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Venkata Srinivasan V, Carter-Dawson L, Patel NB. Retinal Ganglion Cell Content Underlying Standard Automated Perimetry Size I to V Visual Sensitivities in the Non-Human Primate Experimental Glaucoma Model. Invest Ophthalmol Vis Sci 2024; 65:22. [PMID: 38995114 PMCID: PMC11246096 DOI: 10.1167/iovs.65.8.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024] Open
Abstract
Purpose To determine the relationship between visual sensitivities from white-on-white Goldmann size I to V stimuli and the underlying retinal ganglion cell (RGC) content in the non-human primate (NHP) experimental glaucoma model. Methods Normative data were collected from 13 NHPs. Unilateral experimental glaucoma was induced in seven animals with the least variable fields who were monitored using optical coherence tomography and 30-2 full-threshold standard automated perimetry (SAP). At varying endpoints, animals were euthanized followed by perfusion fixation, and 1-mm retinal punches were obtained from 34 corresponding SAP locations. RGCs were immunolabeled with an antibody against an RNA-binding protein (RBPMS) marker and imaged using confocal microscopy. RGC counts from each location were then related to visual sensitivities for each stimulus size, after accounting for ocular magnification. Results At the endpoint, the circumpapillary retinal nerve fiber layer thickness for experimental glaucoma eyes ranged from 47 to 113 µm. RGC density in control eyes was greatest for the 4.24° sample (18,024 ± 6869 cells/mm2) and decreased with eccentricity. Visual sensitivity at each tested location followed that predicted by spatial summation, with the critical area increasing with eccentricity (slope = 0.0036, R2 = 0.44). The relationship between RGC counts and visual sensitivity was described using a two-line fit, where the intercept of the first segment and hinge points were dependent on eccentricity. Conclusions In NHPs, SAP visual thresholds are related to the underlying RGCs. The resulting spatial summation based structure-function model can be used to estimate RGC content from any standard white-on-white stimulus size.
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Affiliation(s)
| | | | - Nimesh B Patel
- University of Houston College of Optometry, Houston, Texas, United States
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2
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McKendrick AM, Turpin A. Understanding and identifying visual field progression. Clin Exp Optom 2024; 107:122-129. [PMID: 38467126 DOI: 10.1080/08164622.2024.2316002] [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] [Received: 05/26/2023] [Accepted: 02/02/2024] [Indexed: 03/13/2024] Open
Abstract
Detecting deterioration of visual field sensitivity measurements is important for the diagnosis and management of glaucoma. This review surveys the current methods for assessing progression that are implemented in clinical devices, which have been used in clinical trials, alongside more recent advances proposed in the literature. Advice is also offered to clinicians on what they can do to improve the collection of perimetric data to help analytical progression methods more accurately predict change. This advice includes a discussion of how frequently visual field testing should be undertaken, with a view towards future developments, such as digital healthcare outside the standard clinical setting and more personalised approaches to perimetry.
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Affiliation(s)
- Allison M McKendrick
- Discipline of Optometry, School of Allied Health, University of Western Australia, Perth, Western Australia, Australia
- Data Analytics, Lions Eye Institute, Perth, Western Australia
- Department of Optometry & Vision Sciences the University of Melbourne
| | - Andrew Turpin
- Data Analytics, Lions Eye Institute, Perth, Western Australia
- School of Population Health, Curtin University, Perth, Western Australia, Australia
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3
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Hunter AML, Anderson RS, Redmond T, Garway-Heath DF, Mulholland PJ. Investigating the Spatiotemporal Summation of Perimetric Stimuli in Dry Age-Related Macular Degeneration. Transl Vis Sci Technol 2023; 12:37. [PMID: 38019498 PMCID: PMC10691387 DOI: 10.1167/tvst.12.11.37] [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] [Received: 03/29/2023] [Accepted: 09/26/2023] [Indexed: 11/30/2023] Open
Abstract
Purpose To measure achromatic spatial, temporal, and spatiotemporal summation in dry age-related macular degeneration (AMD) compared to healthy controls under conditions of photopic gaze-contingent perimetry. Methods Twenty participants with dry AMD (mean age, 74.6 years) and 20 healthy controls (mean age, 67.8 years) performed custom, gaze-contingent perimetry tests. An area-modulation test generated localized estimates of Ricco's area (RA) at 2.5° and 5° eccentricities along the 0°, 90°, 180°, and 270° meridians. Contrast thresholds were measured at the same test locations for stimuli of six durations (3.7-190.4 ms) with a Goldmann III stimulus (GIII, 0.43°) and RA-scaled stimuli. The upper limit (critical duration) of complete temporal summation (using the GIII stimulus) and spatiotemporal summation (using the RA stimuli) was estimated using iterative two-phase regression analysis. Results Median (interquartile range [IQR]) RA estimates were significantly larger in AMD participants (2.5°: 0.21 [0.09-0.41] deg2; 5°: 0.32 [0.15-0.65 deg2]) compared to healthy controls (2.5°: 0.08 [0.05-0.13] deg2; 5°: 0.15 [0.08-0.22] deg2) at all test locations (all P < 0.05). No significant difference in median critical duration was found in AMD participants with the GIII stimulus (19.6 [9.9-30.4] ms) and RA-scaled stimuli (22.9 [13.9-40.3] ms) compared to healthy controls (GIII: 17.0 [11.3-24.0] ms; RA-scaled: 22.4 [14.3-33.1] ms) at all test locations (all P > 0.05). Conclusions Spatial summation is altered in dry AMD, without commensurate changes in temporal summation. Translational Relevance The sensitivity of perimetry to AMD may be improved by utilizing stimuli that probe alterations in spatial summation in the disease.
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Affiliation(s)
- Aoife M. L. Hunter
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Roger S. Anderson
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
- National Institute for Health Research Moorfields Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Tony Redmond
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - David F. Garway-Heath
- National Institute for Health Research Moorfields Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Pádraig J. Mulholland
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
- National Institute for Health Research Moorfields Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
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4
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Montesano G, Redmond T, Mulholland PJ, Garway-Heath DF, Ometto G, Romano D, Antonacci F, Tanga L, Carnevale C, Rossetti LM, Crabb DP, Oddone F. Spatial Summation in the Glaucomatous Macula: A Link With Retinal Ganglion Cell Damage. Invest Ophthalmol Vis Sci 2023; 64:36. [PMID: 38010697 PMCID: PMC10683773 DOI: 10.1167/iovs.64.14.36] [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] [Received: 05/09/2023] [Accepted: 10/03/2023] [Indexed: 11/29/2023] Open
Abstract
Purpose The purpose of this study was to test whether functional loss in the glaucomatous macula is characterized by an enlargement of Ricco's area (RA) through the application of a computational model linking retinal ganglion cell (RGC) damage to perimetric sensitivity. Methods One eye from each of 29 visually healthy subjects <40 years old, 30 patients with glaucoma, and 20 age-similar controls was tested with a 10-2 grid with stimuli of 5 different area sizes. Structural estimates of point-wise RGC density were obtained from optical coherence tomography (OCT) scans. Structural and functional data from the young healthy cohort were used to estimate the parameters of a computational spatial summation model to generate a template. The template was fitted with a Bayesian hierarchical model to estimate the latent RGC density in patients with glaucoma and age-matched controls. We tested two alternative hypotheses: fitting the data by translating the template horizontally (H1: change in RA) or vertically (H2: loss of sensitivity without a change in RA). Root mean squared error (RMSE) of the model fits to perimetric sensitivity were compared. Ninety-five percent confidence intervals were bootstrapped. The dynamic range of the functional and structural RGC density estimates was denoted by their 1st and 99th percentiles. Results The RMSE was 2.09 (95% CI = 1.92-2.26) under H1 and 2.49 (95% CI = 2.24-2.72) under H2 (P < 0.001). The average dynamic range for the structural RGC density estimates was only 11% that of the functional estimates. Conclusions Macular sensitivity loss in glaucoma is better described by a model in which RA changes with RGC loss. Structural measurements have limited dynamic range.
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Affiliation(s)
- Giovanni Montesano
- City, University of London, Optometry and Visual Sciences, London, United Kingdom
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
| | - Tony Redmond
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Pádraig J. Mulholland
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom
| | - David F. Garway-Heath
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
| | - Giovanni Ometto
- City, University of London, Optometry and Visual Sciences, London, United Kingdom
| | - Dario Romano
- ASST Santi Paolo e Carlo, Eye Clinic – University of Milan, Milan, Italy
| | - Federica Antonacci
- ASST Santi Paolo e Carlo, Eye Clinic – University of Milan, Milan, Italy
| | | | | | - Luca M. Rossetti
- ASST Santi Paolo e Carlo, Eye Clinic – University of Milan, Milan, Italy
| | - David P. Crabb
- City, University of London, Optometry and Visual Sciences, London, United Kingdom
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5
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Vrijling ACL, de Boer MJ, Renken RJ, Marsman JBC, Grillini A, Petrillo CE, Heutink J, Jansonius NM, Cornelissen FW. Stimulus contrast, pursuit mode, and age strongly influence tracking performance on a continuous visual tracking task. Vision Res 2023; 205:108188. [PMID: 36773370 DOI: 10.1016/j.visres.2023.108188] [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] [Received: 05/24/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 02/12/2023]
Abstract
Human observers tend to naturally track moving stimuli. This tendency may be exploited towards an intuitive means of screening visual function as an impairment induced reduction in stimulus visibility will decrease tracking performance. Yet, to be able to detect subtle impairments, stimulus contrast is critical. If too high, the decrease in performance may remain undetected. Therefore, for this approach to become reliable and sensitive, we need a detailed understanding of how age, stimulus contrast, and the type of stimulus movement affect continuous tracking performance. To do so, we evaluated how well twenty younger and twenty older participants tracked a semi-randomly moving stimulus (Goldmann size III, 0.43 degrees of visual angle), presented at five contrast levels (5%-10%-20%-40%-80%). The stimulus could move smoothly only (smooth pursuit mode) or in alternation with displacements (saccadic pursuit mode). Additionally, we assessed static foveal and peripheral contrast thresholds. For all participants, tracking performance improved with increasing contrast in both pursuit modes. To reach threshold performance levels, older participants required about twice as much contrast (20% vs. 10% and 40% vs. 20% in smooth and saccadic modes respectively). Saccadic pursuit detection thresholds correlated significantly with static peripheral contrast thresholds (rho = 0.64). Smooth pursuit detection thresholds were uncorrelated with static foveal contrast thresholds (rho = 0.29). We conclude that continuous visual stimulus tracking is strongly affected by stimulus contrast, pursuit mode, and age. This provides essential insights that can be applied towards new and intuitive approaches of screening visual function.
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Affiliation(s)
- A C L Vrijling
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands; Royal Dutch Visio, Centre of Expertise for Blind and Partially Sighted People, Huizen, the Netherlands.
| | - M J de Boer
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - R J Renken
- Cognitive Neuroscience Center, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - J B C Marsman
- Cognitive Neuroscience Center, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | | | | | - J Heutink
- Royal Dutch Visio, Centre of Expertise for Blind and Partially Sighted People, Huizen, the Netherlands; Department of Clinical and Developmental Neuropsychology, University of Groningen, Groningen, the Netherlands
| | - N M Jansonius
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands; Department of Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - F W Cornelissen
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
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6
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Gardiner SK. Longitudinal Signal-to-Noise Ratio of Perimetry at Different Severities of Glaucoma. Transl Vis Sci Technol 2023; 12:30. [PMID: 36811884 PMCID: PMC9970001 DOI: 10.1167/tvst.12.2.30] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 01/25/2023] [Indexed: 02/24/2023] Open
Abstract
Purpose Automated perimetry is relied on for functional assessment of patients with glaucoma, but questions remain about its effective dynamic range and its utility for quantifying rates of progression at different stages of the disease. This study aims to identify the bounds within which estimates of rate are most reliable. Methods Pointwise longitudinal signal-to-noise ratios (LSNR), defined as the rate of change divided by the standard error of the trend line, were calculated for 542 eyes of 273 patients with glaucoma/suspects. The relations between the mean sensitivity within each series and lower percentiles of the distribution of LSNRs (representing progressing series) were analyzed by quantile regression, with 95% confidence intervals derived by bootstrapping. Results The 5th and 10th percentiles of LSNRs reached a minimum at sensitivities 17 to 21 dB. Below this, estimates of rate became more variable, making LSNRs of progressing series less negative. A significant step change in these percentiles also occurred at approximately 31 dB, above which LSNRs of progressing locations became less negative. Conclusions The lower bound of maximum utility for perimetry was ∼17 to 21dB, coinciding with previous results suggesting that below this point, retinal ganglion cell responses saturate and noise overwhelms remaining signal. The upper bound was ∼30 to 31 dB, coinciding with previous results suggesting that above this point, the size III stimulus used is larger than Ricco's area of complete spatial summation. Translational Relevance These results quantify the impact of these two factors on the ability to monitor progression and provide quantifiable targets for attempts to improve perimetry.
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7
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Carvalho J, Invernizzi A, Martins J, Renken RJ, Cornelissen FW. Local neuroplasticity in adult glaucomatous visual cortex. Sci Rep 2022; 12:21981. [PMID: 36539453 PMCID: PMC9767937 DOI: 10.1038/s41598-022-24709-1] [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: 07/03/2022] [Accepted: 11/18/2022] [Indexed: 12/24/2022] Open
Abstract
The degree to which the adult human visual cortex retains the ability to functionally adapt to damage at the level of the eye remains ill-understood. Previous studies on cortical neuroplasticity primarily focused on the consequences of foveal visual field defects (VFD), yet these findings may not generalize to peripheral defects such as occur in glaucoma. Moreover, recent findings on neuroplasticity are often based on population receptive field (pRF) mapping, but interpreting these results is complicated in the absence of appropriate control conditions. Here, we used fMRI-based neural modeling to assess putative changes in pRFs associated with glaucomatous VFD. We compared the fMRI-signals and pRF in glaucoma participants to those of controls with case-matched simulated VFD. We found that the amplitude of the fMRI-signal is reduced in glaucoma compared to control participants and correlated with disease severity. Furthermore, while coarse retinotopic structure is maintained in all participants with glaucoma, we observed local pRF shifts and enlargements in early visual areas, relative to control participants. These differences suggest that the adult brain retains some degree of local neuroplasticity. This finding has translational relevance, as it is consistent with VFD masking, which prevents glaucoma patients from noticing their VFD and seeking timely treatment.
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Affiliation(s)
- Joana Carvalho
- grid.4494.d0000 0000 9558 4598Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands ,grid.421010.60000 0004 0453 9636Pre-Clinical MRI Laboratory, Champalimaud Centre for the Unknown, Avenida de Brasilia, 1400-038 Lisbon, Portugal
| | - Azzurra Invernizzi
- grid.4494.d0000 0000 9558 4598Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands ,grid.59734.3c0000 0001 0670 2351Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY USA
| | - Joana Martins
- grid.4494.d0000 0000 9558 4598Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Remco J. Renken
- grid.4494.d0000 0000 9558 4598Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands ,grid.4494.d0000 0000 9558 4598Cognitive Neuroscience Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Frans W. Cornelissen
- grid.4494.d0000 0000 9558 4598Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Gardiner SK, Mansberger SL. Moving Stimulus Perimetry: A New Functional Test for Glaucoma. Transl Vis Sci Technol 2022; 11:9. [PMID: 36201198 PMCID: PMC9554223 DOI: 10.1167/tvst.11.10.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/30/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose Static pointwise perimetric sensitivities of less than approximately 19 dB are unreliable in glaucoma owing to excessive variability. We propose using moving stimuli to increase detectability, decrease variability, and hence increase this dynamic range. Methods A moving stimulus was designed to travel parallel to the average nerve fiber bundle orientation at each location, and compared against an otherwise identical static stimulus. To assess dynamic range, psychometric functions were measured at 4 locations of each of 10 subjects. To assess clinically realistic test-retest variability, 34 locations of 94 subjects with glaucoma and glaucoma suspects were tested twice, 6 months apart. Pointwise sensitivity estimates were compared using generalized estimating equation regression models. The test-retest limits of agreement for each stimulus were assessed, adjusted for within-eye clustering. Results Using static stimuli, 9 of the 40 psychometric functions had less than a 90% maximum response probability, suggesting being beyond the dynamic range. Eight of those locations had asymptotic maximum of more than 90% with moving stimuli. Sensitivities were higher for moving stimuli (P < 0.001); the difference increased as sensitivity decreased (P < 0.001). Test-retest limits of agreement were narrower for moving stimuli (-6.35 to +6.48 dB) than static stimuli (-12.7 to +7.81 dB). Sixty-two percent of subjects preferred using moving stimuli versus 19% who preferred static stimuli. Conclusions Using a moving stimulus increases perimetric sensitivities in regions of glaucomatous loss. This extends the effective dynamic range, allowing reliable testing later into the disease. Results are more repeatable, and the test is preferred by most subjects. Translational Relevance Moving stimuli allow reliable testing in patients with more severe glaucoma than currently possible.
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Gardiner SK, Swanson WH, Mansberger SL. Long- and Short-Term Variability of Perimetry in Glaucoma. Transl Vis Sci Technol 2022; 11:3. [PMID: 35917137 PMCID: PMC9358297 DOI: 10.1167/tvst.11.8.3] [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: 12/03/2022] Open
Abstract
Purpose Test–retest variability in perimetry consists of short-term and long-term components, both of which impede assessment of progression. By minimizing and quantifying the algorithm-dependent short-term variability, we can quantify the algorithm-independent long-term variability that reflects true fluctuations in sensitivity between visits. We do this at locations with sensitivity both < 28 dB (when the stimulus is smaller than Ricco's area and complete spatial summation can be assumed) and > 28 dB (when partial summation occurs). Methods Frequency-of-seeing curves were measured at four locations of 35 participants with glaucoma. The standard deviation of cumulative Gaussian fits to those curves was modeled for a given sensitivity and used to simulate the expected short-term variability of a 30-presentation algorithm. A separate group of 137 participants was tested twice with that algorithm, 6 months apart. Long-term variance at different sensitivities was calculated as the LOESS fit of observed test–retest variance minus the LOESS fit of simulated short-term variance. Results Below 28 dB, short-term variability increased approximately linearly with increasing loss. Long-term variability also increased with damage below this point, attaining a maximum standard deviation of 2.4 dB at sensitivity 21 dB, before decreasing due to the floor effect of the algorithm. Above 30 dB, the observed test–retest variance was slightly smaller than the simulated short-term variance. Conclusions Long-term and short-term variability both increase with damage for perimetric stimuli smaller than Ricco's area. Above 28 dB, long-term variability constitutes a negligible proportion of test–retest variability. Translational Relevance Fluctuations in true sensitivity increase in glaucoma, even after accounting for increased short-term variability. This long-term variability cannot be reduced by altering testing algorithms alone.
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Tong J, Alonso-Caneiro D, Kalloniatis M, Zangerl B. Prediction of visual field defects from macular optical coherence tomography in glaucoma using cluster analysis. Ophthalmic Physiol Opt 2022; 42:948-964. [PMID: 35598146 PMCID: PMC9544890 DOI: 10.1111/opo.12997] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 11/30/2022]
Abstract
Purpose To assess the accuracy of cluster analysis‐based models in predicting visual field (VF) defects from macular ganglion cell‐inner plexiform layer (GCIPL) measurements in glaucomatous and healthy cohorts. Methods GCIPL measurements were extracted from posterior pole optical coherence tomography (OCT), from locations corresponding to central VF test grids. Models incorporating cluster analysis methods and corrections for age and fovea to optic disc tilt were developed from 493 healthy participants, and 5th and 1st percentile limits of GCIPL thickness were derived. These limits were compared with pointwise 5th and 1st percentile limits by calculating sensitivities and specificities in an additional 40 normal and 37 glaucomatous participants, as well as applying receiver operating characteristic (ROC) curve analyses to assess the accuracy of predicting VF results from co‐localised GCIPL measurements. Results Clustered models demonstrated globally low sensitivity, but high specificity in the glaucoma cohort (0.28–0.53 and 0.77–0.91, respectively), and high specificity in the healthy cohort (0.91–0.98). Clustered models showed similar sensitivities and superior specificities compared with pointwise methods (0.41–0.65 and 0.71–0.98, respectively). There were significant differences in accuracy between clusters, with relatively poor accuracy at peripheral macular locations (p < 0.0001 for all comparisons). Conclusions Cluster analysis‐based models incorporating age correction and holistic consideration of fovea to optic disc tilt demonstrated superior performance in predicting VF results to pointwise methods in both glaucomatous and healthy eyes. However, relatively low sensitivity and poorer performance at the peripheral macula indicate that OCT in isolation may be insufficient to predict visual function across the macula accurately. With modifications to criteria for abnormality, the concepts suggested by the described normative models may guide prioritisation of VF assessment requirements, with the potential to limit excessive VF testing.
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Affiliation(s)
- Janelle Tong
- Centre for Eye Health, University of New South Wales (UNSW), Sydney, New South Wales, Australia.,School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - David Alonso-Caneiro
- Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Queensland University of Technology, Kelvin Grove, Queensland, Australia
| | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales (UNSW), Sydney, New South Wales, Australia.,School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - Barbara Zangerl
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia.,Coronary Care Unit, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
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11
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Tong J, Phu J, Alonso-Caneiro D, Khuu SK, Kalloniatis M. Clinical Evaluations of Macular Structure-Function Concordance With and Without Drasdo Displacement. Transl Vis Sci Technol 2022; 11:18. [PMID: 35438719 PMCID: PMC9034708 DOI: 10.1167/tvst.11.4.18] [Citation(s) in RCA: 3] [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 The purpose of this study was to compare concordance between ganglion cell-inner plexiform layer (GCIPL) data from the Cirrus optical coherence tomographer (OCT) Ganglion Cell Analysis (GCA) and visual fields (VFs), with and without Drasdo displacement. Methods From 296 open-angle glaucoma participants, GCIPL deviation and raw thickness data were extracted over locations per the 10-2 VF test grid, with and without application of Drasdo displacement, with global and eccentricity-dependent sensitivities and specificities calculated for both. With OCT and VF data classified as within or outside normative limits, pattern deviation values were compared using paired t-tests and Spearman correlations. Regression models were applied to pattern deviation values as a function of GCIPL thickness, and differences in model performance with and without displacement were compared using extra sums-of-squares F tests. Results There were small but significant improvements in global specificity without displacement (0.58-0.59 with displacement and 0.61 without displacement), without notable differences in sensitivity (0.77-0.78 with displacement and 0.76-0.78 without displacement). At abnormal VF locations and without displacement, a higher proportion of correct OCT classifications (P = 0.0008) and significant correlation with worsening pattern deviation values were observed (r = 0.50, P = 0.002). Regression models indicated significantly steeper slopes with Drasdo displacement centrally (P = 0.002-0.04). Conclusions With GCA deviation maps, small improvements in structure-function concordance were observed without displacement, which are unlikely to be clinically meaningful. Using GCIPL thickness data, significantly better structure-function concordance was observed centrally with Drasdo displacement. Translational Relevance Applying Drasdo displacement on probability-based reports is unlikely to alter clinical impressions of structure-function concordance, but applying displacement with GCIPL thickness data may improve detection of structure-function concordance.
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Affiliation(s)
- Janelle Tong
- Centre for Eye Health, University of New South Wales (UNSW), Sydney, New South Wales, Australia.,School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - Jack Phu
- Centre for Eye Health, University of New South Wales (UNSW), Sydney, New South Wales, Australia.,School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - David Alonso-Caneiro
- Queensland University of Technology, Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Queensland, Australia
| | - Sieu K Khuu
- School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales (UNSW), Sydney, New South Wales, Australia.,School of Optometry and Vision Science, University of New South Wales (UNSW), Sydney, New South Wales, Australia
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12
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Bedggood P, Prea SM, Kong YXG, Vingrys AJ. Scaling the size of perimetric stimuli reduces variability and returns constant thresholds across the visual field. J Vis 2021; 21:2. [PMID: 34617957 PMCID: PMC8504188 DOI: 10.1167/jov.21.11.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The conventional stimulus for standard automated perimetry is fixed in size, giving elevated contrast thresholds and reduced test reliability in the periphery. Here, we test the hypothesis that appropriate scaling of the size of perimetric stimuli will return fixed thresholds and reduced variability across the visual field. We derived frequency-of-seeing (FOS) curves in five healthy subjects at central (3 degrees) and peripheral (27 degrees) locations with a method of constant stimuli (MOCS) using a desktop LCD display. FOS curves for a Goldmann III (GIII) stimulus were compared with those for size scaled spots. To consider clinical translation, we tested a further five healthy subjects (22–24 years) with the Melbourne Rapid Fields (MRF) tablet perimeter at several locations spanning 1 degree to 25 degrees from fixation, deriving FOS curves (MOCS) and also conducting repeated adaptive clinical thresholding to assess intra- and interobserver variability. We found that GIII contrast thresholds were significantly elevated in the periphery compared with the parafovea, with concomitant reduction of FOS slope. Using appropriately size scaled spots, threshold and slope differences between these locations were significantly reduced. FOS data collected with the tablet perimeter confirmed that size scaling confers broad equivalence of the shape of the FOS curve across the visual field. Repeated adaptive thresholding with size scaled stimuli gave relatively constant intra-observer variability across the visual field, which compares favorably with published normative data obtained with the GIII stimulus. The reduced variability will improve signal-to-noise ratio for correct classification of normal visual field test results, whereas the lower contrast thresholds yield greater dynamic range, which should improve the ability to reliably monitor moderate defects.
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Affiliation(s)
- Phillip Bedggood
- Department of Optometry & Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.,
| | - Selwyn Marc Prea
- Department of Optometry & Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.,
| | - Yu Xiang George Kong
- Royal Victorian Eye and Ear Hospital, East Melbourne, Australia.,Centre for Eye Research Australia, East Melbourne, Australia.,
| | - Algis J Vingrys
- Department of Optometry & Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.,
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13
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Pérez-Carrasco MJ, Carballo-Álvarez J, Barbur JL, Puell MC. Relationship Between Flicker Modulation Sensitivity and Retinal Ganglion Cell Related Layer Thicknesses. Transl Vis Sci Technol 2021; 10:16. [PMID: 34647964 PMCID: PMC8525864 DOI: 10.1167/tvst.10.12.16] [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
Purpose Early detection of structural changes in retinal ganglion cells (RGCs) and corresponding changes in visual function is important in early degenerative diseases of the retina, but the sensitivity of both measurements is limited by the inherent variability in healthy subjects. This study investigates the relationships between RGC-related layer thicknesses and foveal and parafoveal flicker modulation sensitivity (FMS) across photopic and mesopic light levels in healthy subjects. Methods Photopic and mesopic FMS was measured in 56 young adults, at the point of fixation and at an eccentricity of 5 degrees, in each of the four quadrants. Spectral-domain optical coherence tomography (SD-OCT) was used to measure retinal thicknesses. Relationships between foveal and parafoveal FMS and the retinal thickness in the corresponding region were examined after adjusting for confounding variables. Results Total macular and inner retinal layer (IRL) thicknesses in the parafoveal ring were significant predictors of photopic (P = 0.034) and mesopic (P = 0.034) parafoveal FMS, respectively. The superior peripapillary retinal nerve fiber layer (pRNFL) thickness was a contributing factor to the inferior parafoveal FMS (photopic: P = 0.006 and mesopic: P = 0.021) and the inferior pRNFL thickness was also a contributing factor to the superior parafoveal FMS (photopic: P < 0.001 and mesopic: P = 0.015). Conclusions The pRNFL thicknesses predict parafoveal FMS for both mesopic and photopic conditions in healthy eyes. Translational Relevance The measurement of rapid flicker sensitivity in the parafoveal retina together with the pRNFL thickness profiles measured before the onset of disease, may provide a more sensitive biomarker for detecting loss of sensitivity caused by the earliest neurodegenerative changes in the eyes.
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Affiliation(s)
- María J Pérez-Carrasco
- Applied Vision Research Group, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
| | - Jesús Carballo-Álvarez
- Centre for Applied Vision Research, The Henry Wellcome Laboratories for Vision Science, School of Health Sciences, City, University of London, London, UK
| | - John L Barbur
- Centre for Applied Vision Research, The Henry Wellcome Laboratories for Vision Science, School of Health Sciences, City, University of London, London, UK
| | - María C Puell
- Applied Vision Research Group, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Madrid, Spain
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14
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Antwi-Boasiako K, Carter-Dawson L, Harwerth R, Gondo M, Patel N. The Relationship Between Macula Retinal Ganglion Cell Density and Visual Function in the Nonhuman Primate. Invest Ophthalmol Vis Sci 2021; 62:5. [PMID: 33393971 PMCID: PMC7794274 DOI: 10.1167/iovs.62.1.5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Purpose Loss of ganglion cell inner plexiform layer (GCIPL) and visual sensitivity in the macula region are known to occur at all stages of glaucoma. While both are dependent on the underlying retinal ganglion cells (RGCs), the relationship between structure and function is modest. We hypothesize that the imprecise relationship is due to a lack of direct correspondence between in vivo measures and RGC counts, as well as the relatively large stimulus size used by standard perimetry, which exceeds spatial summation. Methods The relationship between optical coherence tomography (OCT)–derived GCIPL thickness and corresponding inner cell density from retinal flat mounts was determined for four nonhuman primates with varying stages of neuropathy. Normative data for 10-2 threshold using Goldman size I to V stimuli were established for 10 animals, 4 of which were then followed longitudinally with OCT and perimetry. The relationship between GCIPL volume, which incorporated stimulus size after removal of residual thickness, and differential light sensitivity was determined for both experimental glaucoma and healthy eyes. Results Peak inner retinal cell density was 63,052 ± 9238 cells/mm2 in the healthy eye. Cell density was related to both GCIPL thickness and eccentricity (R2 = 0.74, P < .01). For all 10-2 eccentricities, size III stimuli were greater than the critical area (P < 0.01). Based on the structural and histologic relationship, the critical area corresponds to approximately 156 RGCs. Conclusions The relationship between cell density and GCIPL thickness is dependent on retinal eccentricity. For 10-2 perimetry, perimetric loss, especially at earlier stages of neuropathy, may best be detected using size II or smaller stimuli.
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Affiliation(s)
| | | | - Ronald Harwerth
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Margaret Gondo
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Nimesh Patel
- College of Optometry, University of Houston, Houston, Texas, United States
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15
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Cho H, Hwang YH, Chung JK, Lee KB, Park JS, Kim HG, Jeong JH. Deep Learning Ensemble Method for Classifying Glaucoma Stages Using Fundus Photographs and Convolutional Neural Networks. Curr Eye Res 2021; 46:1516-1524. [PMID: 33820457 DOI: 10.1080/02713683.2021.1900268] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Purpose: This study developed and evaluated a deep learning ensemble method to automatically grade the stages of glaucoma depending on its severity.Materials and Methods: After cross-validation of three glaucoma specialists, the final dataset comprised of 3,460 fundus photographs taken from 2,204 patients were divided into three classes: unaffected controls, early-stage glaucoma, and late-stage glaucoma. The mean deviation value of standard automated perimetry was used to classify the glaucoma cases. We modeled 56 convolutional neural networks (CNN) with different characteristics and developed an ensemble system to derive the best performance by combining several modeling results.Results: The proposed method with an accuracy of 88.1% and an average area under the receiver operating characteristic of 0.975 demonstrates significantly better performance to classify glaucoma stages compared to the best single CNN model that has an accuracy of 85.2% and an average area under the receiver operating characteristic of 0.950. The false negative is the least adjacent misprediction, and it is less in the proposed method than in the best single CNN model.Conclusions: The method of averaging multiple CNN models can better classify glaucoma stages by using fundus photographs than a single CNN model. The ensemble method would be useful as a clinical decision support system in glaucoma screening for primary care because it provides high and stable performance with a relatively small amount of data.
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Affiliation(s)
- Hyeonsung Cho
- Intelligence and Robot System Research Group, Electronics & Telecommunication Research Institute, Daejeon, Republic of Korea
| | - Young Hoon Hwang
- Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Jae Keun Chung
- Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Kwan Bok Lee
- Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Ji Sang Park
- Intelligence and Robot System Research Group, Electronics & Telecommunication Research Institute, Daejeon, Republic of Korea
| | - Hong-Gee Kim
- Biomedical Knowledge Engineering Laboratory, Seoul National University, Seoul, Republic of Korea
| | - Jae Hoon Jeong
- Department of Ophthalmology, Konyang University Hospital, Konyag University College of Medicine, Daejeon, Republic of Korea
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16
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Phu J, Kalloniatis M. A Strategy for Seeding Point Error Assessment for Retesting (SPEAR) in Perimetry Applied to Normal Subjects, Glaucoma Suspects, and Patients With Glaucoma. Am J Ophthalmol 2021; 221:115-130. [PMID: 32777379 DOI: 10.1016/j.ajo.2020.07.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/26/2020] [Accepted: 07/28/2020] [Indexed: 11/17/2022]
Abstract
PURPOSE We sought to determine the impact of seeding point errors (SPEs) as a source of low test reliability in perimetry and to develop a strategy to mitigate this error early in the test. DESIGN Cross-sectional study. METHODS Visual field test results from 1 eye of 364 patients (77 normal eyes, 178 glaucoma suspect eyes, and 109 glaucoma eyes) were used to develop models for identifying SPE. Two test cohorts (326 undertaking Swedish interactive thresholding algorithm [SITA]-Faster and 327 glaucoma eyes undertaking SITA-Standard) were used to prospectively evaluate the models for identifying SPEs. Global visual field metrics were compared among reliable and unreliable results. Regression models were used to identify factors distinguishing SPEs from non-SPEs. Models were evaluated using receiver operating characteristic (ROC) curves. RESULTS In the test cohorts, SITA-Faster produced a higher rate of unreliable visual field results (30%-49.7%) compared with SITA-Standard (10.8%-16.6%). SPEs contributed to most of the unreliable results in SITA-Faster (57.5%-64.9%) compared with gaze tracker deviations accounting for most of the unreliable results in SITA-Standard (40%-77.8%). In SITA-Faster, results with SPEs had worse global indices and more clusters of sensitivity reduction than reliable results. Our best model (using 9 test locations) can identify SPEs with an area under the ROC curve of 0.89. CONCLUSION SPEs contribute to a large proportion of unreliable visual field test results, particularly when using SITA-Faster. We propose a useful model for identifying SPEs early in the test that can then guide retesting using both SITA algorithms. We provide a simplified framework for the perimetrist to improve the overall fidelity of the test result.
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Affiliation(s)
- Jack Phu
- Centre for Eye Health and the School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales, Australia.
| | - Michael Kalloniatis
- Centre for Eye Health and the School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales, Australia
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17
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Altered spatial summation optimizes visual function in axial myopia. Sci Rep 2020; 10:12179. [PMID: 32699286 PMCID: PMC7376210 DOI: 10.1038/s41598-020-67893-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/28/2020] [Indexed: 12/27/2022] Open
Abstract
This study demonstrates significant differences between the area of complete spatial summation (Ricco's area, RA) in eyes with and without non-pathological, axial myopia. Contrast thresholds were measured for six stimuli (0.01-2.07 deg2) presented at 10º eccentricity in 24 myopic subjects and 20 age-similar non-myopic controls, with RA estimated using iterative two-phase regression analysis. To explore the effects of axial length-induced variations in retinal image size (RIS) on the measurement of RA, refractive error was separately corrected with (i) trial lenses at the anterior focal point (near constant inter-participant RIS in mm), and (ii) contact lenses (RIS changed with axial length). For spectacle corrected measurements, RA was significantly larger in the myopic group, with a significant positive correlation also being observed between RA and measures of co-localised peripheral ocular length. With contact lens correction, there was no significant difference in RA between the groups and no relationship with peripheral ocular length. The results suggest RA changes with axial elongation in myopia to compensate for reduced retinal ganglion cell density. Furthermore, as these changes are only observed when axial length induced variations in RIS are accounted for, they may reflect a functional adaptation of the axially-myopic visual system to an enlarged RIS.
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18
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João CAR, Scanferla L, Jansonius NM. Retinal Contrast Gain Control and Temporal Modulation Sensitivity Across the Visual Field in Glaucoma at Photopic and Mesopic Light Conditions. Invest Ophthalmol Vis Sci 2020; 60:4270-4276. [PMID: 31618763 DOI: 10.1167/iovs.19-27123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Glaucoma affects many aspects of visual performance, including adaptation, and this may depend on ambient luminance. We determine the influence of glaucoma and luminance on temporal aspects of adaptation, specifically on contrast gain control and temporal modulation sensitivity (TMS). Methods This case-control study included 12 glaucoma patients and 25 age-similar controls (50-70 years). Threshold perimetry was performed with a minimized testing grid (fovea and four peripheral locations). Stimuli (Goldmann size III 50 ms increment/decrement) were presented on a time-varying background with sinusoidally-modulated luminance (amplitude 60%; frequency 0-30 Hz; mean background luminance, 1 and 100 cd/m2). TMS (2.5-30 Hz) was measured in the same locations with a sinusoidally-modulated stimulus (Goldmann size IV, 334 ms) on a steady background (1 and 100 cd/m2). Results In healthy subjects, contrast sensitivity decreased with increasing background modulation frequency and increased again at very high frequencies, indicating contrast gain control. Minimum sensitivity was located between 2.5 and 20 Hz, depending on luminance and eccentricity. In glaucoma patients, the same frequency dependency was found (P = 0.12) but with an overall reduced sensitivity (P = 1 × 10-5), independent of luminance (P = 0.20). Decrements differentiated better between glaucoma and healthy subjects than increments (P = 0.004). TMS was reduced in glaucoma (P = 5 × 10-6) across all frequencies and luminance levels, with complete loss for high frequencies at 1 cd/m2. Conclusions Contrast gain control is largely unaffected in glaucoma, suggesting intact amacrine cell function. Perimetry with decrements or a high-frequency stimulus on a low-luminance background seems best to differentiate between glaucoma and healthy subjects.
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Affiliation(s)
- Catarina A R João
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Graduate School of Medical Sciences (Research School of Behavioural and Cognitive Neurosciences), University of Groningen, Groningen, The Netherlands
| | - Lorenzo Scanferla
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Graduate School of Medical Sciences (Research School of Behavioural and Cognitive Neurosciences), University of Groningen, Groningen, The Netherlands
| | - Nomdo M Jansonius
- Department of Ophthalmology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.,Graduate School of Medical Sciences (Research School of Behavioural and Cognitive Neurosciences), University of Groningen, Groningen, The Netherlands
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19
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Phu J, Khuu SK, Agar A, Kalloniatis M. Clinical Evaluation of Swedish Interactive Thresholding Algorithm-Faster Compared With Swedish Interactive Thresholding Algorithm-Standard in Normal Subjects, Glaucoma Suspects, and Patients With Glaucoma. Am J Ophthalmol 2019; 208:251-264. [PMID: 31470001 DOI: 10.1016/j.ajo.2019.08.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 07/06/2019] [Accepted: 08/19/2019] [Indexed: 11/30/2022]
Abstract
PURPOSE To compare the visual fields results obtained using the Swedish interactive thresholding algorithm-Standard (SS) and the Swedish interactive thresholding algorithm-Faster (SFR) in normal subjects, glaucoma suspects, and patients with glaucoma and to quantify potential time-saving benefits of the SFR algorithm. DESIGN Prospective, cross-sectional study. METHODS One randomly selected eye from 364 patients (77 normal subjects, 178 glaucoma suspects, and 109 patients with glaucoma) seen in a single institution underwent testing using both SS and SFR on the Humphrey Field Analyzer. Cumulative test time using each algorithm was compared after accounting for different rates of test reliability. Pointwise and cluster analysis was performed to determine whether there were systematic differences between algorithms. RESULTS Using SFR had a greater rate of unreliable results (29.3%) compared with SS (7.7%, P < .0001). This was mainly because of high false positive rates and seeding point errors. However, modeled test times showed that using SFR could obtain a greater number of reliable results within a shorter period of time. SFR resulted in higher sensitivity values (on average 0.5 dB for patients with glaucoma) that was greater under conditions of field loss (<19 dB). Cluster analysis showed no systematic patterns of sensitivity differences between algorithms. CONCLUSIONS After accounting for different rates of test reliability, SFR can result in significant time savings compared with SS. Clinicians should be cognizant of false positive rates and seeding point errors as common sources of error for SFR. Results between algorithms are not directly interchangeable, especially if there is a visual field deficit <19 dB.
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Affiliation(s)
- Jack Phu
- Centre for Eye Health, University of New South Wales, Kensington, New South Wales; School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales.
| | - Sieu K Khuu
- School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales
| | - Ashish Agar
- Centre for Eye Health, University of New South Wales, Kensington, New South Wales; Department of Ophthalmology, Prince of Wales Hospital, Randwick, New South Wales
| | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales, Kensington, New South Wales; School of Optometry and Vision Science, University of New South Wales, Kensington, New South Wales
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20
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Phu J, Kalloniatis M, Wang H, Khuu SK. Optimising the Structure-Function Relationship at the Locus of Deficit in Retinal Disease. Front Neurosci 2019; 13:306. [PMID: 31024235 PMCID: PMC6467237 DOI: 10.3389/fnins.2019.00306] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/18/2019] [Indexed: 11/13/2022] Open
Abstract
Technologies such as optical coherence tomography have facilitated the visualization of anatomical tissues such as that of the retina. The availability of in vivo retinal anatomical data has led to the hypothesis that it may be able to accurately predict visual function from anatomical information. However, accurate determination of the structure-function relationship has remained elusive in part due to contributions of non-retinal sources of variability, thus imposing potential limitations in the fidelity of the relationship. Furthermore, differences in manifestation of functional loss due to different retinal loci of change (inner retina or outer retinal elements) have also been the subject of debate. Here, we assessed the application of a novel, more objective psychophysical paradigm to better characterize the relationship between functional and structural characteristics in the eye. Using ocular diseases with known loci of anatomical change (glaucoma, inner retinal loss; and retinitis pigmentosa, outer retinal loss), we compared conventional more subjective psychophysical techniques that may be contaminated by the presence of non-retinal sources of variability with our more objective approach. We show that stronger correlations between underlying retinal structure and visual function can be achieved across a breadth of anatomical change by using a more objective psychophysical paradigm. This was independent of the locus of structural loss (at the ganglion cells for glaucoma or photoreceptors for retinitis pigmentosa), highlighting the role of downstream retinal elements to serve as anatomical limiting factors for studying the structure-function relationship. By reducing the contribution of non-retinal sources of variability in psychophysical measurements, we herein provide a structure-function model with higher fidelity. This reinforces the need to carefully consider the psychophysical protocol when examining the structure-function relationship in sensory systems.
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Affiliation(s)
- Jack Phu
- Centre for Eye Health, The University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, The University of New South Wales, Kensington, NSW, Australia
| | - Michael Kalloniatis
- Centre for Eye Health, The University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, The University of New South Wales, Kensington, NSW, Australia
| | - Henrietta Wang
- Centre for Eye Health, The University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, The University of New South Wales, Kensington, NSW, Australia
| | - Sieu K Khuu
- School of Optometry and Vision Science, The University of New South Wales, Kensington, NSW, Australia
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21
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Gardiner SK. Differences in the Relation Between Perimetric Sensitivity and Variability Between Locations Across the Visual Field. Invest Ophthalmol Vis Sci 2019; 59:3667-3674. [PMID: 30029253 PMCID: PMC6054428 DOI: 10.1167/iovs.18-24303] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Purpose Perimetric sensitivities become more variable with glaucomatous functional loss. This study examines the extent to which this relation varies between locations, and whether this can be predicted by eccentricity-related differences in spatial summation. Methods Longitudinal series of visual fields from standard automated perimetry were obtained from participants with suspected or extant glaucoma. For each location in the 24-2 visual field, heterogeneous fixed-effects models were fit to the data, assuming that variability increased exponentially as sensitivity decreased. The predicted variability at each location was calculated when sensitivity was either 30 dB or 25 dB. Results Variability significantly increased with damage at all 52 locations. When sensitivity was 30 dB, variability increased with eccentricity, with P = 0.0003. The average SD was 1.54 dB at the four most central locations, versus 1.74 dB at the most peripheral locations. When sensitivity was 25 dB, variability did not vary predictably with eccentricity, with P = 0.340. The average SD was 2.36 dB at the four central locations, versus 2.24 dB at the most peripheral locations. Conclusions The relation between sensitivity and variability differed by eccentricity. Among healthy locations, variability was lower centrally, where the stimulus size is larger than Ricco's area, than peripherally. Among damaged locations, variability did not systematically vary with eccentricity. This could be because Ricco's area expands in glaucoma, such that stimuli were now smaller than this area at all locations.
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Affiliation(s)
- Stuart K Gardiner
- Devers Eye Institute, Legacy Health, Portland, Oregon, United States
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22
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Swanson WH, King BJ. Comparison of defect depths for sinusoidal and circular perimetric stimuli in patients with glaucoma. Ophthalmic Physiol Opt 2019; 39:26-36. [PMID: 30628740 PMCID: PMC6334661 DOI: 10.1111/opo.12598] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 11/19/2018] [Indexed: 11/27/2022]
Abstract
Purpose Clinical use of perimetric testing in patients with glaucoma typically assumes that perimetric defects will be less deep for larger than smaller stimuli. However, studies have shown that very large sinusoidal stimuli can yield similar defects as small circular stimuli. In order to provide guidelines for new perimetric stimuli, we tested patients with glaucoma using five different stimuli and compared defects to their patterns of retinal nerve fibre layer (RNFL) damage. Methods Twenty subjects with glaucoma were imaged with optical coherence tomography (OCT) volume scans to allow for en face RNFL images and were also tested on a custom perimetry station with five stimuli: Goldmann sizes III and V, a two‐dimensional Gaussian blob (standard deviation 0.5°) and a 0.5 cycle degree−1 sinusoidal grating presented two ways: flickered at 5 Hz, and pulsed for 200 ms instead of flickered. En face RNFL images were reviewed with the visual field locations overlaid, and each location was labelled for a patient as either no visible RNFL defect or as wedge, slit, edge, or diffuse defect. Nineteen age‐similar controls were tested with the same stimuli to define depth of defect as difference from mean normal. Bland‐Altman analysis was used to test three predictions of neural modelling by making five comparisons. Results Bland‐Altman analysis confirmed the three predictions. The flickered sinusoid gave deeper defects in damaged areas than the pulsed sinusoid (r = 0.25, p < 0.0001). When comparing data for sizes III and V there was increased spread of the data in deeper defects in the direction of size III having deeper defect (r = 0.35, p < 0.0001). The size V stimulus yielded shallower defects than a stimulus of similar size but with blurred edges (r = 0.20, p = 0.0004). Conclusions On average, all stimuli produced similar results comparing across type of RNFL damage. However, there were systematic patterns consistent with predictions of neural modelling: in damaged areas, depth of defect tended to be greater for the flickered sinusoid than the pulsed sinusoid, greater for the size III stimulus than the size V stimulus, and greater for the Gaussian blob than for the size V stimulus.
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Affiliation(s)
| | - Brett J King
- Indiana University School of Optometry, Bloomington, USA
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23
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Ly A, Phu J, Katalinic P, Kalloniatis M. An evidence-based approach to the routine use of optical coherence tomography. Clin Exp Optom 2018; 102:242-259. [PMID: 30560558 PMCID: PMC6590481 DOI: 10.1111/cxo.12847] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 09/13/2018] [Accepted: 10/05/2018] [Indexed: 02/06/2023] Open
Abstract
Optical coherence tomography is an imaging technology that has revolutionised the detection, assessment and management of ocular disease. It is now a mainstream technology in clinical practice and is performed by non-specialised personnel in some settings. This article provides a clinical perspective on the implications of that movement and describes best practice using multimodal imaging and an evidence-based approach. Practical, illustrative guides on the interpretation of optical coherence tomography are provided for three major diseases of the ocular fundus, in which optical coherence tomography is often crucial to management: age-related macular degeneration, diabetic retinopathy and glaucoma. Topics discussed include: cross-sectional and longitudinal signs in ocular disease, so-called 'red-green' disease whereby clinicians rely on machine/statistical comparisons for diagnosis in managing treatment-naïve patients, and the utility of optical coherence tomography angiography and machine learning.
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Affiliation(s)
- Angelica Ly
- Centre for Eye Health, The University of New South Wales, Sydney, New South Wales, Australia.,Faculty of Science, School of Optometry and Vision Science, The University of New South Wales, Sydney, New South Wales, Australia
| | - Jack Phu
- Centre for Eye Health, The University of New South Wales, Sydney, New South Wales, Australia.,Faculty of Science, School of Optometry and Vision Science, The University of New South Wales, Sydney, New South Wales, Australia
| | - Paula Katalinic
- Centre for Eye Health, The University of New South Wales, Sydney, New South Wales, Australia.,Faculty of Science, School of Optometry and Vision Science, The University of New South Wales, Sydney, New South Wales, Australia
| | - Michael Kalloniatis
- Centre for Eye Health, The University of New South Wales, Sydney, New South Wales, Australia.,Faculty of Science, School of Optometry and Vision Science, The University of New South Wales, Sydney, New South Wales, Australia
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24
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Phu J, Kalloniatis M, Wang H, Khuu SK. Differences in Static and Kinetic Perimetry Results are Eliminated in Retinal Disease when Psychophysical Procedures are Equated. Transl Vis Sci Technol 2018; 7:22. [PMID: 30280007 PMCID: PMC6166892 DOI: 10.1167/tvst.7.5.22] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 08/13/2018] [Indexed: 12/20/2022] Open
Abstract
Purpose We tested the hypothesis that clinical statokinetic dissociation (SKD, defined as the difference in sensitivity to static and kinetic stimuli) at the scotoma border in retinal disease is due to individual criterion bias and that SKD can be eliminated by equating the psychophysical procedures for testing static and kinetic stimulus detection. Methods Six subjects with glaucoma and six with retinitis pigmentosa (RP) were tested. Clinical procedures (standard automated perimetry [SAP] and manual kinetic perimetry [MKP]) were used to determine clinical SKD and the region of interest for laboratory-based testing. Two-way Method of Limits (MoL) was used to establish the isocontrast region at the scotoma border in glaucoma and RP subjects. Method of Constant Stimuli (MoCS) and a two-interval forced choice (2IFC) procedure then were used to present static or kinetic (inward or outward) stimuli at different eccentricities within the isocontrast region. The results were fitted with psychometric functions to determine threshold eccentricities. Results Clinical SKD was found in glaucoma and RP subjects, with variable magnitude among subjects, but significantly exceeding expected typical measurement variability. The resultant psychometric functions when using MoCS and 2IFC showed equal sensitivity to static and kinetic targets, thus eliminating SKD. Conclusions Clinical SKD found using clinical techniques is due to methodologic differences and criterion bias, and is eliminated by using an equated and more objective psychophysical task, similar to normal subjects. Translational relevance Eliminating SKD using a psychophysical approach minimizing criterion bias suggests that it is not useful to distinguish between normal and diseased fields.
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Affiliation(s)
- Jack Phu
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
| | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
| | - Henrietta Wang
- Centre for Eye Health, University of New South Wales, Kensington, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
| | - Sieu K Khuu
- School of Optometry and Vision Science, University of New South Wales, Kensington, NSW, Australia
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25
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Phu J, Khuu SK, Bui BV, Kalloniatis M. A Method Using Goldmann Stimulus Sizes I to V-Measured Sensitivities to Predict Lead Time Gained to Visual Field Defect Detection in Early Glaucoma. Transl Vis Sci Technol 2018; 7:17. [PMID: 29892496 PMCID: PMC5993363 DOI: 10.1167/tvst.7.3.17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 04/24/2018] [Indexed: 11/24/2022] Open
Abstract
Purpose To predict the lead time (difference in time taken for a visual field [VF] defect to be detected) obtained when using stimulus sizes within or near the size of the critical area of spatial summation (Ac), and to test these predictions using sensitivity measurements from a cohort of glaucoma patients. Methods Thirty-seven patients with early open-angle glaucoma and 60 healthy observers underwent VF testing on the Humphrey Field Analyzer in full threshold mode using Goldmann stimulus sizes I to V (GI-V) across the 30-2 test grid. We used the sensitivities measured using GI to V in healthy patients to predict the lead time gained by using stimulus sizes within the size of Ac at all locations within the 30-2 grid. Then, we used sensitivities measured in the glaucoma patients to test this predictive model. Results Median lead time to VF defect detection when using stimulus sizes within Ac compared with stimulus sizes larger than Ac was 4.1 years across the 30-2 test grid (interquartile range, 3.1 and 5.1 years). Sensitivities of the glaucoma patients showed good agreement with the predictive model of lead time gained (77.5%-84.3% were within ±3 dB). Conclusions Our model predicted substantial lead time differences when using stimulus sizes within or near Ac. Such stimulus sizes could potentially detect VF defects, on average, 4 years earlier than current paradigms. Translational Relevance Stimulus sizes within or near Ac may be more suitable for early detection of glaucomatous VF defects. Larger stimulus sizes may be more suitable for later monitoring of established disease.
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Affiliation(s)
- Jack Phu
- Centre for Eye Health, University of New South Wales Sydney, Sydney, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales Sydney, Sydney, NSW, Australia
| | - Sieu K Khuu
- School of Optometry and Vision Science, University of New South Wales Sydney, Sydney, NSW, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Michael Kalloniatis
- Centre for Eye Health, University of New South Wales Sydney, Sydney, NSW, Australia.,School of Optometry and Vision Science, University of New South Wales Sydney, Sydney, NSW, Australia
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26
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Je S, Ennis FA, Woodhouse JM, Sengpiel F, Redmond T. Spatial summation across the visual field in strabismic and anisometropic amblyopia. Sci Rep 2018; 8:3858. [PMID: 29497120 PMCID: PMC5832776 DOI: 10.1038/s41598-018-21620-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 02/07/2018] [Indexed: 11/26/2022] Open
Abstract
Ricco's area (the largest area of visual space in which stimulus area and intensity are inversely proportional at threshold) has previously been hypothesised to be a result of centre/surround antagonism in retinal ganglion cell receptive fields, but recent evidence suggests a sizeable cortical contribution. Here, Ricco's area was measured in amblyopia, a condition in which retinal receptive fields are normal, to better understand its physiological basis. Spatial summation functions were determined at 12 visual field locations in both eyes of 14 amblyopic adults and 15 normal-sighted controls. Ricco's area was significantly larger in amblyopic eyes than in fellow non-amblyopic eyes. Compared to the size of Ricco's area in control eyes, Ricco's area measured significantly larger in amblyopic eyes. Additionally, Ricco's area in the fellow, non-amblyopic eye of amblyopic participants measured significantly smaller than in control eyes. Compared to controls, Ricco's area was larger in amblyopic eyes and smaller in fellow non-amblyopic eyes. Amblyopia type, binocularity, and inter-ocular difference in visual acuity were significantly associated with inter-ocular differences in Ricco's area in amblyopes. The physiological basis for Ricco's area is unlikely to be confined to the retina, but more likely representative of spatial summation at multiple sites along the visual pathway.
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Affiliation(s)
- Shindy Je
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Fergal A Ennis
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - J Margaret Woodhouse
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Frank Sengpiel
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Tony Redmond
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
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