM, Hogg RE, Bargary G, Lawrance-Owen AJ, Mollon JD. Do different 'magnocellular tasks' probe the same neural substrate? Proc Biol Sci 2012; 279:4263-71. [PMID: 22896642 DOI: 10.1098/rspb.2012.1430] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The sensory abnormalities associated with disorders such as dyslexia, autism and schizophrenia have often been attributed to a generalized deficit in the visual magnocellular-dorsal stream and its auditory homologue. To probe magnocellular function, various psychophysical tasks are often employed that require the processing of rapidly changing stimuli. But is performance on these several tasks supported by a common substrate? To answer this question, we tested a cohort of 1060 individuals on four 'magnocellular tasks': detection of low-spatial-frequency gratings reversing in contrast at a high temporal frequency (so-called frequency-doubled gratings); detection of pulsed low-spatial-frequency gratings on a steady luminance pedestal; detection of coherent motion; and auditory discrimination of temporal order. Although all tasks showed test-retest reliability, only one pair shared more than 4 per cent of variance. Correlations within the set of 'magnocellular tasks' were similar to the correlations between those tasks and a 'non-magnocellular task', and there was little consistency between 'magnocellular deficit' groups comprising individuals with the lowest sensitivity for each task. Our results suggest that different 'magnocellular tasks' reflect different sources of variance, and thus are not general measures of 'magnocellular function'.
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Affiliation(s)
- Patrick T Goodbourn
- Department of Experimental Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK.
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31
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Fortune B, Burgoyne CF, Cull GA, Reynaud J, Wang L. Structural and functional abnormalities of retinal ganglion cells measured in vivo at the onset of optic nerve head surface change in experimental glaucoma. Invest Ophthalmol Vis Sci 2012; 53:3939-50. [PMID: 22589428 DOI: 10.1167/iovs.12-9979] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To compare peripapillary retinal nerve fiber layer thickness (RNFLT), RNFL retardance, and retinal function at the onset of optic nerve head (ONH) surface topography change in experimental glaucoma (EG). METHODS Thirty-three rhesus macaques had three or more weekly baseline measurements in both eyes of ONH surface topography, peripapillary RNFLT, RNFL retardance, and multifocal electroretinography (mfERG). Laser photocoagulation was then applied to the trabecular meshwork of one eye to induce chronic elevation of IOP and weekly recordings continued alternating between ONH surface topography and RNFLT during one week and RNFL retardance and mfERG the next week. Data were pooled for the group at the onset of ONH surface topography change in each EG eye, which was defined as the first date when either the mean position of the disc (MPD) fell below the 95% confidence limit of each eye's individual baseline range and/or when the topographic change analysis (TCA) map was subjectively judged as having demonstrated change, whichever came first. Analysis of variance with post hoc tests corrected for multiple comparisons were used to assess parameter changes. RESULTS At onset of ONH surface topography change, there was no significant difference for RNFLT versus baseline or fellow control eyes. RNFL retardance and mfERG were significantly reduced in the recordings just prior (median of 9 days) to ONH onset (P < 0.01) and had progressed significantly (P < 0.001) an average of 17 days later (median of 7 days after ONH onset). RNFLT did not exhibit significant thinning until 15 days after onset of ONH surface topography change (P < 0.001). CONCLUSIONS These results support the hypothesis that during the course of glaucomatous neurodegeneration, axonal cytoskeletal and retinal ganglion cell functional abnormalities exist before thinning of peripapillary RNFL axon bundles begins.
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Affiliation(s)
- Brad Fortune
- Devers Eye Institute, Discoveries in Sight Research Laboratories, Legacy Research Institute, Legacy Health, Portland, Oregon, USA.
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Nickells RW. The cell and molecular biology of glaucoma: mechanisms of retinal ganglion cell death. Invest Ophthalmol Vis Sci 2012; 53:2476-81. [PMID: 22562845 DOI: 10.1167/iovs.12-9483h] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Robert W Nickells
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA.
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Malik R, Swanson WH, Garway-Heath DF. 'Structure-function relationship' in glaucoma: past thinking and current concepts. Clin Exp Ophthalmol 2012; 40:369-80. [PMID: 22339936 DOI: 10.1111/j.1442-9071.2012.02770.x] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An understanding of the relationship between functional and structural measures in primary open-angle glaucoma is necessary for both grading the severity of disease and for understanding the natural history of the condition. This article outlines the current evidence for the nature of this relationship and highlights the current mathematical models linking structure and function. Large clinical trials demonstrate that both structural and functional change are apparent in advanced stages of disease, and at an individual level, detectable structural abnormality may precede functional abnormality in some patients, whereas the converse is true in other patients. Although the exact nature of the 'structure-function' relationship in primary open-angle glaucoma is still the topic of scientific debate and the subject of continuing research, this article aims to provide the clinician with an understanding of the past concepts and contemporary thinking in relation to the structure-function relationship in primary open-angle glaucoma.
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Affiliation(s)
- Rizwan Malik
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust & UCL Institute of Ophthalmology, London, UK
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Cao D, Zele AJ, Pokorny J, Lee DY, Messner LV, Diehl C, Ksiazek S. Functional loss in the magnocellular and parvocellular pathways in patients with optic neuritis. Invest Ophthalmol Vis Sci 2011; 52:8900-7. [PMID: 22016061 DOI: 10.1167/iovs.11-7644] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To evaluate contrast threshold and contrast gain in patients with optic neuritis under conditions designed to favor mediation by either the inferred magnocellular (MC) or parvocellular (PC) pathway. METHODS Achromatic and chromatic contrast discrimination was measured in 11 patients with unilateral or bilateral optic neuritis and in 18 age-matched controls with normal vision, using achromatic steady- and pulsed-pedestal paradigms to bias performance toward the MC or PC pathway, respectively. In addition, L-M chromatic discrimination at equiluminance was evaluated using the steady-pedestal paradigm. A physiologically plausible model could describe the data with parameters accounting for contrast gain and contrast sensitivity in the inferred MC or PC pathway. The fitted parameters from the eye affected by optic neuritis were compared with those from the normal eye using generalized estimation equation (GEE) models that can account for within-subject correlations. RESULTS Compared with normal eyes, the affected eyes had significantly higher saturation parameters when measured with both the achromatic pulsed-pedestal paradigm (GEE: β [SE] = 0.35 [0.06]; P < 0.001) and the chromatic discrimination paradigm (β [SE] = 0.18 [0.08]; P = 0.015), suggesting that contrast gain in the inferred PC pathway is reduced; the affected eyes also had reduced absolute sensitivity in the inferred MC pathway measured with the achromatic steady-pedestal paradigm (β [SE] = 0.12 [0.04]; P = 0.005). CONCLUSIONS Optic neuritis produced large sensitivity losses mediated by the MC pathway and contrast gain losses in the inferred PC pathway. A clinical framework is presented for interpreting contrast sensitivity and gain loss to chromatic and achromatic stimuli in terms of retinal and postretinogeniculate loci contributions to detection and discrimination.
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Affiliation(s)
- Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1905 W.Taylor Street, Room 149, Chicago, IL 60615, USA.
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Dai H, Mu KT, Qi JP, Wang CY, Zhu WZ, Xia LM, Chen ZQ, Zhang H, Ai F, Morelli JN. Assessment of lateral geniculate nucleus atrophy with 3T MR imaging and correlation with clinical stage of glaucoma. AJNR Am J Neuroradiol 2011; 32:1347-53. [PMID: 21757515 DOI: 10.3174/ajnr.a2486] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Although previous animal studies have shown structural changes in ocular hypertension such as atrophy of the LGN, such changes have not been thoroughly studied in human glaucoma patients nor correlation made with clinical stage. Our aim was to investigate prospectively LGN atrophy in patients with POAG using 3T MR imaging and correlation with the clinical stage of disease. MATERIALS AND METHODS Twenty-six patients with known POAG and 26 age-matched healthy volunteers were included in this institutional review board-approved study. All subjects underwent imaging on a 3T MR imaging system with a PD and GM sequence. LGN height and volume were measured by 2 blinded neuroradiologists. Measurements were compared and correlated with clinical glaucoma severity as assessed by static threshold visual field parameters. RESULTS Average maximum LGN height in patients with glaucoma on PD images was 4.36 ± 0.61 mm (right) and 4.31 ± 0.61 mm (left), significantly less (P < 10⁻³) than respective measurements of 5.05 ± 0.41 and 4.99 ± 0.41 mm in volunteers. With the GM sequences, such respective measurements were also less (P < 10⁻³) in patients with glaucoma (4.20 ± 0.71 mm right, 4.00 ± 0.85 mm left) versus respective measurements in volunteers (4.88 ± 0.51 mm right, 4.77 ± 0.47 mm left). Average LGN volumes in the patient group were 98.0 ± 27.2 mm³ (right) and 93.7 ± 25.8 mm³ (left) with the PD sequence versus respective measurements of 85.2 ± 27.1 and 80.5 ± 23.6 mm³ with the GM sequence. All height and volume measurements were greater in volunteers (P < 10⁻³). In the patient group, both maximum height and volume of the LGN with both sequences were significantly correlated with cumulative clinical glaucoma stage (P < .05). CONCLUSIONS MR imaging measurements of LGN height and volume are diminished in patients with glaucoma, with the extent of atrophy correlating to clinical stage, suggesting a novel imaging marker of disease severity.
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Affiliation(s)
- H Dai
- Department of Radiology, Tongji Hospital, Huazhong University of Science and Technology University, Wuhan, China
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Swanson WH, Sun H, Lee BB, Cao D. Responses of primate retinal ganglion cells to perimetric stimuli. Invest Ophthalmol Vis Sci 2011; 52:764-71. [PMID: 20881286 DOI: 10.1167/iovs.10-6158] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Perimetry is used clinically to assess glaucomatous ganglion cell loss. It has been proposed that frequency-doubling stimuli are better than the conventional size III perimetric stimulus in preferentially stimulating magnocellular (M) versus parvocellular (P) ganglion cells. However, little is known about how primate ganglion cells respond to perimetric stimuli. The authors recorded contrast responses of M and P ganglion cells to size III and frequency-doubling stimuli and compared contrast gain of M and P cells to these stimuli to assess the ability of these stimuli to preferentially stimulate M versus P cells. METHODS Data were recorded from 69 macaque retinal ganglion cells, by an in vivo preparation, at eccentricities of 5° to 15°. The size III stimulus was a circular luminance increment 26 min arc in diameter, 200 ms in duration. The frequency-doubling stimulus was a sinusoidal grating (0.5 cyc/deg) temporally modulated in counterphase at 13 Hz. A Michaelis-Menten function was fit to each cell's contrast responses to assess contrast gain. RESULTS For both size III and frequency-doubling stimuli, ganglion cell responses increased linearly at low contrasts, and then the increase slowed at high contrasts (saturation). The mean (± SE) difference in estimated log contrast gain between M and P cells for the size III stimulus was significantly higher than that for the frequency-doubling stimulus (1.24 ± 0.09 vs. 0.89 ± 0.13; P < 0.01). CONCLUSIONS The size III stimulus was superior to the frequency-doubling stimulus in preferentially stimulating M cells versus P cells.
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Affiliation(s)
- William H Swanson
- School of Optometry, Indiana University, Bloomington, Indiana 47405-3680, USA.
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Sehi M, Grewal DS, Goodkin ML, Greenfield DS. Reversal of retinal ganglion cell dysfunction after surgical reduction of intraocular pressure. Ophthalmology 2010; 117:2329-36. [PMID: 20920827 DOI: 10.1016/j.ophtha.2010.08.049] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 08/26/2010] [Accepted: 08/27/2010] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The pattern electroretinogram optimized for glaucoma screening (PERGLA) is a noninvasive method of objectively measuring retinal ganglion cell (RGC) function. This study was undertaken to quantify the RGC response to intraocular pressure (IOP) reduction after glaucoma surgery. DESIGN Prospective cohort study. PARTICIPANTS Forty-seven eyes of 47 patients with uncontrolled IOP or progressive glaucomatous optic neuropathy receiving maximal medical therapy requiring trabeculectomy or aqueous drainage device implantation who met eligibility criteria. METHODS Eyes with visual acuity less than 20/30, corneal or retinal pathologic features, or unreliable standard automated perimetry (SAP) results were excluded. All patients underwent complete ocular examination, arterial blood pressure, SAP, and PERGLA at 2 sessions before surgery and at 3 months after surgery. Mean ocular perfusion pressure (MOPP) was calculated. Each measure of PERGLA amplitude and phase was an average of 600 artifact-free signal registrations. MAIN OUTCOME MEASURES Intraocular pressure and PERGLA amplitude and phase. RESULTS Forty-seven eyes of 47 patients (mean age ± standard deviation [SD], 69.9 ± 11.3 years) were enrolled. Thirty-four eyes (72%) underwent trabeculectomy with antifibrosis therapy; 13 eyes (28%) underwent glaucoma drainage implant surgery. Mean ± SD postoperative IOP (10.4 ± 4.6 mmHg) was significantly (P< 0.001) reduced compared with that before surgery (19.7 ± 8.6 mmHg). Mean ± SD postoperative PERGLA amplitude (0.46 ± 0.22 μV) was significantly (P = 0.001) increased compared with preoperative PERGLA amplitude (0.37 ± 0.18 μV). Mean ± SD postoperative PERGLA phase (1.72 ± 0.20 π-radian) was significantly (P = 0.01) reduced compared with preoperative PERGLA phase (1.81 ± 0.22 π-radian). Mean ± SD postoperative MOPP (53.1 ± 6.4 mmHg) was significantly (P < 0.001) increased compared with mean ± SD preoperative MOPP (45.8 ± 10.1 mmHg). No correlation (P > 0.05) was identified between change in PERGLA amplitude and change in IOP or MOPP. CONCLUSIONS Reversal of RGC dysfunction occurs after surgical reduction of IOP and may be quantified using PERGLA.
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Affiliation(s)
- Mitra Sehi
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Palm Beach Gardens, Florida 33418, USA.
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Magnocellular and parvocellular pathway mediated luminance contrast discrimination in amblyopia. Vision Res 2010; 50:969-76. [PMID: 20211198 DOI: 10.1016/j.visres.2010.03.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 03/02/2010] [Accepted: 03/02/2010] [Indexed: 11/21/2022]
Abstract
To evaluate whether luminance contrast discrimination losses in amblyopia on putative magnocellular (MC) and parvocellular (PC) pathway tasks reflect deficits at retinogeniculate or cortical sites. Fifteen amblyopes including six anisometropes, seven strabismics, two mixed and 12 age-matched controls were investigated. Contrast discrimination was measured using established psychophysical procedures that differentiate MC and PC processing. Data were described with a model of the contrast response of primate retinal ganglion cells. All amblyopes and controls displayed the same contrast signatures on the MC and PC tasks, with three strabismics having reduced sensitivity. Amblyopic PC contrast gain was similar to electrophysiological estimates from visually normal, non-human primates. Sensitivity losses evident in a subset of the amblyopes reflect cortical summation deficits, with no change in retinogeniculate contrast responses. The data do not support the proposal that amblyopic contrast sensitivity losses on MC and PC tasks reflect retinogeniculate deficits, but rather are due to anomalous post-retinogeniculate cortical processing of retinal signals.
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