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Ghasia F, Tychsen L. Inter-Ocular Fixation Instability of Amblyopia: Relationship to Visual Acuity, Strabismus, Nystagmus, Stereopsis, Vergence, and Age. Am J Ophthalmol 2024; 267:230-248. [PMID: 38944136 DOI: 10.1016/j.ajo.2024.06.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/21/2024] [Accepted: 06/14/2024] [Indexed: 07/01/2024]
Abstract
PURPOSE Amblyopia damages visual sensory and ocular motor functions. One manifestation of the damage is abnormal fixational eye movements. Tiny fixation movements are normal; however, when these exceed a normal range, the behavior is labeled "fixation instability" (FI). Here we compare FI between normal and amblyopic subjects, and evaluate the relationship between FI and severity of amblyopia, strabismus angle, nystagmus, stereopsis, vergence, and subject age. METHODS Fixation eye movements were recorded using infrared video-oculography from 47 controls (15.3 ± 12.2 years of age) and 104 amblyopic subjects (13.3 ± 11.2 years of age) during binocular and monocular viewing. FI and vergence instability were quantified as the bivariate contour ellipse area (BCEA). We also calculated the ratio of FI between the 2 eyes: right eye/left eye for controls, amblyopic eye/fellow eye for amblyopes. Multiple regression analysis evaluated how FI related to a range of visuo-motor measures. RESULTS During binocular viewing, the FI of fellow and amblyopic eye, vergence instability, and inter-ocular FI ratios were least in anisometropic and most in mixed amblyopia (P < .05). Each correlated positively with the strabismus angle (P < .01). During monocular viewing, subjects with deeper amblyopia (P < .01) and larger strabismus angles (P < .05) had higher inter-ocular FI ratios. In all, 27% of anisometropic and >65% of strabismic/mixed amblyopes had nystagmus. Younger age and nystagmus increased FI and vergence instability (P < .05) but did not affect the inter-ocular FI ratios (P > .05). CONCLUSIONS Quantitative recording of perturbed eye movements in children reveal a major functional deficit linked to amblyopia. Imprecise fixation, measured as inter-ocular FI ratios, may be used as a robust marker for amblyopia and strabismus severity. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.
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Affiliation(s)
- Fatema Ghasia
- From the Neurosciences and Ocular Motility Laboratory (F.G.), Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA.
| | - Lawrence Tychsen
- Department of Ophthalmology and Visual Sciences (L.T.), St Louis Children's Hospital at Washington University School of Medicine, St. Louis, Missouri, USA
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Cakir GB, Murray J, Dulaney C, Ghasia F. Multifaceted Interactions of Stereoacuity, Inter-Ocular Suppression, and Fixation Eye Movement Abnormalities in Amblyopia and Strabismus. Invest Ophthalmol Vis Sci 2024; 65:19. [PMID: 38470326 PMCID: PMC10941996 DOI: 10.1167/iovs.65.3.19] [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: 10/23/2023] [Accepted: 02/19/2024] [Indexed: 03/13/2024] Open
Abstract
Purpose Amblyopic and strabismus subjects experience inter-ocular suppression, impaired stereoacuity, and increased fixation instability. The purpose of the study was to investigate factors affecting suppression and stereoacuity and examine their relationship to fixation eye movement (FEM) abnormalities. Methods We recruited 14 controls and 46 amblyopic subjects (anisometropic = 18, strabismic = 14, and mixed = 14) and 11 subjects with strabismus without amblyopia. We utilized the dichoptic motion coherence test to quantify suppression, and stereoacuity was assessed using the Titmus Fly test. We recorded FEMs using high-resolution video-oculography and classified subjects that did not have nystagmus (n = 27) versus those with nystagmus (n = 32; fusion maldevelopment nystagmus [FMN], n = 10) and nystagmus that did not meet the criteria of FMN (n = 20). We also recorded FEMs under dichoptic viewing (DcV) at varied fellow eye (FE) contrasts and computed the amplitude and velocity of the fast and slow FEMs and vergence instability. Results Inter-ocular suppression and stereoacuity deficits were closely correlated with an amblyopic eye (AE), visual acuity, and strabismus angle. Subjects with nystagmus displayed more pronounced stereoacuity deficits than those without nystagmus. Strabismic subjects with and without amblyopia, who demonstrated a fixation switch at 100% FE contrast, had lower inter-ocular suppression than subjects lacking a fixation switch under DcV. Amplitude of fast FEMs and velocity of slow FEMs, and vergence instability were increased as the FE contrast was lowered in both amblyopic and strabismic subjects. Conclusions The current study highlights the intricate relationships between AE visual acuity, eye deviation, and FEM abnormalities on suppression and stereoacuity deficits and underscores the need to evaluate FEM abnormalities while assessing dichoptic treatment outcomes.
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Affiliation(s)
- Gokce Busra Cakir
- Ocular Motility & Vision Neurosciences Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Jordan Murray
- Ocular Motility & Vision Neurosciences Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Cody Dulaney
- Ocular Motility & Vision Neurosciences Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Fatema Ghasia
- Ocular Motility & Vision Neurosciences Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
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Mompart-Martínez R, Argilés M, Cardona G, Cavero-Roig L, González-Sanchís L, Pighin MS. The Relationship between Fixation Stability and Retinal Structural Parameters in Children with Anisometropic, Strabismic and Mixed Amblyopia. Life (Basel) 2023; 13:1517. [PMID: 37511892 PMCID: PMC10381323 DOI: 10.3390/life13071517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 06/28/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023] Open
Abstract
(1) Background: Amblyopia is an ocular condition leading to structural and functional changes. The relationship between these changes is complex and remains poorly understood. (2) Methods: Participants included 31 children aged 5 to 9 years with strabismic (n = 9), anisometropic (n = 16) and mixed (n = 6) unilateral amblyopia, and 14 age-matched non-amblyopic children. The 95% and 63% Bivariate Contour Ellipse Area (BCEA), axial length, Foveal Avascular Zone (FAZ) area, center macular thickness and volume were assessed. The relationship between these parameters was explored. (3) Results: Statistically significant differences were found among the four groups in best corrected distance visual acuity (BCVA) (p < 0.001), BCEA 95% (p = 0.002) and BCEA 63% (p = 0.002), but not in the FAZ area, central macular thickness, central macular volume and axial length. Eyes with amblyopia had poorer BCVA and larger fixation instability than controls. Inter-ocular differences were more significant in patients with strabismic amblyopia, particularly in BCVA (p = 0.003), central macular thickness (p < 0.001) and central macular volume (p = 0.002). In amblyopic eyes, BCEA 95% and 63% were correlated with BCVA, but not with the FAZ area. (4) Conclusion: Amblyopia is associated with a reduction in fixation stability and BCVA, although there is a general lack of correlation with structural changes, suggesting a complex interaction between anatomy and function in amblyopia.
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Affiliation(s)
- Raquel Mompart-Martínez
- Institut Català de la Retina (ICR), 08022 Barcelona, Spain
- Department of Optics and Optometry, Universitat Politècnica de Catalunya (UPC), 08222 Terrassa, Spain
| | - Marc Argilés
- Department of Optics and Optometry, Universitat Politècnica de Catalunya (UPC), 08222 Terrassa, Spain
- Center for Sensors, Instruments, and Systems Development (CD6), Universitat Politècnica de Catalunya (UPC), 08222 Terrassa, Spain
| | - Genis Cardona
- Department of Optics and Optometry, Universitat Politècnica de Catalunya (UPC), 08222 Terrassa, Spain
- Applied Optics and Image Processing Group (GOAPI), Universitat Politècnica de Catalunya (UPC), 08222 Terrassa, Spain
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Meo M, Del Punta JA, Sánchez I, de Luis García R, Gasaneo G, Martin R. A dynamical method to objectively assess infantile nystagmus based on eye tracking. A pilot study. JOURNAL OF OPTOMETRY 2023:S1888-4296(23)00002-X. [PMID: 36697270 DOI: 10.1016/j.optom.2023.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/29/2022] [Accepted: 01/01/2023] [Indexed: 06/17/2023]
Abstract
PURPOSE The purpose of this research is to propose a new method for the easy, inexpensive and objective quantification of nystagmus using eye-tracking records collected during a simple reading task that could be implantable in clinical practice to assess patients with nystagmus. METHODS This is a prospective, observational pilot study. Eye movements of 4 nystagmus patients and 9 healthy children during a reading task (a paragraph with 82 words) on a 15'' monitor were collected and compared. Data are time series indicating the gaze position on the screen. Two quantifiers were proposed: IndS (based on the speed of movements) and IndF (based on the variation of the gaze trajectory). RESULTS The indices proposed reflect differences in the behavior of eye movements between the two groups. Nystagmus patients present higher values of IndS - indicating smaller number of slow movements (16% of movements with speeds <0.33 1/s for nystagmus and 85% for the control group, with p = 0.01) - and higher values of IndF - indicating higher gaze fluctuation (p = 0.01). Differences were not related with reading speed as show the mean and standard deviation: the nystagmus group required 115±45 s to complete the task and the control group 151±85 s; p = 0.73. CONCLUSIONS The proposed indices provide a new method that allows an objective assessment of nystagmus, with potential use in clinical and research practice to improve the follow-up of patients by monitoring the nystagmus over time or treatment.
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Affiliation(s)
- Marcos Meo
- Instituto de Física del Sur, Departamento de Física, Universidad Nacional del Sur (UNS) - CONICET, 8000 Bahía Blanca, Argentina
| | - Jessica Adriana Del Punta
- Instituto de Física del Sur, Departamento de Física, Universidad Nacional del Sur (UNS) - CONICET, 8000 Bahía Blanca, Argentina; Departamento de Matemática, Universidad Nacional del Sur (UNS), 8000 Bahía Blanca, Argentina
| | - Irene Sánchez
- Optometry Research Group, IOBA Eye Institute. School of Optometry, University of Valladolid. 47011 Valladolid, Spain; Departamento de Física Teórica Atómica y Óptica. Universidad de Valladolid, 47011 Valladolid, Spain.
| | - Rodrigo de Luis García
- Laboratorio de Procesado de Imagen (LPI). Universidad de Valladolid, 47011 Valladolid, Spain
| | - Gustavo Gasaneo
- Instituto de Física del Sur, Departamento de Física, Universidad Nacional del Sur (UNS) - CONICET, 8000 Bahía Blanca, Argentina; Centro Integral de Neurociencias Aplicadas, 8000 Bahía Blanca, Argentina
| | - Raúl Martin
- Optometry Research Group, IOBA Eye Institute. School of Optometry, University of Valladolid. 47011 Valladolid, Spain; Departamento de Física Teórica Atómica y Óptica. Universidad de Valladolid, 47011 Valladolid, Spain
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Hong J, Kuo D, Su H, Li L, Guo Y, Chu H, Fu J. Ocular and visual perceptive factors associated with treatment outcomes in patients with anisometropic amblyopia. BMC Ophthalmol 2023; 23:21. [PMID: 36635654 PMCID: PMC9837961 DOI: 10.1186/s12886-023-02770-2] [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: 02/18/2022] [Accepted: 01/04/2023] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND The aim of this observational study was to identify ocular and visual perceptive risk factors related to treatment results following refractive correction and patching in children with anisometropic amblyopia, who were between the ages of 4 to 14 years old. METHODS One-hundred and two children with newly diagnosed anisometropic amblyopia were recruited. Successful treatment of amblyopia was defined as the final best corrected visual acuity (BCVA) better than or equal to 0.1 logMAR and amblyopic eye BCVA within 1 line of the sound eye BCVA by the end of the treatment period. BCVA, cycloplegic refraction, stereoacuity, perceptual eye position (PEP) and interocular suppression were measured. RESULTS Of these patients, 45.10% achieved successful treatment of amblyopia after refractive correction and patching for 10.5 months. The mean age was not significantly different between patients who were successfully and unsuccessfully treated (5.50 ± 1.59 years vs 6.14 ± 2.19 years, respectively). Patients who failed treatment had significantly larger interocular difference of BCVA at the time of initial treatment (successful group: 0.33 ± 0.29 logMAR, unsuccessful group: 0.65 ± 0.35 logMAR) and after refractive adaptation (successful group: 0.15 ± 0.13 logMAR, unsuccessful group: 0.42 ± 0.35 logMAR). They also had higher spherical equivalent (SE) of amblyopic eyes (successful group: 3.08 ± 3.61 D, unsuccessful group: 5.27 ± 3.38 D), bigger interocular difference of SE (successful group: 0.94 ± 2.71 D, unsuccessful group: 3.09 ± 3.05 D), worse stereoacuity (successful group: 2.32 ± 0.37 log seconds of arc, unsuccessful group: 2.75 ± 0.32 log seconds of arc), larger vertical PEP deviation (successful group: 6.41 ± 6.08 pixel, unsuccessful group: 19.07 ± 24.96 pixel) and deeper interocular suppression (successful group: 21.7 ± 19.7%, unsuccessful group: 37.8 ± 27.1%) than those of successfully treated patients. The most influential treatment failure risk factors were larger vertical PEP deviation [adjusted odds ratio (OR) (95% confidence interval) 1.12 (1.02-1.22)] and worse stereoacuity [adjusted odds ratio (OR) (95% confidence interval) 7.72 (1.50-39.85)] in multiple logistic regression analysis. CONCLUSIONS Larger vertical PEP deviation and worse stereoacuity were the most influential treatment failure risk factors in children with anisometropic amblyopia. The vertical PEP deviation and stereoacuity, which can reflect interocular interaction, may be useful in predicting the response to therapy.
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Affiliation(s)
- Jie Hong
- grid.414373.60000 0004 1758 1243Beijing Ophthalmology & Visual Sciences Key Lab, Dongcheng District, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang Street, Beijing, China
| | - Debbie Kuo
- grid.416759.80000 0004 0460 3124Palo Alto Medical Foundation, Palo Alto, CA USA
| | - Han Su
- grid.414373.60000 0004 1758 1243Beijing Ophthalmology & Visual Sciences Key Lab, Dongcheng District, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang Street, Beijing, China
| | - Lei Li
- grid.414373.60000 0004 1758 1243Beijing Ophthalmology & Visual Sciences Key Lab, Dongcheng District, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang Street, Beijing, China
| | - Yanan Guo
- grid.414373.60000 0004 1758 1243Beijing Ophthalmology & Visual Sciences Key Lab, Dongcheng District, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang Street, Beijing, China
| | - Hang Chu
- Guangdong Medical Device Research Institute, Guangzhou, China
| | - Jing Fu
- grid.414373.60000 0004 1758 1243Beijing Ophthalmology & Visual Sciences Key Lab, Dongcheng District, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, 1 Dongjiaominxiang Street, Beijing, China
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Ghasia F, Wang J. Amblyopia and fixation eye movements. J Neurol Sci 2022; 441:120373. [DOI: 10.1016/j.jns.2022.120373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/05/2022] [Accepted: 07/31/2022] [Indexed: 11/29/2022]
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Chow A, Nallour Raveendran R, Erkelens I, Babu R, Thompson B. Increased saccadic latency in Amblyopia: Oculomotor and attentional factors. Vision Res 2022; 197:108059. [DOI: 10.1016/j.visres.2022.108059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 04/04/2022] [Accepted: 04/19/2022] [Indexed: 11/15/2022]
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Fixation instability, astigmatism, and lack of stereopsis as factors impeding recovery of binocular balance in amblyopia following binocular therapy. Sci Rep 2022; 12:10311. [PMID: 35725590 PMCID: PMC9209502 DOI: 10.1038/s41598-022-13947-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/31/2022] [Indexed: 11/22/2022] Open
Abstract
Dichoptic therapy is a promising method for improving vision in pediatric and adult patients with amblyopia. However, a systematic understanding about changes in specific visual functions and substantial variation of effect among patients is lacking. Utilizing a novel stereoscopic augmented-reality based training program, 24 pediatric and 18 adult patients were trained for 20 h along a three-month time course with a one-month post-training follow-up for pediatric patients. Changes in stereopsis, distance and near visual acuity, and contrast sensitivity for amblyopic and fellow eyes were measured, and interocular differences were analyzed. To reveal what contributes to successful dichoptic therapy, ANCOVA models were used to analyze progress, considering clinical baseline parameters as covariates that are potential requirements for amblyopic recovery. Significant and lasting improvements have been achieved in stereoacuity, interocular near visual acuity, and interocular contrast sensitivity. Importantly, astigmatism, fixation instability, and lack of stereopsis were major limiting factors for visual acuity, stereoacuity, and contrast sensitivity recovery, respectively. The results demonstrate the feasibility of treatment-efficacy prediction in certain aspects of dichoptic amblyopia therapy. Furthermore, our findings may aid in developing personalized therapeutic protocols, capable of considering individual clinical status, to help clinicians in tailoring therapy to patient profiles for better outcome.
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Murray J, Gupta P, Dulaney C, Garg K, Shaikh AG, Ghasia FF. Effect of Viewing Conditions on Fixation Eye Movements and Eye Alignment in Amblyopia. Invest Ophthalmol Vis Sci 2022; 63:33. [PMID: 35212720 PMCID: PMC8883146 DOI: 10.1167/iovs.63.2.33] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Patients with amblyopia are known to have fixation instability, which arises from alteration of physiologic fixation eye movements (FEMs) and nystagmus. We assessed the effects of monocular, binocular, and dichoptic viewing on FEMs and eye alignment in patients with and without fusion maldevelopment nystagmus (FMN). Methods Thirty-four patients with amblyopia and seven healthy controls were recruited for this study. Eye movements were recorded using infrared video-oculography during (1) fellow eye viewing (FEV), (2) amblyopic eye viewing (AEV), (3) both eye viewing (BEV), and (4) dichoptic viewing (DcV) at varying fellow eye (FE) contrasts. The patients were classified per the clinical type of amblyopia and FEM waveforms into those without nystagmus, those with nystagmus with and without FMN. Fixational saccades and intersaccadic drifts, quick and slow phases of nystagmus, and bivariate contour ellipse area were analyzed in the FE and amblyopic eye (AE). Results We found that FEMs are differentially affected with increased amplitude of quick phases of FMN observed during AEV than BEV and during DcV at lower FE contrasts. Increased fixation instability was seen in anisometropic patients at lower FE contrasts. Incomitance of eye misalignment was seen with the greatest increase during FEV. Strabismic/mixed amblyopia patients without FMN were more likely to demonstrate a fixation switch where the AE attends to the target during DcV than patients with FMN. Conclusions Our findings suggest that FEM abnormalities modulate with different viewing conditions as used in various amblyopia therapies. Increased FEM abnormalities could affect the visual function deficits and may have treatment implications.
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Affiliation(s)
- Jordan Murray
- Visual Neurosciences and Ocular Motility Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Palak Gupta
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States.,Daroff-Dell'Osso Ocular Motility Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States
| | - Cody Dulaney
- Visual Neurosciences and Ocular Motility Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States
| | - Kiran Garg
- Case Western Reserve University, Cleveland, Ohio, United States
| | - Aasef G Shaikh
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States.,Daroff-Dell'Osso Ocular Motility Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States.,Department of Neurology, Neurological Institute, University Hospitals, Cleveland, Ohio, United States
| | - Fatema F Ghasia
- Visual Neurosciences and Ocular Motility Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States.,Daroff-Dell'Osso Ocular Motility Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States
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Gupta P, Beylergil S, Murray J, Jacobs J, Kilbane C, Shaikh AG, Ghasia FF. Effects of Parkinson Disease on Blur-Driven and Disparity-Driven Vergence Eye Movements. J Neuroophthalmol 2021; 41:442-451. [PMID: 34788236 DOI: 10.1097/wno.0000000000001422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
ABSTRACT Synchronous movements of the 2 eyes in the opposite direction, disconjugate movements such as vergence, facilitate depth perception. The vergence eye movements are affected in Parkinson disease (PD). Visual blur (accommodation) and fusion (retinal disparity) are important triggers for the vergence. The neural circuit responsible for blur-driven and disparity-driven vergence is tightly coupled. We investigated the effect of PD on these 2 vergence paradigms. In the experiment involving 14 patients with PD and 6 healthy controls, substantial differences between blur-driven and disparity-driven vergence were found. The gain (ratio of actual vs desired eye movements) was reduced in patients with PD in case of disparity-driven vergence but not in blur-driven vergence. The latency of disparity-driven vergence onset was significantly longer for patients with PD compared with healthy controls. Four strategies were used to drive disparity-driven vergence: a) pure disconjugate vergence, b) conjugate saccadic movements, c) disconjugate vergence followed by saccadic movements, and d) conjugate saccades followed by disconjugate vergence movements. Blur-driven vergence had only 2 strategies: a) conjugate saccades followed by disconjugate vergence and b) conjugate saccadic movements only. The results are consistent with the prediction that PD primarily affects disparity-driven vergence, but there are some effects on the strategies to execute blur-driven vergence. We speculate that the deep cerebellar nuclei and the supraoculomotor area of the midbrain that carry the disparity-driven and blur-driven vergence are affected in PD. It is possible to modulate their function through projections to the subthalamic nuclei.
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Affiliation(s)
- Palak Gupta
- Department of Biomedical Engineering (PG, SB, AGS), Case Western Reserve University, Cleveland, Ohio; Daroff-Dell'Osso Ocular Motility Laboratory (PG, SB, JJ, AGS, FFG), Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio; Cole Eye Institute (JM, FFG), Cleveland Clinic, Cleveland, Ohio; and Department of Neurology (CK, AGS), Neurological Institute, University Hospitals, Cleveland, Ohio
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Candy TR, Cormack LK. Recent understanding of binocular vision in the natural environment with clinical implications. Prog Retin Eye Res 2021; 88:101014. [PMID: 34624515 PMCID: PMC8983798 DOI: 10.1016/j.preteyeres.2021.101014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 09/26/2021] [Accepted: 09/29/2021] [Indexed: 10/20/2022]
Abstract
Technological advances in recent decades have allowed us to measure both the information available to the visual system in the natural environment and the rich array of behaviors that the visual system supports. This review highlights the tasks undertaken by the binocular visual system in particular and how, for much of human activity, these tasks differ from those considered when an observer fixates a static target on the midline. The everyday motor and perceptual challenges involved in generating a stable, useful binocular percept of the environment are discussed, together with how these challenges are but minimally addressed by much of current clinical interpretation of binocular function. The implications for new technology, such as virtual reality, are also highlighted in terms of clinical and basic research application.
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Affiliation(s)
- T Rowan Candy
- School of Optometry, Programs in Vision Science, Neuroscience and Cognitive Science, Indiana University, 800 East Atwater Avenue, Bloomington, IN, 47405, USA.
| | - Lawrence K Cormack
- Department of Psychology, Institute for Neuroscience, and Center for Perceptual Systems, The University of Texas at Austin, Austin, TX, 78712, USA.
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Shemesh AA, Kocoglu K, Akdal G, Ala RT, Halmagyi GM, Zee DS, Otero-Millan J. Modeling the interaction among three cerebellar disorders of eye movements: periodic alternating, gaze-evoked and rebound nystagmus. J Comput Neurosci 2021; 49:295-307. [PMID: 34003422 PMCID: PMC9169448 DOI: 10.1007/s10827-021-00790-9] [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: 06/03/2020] [Revised: 04/28/2021] [Accepted: 05/04/2021] [Indexed: 10/21/2022]
Abstract
A woman, age 44, with a positive anti-YO paraneoplastic cerebellar syndrome and normal imaging developed an ocular motor disorder including periodic alternating nystagmus (PAN), gaze-evoked nystagmus (GEN) and rebound nystagmus (RN). During fixation there was typical PAN but changes in gaze position evoked complex, time-varying oscillations of GEN and RN. To unravel the pathophysiology of this unusual pattern of nystagmus, we developed a mathematical model of normal function of the circuits mediating the vestibular-ocular reflex and gaze-holding including their adaptive mechanisms. Simulations showed that all the findings of our patient could be explained by two, small, isolated changes in cerebellar circuits: reducing the time constant of the gaze-holding integrator, producing GEN and RN, and increasing the gain of the vestibular velocity-storage positive feedback loop, producing PAN. We conclude that the gaze- and time-varying pattern of nystagmus in our patient can be accounted for by superposition of one model that produces typical PAN and another model that produces typical GEN and RN, without requiring a new oscillator in the gaze-holding system or a more complex, nonlinear interaction between the two models. This analysis suggest a strategy for uncovering gaze-evoked and rebound nystagmus in the setting of a time-varying nystagmus such as PAN. Our results are also consistent with current ideas of compartmentalization of cerebellar functions for the control of the vestibular velocity-storage mechanism (nodulus and ventral uvula) and for holding horizontal gaze steady (the flocculus and tonsil).
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Affiliation(s)
- Ari A Shemesh
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Koray Kocoglu
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylül University, İzmir, Turkey
| | - Gülden Akdal
- Department of Neurosciences, Institute of Health Sciences, Dokuz Eylül University, İzmir, Turkey
- Department of Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Rahmi Tümay Ala
- Department of Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - G Michael Halmagyi
- Department of Neurology, Royal Prince Alfred Hospital and University of Sydney, Sydney, Australia
| | - David S Zee
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Departments of Ophthalmology, Otolaryngology-Head and Neck Surgery and Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jorge Otero-Millan
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- School of Optometry, University of California Berkeley, Berkeley, CA, USA.
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Martin TL, Murray J, Garg K, Gallagher C, Shaikh AG, Ghasia FF. Fixation eye movement abnormalities and stereopsis recovery following strabismus repair. Sci Rep 2021; 11:14417. [PMID: 34257361 PMCID: PMC8277881 DOI: 10.1038/s41598-021-93919-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 06/30/2021] [Indexed: 02/06/2023] Open
Abstract
We evaluated the effects of strabismus repair on fixational eye movements (FEMs) and stereopsis recovery in patients with fusion maldevelopment nystagmus (FMN) and patients without nystagmus. Twenty-one patients with strabismus, twelve with FMN and nine without nystagmus, were tested before and after strabismus repair. Eye-movements were recorded during a gaze-holding task under monocular viewing conditions. Fast (fixational saccades and quick phases of nystagmus) and slow (inter-saccadic drifts and slow phases of nystagmus) FEMs and bivariate contour ellipse area (BCEA) were analyzed in the viewing and non-viewing eye. Strabismus repair improved the angle of strabismus in subjects with and without FMN, however patients without nystagmus were more likely to have improvement in stereoacuity. The fixational saccade amplitudes and intersaccadic drift velocities in both eyes decreased after strabismus repair in subjects without nystagmus. The slow phase velocities were higher in patients with FMN compared to inter-saccadic drifts in patients without nystagmus. There was no change in the BCEA after surgery in either group. In patients without nystagmus, the improvement of the binocular function (stereopsis), as well as decreased fixational saccade amplitude and intersaccadic drift velocity, could be due, at least partially, to central adaptive mechanisms rendered possible by surgical realignment of the eyes. The absence of improvement in patients with FMN post strabismus repair likely suggests the lack of such adaptive mechanisms in patients with early onset infantile strabismus. Assessment of fixation eye movement characteristics can be a useful tool to predict functional improvement post strabismus repair.
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Affiliation(s)
- Talora L Martin
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
- Visual Neurosciences and Ocular Motility Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jordan Murray
- Visual Neurosciences and Ocular Motility Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Kiran Garg
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
- Visual Neurosciences and Ocular Motility Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Charles Gallagher
- Visual Neurosciences and Ocular Motility Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Aasef G Shaikh
- Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
- Daroff-Del'Osso Ocular Motility Laboratory, Cleveland VA Medical Center, Cleveland, OH, USA
- Neurology Service, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Fatema F Ghasia
- Visual Neurosciences and Ocular Motility Laboratory, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA.
- Daroff-Del'Osso Ocular Motility Laboratory, Cleveland VA Medical Center, Cleveland, OH, USA.
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Scaramuzzi M, Murray J, Nucci P, Shaikh AG, Ghasia FF. Fixational eye movements abnormalities and rate of visual acuity and stereoacuity improvement with part time patching. Sci Rep 2021; 11:1217. [PMID: 33441575 PMCID: PMC7806581 DOI: 10.1038/s41598-020-79077-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/03/2020] [Indexed: 11/09/2022] Open
Abstract
Residual amblyopia is seen in 40% of amblyopic patients treated with part-time patching. Amblyopic patients with infantile onset strabismus or anisometropia can develop fusion maldevelopment nystagmus syndrome (FMNS). The purpose of this study was to understand the effects of presence of FMNS and clinical subtype of amblyopia on visual acuity and stereo-acuity improvement in children treated with part-time patching. Forty amblyopic children who had fixation eye movement recordings and at least 12 months of follow-up after initiating part-time patching were included. We classified amblyopic subjects per the fixational eye movements characteristics into those without any nystagmus, those with FMNS and patients with nystagmus without any structural anomalies that do not meet the criteria of FMNS or idiopathic infantile nystagmus. We also classified the patients per the clinical type of amblyopia. Patching was continued until amblyopia was resolved or no visual acuity improvement was noted at two consecutive visits. Children with anisometropic amblyopia and without FMNS have a faster improvement and plateaued sooner. Regression was only seen in patients with strabismic/mixed amblyopia particularly those with FMNS. Patients with FMNS had improvement in visual acuity but poor stereopsis with part-time patching and required longer duration of treatment.
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Affiliation(s)
- Matteo Scaramuzzi
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Neuroscience, Unit of Ophthalmology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
- DISCCO, University of Milan, Milan, Italy
| | - Jordan Murray
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Aasef G Shaikh
- Daroff-Dell'Osso Ocular Motility Laboratory, Cleveland, OH, USA
- Case Medical Center, Case Western Reserve University, Cleveland, OH, USA
| | - Fatema F Ghasia
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA.
- Case Medical Center, Case Western Reserve University, Cleveland, OH, USA.
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Scaramuzzi M, Murray J, Otero-Millan J, Nucci P, Shaikh AG, Ghasia FF. Part time patching treatment outcomes in children with amblyopia with and without fusion maldevelopment nystagmus: An eye movement study. PLoS One 2020; 15:e0237346. [PMID: 32790721 PMCID: PMC7425965 DOI: 10.1371/journal.pone.0237346] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/23/2020] [Indexed: 11/19/2022] Open
Abstract
PURPOSE We investigated how the abnormalities of fixation eye movements (FEMs) of the amblyopic eye were linked with treatment outcomes following part-time patching therapy in children with amblyopia. METHODS We recruited 53 patients, with at least 12 months of patching, and measured FEMs at the end of treatment. Subjects were classified based on FEM waveforms (those without nystagmus = 21, those with nystagmus without fusion maldevelopment nystagmus (FMN) = 21, and those with FMN = 11) and based on clinical type of amblyopia (anisometropic = 18, strabismic = 6, and mixed = 29). The treatment outcomes such as duration of treatment of receiving part-time patching therapy, visual acuity and stereo-acuity deficits at the end of treatment were determined. Bivariate contour ellipse area (BCEA), fast (fixational saccade/quick phases), and slow (inter-saccadic drifts/slow phases) FEMs of the fellow and amblyopic eye were analyzed. RESULTS Anisometropic group had less residual amblyopia (0.23±0.19logMAR acuity) compared to strabismic/mixed (0.36±0.26) groups (p = 0.007). Treatment duration in patients without nystagmus was lower (12.6±9.5months) compared to nystagmus without FMN (25.6±23.2) and FMN (29.5±20.4) groups (p = 0.006). Patients without nystagmus had better stereopsis at the end of treatment (2.3±0.84logarcsecs) compared to nystagmus without FMN (2.6±0.84) group (p = 0.003). The majority of patients with FMN (8/11) had absent stereopsis. BCEA of the amblyopic eye was higher in patients with greater residual visual acuity deficits in patients without nystagmus. No such association was seen in Nystagmus no FMN and FMN groups. Increased amplitude of fast FEMs, increased eye position variance and eye velocity of slow FEMs were seen in patients who had received longer duration of part time patching therapy and in those with greater residual amblyopia, and poor stereopsis at the end of treatment. CONCLUSIONS Assessment of FEM waveforms and fast and slow FEM characteristics are important measures while describing fixation instability in amblyopia. Several FEM abnormalities were associated with stereo-acuity and visual acuity deficits and treatment duration in patients with amblyopia treated with part time patching therapy.
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Affiliation(s)
- Matteo Scaramuzzi
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States of America
- Department of Neuroscience, Unit of Ophthalmology, Istituto Giannina Gaslini, Genoa, Italy
- DISCCO, University of Milan, Milan, Italy
| | - Jordan Murray
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States of America
| | - Jorge Otero-Millan
- Department of Neurology, The Johns Hopkins University, Baltimore, MD, United States of America
| | | | - Aasef G. Shaikh
- Daroff—Dell’Osso Ocular Motility Laboratory, Cleveland, OH, United States of America
- Case Medical Center, Case Western Reserve University, Cleveland, OH, United States of America
| | - Fatema F. Ghasia
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States of America
- Daroff—Dell’Osso Ocular Motility Laboratory, Cleveland, OH, United States of America
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