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Turuwhenua J, LinTun Z, Norouzifard M, Edmonds M, Findlay R, Black J, Thompson B. Automated visual acuity estimation by optokinetic nystagmus using a stepped sweep stimulus. Ophthalmic Physiol Opt 2024; 44:1500-1512. [PMID: 39258616 DOI: 10.1111/opo.13391] [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: 04/16/2024] [Revised: 08/22/2024] [Accepted: 08/27/2024] [Indexed: 09/12/2024]
Abstract
PURPOSE To describe an automatic system for objective measurement of visual acuity (VA) using optokinetic nystagmus (OKN). This pilot study tested the system's sensitivity and specificity for detecting reduced VA in healthy adults by comparing VA-OKN to VA with an Early Treatment of Diabetic Retinopathy Study (ETDRS) chart (VA-ETDRS). METHODS Adult participants (age 30 ± 12 years) with either reduced VA (n = 11, VA-ETDRS > 0.20 logMAR) or normal VA (n = 12, VA-ETDRS ≤ 0.20 logMAR) completed monocular VA-OKN measurements in each eye. The VA-OKN stimulus was an array of drifting (5°/s) vanishing discs presented in descending/ascending size order (0.00-1.00 logMAR in 0.10 steps). The stimulus was stepped every 2 s, and 10 sweeps were shown per eye (five ascending and five descending). Eye-tracking data determined when OKN activity ceased (descending sweep) or began (ascending sweep), which was used to determine VA-OKN for each sweep. The estimates were averaged across sweeps to produce an automated VA-OKN. The automated sweeps were then provided in randomised order to a reviewer blinded to the VA-ETDRS findings who determined a final VA-OKN for an eye. RESULTS A single randomly selected eye from each observer was used for analysis. The sensitivity and specificity of VA-OKN using the same 0.20 logMAR threshold as VA-ETDRS was 100%. Comparisons between the VA-OKN and VA-ETDRS measures were made for participants in the reduced VA group. There was no significant difference between VA-OKN and VA-ETDRS (p = 0.55) and the two measures produced comparable values (r2 = 0.84, 95% limits of agreement = 0.19 logMAR, intra-class correlation coefficient = 0.90 [95% CI:0.68-0.97]). CONCLUSIONS Visual acuity using optokinetic nystagmus correctly identified a VA deficit in adults and for those with a VA deficit, VA-OKN was strongly correlated with the gold-standard clinical measure of VA. OKN is a promising method which has the potential for use in cognitively impaired adults and pre-verbal children.
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Affiliation(s)
- Jason Turuwhenua
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Zaw LinTun
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Mohammad Norouzifard
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | | | - Rebecca Findlay
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Joanna Black
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Benjamin Thompson
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
- School of Optometry and Vision Science, The University of Waterloo, Waterloo, Ontario, Canada
- Centre for Eye and Vision Research, Shatin, Hong Kong
- Liggins Institute, The University of Auckland, Auckland, New Zealand
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Rodwell V, Birchall A, Yoon HJ, Kuht HJ, Norton WHJ, Thomas MG. A novel portable flip-phone based visual behaviour assay for zebrafish. Sci Rep 2024; 14:236. [PMID: 38168485 PMCID: PMC10762252 DOI: 10.1038/s41598-023-51001-7] [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: 10/04/2023] [Accepted: 12/28/2023] [Indexed: 01/05/2024] Open
Abstract
The optokinetic reflex (OKR) serves as a vital index for visual system development in early life, commonly observed within the first six months post-birth in humans. Zebrafish larvae offer a robust and convenient model for OKR studies due to their rapid development and manageable size. Existing OKR assays often involve cumbersome setups and offer limited portability. In this study, we present an innovative OKR assay that leverages the flexible screen of the Samsung Galaxy Z Flip to optimize setup and portability. We conducted paired slow-phase velocity measurements in 5-day post-fertilization (dpf) zebrafish larvae (n = 15), using both the novel flip-phone-based assay and a traditional liquid-crystal display (LCD) arena. Utilizing Bland-Altman plots, we assessed the agreement between the two methods. Both assays were efficacious in eliciting OKR, with eye movement analysis indicating high tracking precision in the flip-phone-based assay. No statistically significant difference was observed in slow-phase velocities between the two assays (p = 0.40). Our findings underscore the feasibility and non-inferiority of the flip-phone-based approach, offering streamlined assembly, enhanced portability, and the potential for cost-effective alternatives. This study contributes to the evolution of OKR assay methodologies, aligning them with emerging research paradigms.
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Affiliation(s)
- Vanessa Rodwell
- The University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK
| | - Annabel Birchall
- The University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK
| | - Ha-Jun Yoon
- The University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK
| | - Helen J Kuht
- The University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK
| | - William H J Norton
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
| | - Mervyn G Thomas
- The University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX, UK.
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Johnson LL, Hebert S, Kueppers RB, McLoon LK. Nystagmus Associated With the Absence of MYOD Expression Across the Lifespan in Extraocular and Limb Muscles. Invest Ophthalmol Vis Sci 2023; 64:24. [PMID: 37703038 PMCID: PMC10503593 DOI: 10.1167/iovs.64.12.24] [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: 04/04/2023] [Accepted: 08/18/2023] [Indexed: 09/14/2023] Open
Abstract
Purpose The extraocular muscles (EOMs) undergo significant levels of continuous myonuclear turnover and myofiber remodeling throughout life, in contrast to limb skeletal muscles. Activation of the myogenic pathway in muscle precursor cells is controlled by myogenic transcription factors, such as MYOD. Limb muscles from MyoD-/- mice develop normally but have a regeneration defect, and these mice develop nystagmus. We examined MyoD-/- mice to determine if they have an aging phenotype. Methods Eye movements of aging MyoD-/- mice and littermate controls (wild type) were examined using optokinetic nystagmus (OKN). We assessed limb muscle function, changes to myofiber number, mean cross-sectional area, and abundance of the PAX7 and PITX2 populations of myogenic precursor cells. Results Aging did not significantly affect limb muscle function despite decreased mean cross-sectional areas at 18+ months. Aging wild type mice had normal OKN responses; all aging MyoD-/- mice had nystagmus. With OKN stimulus present, the MyoD-/- mice at all ages had shorter slow phase durations compared to wild type age matched controls. In the dark, the MyoD-/- mice had a shorter slow phase duration with age. This correlated with significantly decreased fiber numbers and cross-sectional areas. The EOM in MyoD-/- mice had increased numbers of PAX7-positive satellite cells and significantly decreased PITX2-positive myonuclei. Conclusions The absence of MYOD expression in aging mice causes a decrease in on-going myofiber remodeling, EOM fiber size, and number, and is associated with the development of spontaneous nystagmus. These results suggest that muscle-specific mutations can result in nystagmus, with increasing aging-related changes in the MyoD-/- EOM.
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Affiliation(s)
- Laura L. Johnson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
- Graduate Program in Molecular, Cellular, Developmental Biology and Genetics, University of Minnesota, Minneapolis, Minnesota, United States
| | - Sadie Hebert
- Department of Biology Teaching and Learning, University of Minnesota, Minneapolis, Minnesota, United States
| | - Rachel B. Kueppers
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
| | - Linda K. McLoon
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
- Graduate Program in Molecular, Cellular, Developmental Biology and Genetics, University of Minnesota, Minneapolis, Minnesota, United States
- Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, United States
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Tobener E, Searer A, Doettl S, Plyler P. Oculomotor Findings in Videonystagmography across the Lifespan. J Am Acad Audiol 2023; 34:11-18. [PMID: 39288905 DOI: 10.1055/s-0042-1760437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
BACKGROUND When performing oculomotor testing during standard videonystagmography (VNG), the vestibular system is not actively stimulated. Therefore, responses are generated from the cerebellum, brainstem, and oculomotor tract. Many patients seen for vestibular testing fall outside of the standard age norms, making it difficult to determine whether an abnormal finding is due to age or oculomotor dysfunction. PURPOSE The purpose of this study was to further evaluate the effect of age on a standard clinical VNG oculomotor test battery consisting of saccades, smooth pursuit, and optokinetic (OPK) testing. RESEARCH DESIGN This is a cross-sectional, between-group prospective study comparing oculomotor tests between age groups. STUDY SAMPLE Twenty-one older adults between the ages of 60 and 90 years with no history of central or peripheral vestibular dysfunction were included in the study. Previously collected data from 29 children aged 4 to 6 years and 33 adults aged 20 to 60 years were also included. DATA COLLECTION AND ANALYSIS Participants completed oculomotor testing using infrared goggles consisting of saccades, smooth pursuit, and OPK. Statistical analyses were completed using multivariate analysis of variance and analysis of variance and follow-up analysis when indicated. RESULTS Significant group differences were noted for saccade latency and speed, smooth pursuit gain, and OPK gain and speed. Children and older adults demonstrated longer saccade latencies compared with the controls, and older adults exhibited slower saccade speed than the controls and children. These results also indicated that smooth pursuit gain was reduced for children and older adults compared with controls, and gain decreased across all groups as frequency increased. Analyses of OPK results indicated older adults had reduced gain and speed compared with the children and control group. CONCLUSIONS The findings of prolonged saccade latencies and reduced smooth pursuit gain in both children and older adults suggest possible cerebellar rather than attentional effects. However, other findings such as reduced saccade speed and reduced OPK gain were noted only in the older adults, which suggests oculomotor degeneration and/or insufficient coverage of the visual field during testing, respectively. These results also indicate the importance of age-specific normative data for use in clinical oculomotor testing.
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Affiliation(s)
- Elizabeth Tobener
- Department of Audiology and Speech Pathology, University of Tennessee Health Science Center, Knoxville, Tennessee
| | - Ashlee Searer
- Department of Audiology and Speech Pathology, University of Tennessee Health Science Center, Knoxville, Tennessee
| | - Steven Doettl
- Department of Audiology and Speech Pathology, University of Tennessee Health Science Center, Knoxville, Tennessee
| | - Patrick Plyler
- Department of Audiology and Speech Pathology, University of Tennessee Health Science Center, Knoxville, Tennessee
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Smartphone video nystagmography using convolutional neural networks: ConVNG. J Neurol 2022; 270:2518-2530. [PMID: 36422668 PMCID: PMC10129923 DOI: 10.1007/s00415-022-11493-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 11/27/2022]
Abstract
Abstract
Background
Eye movement abnormalities are commonplace in neurological disorders. However, unaided eye movement assessments lack granularity. Although videooculography (VOG) improves diagnostic accuracy, resource intensiveness precludes its broad use. To bridge this care gap, we here validate a framework for smartphone video-based nystagmography capitalizing on recent computer vision advances.
Methods
A convolutional neural network was fine-tuned for pupil tracking using > 550 annotated frames: ConVNG. In a cross-sectional approach, slow-phase velocity of optokinetic nystagmus was calculated in 10 subjects using ConVNG and VOG. Equivalence of accuracy and precision was assessed using the “two one-sample t-test” (TOST) and Bayesian interval-null approaches. ConVNG was systematically compared to OpenFace and MediaPipe as computer vision (CV) benchmarks for gaze estimation.
Results
ConVNG tracking accuracy reached 9–15% of an average pupil diameter. In a fully independent clinical video dataset, ConVNG robustly detected pupil keypoints (median prediction confidence 0.85). SPV measurement accuracy was equivalent to VOG (TOST p < 0.017; Bayes factors (BF) > 24). ConVNG, but not MediaPipe, achieved equivalence to VOG in all SPV calculations. Median precision was 0.30°/s for ConVNG, 0.7°/s for MediaPipe and 0.12°/s for VOG. ConVNG precision was significantly higher than MediaPipe in vertical planes, but both algorithms’ precision was inferior to VOG.
Conclusions
ConVNG enables offline smartphone video nystagmography with an accuracy comparable to VOG and significantly higher precision than MediaPipe, a benchmark computer vision application for gaze estimation. This serves as a blueprint for highly accessible tools with potential to accelerate progress toward precise and personalized Medicine.
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McDonald MA, Stevenson CH, Kersten HM, Danesh-Meyer HV. Eye Movement Abnormalities in Glaucoma Patients: A Review. Eye Brain 2022; 14:83-114. [PMID: 36105571 PMCID: PMC9467299 DOI: 10.2147/eb.s361946] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 07/09/2022] [Indexed: 11/23/2022] Open
Abstract
Glaucoma is a common condition that relies on careful clinical assessment to diagnose and determine disease progression. There is growing evidence that glaucoma is associated not only with loss of retinal ganglion cells but also with degeneration of cortical and subcortical brain structures associated with vision and eye movements. The effect of glaucoma pathophysiology on eye movements is not well understood. In this review, we examine the evidence surrounding altered eye movements in glaucoma patients compared to healthy controls, with a focus on quantitative eye tracking studies measuring saccades, fixation, and optokinetic nystagmus in a range of visual tasks. The evidence suggests that glaucoma patients have alterations in several eye movement domains. Patients exhibit longer saccade latencies, which worsen with increasing glaucoma severity. Other saccadic abnormalities include lower saccade amplitude and velocity, and difficulty inhibiting reflexive saccades. Fixation is pathologically altered in glaucoma with reduced stability. Optokinetic nystagmus measures have also been shown to be abnormal. Complex visual tasks (eg reading, driving, and navigating obstacles), integrate these eye movements and result in behavioral adaptations. The review concludes with a summary of the evidence and recommendations for future research in this emerging field.
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Affiliation(s)
- Matthew A McDonald
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Clark H Stevenson
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Hannah M Kersten
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.,Eye Institute, Auckland, New Zealand
| | - Helen V Danesh-Meyer
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand.,Eye Institute, Auckland, New Zealand
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Taore A, Lobo G, Turnbull PR, Dakin SC. Diagnosis of colour vision deficits using eye movements. Sci Rep 2022; 12:7734. [PMID: 35562176 PMCID: PMC9095692 DOI: 10.1038/s41598-022-11152-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 04/08/2022] [Indexed: 11/09/2022] Open
Abstract
We set out to develop a simple objective test of functional colour vision based on eye movements made in response to moving patterns. We exploit the finding that while the motion of a colour-defined stimulus can be cancelled by adding a low-contrast luminance-defined stimulus moving in the opposite direction, the "equivalent luminance contrast" required for such cancellation is reduced when colour vision is abnormal. We used a consumer-grade infrared eye-tracker to measure eye movements made in response to coloured patterns drifting at different speeds. An automated analysis of these movements estimated individuals' red-green equiluminant point and their equivalent luminance contrast. We tested 34 participants: 23 colour vision normal controls, 9 deuteranomalous and 2 protanomalous individuals. We obtained reliable estimates of strength of directed eye movements (i.e. combined optokinetic and voluntary tracking) for stimuli moving at 16 deg/s and could use these data to classify participants' colour vision status with a sensitivity rate of 90.9% and a specificity rate of 91.3%. We conclude that an objective test of functional colour vision combining a motion-nulling technique with an automated analysis of eye movements can diagnose and assess the severity of protanopia and deuteranopia. The test places minimal demands on patients (who simply view a series of moving patterns for less than 90 s), requires modest operator expertise, and can be run on affordable hardware.
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Affiliation(s)
- Aryaman Taore
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand.
- New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand.
| | - Gabriel Lobo
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Philip R Turnbull
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
- New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Steven C Dakin
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
- New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
- UCL Institute of Ophthalmology, University College London, London, UK
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Kullmann A, Ashmore RC, Braverman A, Mazur C, Snapp H, Williams E, Szczupak M, Murphy S, Marshall K, Crawford J, Balaban CD, Hoffer M, Kiderman A. Portable eye-tracking as a reliable assessment of oculomotor, cognitive and reaction time function: Normative data for 18-45 year old. PLoS One 2021; 16:e0260351. [PMID: 34807938 PMCID: PMC8608311 DOI: 10.1371/journal.pone.0260351] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 11/08/2021] [Indexed: 01/29/2023] Open
Abstract
Eye movements measured by high precision eye-tracking technology represent a sensitive, objective, and non-invasive method to probe functional neural pathways. Oculomotor tests (e.g., saccades and smooth pursuit), tests that involve cognitive processing (e.g., antisaccade and predictive saccade), and reaction time tests have increasingly been showing utility in the diagnosis and monitoring of mild traumatic brain injury (mTBI) in research settings. Currently, the adoption of these tests into clinical practice is hampered by a lack of a normative data set. The goal of this study was to construct a normative database to be used as a reference for comparing patients' results. Oculomotor, cognitive, and reaction time tests were administered to male and female volunteers, aged 18-45, who were free of any neurological, vestibular disorders, or other head injuries. Tests were delivered using either a rotatory chair equipped with video-oculography goggles (VOG) or a portable virtual reality-like VOG goggle device with incorporated infrared eye-tracking technology. Statistical analysis revealed no effects of age on test metrics when participant data were divided into pediatric (i.e.,18-21 years, following FDA criteria) and adult (i.e., 21-45 years) groups. Gender (self-reported) had an effect on auditory reaction time, with males being faster than females. Pooled data were used to construct a normative database using 95% reference intervals (RI) with 90% confidence intervals on the upper and lower limits of the RI. The availability of these RIs readily allows clinicians to identify specific metrics that are deficient, therefore aiding in rapid triage, informing and monitoring treatment and/or rehabilitation protocols, and aiding in the return to duty/activity decision. This database is FDA cleared for use in clinical practice (K192186).
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Affiliation(s)
- Aura Kullmann
- Neurolign USA LLC, a Subsidiary of Neurolign Technologies Inc. (formerly Neuro Kinetics, Inc.), Pittsburgh, Pennsylvania, United States of America
| | - Robin C. Ashmore
- Neurolign USA LLC, a Subsidiary of Neurolign Technologies Inc. (formerly Neuro Kinetics, Inc.), Pittsburgh, Pennsylvania, United States of America
| | - Alexandr Braverman
- Department of Statistics and Data Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Christian Mazur
- Neurolign USA LLC, a Subsidiary of Neurolign Technologies Inc. (formerly Neuro Kinetics, Inc.), Pittsburgh, Pennsylvania, United States of America
| | - Hillary Snapp
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Erin Williams
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Mikhaylo Szczupak
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Sara Murphy
- Naval Medical Center, San Diego, California, United States of America
- Department of Defense, Hearing Center of Excellence, San Antonio, Texas, United States of America
| | - Kathryn Marshall
- Department of Defense, Hearing Center of Excellence, San Antonio, Texas, United States of America
- Madigan Army Medical Center, Tacoma, Washington, United States of America
| | - James Crawford
- Madigan Army Medical Center, Tacoma, Washington, United States of America
| | - Carey D. Balaban
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Michael Hoffer
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
- Department of Neurological Surgery, Miller School of Medicine, University of Miami, Miami, Florida, United States of America
| | - Alexander Kiderman
- Neurolign USA LLC, a Subsidiary of Neurolign Technologies Inc. (formerly Neuro Kinetics, Inc.), Pittsburgh, Pennsylvania, United States of America
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Kullmann A, Ashmore RC, Braverman A, Mazur C, Snapp H, Williams E, Szczupak M, Murphy S, Marshall K, Crawford J, Balaban CD, Hoffer M, Kiderman A. Normative data for ages 18-45 for ocular motor and vestibular testing using eye tracking. Laryngoscope Investig Otolaryngol 2021; 6:1116-1127. [PMID: 34667856 PMCID: PMC8513422 DOI: 10.1002/lio2.632] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/26/2021] [Accepted: 07/29/2021] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVE Eye tracking technology has been employed in assessing ocular motor and vestibular function following vestibular and neurologic conditions, including traumatic brain injury (TBI). Assessments include tests that provide visual and motion (rotation) stimuli while recording horizontal, vertical, and torsional eye movements. While some of these tests have shown diagnostic promise in previous studies, their use in clinical practice is limited by the lack of normative data. The goal of this study was to construct normative reference ranges to be used when comparing patients' results. METHODS Optokinetic response, subjective visual horizontal and vertical, and rotation tests were administered to male and female volunteers, ages 18-45, who were free from neurological, vestibular disorders, or other head injuries. Tests were administered using either a rotatory chair or a portable virtual reality-like goggle equipped with video-oculography. RESULTS Reference values for eye movements in response to different patterns of stimuli were analyzed from 290 to 449 participants. Analysis of gender (self-reported) or age when grouped as pediatric (late adolescent; 18-21 years of age) and adult (21-45 years of age) revealed no effects on the test metrics. Data were pooled and presented for each test metric as the 95% reference interval (RI) with 90% confidence intervals (CI) on upper and lower limits of the RI. CONCLUSIONS This normative database can serve as a tool to aid in diagnosis, treatment, and/or rehabilitation protocols for vestibular and neurological conditions, including mild TBI (mTBI). This database has been cleared by the FDA for use in clinical practice (K192186). LEVEL OF EVIDENCE 2b.
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Affiliation(s)
- Aura Kullmann
- Neurolign USA LLC, A Subsidiary of Neurolign Technologies Inc. (formerly Neuro Kinetics, Inc.)PittsburghPennsylvaniaUSA
| | - Robin C. Ashmore
- Neurolign USA LLC, A Subsidiary of Neurolign Technologies Inc. (formerly Neuro Kinetics, Inc.)PittsburghPennsylvaniaUSA
| | | | - Christian Mazur
- Neurolign USA LLC, A Subsidiary of Neurolign Technologies Inc. (formerly Neuro Kinetics, Inc.)PittsburghPennsylvaniaUSA
| | - Hillary Snapp
- Department of OtolaryngologyMiller School of Medicine, University of MiamiMiamiFloridaUSA
| | - Erin Williams
- Department of OtolaryngologyMiller School of Medicine, University of MiamiMiamiFloridaUSA
| | - Mikhaylo Szczupak
- Department of OtolaryngologyMiller School of Medicine, University of MiamiMiamiFloridaUSA
| | - Sara Murphy
- Naval Medical CenterSan DiegoCaliforniaUSA
- Department of DefenseHearing Center of ExcellenceSan AntonioTexasUSA
| | - Kathryn Marshall
- Department of DefenseHearing Center of ExcellenceSan AntonioTexasUSA
- Madigan Army Medical CenterTacomaWashingtonUSA
| | | | - Carey D. Balaban
- Department of OtolaryngologyUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Michael Hoffer
- Department of OtolaryngologyMiller School of Medicine, University of MiamiMiamiFloridaUSA
- Department of Neurological SurgeryMiller School of Medicine, University of MiamiMiamiFloridaUSA
| | - Alexander Kiderman
- Neurolign USA LLC, A Subsidiary of Neurolign Technologies Inc. (formerly Neuro Kinetics, Inc.)PittsburghPennsylvaniaUSA
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Sugita Y, Yamamoto H, Maeda Y, Furukawa T. Influence of Aging on the Retina and Visual Motion Processing for Optokinetic Responses in Mice. Front Neurosci 2020; 14:586013. [PMID: 33335469 PMCID: PMC7736246 DOI: 10.3389/fnins.2020.586013] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/10/2020] [Indexed: 11/13/2022] Open
Abstract
The decline in visual function due to normal aging impacts various aspects of our daily lives. Previous reports suggest that the aging retina exhibits mislocalization of photoreceptor terminals and reduced amplitudes of scotopic and photopic electroretinogram (ERG) responses in mice. These abnormalities are thought to contribute to age-related visual impairment; however, the extent to which visual function is impaired by aging at the organismal level is unclear. In the present study, we focus on the age-related changes of the optokinetic responses (OKRs) in visual processing. Moreover, we investigated the initial and late phases of the OKRs in young adult (2-3 months old) and aging mice (21-24 months old). The initial phase was evaluated by measuring the open-loop eye velocity of OKRs using sinusoidal grating patterns of various spatial frequencies (SFs) and moving at various temporal frequencies (TFs) for 0.5 s. The aging mice exhibited initial OKRs with a spatiotemporal frequency tuning that was slightly different from those in young adult mice. The late-phase OKRs were investigated by measuring the slow-phase velocity of the optokinetic nystagmus evoked by sinusoidal gratings of various spatiotemporal frequencies moving for 30 s. We found that optimal SF and TF in the normal aging mice are both reduced compared with those in young adult mice. In addition, we measured the OKRs of 4.1G-null (4.1G -/-) mice, in which mislocalization of photoreceptor terminals is observed even at the young adult stage. We found that the late phase OKR was significantly impaired in 4.1G - / - mice, which exhibit significantly reduced SF and TF compared with control mice. These OKR abnormalities observed in 4.1G - / - mice resemble the abnormalities found in normal aging mice. This finding suggests that these mice can be useful mouse models for studying the aging of the retinal tissue and declining visual function. Taken together, the current study demonstrates that normal aging deteriorates to visual motion processing for both the initial and late phases of OKRs. Moreover, it implies that the abnormalities of the visual function in the normal aging mice are at least partly due to mislocalization of photoreceptor synapses.
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Affiliation(s)
- Yuko Sugita
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Haruka Yamamoto
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Yamato Maeda
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
| | - Takahisa Furukawa
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Osaka, Japan
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Supranuclear eye movements and nystagmus in children: A review of the literature and guide to clinical examination, interpretation of findings and age-appropriate norms. Eye (Lond) 2018; 33:261-273. [PMID: 30353137 PMCID: PMC6367391 DOI: 10.1038/s41433-018-0216-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 08/30/2018] [Indexed: 11/08/2022] Open
Abstract
Abnormal eye movements in children, including nystagmus, present a significant challenge to ophthalmologists and other healthcare professionals. Similarly, examination of supranuclear eye movements and nystagmus in children and interpretation of any resulting clinical signs can seem very complex. A structured assessment is often lacking although in many cases, simple clinical observations, combined with a basic understanding of the underlying neurology, can hold the key to clinical diagnosis. As the range of underlying diagnoses for children with abnormal eye movements is broad, recognising clinical patterns and understanding their neurological basis is also imperative for ongoing management. Here, we present a review and best practice guide for a structured, methodical clinical examination of supranuclear eye movements and nystagmus in children, a guide to clinical interpretation and age-appropriate norms. We also detail the more common specific clinical findings and how they should be interpreted and used to guide further management. In summary, this review will encourage clinicians to combine a structured assessment and a logical interpretation of the resulting clinical signs, in order to recognise patterns of presentation and avoid unnecessary investigations and protracted delays in diagnosis and clinical care.
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Psychophysical testing in rodent models of glaucomatous optic neuropathy. Exp Eye Res 2015; 141:154-63. [PMID: 26144667 DOI: 10.1016/j.exer.2015.06.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 06/08/2015] [Accepted: 06/29/2015] [Indexed: 12/14/2022]
Abstract
Processing of visual information begins in the retina, with photoreceptors converting light stimuli into neural signals. Ultimately, signals are transmitted to the brain through signaling networks formed by interneurons, namely bipolar, horizontal and amacrine cells providing input to retinal ganglion cells (RGCs), which form the optic nerve with their axons. As part of the chronic nature of glaucomatous optic neuropathy, the increasing and irreversible damage and ultimately loss of neurons, RGCs in particular, occurs following progressive damage to the optic nerve head (ONH), eventually resulting in visual impairment and visual field loss. There are two behavioral assays that are typically used to assess visual deficits in glaucoma rodent models, the visual water task and the optokinetic drum. The visual water task can assess an animal's ability to distinguish grating patterns that are associated with an escape from water. The optokinetic drum relies on the optomotor response, a reflex turning of the head and neck in the direction of the visual stimuli, which usually consists of rotating black and white gratings. This reflex is a physiological response critical for keeping the image stable on the retina. Driven initially by the neuronal input from direction-selective RGCs, this reflex is comprised of a number of critical sensory and motor elements. In the presence of repeatable and defined stimuli, this reflex is extremely well suited to analyze subtle changes in the circuitry and performance of retinal neurons. Increasing the cycles of these alternating gratings per degree, or gradually reducing the contrast of the visual stimuli, threshold levels can be determined at which the animal is no longer tracking the stimuli, and thereby visual function of the animal can be determined non-invasively. Integrating these assays into an array of outcome measures that determine multiple aspects of visual function is a central goal in vision research and can be realized, for example, by the combination of measuring optomotor reflex function with electroretinograms (ERGs) and optical coherence tomography (OCT) of the retina. These structure-function correlations in vivo are urgently needed to identify disease mechanisms as potential new targets for drug development. Such a combination of the experimental assessment of the optokinetic reflex (OKR) or optomotor response (OMR) with other measures of retinal structure and function is especially valuable for research on GON. The chronic progression of the disease is characterized by a gradual decrease in function accompanied by a concomitant increase in structural damage to the retina, therefore the assessment of subtle changes is key to determining the success of novel intervention strategies.
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Turuwhenua J, Yu TY, Mazharullah Z, Thompson B. A method for detecting optokinetic nystagmus based on the optic flow of the limbus. Vision Res 2014; 103:75-82. [DOI: 10.1016/j.visres.2014.07.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/11/2014] [Accepted: 07/13/2014] [Indexed: 01/25/2023]
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Abstract
PURPOSE OF REVIEW Mechanisms underlying infantile nystagmus are unclear. The aim of this review is to outline recent developments in understanding the aetiology of infantile nystagmus. RECENT FINDINGS There have been advances in understanding mechanisms underlying idiopathic infantile nystagmus, which has progressed through determining the role of the FRMD7 gene in controlling neurite outgrowth, and albinism, in which recent models have investigated the possibility of retinal miswiring leading to nystagmus. We also briefly review aetiology of infantile nystagmus in afferent visual deficits caused by ocular disease, and PAX6 mutations. Improved phenotypical characterization of all these infantile nystagmus subtypes has been achieved recently through high-resolution retinal imaging using optical coherence tomography. Several new hypotheses proposing common mechanisms that could underlie various infantile nystagmus subtypes are also highlighted. SUMMARY Although there is still no consensus of opinion regarding the mechanisms causing infantile nystagmus, identification of new genes and determining their cellular function, phenotypical characterization of genetic subtypes, and improvements in animal models have significantly advanced our understanding of infantile nystagmus. These recent developments pave the way to achieving a much clearer picture of infantile nystagmus aetiology in the future.
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O'Connor E, Margrain TH, Freeman TCA. Age, eye movement and motion discrimination. Vision Res 2010; 50:2588-99. [PMID: 20732343 DOI: 10.1016/j.visres.2010.08.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 08/12/2010] [Accepted: 08/13/2010] [Indexed: 11/27/2022]
Abstract
Age is known to affect sensitivity to retinal motion. However, little is known about how age might affect sensitivity to motion during pursuit. We therefore investigated direction discrimination and speed discrimination when moving stimuli were either fixated or pursued. Our experiments showed: (1) age influences direction discrimination at slow speeds but has little affect on speed discrimination; (2) the faster eye movements made in the pursuit conditions produced poorer direction discrimination at slower speeds, and poorer speed discrimination at all speeds; (3) regardless of eye-movement condition, observers always combined retinal and extra-retinal motion signals to make their judgements. Our results support the idea that performance in these tasks is limited by the internal noise associated with retinal and extra-retinal motion signals, both of which feed into a stage responsible for estimating head-centred motion. Imprecise eye movement, or later noise introduced at the combination stage, could not explain the results.
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Affiliation(s)
- Emer O'Connor
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff CF10 3YT, UK
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Kolarik AJ, Margrain TH, Freeman TCA. Precision and accuracy of ocular following: influence of age and type of eye movement. Exp Brain Res 2009; 201:271-82. [PMID: 19841914 DOI: 10.1007/s00221-009-2036-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 09/24/2009] [Indexed: 11/28/2022]
Abstract
Previous work on ocular-following emphasises the accuracy of tracking eye movements. However, a more complete understanding of oculomotor control should account for variable error as well. We identify two forms of precision: 'shake', occurring over shorter timescales; 'drift', occurring over longer timescales. We show how these can be computed across a series of eye movements (e.g. a sequence of slow-phases or collection of pursuit trials) and then measure accuracy and precision for younger and older observers executing different types of eye movement. Overall, we found older observers were less accurate over a range of stimulus speeds and less precise at faster eye speeds. Accuracy declined more steeply for reflexive eye movements and shake was independent of speed. In all other instances, the two measures of precision expanded non-linearly with mean eye speed. We also found that shake during fixation was similar to shake for reflexive eye movement. The results suggest that deliberate and reflexive eye movement do not share a common non-linearity or a common noise source. The relationship of our data to previous studies is discussed, as are the consequences of imprecise eye movement for models of oculomotor control and perception during eye movement.
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Affiliation(s)
- Andrew J Kolarik
- School of Psychology, Cardiff University, Tower Building, Park Place, Cardiff, CF10 3AT, UK
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Kato M, de Wit TC, Stasiewicz D, von Hofsten C. Sensitivity to second-order motion in 10-month-olds. Vision Res 2008; 48:1187-95. [DOI: 10.1016/j.visres.2007.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Revised: 10/04/2007] [Accepted: 10/09/2007] [Indexed: 10/22/2022]
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Abstract
Human head movement control can be considered as part of the oculomotor system since the control of gaze involves coordination of the eyes and head. Humans show a remarkable degree of flexibility in eye-head coordination strategies, nonetheless an individual will often demonstrate stereotypical patterns of eye-head behaviour for a given visual task. This review examines eye-head coordination in laboratory-based visual tasks, such as saccadic gaze shifts and combined eye-head pursuit, and in common tasks in daily life, such as reading. The effect of the aging process on eye-head coordination is then reviewed from infancy through to senescence. Consideration is also given to how pathology can affect eye-head coordination from the lowest through to the highest levels of oculomotor control, comparing conditions as diverse as eye movement restrictions and schizophrenia. Given the adaptability of the eye-head system we postulate that this flexible system is under the control of the frontal cortical regions, which assist in planning, coordinating and executing behaviour. We provide evidence for this based on changes in eye-head coordination dependant on the context and expectation of presented visual stimuli, as well as from changes in eye-head coordination caused by frontal lobe dysfunction.
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Affiliation(s)
- Frank Antony Proudlock
- Ophthalmology Group, RKCSB, Leicester Royal Infirmary, University Hospitals of Leicester, University of Leicester, Leicester, UK.
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Kerber KA, Ishiyama GP, Baloh RW. A longitudinal study of oculomotor function in normal older people. Neurobiol Aging 2006; 27:1346-53. [PMID: 16122840 DOI: 10.1016/j.neurobiolaging.2005.07.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 06/28/2005] [Accepted: 07/06/2005] [Indexed: 11/25/2022]
Abstract
Cross-sectional studies have found declines in most measures of oculomotor function in older subjects compared to young controls, but no prior study has followed the same subjects over time. We measured saccade peak velocity, saccade delay time, smooth pursuit, optokinetic nystagmus (OKN), visual-vestibular-ocular-reflex (VVOR), fixation suppression of the vestibulo-ocular reflex (VOR-fix), and the vestibulo-ocular reflex in 53 subjects (older than 75 years) able to complete at least 9 yearly evaluations. In addition at each visit all patients underwent a complete history and examination, a gait and balance assessment, mini-mental status evaluation, and visual acuity testing. A subset of subjects completed 12 yearly evaluations (14 patients). Despite significant declines of most variables over time, smooth pursuit gain and saccade peak velocity remained stable during the duration of the study both in the 9-year group and the patients completing 12 years. Decline in OKN, VVOR, and VOR were significantly correlated (P<0.001) with decline in the Tinetti gait and balance score, even after controlling for age. In normal healthy older subjects, smooth pursuit and saccade peak velocity are relatively maintained while OKN, VVOR, and VOR function decline. The significant correlation between decline in oculomotor measures and gait and balance measures (even after controlling for age) suggests a common mechanism for the decline in both measures.
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Affiliation(s)
- Kevin A Kerber
- Department of Neurology, Reed Neurological Research Center, 710 Westwood Plaza, Box 951769, UCLA School of Medicine, Los Angeles, CA, USA
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