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Ma MML, Scheiman M. Divergence excess and basic exotropia types of intermittent exotropia: a major review. Part 1: prevalence, classification, risk factors, natural history and clinical characteristics. Strabismus 2023; 31:97-128. [PMID: 37489263 DOI: 10.1080/09273972.2023.2227681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
INTRODUCTION Intermittent exotropia (IXT) is a common form of strabismus. It is an outward deviation of one eye typically when viewing at distance. Symptoms include, but are not limited to double vision, eyes feeling tired, excessive blinking, and reduced quality of life. Its clinical characteristics are distinctive from other types of strabismus. This paper provides a comprehensive review of prevalence, classification, risk factors, natural history and clinical characteristics of the divergence excess and basic exotropia types of IXT. METHODS Search strategies involving combination of keywords including intermittent exotropia, exotropia, divergences excess, basic exotropia, prevalence, incidence, classification, terminology, risk factor, natural history, observation, angle of deviation, control, control score, symptom, quality of life, suppression, anomalous retinal correspondence, AC/A, accommodative convergence/accommodation, accommodative convergence, convergence, accommodation, vergence, incomitance and vertical were used in Medline. All English articles from 1900/01/01 to 2020/09/01 were reviewed. The reference list of the identified article was also checked for additional relevant article. Studies focused on animal model or strabismus associated with neurologic disorder or injury were excluded. RESULTS The estimated prevalence of IXT in children ranges from 0.1% to 3.7%. Hypoxia at birth and being female are potential risk factors of IXT. Using validated measures of control, multicenter prospective studies showed that the rate of conversion from IXT to constant exotropia is low. The angle of deviation is the most reported outcome measure in studies of IXT. It is often used to represent the severity of the condition and has been suggested as one of the four core outcomes for studies of the surgical management of IXT. Control of exodeviation is one of the four suggested core outcomes for study of surgery of IXT and is considered the main parameter of disease severity. Several validated tools for quality of life score are available to evaluate the subjective severity of IXT. DISCUSSION We reviewed the prevalence, classification, risk factors, natural history and clinical characteristics of the divergence excess and basic exotropia types of IXT. Further research into these areas, especially its clinical characteristics (e.g. suppression, dual retinal correspondence), will increase our understanding of this condition and potentially lead to better management of this common form of strabismus.
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Affiliation(s)
- Martin Ming-Leung Ma
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou
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Wang X, Lu L, Liao M, Wei H, Chen X, Huang X, Liu L, Gong Q. Abnormal cortical morphology in children and adolescents with intermittent exotropia. Front Neurosci 2022; 16:923213. [PMID: 36267233 PMCID: PMC9577327 DOI: 10.3389/fnins.2022.923213] [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] [Received: 04/19/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose To investigate cortical differences, age-related cortical differences, and structural covariance differences between children with intermittent exotropia (IXT) and healthy controls (HCs) using high-resolution magnetic resonance imaging (MRI). Methods Sixteen IXT patients and 16 HCs underwent MRI using a 3-T MR scanner. FreeSurfer software was used to obtain measures of cortical volume, thickness, and surface area. Group differences in cortical thickness, volume and surface area were examined using a general linear model with intracranial volume (ICV), age and sex as covariates. Then, the age-related cortical differences between the two groups and structural covariance in abnormal morphometric changes were examined. Results Compared to HCs, IXT patients demonstrated significantly decreased surface area in the left primary visual cortex (PVC), and increased surface area in the left inferior temporal cortex (ITC). We also found increased cortical thickness in the left orbitofrontal cortex (OFC), right middle temporal cortex (MT), and right inferior frontal cortex (IFC). No significant differences were found in cortical volume between the two groups. There were several negative correlations between neuroanatomic measurements and age in the HC group that were not observed in the IXT group. In addition, we identified altered patterns of structural correlations across brain regions in patients with IXT. Conclusion To our knowledge, this study is the first to characterize the cortical morphometry of the children and adolescents with IXT. Based on our results, children and adolescents with IXT exhibited significant alterations in the PVC and association cortices, different cortical morphometric development patterns, and disrupted structural covariance across brain regions.
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Affiliation(s)
- Xi Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Optometry and Vision Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Lu Lu
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
| | - Meng Liao
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Optometry and Vision Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Hong Wei
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Optometry and Vision Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaohang Chen
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Optometry and Vision Sciences, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoqi Huang
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Xiaoqi Huang,
| | - Longqian Liu
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Optometry and Vision Sciences, West China Hospital, Sichuan University, Chengdu, China
- Longqian Liu,
| | - Qiyong Gong
- Huaxi MR Research Center (HMRRC), Department of Radiology, West China Hospital, Sichuan University, Chengdu, China
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Wang Y, Zhong J, Cheng M, Li J, Ma K, Hu X, Li N, Liang H, Zhu Z, Zhou J, Yuan J. A novel clinical dynamic stereopsis assessment based on autostereoscopic display system. ANNALS OF TRANSLATIONAL MEDICINE 2022; 10:656. [PMID: 35845544 PMCID: PMC9279808 DOI: 10.21037/atm-21-6700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 04/29/2022] [Indexed: 11/25/2022]
Abstract
Background Although it is recognized that dynamic stereopsis is vital in daily life, there is still room for improvement in assessment methods. A novel clinical dynamic stereopsis assessment method was created based on an autostereoscopic display system that did not require additional auxiliary glasses. This study evaluated the optical parameters and clinical performance of the autostereoscopic display system for clinical dynamic stereopsis assessment. Methods The autostereoscopic dynamic stereopsis assessment device was based on a directional backlight technology. Experiment 1 was performed under the same environmental conditions to compare luminance, crosstalk, and spectrum between the autostereoscopic dynamic stereopsis assessment device and the conventional dynamic random-dot stereopsis measuring instrument. Experiment 2 was an observational, analytic, cross-sectional study involving 135 healthy participants, each of whom was asked to complete measurements on both the autostereoscopic and conventional devices in random order. Stereo acuity, operating time, acceptance, and visual fatigue scores were recorded for clinical evaluation. Results The autostereoscopic device had brighter luminance (139 and 140 cd/m2 for 2 eyes, respectively), lower crosstalk (4.50% for both eyes), and higher color restoration degree than those of the conventional instrument. Clinically, the novel dynamic stereopsis assessment was as accurate as the traditional method [170" (0.00") and 170" (0.00") respectively; P=0.317], and with more efficiency (166±58.9 and 298±116 s, respectively; P<0.001), higher acceptance (3.36±0.93 and 2.02±0.59 points, respectively; P<0.001), lesser fatigue (0.27±0.46 and 0.73±0.66 points, respectively; P<0.001). The autostereoscopic dynamic stereopsis assessment device with brighter luminance, lower crosstalk, and higher color restoration degree was more effective than the traditional instrument at displaying dynamic clues for clinical dynamic stereopsis assessment. Furthermore, its high-quality image and user-friendly interface provided accurate assessment results in all 3 dynamic stereopsis assessment task conditions, with a higher level of acceptance and lesser visual fatigue, than the traditional assessment method. Conclusions The autostereoscopic device has excellent functions in both optical parameters and clinical performance, and therefore has the potential to be applied and popularized in future assessments.
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Affiliation(s)
- Yiyao Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Jing Zhong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Mengyi Cheng
- State Key Laboratory of Optoelectronic Materials and Technology, School of Physics, Sun Yat-sen University, Guangzhou, China
| | - Jijing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Ke Ma
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Xiaoqing Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
| | - Naiyang Li
- Eye Center, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, China
| | - Haowen Liang
- State Key Laboratory of Optoelectronic Materials and Technology, School of Physics, Sun Yat-sen University, Guangzhou, China
| | - Zhengyuan Zhu
- Shenzhen CESI Information Technology Co., Ltd., Shenzhen, China
| | - Jianying Zhou
- State Key Laboratory of Optoelectronic Materials and Technology, School of Physics, Sun Yat-sen University, Guangzhou, China
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China
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Chen ST, Tung HC, Chen YT, Tien CL, Yeh CW, Lian JS, Cheng CY. The influence of contact lenses with different optical designs on the binocular vision and visual behavior of young adults. Sci Rep 2022; 12:6573. [PMID: 35449200 PMCID: PMC9023515 DOI: 10.1038/s41598-022-10580-7] [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] [Received: 01/15/2022] [Accepted: 04/11/2022] [Indexed: 11/10/2022] Open
Abstract
Theoretically, contact lenses change the accommodation and vergence demands of the eyes and directly or indirectly influence binocular vision. The purpose of this study was to investigate the influence of different optical designs of contact lenses on binocular vision and visual behavior among young adults. In this randomized, single-blinded experimental study, visual behavioral performance (VBP) and Ocular Surface Disease Index questionnaires were used for preliminary screening. Nineteen myopic subjects aged 20-26 years (21.59 ± 1.40 years) participated in the study. Baseline values for subjective refraction and binocular visual functions were evaluated. All the subjects were randomly grouped to wear different optical designs of single-vision, progressive, and bifocal contact lenses. Eye examinations were performed on the first day (CL baseline), 2nd week, and 4th week of wearing the lenses. In addition, subjects completed the VBP and visual quality questionnaire again at the end of the examination. Single-vision contact lenses (Lens 1) increased accommodative lag, negative relative accommodation, and distant and near vergence; however, vergence facilities, accommodative facilities, heterophoria, and the comfort and posture balance dimensions in the VBP questionnaire were improved. Progressive contact lenses (Lens 2) reduced the lag of accommodation and near vergence; in addition, vergence facilities and accommodative facilities were also improved. Bifocal contact lenses (Lens 3) affected negative and positive relative accommodation, but vergence facilities and accommodative facilities also progressed. Furthermore, both progressive (Lens 2) and bifocal (Lens 3) contact lenses enhanced overall visual behavioral performance. In terms of visual quality, single-vision contact lenses (Lens 1) were the most comfortable, progressive and bifocal contact lenses reduced distant visual acuity and stability, progressive contact lenses (Lens 2) had more complaints about halos at night, and bifocal contact lens (Lens 3) users were more likely to have double vision. Compared with single-vision contact lenses, progressive and bifocal contact lenses relaxed accommodation, reduced the lag of accommodation, and improved visual behavioral performance. Although the vergence function showed a significant change, it did not show worse trends when wearing contact lenses. Contact lenses with different optical designs have a great influence on binocular vision and visual behavioral performance.
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Affiliation(s)
- Shyan-Tarng Chen
- Department of Optometry, Chung Shan Medical University, Taichung, Taiwan.,Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan
| | | | - Yan-Ting Chen
- Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Chuen-Lin Tien
- Department of Electrical Engineering, Feng Chia University, Taichung, Taiwan
| | - Chih-Wei Yeh
- Department of Optometry, Chung Shan Medical University, Taichung, Taiwan
| | - Jheng-Sin Lian
- Shu-Zen Junior College of Medicine and Management, Kaohsiung, Taiwan
| | - Ching-Ying Cheng
- Department of Optometry, Chung Shan Medical University, Taichung, Taiwan. .,Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung, Taiwan.
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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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Economides JR, Adams DL, Horton JC. Interocular Suppression in Primary Visual Cortex in Strabismus. J Neurosci 2021; 41:5522-5533. [PMID: 33941649 PMCID: PMC8221600 DOI: 10.1523/jneurosci.0044-21.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/22/2021] [Accepted: 04/27/2021] [Indexed: 11/21/2022] Open
Abstract
People with strabismus acquired during childhood do not experience diplopia (double vision). To investigate how perception of the duplicate image is suppressed, we raised two male monkeys with alternating exotropia by disinserting the medial rectus muscle in each eye at age four weeks. Once the animals were mature, they were brought to the laboratory and trained to fixate a small spot while recordings were made in primary visual cortex (V1). Drifting gratings were presented to the receptive fields of 500 single neurons for eight interleaved conditions: (1) right eye monocular; (2) left eye monocular; (3) right eye's field, right eye fixating; (4) right eye's field, left eye fixating; (5) left eye's field, right eye fixating; (6) left eye's field, left eye fixating; (7) both eyes' fields, right eye fixating; (8) both eyes' fields, left eye fixating. As expected, ocular dominance histograms showed a monocular bias compared with normal animals, but many cells could still be driven via both eyes. Overall, neuronal responses were not affected by switches in ocular fixation. Individual neurons exhibited binocular interactions, but mean population indices indicated no net interocular suppression or facilitation. Even neurons located in cortex with reduced cytochrome oxidase (CO) activity, representing portions of the nasal visual field where perception is suppressed during binocular viewing, showed no net inhibition. These data indicate that V1 neurons do not appear to reflect strabismic suppression and therefore the elimination of diplopia is likely to be mediated at a higher cortical level.SIGNIFICANCE STATEMENT In patients with strabismus, images fall on non-corresponding points in the two retinas. Only one image is perceived, because signals emanating from the other eye that convey the duplicate image are suppressed. The benefit is that diplopia is prevented, but the penalty is that the visual feedback required to adjust eye muscle tone to realign the globes is eliminated. Here, we report the first electrophysiological recordings from the primary visual cortex (V1) in awake monkeys raised with strabismus. The experiments were designed to reveal how perception of double images is avoided.
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Affiliation(s)
- John R Economides
- Program in Neuroscience, Department of Ophthalmology, University of California, San Francisco, California 94143
| | - Daniel L Adams
- Program in Neuroscience, Department of Ophthalmology, University of California, San Francisco, California 94143
| | - Jonathan C Horton
- Program in Neuroscience, Department of Ophthalmology, University of California, San Francisco, California 94143
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Zhong J, Deng D, Chen Z, Li J, Yuan J, Feng L, Yu M. A novel dynamic random-dot stereopsis assessment to measure stereopsis in intermittent exotropia. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:308. [PMID: 33708935 PMCID: PMC7944283 DOI: 10.21037/atm-20-3896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background To investigate dynamic stereopsis in intermittent exotropia [X(T)] patients using a novel dynamic random-dot stereopsis assessment method. Methods A novel dynamic random-dot stereopsis test was performed using novel self-programmed software, which consisted of red and green dots and four blocks on the screen. The test included motion + disparity (MD), motion (M), and disparity (D), where the D cues ranged from 200 to 1,200 arc-seconds. The characteristics of preoperative dynamic stereopsis in 83 X(T) patients and associations with clinical features were analysed, and the prognosis was followed up on the 1st day and at the 2nd, 6th and 12th months postoperatively. Results Preoperatively, the mean reciprocal values of near and far stereopsis were 0.013±0.0016 and 0.0011±0.0005 arc-seconds in static stereopsis patients, respectively, and the MD, M, and D values were 0.002±0.0002, 0.0018±0.0001, and 0.0012±0.0002 arc-seconds in dynamic stereopsis, respectively. The MD value was negatively correlated with the Newcastle control score, disease course, and prism deviations (P<0.05), M was correlated with disease course and the Newcastle control score (P<0.05), and D was not correlated with any clinical features. Postoperative dynamic stereopsis improved from the 1st day and gradually peaked at the 6th month, while static stereopsis showed a decreased tendency in near but not far stereopsis. Conclusions The dynamic stereopsis quantitative evaluation method based on random dots is a feasible test and shows that destruction of X(T) patients’ dynamic stereopsis is affected by age at surgery, disease course, strabismus controllability and the strabismus degree.
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Affiliation(s)
- Jing Zhong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Daming Deng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Zidong Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jinrong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Junpeng Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Lei Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Minbin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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Strong fixation preference in patients with manifest exotropia: Does it matter or not? Int Ophthalmol 2020; 41:527-532. [PMID: 33052500 DOI: 10.1007/s10792-020-01603-1] [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: 05/01/2020] [Accepted: 10/01/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE To evaluate the influence of strong fixation preference on clinical and surgical outcomes, in non-amblyopic patients with basic-type intermittent exotropia (IXT). MATERIALS AND METHODS The records of patients were retrospectively investigated. Non-amblyopic patients with the diagnosis of basic-type IXT were enrolled and divided into two groups according to the presence of strong fixation preference (SFP). Best-corrected visual acuity, refractive errors, deviations in near and distance, convergence patterns, motor fusion, stereopsis were evaluated and compared. Patients who underwent surgery in each group composed subgroups and postoperative deviations, convergence patterns, motor fusion, and stereopsis were compared. RESULTS Seventy-seven patients were enrolled and divided into two groups according to the presence of SFP: patients with SFP composed Group 1 and patients with alternating fixation composed Group 2. Statistically significant difference was seen between groups in terms of motor fusion (p: 0.02). Other parameters did not differ between groups. Data obtained from patients in subgroups of each group were not statistically different. CONCLUSION The evaluation of basic-type exotropic patients according to their fixation preference revealed us that motor fusion might be affected by strong fixation preference. We also observed that SFP did not affect surgical success rates, convergence patterns, and stereopsis of exotropic patients.
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Xi S, Yao J, Zhang S, Liu R, Wu L, Ye X, Zhang P, Wen W, Zhao C. Disrupted neural signals in patients with concomitant exotropia. Ophthalmic Physiol Opt 2020; 40:650-659. [PMID: 32672862 DOI: 10.1111/opo.12715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 01/13/2023]
Abstract
PURPOSE Decreased binocular and oculomotor function in strabismics has recently been considered as cortical in origin. This study aimed to investigate functional abnormalities using a frequency-specific neuroimaging method in patients with concomitant exotropia (XT), and to demonstrate the clinical implications. METHODS Resting-state functional magnetic resonance imaging data were collected in 26 XT patients and 26 matched controls. To evaluate the local spontaneous neural activity, the amplitude of low frequency fluctuations (ALFF) was calculated in the typical frequency band (0.01-0.08 Hz) as well as five narrowly-defined frequency bands (slow-6: 0-0.01 Hz, slow-5: 0.01-0.027 Hz, slow-4: 0.027-0.073 Hz, slow-3: 0.073-0.167 Hz, and slow-2: 0.167-0.25 Hz), respectively. RESULTS Patients with XT showed decreased ALFF in the bilateral parieto-occipital sulcus (POS), and increased ALFF in the bilateral thalamus within the typical frequency band. Frequency-dependent ALFF alterations were found in the higher visual areas such as the right lateral occipital complex (LOC). Furthermore, ALFF in the right LOC in the slow-5 band was positively correlated with fusion control score (r = 0.70, p < 0.0001) and binocular function score (r = 0.67, p = 0.0002). Regression analyses showed that early age of onset remained the only significant explanatory factor for ALFF reduction in the right POS in the typically-measured frequency band (also referred to as the typical frequency band) (Odds ratio, 0.038; 95% confidence interval, 0.001 to 0.075). CONCLUSIONS Our findings provide spatial information regarding the functionally disrupted regions in XT. Moreover, the frequency-dependent ALLF alteration in the right LOC might reflect a potential plastic capacity in binocular function, which could be a potential objective index for evaluating disease severity.
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Affiliation(s)
- Sida Xi
- Eye Research Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Jing Yao
- Eye Research Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Shujie Zhang
- Eye Research Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Rui Liu
- Eye Research Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Lianqun Wu
- Eye Research Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Xinpei Ye
- Department of Radiology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Peng Zhang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Wen Wen
- Eye Research Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Chen Zhao
- Eye Research Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Ministry of Health, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China.,State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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10
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Different surgical outcomes in infantile exotropia according to onset time. J AAPOS 2019; 23:317.e1-317.e6. [PMID: 31654771 DOI: 10.1016/j.jaapos.2019.08.275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/15/2019] [Accepted: 08/04/2019] [Indexed: 11/21/2022]
Abstract
PURPOSE To determine whether age of onset influences surgical outcomes in infantile exotropia. METHODS The medical records of patients at our tertiary care facility who underwent bilateral lateral rectus recession for infantile exotropia during the period 2004-2013 were reviewed retrospectively. Patients were grouped by onset age: 6 months or earlier (E6 group) or later than 6 months (L6 group). Motor outcomes, near stereoacuity, and distance fusional status in both groups were evaluated. RESULTS A total of 134 patients were included: 35 in the E6 group and 99 in the L6 group. At a mean follow-up of 4.6 years, recurrence occurred in 12 (34%) of the E6 group and 38 (38%) of the L6 group (P = 0.496). Overcorrection occurred in 3 (9%) of the E6 group and in 4 (4%) of the L6 group (P = 0.341). In the analysis of 109 patients eligible for sensory examinations, the E6 group demonstrated a higher proportion of patients with reduced stereoacuity of 80 arcsec or worse (54% vs 25% [P = 0.007]) and suppression (46% vs 12% [P < 0.001]) compared with those in the L6 group. In logistic regression analyses, onset of ≤6 months was significantly associated with reduced stereoacuity (OR = 6.42) and suppression (OR = 37.67) but not with recurrence or overcorrection. CONCLUSIONS In our study cohort, age of onset ≤6 months was associated with worse sensory prognosis for children with infantile exotropia but not with a difference in motor outcomes.
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Wen Y, Yan J, Wang Z, Shen T, Qiu X, Deng D, Chen J. Topographical profiles of macula and optic nerve head in concomitant strabismus patients as measured using OCT and CSLO. Graefes Arch Clin Exp Ophthalmol 2019; 258:675-682. [PMID: 31754829 DOI: 10.1007/s00417-019-04507-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/24/2019] [Accepted: 10/07/2019] [Indexed: 01/26/2023] Open
Abstract
PURPOSE Investigate morphological changes of macula and optic nerve head (ONH) in concomitant strabismic patients using optical coherence tomography (OCT) and confocal scanning laser ophthalmoscopy (CSLO). METHODS A cross-sectional study conducted from April 2017 to February 2018 at the Zhongshan Ophthalmic Center, Sun Yat-sen University. Spectral-domain (SD)-OCT and CSLO were used to observe morphological changes of macula and ONH in concomitant strabismic patients with normal vision and healthy controls. In each subject, a 6-mm diameter zone centered at the fovea was scanned and topographical images of the ONH and peripapillary retina were generated. Fundus parameters were recorded and analyzed. RESULTS A total of 138 cases, including 29 patients with concomitant esotropia (ET), 38 constant exotropia (XT), 42 intermittent exotropia (IXT), and 29 healthy controls, were recruited. Compared with controls, OCT revealed that the thickness of nasal intraretinal layers (IRLs) in ET patients was significantly increased, particularly in ganglion cell layer (GCL) and inner nuclear layer (INL). In XT patients, the temporal half of outer retinal layers (ORLs) showed significant increases in thickness. CSLO findings revealed significant changes in the ONH of ET patients consisting of a thinner retinal nerve fiber layer (RNFL) and a decreased RNFL cross-sectional area, height variation contour, maximum contour depression, and contour line modulation (CLM) temporal-superior area. The nasal-superior cup area and rim volume in XT patients were significantly increased. CONCLUSION Topographical profiles of the macula and ONH in concomitant strabismic patients with normal vision present with specific regularities.
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Affiliation(s)
- Yun Wen
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, People's Republic of China
| | - Jianhua Yan
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, People's Republic of China. .,The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, People's Republic of China.
| | - Zhonghao Wang
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, People's Republic of China
| | - Tao Shen
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, People's Republic of China
| | - Xuan Qiu
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, People's Republic of China
| | - Daming Deng
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, People's Republic of China
| | - Jingchang Chen
- The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, People's Republic of China
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Zhong J, Deng DM, Chen ZD, Li JR, Yuan JP, Feng L, Wang AH, Yu MB. Evaluation of dynamic stereopsis in intermittent exotropia patients. Int J Ophthalmol 2019; 12:83-88. [PMID: 30662845 DOI: 10.18240/ijo.2019.01.13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 09/29/2018] [Indexed: 11/23/2022] Open
Abstract
AIM To delineate the characteristics of the dynamic stereopsis test and analyze related parameters in intermittent exotropia [X(T)] patients. METHODS Fifty-seven X(T) patients and 55 normal subjects were enrolled in this study. The normal and X(T) groups were used to test the reproducibility and reliability of the dynamic stereopsis test, and Bangerter filters with densities of 0.2 were then used to simulate suppression to test for traditional and dynamic stereopsis. In the X(T) group, the measurements included 1) dynamic stereopsis test comprising three parts: motion+disparity, motion only and disparity only; 2) ocular deviation angle; 3) Bagolini striated lens test; 4) disease course; and 5) Titmus stereopsis test. RESULTS The test-retest reliability of the dynamic stereopsis method was 0.901 in the normal and X(T) groups, and none of the X(T) patients were able to pass the static and dynamic stereopsis tests after using the 0.2 Bangerter filter. The accuracy rate was greater than 80% in the normal group and 31.81%, 36.36%, and 45.45% for the motion+disparity, motion-only and disparity-only components of the traditional test for X(T) patients diagnosed with stereoblindness via traditional tests, respectively. Patients with a long disease course (>1y) had worse dynamic stereopsis than those with a short disease course (<1y; P<0.05, Chi-square test). The deviation angle was not correlated with the motion+disparity, disparity-only, or the motion-only test components (all P>0.05, Chi-square test). CONCLUSION Dynamic stereopsis is preserved in certain X(T) patients diagnosed with stereoblindness via traditional tests. A long disease course was shown to be a negative factor for dynamic stereopsis in X(T) patients which might be associated with worse progression, and provide good references clinically.
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Affiliation(s)
- Jing Zhong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Da-Ming Deng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Zi-Dong Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Jin-Rong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Jun-Peng Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Lei Feng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
| | - Ai-Hou Wang
- Department of Ophthalmology, Cathay General Hospital, Taipei 10001, Taiwan, China.,Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei 10001, Taiwan, China
| | - Min-Bin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, Guangdong Province, China
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Li X, Yang C, Zhang G, Zhang Y, Lan J, Chu H, Li J, Xie W, Wang S, Wiederhold BK, Wiederhold MD, Yan L, Zeng J. Intermittent Exotropia Treatment with Dichoptic Visual Training Using a Unique Virtual Reality Platform. CYBERPSYCHOLOGY BEHAVIOR AND SOCIAL NETWORKING 2019; 22:22-30. [PMID: 30457355 DOI: 10.1089/cyber.2018.0259] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Xue Li
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Cheng Yang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Guanrong Zhang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Yan Zhang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Jianqing Lan
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Hang Chu
- National Engineering Research Center for Healthcare Devices, Guangzhou, China
| | - Juan Li
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wenjuan Xie
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Shujun Wang
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | | | - Mark D. Wiederhold
- Virtual Reality Medical Center, Scripps Memorial Hospital, La Jolla, California
| | - Li Yan
- National Engineering Research Center for Healthcare Devices, Guangzhou, China
| | - Jin Zeng
- Department of Ophthalmology, Guangdong Eye Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
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Agaoglu S, Agaoglu MN, Das VE. Motion Information via the Nonfixating Eye Can Drive Optokinetic Nystagmus in Strabismus. Invest Ophthalmol Vis Sci 2016; 56:6423-32. [PMID: 26444723 DOI: 10.1167/iovs.15-16923] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Strabismic patients can perceptually suppress information from one eye to avoid double vision. However, evidence from prior studies shows that some parts of the visual field of the deviated eye are not suppressed. Our goal here was to investigate whether motion information available only to the deviated eye can be utilized by the oculomotor system to drive eye movements. METHODS Binocular eye movements were acquired in two exotropic monkeys in a dichoptic viewing task in which the fixating eye viewed a stationary spot and the deviated eye viewed a 10° × 10° stationary patch that contained a drifting grating stimulus moving at 10°/s to the right or left for 20 seconds. Spatial location and contrast of the grating were systematically varied in subsequent trials. For each trial, mean slow-phase velocity of the optokinetic nystagmus (OKN) elicited by grating motion was calculated. RESULTS We found that OKN responses can be elicited by a motion stimulus presented to the foveal region of the deviated eye. Optokinetic nystagmus magnitude varied depending on which eye was viewing the drifting grating and correlated well with fixation preference and fixation stability (indicators of amblyopia). The magnitude of OKN increased for increased relative contrast of the motion stimulus compared to the fixation spot. CONCLUSIONS Our results show that motion information available only to the deviated eye can drive optokinetic eye movements. We conclude that the brain has access to visual information from portions of the deviated eye (including the fovea) in strabismus that it can use to drive eye movements.
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Abstract
In February 2012, the author acquired improved stereoscopic vision after viewing Martin Scorsese's film Hugo in 3D. The author had been deficient in stereo vision all of his life because in the first two decades, one eye deviated outward from the gaze position of the other. At that time, he was an alternator (alternating exotrope) showing strabismus (>20 prism diopters) without amblyopia. After viewing the 2-hour film, the Wirt stereo threshold decreased from 200 to 80 arcsec, and stereoscopic vision became a vivid experience. Exophoria decreased to 7 prism diopters. Numerous personal and research experiences throughout the author's career helped to interpret the phenomenon, which suggests a powerful new method for treating stereo-deficient patients.
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Read JC, Bohr I. User experience while viewing stereoscopic 3D television. ERGONOMICS 2014; 57:1140-53. [PMID: 24874550 PMCID: PMC4118898 DOI: 10.1080/00140139.2014.914581] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 03/27/2014] [Indexed: 05/25/2023]
Abstract
3D display technologies have been linked to visual discomfort and fatigue. In a lab-based study with a between-subjects design, 433 viewers aged from 4 to 82 years watched the same movie in either 2D or stereo 3D (S3D), and subjectively reported on a range of aspects of their viewing experience. Our results suggest that a minority of viewers, around 14%, experience adverse effects due to viewing S3D, mainly headache and eyestrain. A control experiment where participants viewed 2D content through 3D glasses suggests that around 8% may report adverse effects which are not due directly to viewing S3D, but instead are due to the glasses or to negative preconceptions about S3D (the 'nocebo effect'). Women were slightly more likely than men to report adverse effects with S3D. We could not detect any link between pre-existing eye conditions or low stereoacuity and the likelihood of experiencing adverse effects with S3D.
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Affiliation(s)
- Jenny C.A. Read
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Iwo Bohr
- Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
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Agaoglu MN, LeSage SK, Joshi AC, Das VE. Spatial patterns of fixation-switch behavior in strabismic monkeys. Invest Ophthalmol Vis Sci 2014; 55:1259-68. [PMID: 24508786 DOI: 10.1167/iovs.13-13460] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Patients with strabismus perceptually suppress information from one eye to avoid double vision. Mechanisms of visual suppression likely lead to fixation-switch behavior wherein the subject acquires targets with a specific eye depending on target location in space. The purpose of this study was to investigate spatial patterns of fixation-switch behavior in strabismic monkeys. METHODS Eye movements were acquired in three exotropic and one esotropic monkey in a binocular viewing saccade task. Spatial patterns of fixation were analyzed by calculating incidence of using either eye to fixate targets presented at various gaze locations. RESULTS Broadly, spatial fixation patterns and fixation-switch behavior followed expectations if a portion of the temporal retina was suppressed in exotropia and a portion of the nasal retina was suppressed in esotropia. Fixation-switch occurred for horizontal target locations that were approximately greater than halfway between the lines of sight of the foveating and strabismic eyes. Surprisingly, the border between right eye and left eye fixation zones was not sharply defined and there was a significant extent (>10°) over which the monkeys could acquire a target with either eye. CONCLUSIONS We propose that spatial fixation patterns in strabismus can be accounted for in a decision framework wherein the oculomotor system has access to retinal error information from each eye and the brain chooses between them to prepare a saccade. For target locations approximately midway between the two foveae, strength of retinal error representations from each eye is almost equal, leading to trial-to-trial variability in choice of fixating eye.
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Chung SA, Rhiu S, Han SH, Lee JB. Photophobia measurement in intermittent exotropia using the contrast sensitivity test. Graefes Arch Clin Exp Ophthalmol 2012; 251:1405-11. [PMID: 23254486 DOI: 10.1007/s00417-012-2241-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/24/2012] [Accepted: 12/04/2012] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND To assess the presence and extent of photophobia in children with intermittent exotropia (X[T]) using the contrast sensitivity test. METHODS Fifty-eight children with X(T) and 34 normal controls were studied with the functional acuity contrast test. Each participant viewed the stimuli of contrast monocularly and binocularly under photopic and mesopic conditions, performed with and without glare. Photophobia was defined as a reduction of contrast sensitivity caused by glare light. We compared the photophobia of children with X(T) to that of normal controls, and to the photophobia 3 months after muscle surgery. RESULTS With stimuli of glare, the contrast sensitivity of children with X(T) was suppressed at intermediate spatial frequencies under mesopic condition (p = 0.006 for 6 cycles per degree [cpd], p = 0.027 for 12 cpd), whereas that of normal controls showed no difference. It occurred when X(T) patients viewed targets binocularly, and significantly improved after strabismus surgery (p = 0.003 at 6 cpd). The measured photophobia of X(T) was strongly correlated to the photophobia symptoms reported by parents (p = 0.002). CONCLUSIONS The mesopic contrast sensitivity with glare can represent the photophobia of children with X(T). Contrast sensitivity may be a useful measure for monitoring symptoms related to X(T).
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Affiliation(s)
- Seung Ah Chung
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea
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Binocular retinal image differences influence eye-position signals for perceived visual direction. Vision Res 2012; 62:220-7. [PMID: 22560955 DOI: 10.1016/j.visres.2012.04.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 04/17/2012] [Accepted: 04/19/2012] [Indexed: 11/23/2022]
Abstract
Correctly perceiving the direction of a visible object with respect to one's self (egocentric visual direction) requires that information about the location of the image on the retina (oculocentric visual direction) be combined with signals about the position of the eyes in the head. The Wells-Hering laws that govern the perception of visual direction and modern restatements of these laws assume implicitly that retinal and eye-position information are independent of one another. By measuring observers' manual pointing responses to targets in different horizontal locations, we show that retinal and eye-position information are not treated independently in the brain. In particular, decreasing the relative visibility of one eye's retinal image reduces the strength of the eye-position signal associated with that eye. The results can be accounted for by interactions between eye-specific retinal and eye-position signals at a common neural location.
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