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Jia Y, Ye Q, Liu J, Feng L, Xu Z, He Y, Zhou Y, Chen X, Yao Y, Thompson B, Li J. Associations between the cause of amblyopia and pre-treatment contrast sensitivity, stereoacuity, fixation, and nystagmus. Heliyon 2024; 10:e28857. [PMID: 38596124 PMCID: PMC11002286 DOI: 10.1016/j.heliyon.2024.e28857] [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: 10/25/2023] [Revised: 03/26/2024] [Accepted: 03/26/2024] [Indexed: 04/11/2024] Open
Abstract
Purpose To explore the association between the cause of amblyopia and pre-treatment contrast sensitivity, stereoacuity, fixation and nystagmus. Design Retrospective cohort study. Methods A retrospective review was conducted for 3408 patients with amblyopia who had not yet started amblyopia treatment utilizing a large amblyopia patient database maintained at Zhongshan Ophthalmic Centre. Six amblyogenic factor subtypes were identified: anisometropia, isoametropia, strabismus, anisometropia and strabismus, monocular visual deprivation, and binocular visual deprivation amblyopia. Monocular best corrected visual acuity (BCVA), the contrast sensitivity function (CSF), fixation, and stereopsis were compared between the subtypes before and after propensity score matching (PSM) for age and sex. Results The two deprivation groups had poorer BCVA and CSF than the other groups. There were no systematic differences in CSF between the non-deprivation groups. Nystagmus was more common in the bilateral amblyopia groups compared to the monocular amblyopia groups. Eccentric fixation was uncommon with the exception of the anisometropia and strabismus group which had an eccentric fixation rate of 20%. Distance stereoacuity measured without monocular cues was absent for almost all patients. The results were consistent when analyzed using PSM. Conclusion Visual deprivation causes more severe amblyopia than other amblyogenic factors. For non-deprivation amblyopia subtypes, individual differences such as variation in the severity of the amblyogenic factor might be more important in determining pre-treatment vision than whether amblyopia was caused by refractive error, strabismus or both.
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Affiliation(s)
- Yu Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
- Centre for Eye and Vision Research, 17W Science Park, Hong Kong
| | - Qingqing Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jing Liu
- 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
| | - Zixuan Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yunsi He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yusong Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xiaolan Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Ying Yao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Benjamin Thompson
- Centre for Eye and Vision Research, 17W Science Park, Hong Kong
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
- Liggins Institute, The University of Auckland, Auckland, New Zealand
| | - Jinrong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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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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Tsaousis KT, Mousteris G, Diakonis V, Chaloulis S. Current Developments in the Management of Amblyopia with the Use of Perceptual Learning Techniques. MEDICINA (KAUNAS, LITHUANIA) 2023; 60:48. [PMID: 38256309 PMCID: PMC10821148 DOI: 10.3390/medicina60010048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/22/2023] [Accepted: 12/25/2023] [Indexed: 01/24/2024]
Abstract
Background and Objectives: Amblyopia is a neurodevelopmental disorder caused by interocular suppression of visual input, affecting visual acuity, stereopsis, contrast sensitivity, and other visual functions. Conventional treatment comprises occlusion of the sound eye. In recent years, novel therapies that deploy perceptual learning (PL) principles have been introduced. The purpose of this study is to assess the latest scientific data on this topic. Materials and Methods: For this purpose, we conducted a literature search for relevant studies published during the previous 4 years (2020-2023). Results: A plethora of visual perceptual learning protocols have been recently developed. Dichoptic video games, contrast rebalanced movies, and online perceptual training platforms are the main formats. Perceptual learning activates neuroplasticity, overcomes interocular suppression, and improves the visual impairments induced by amblyopia. Conclusions: This novel treatment is effective in both children and adults, as well as in patients non-responding to patching.
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Affiliation(s)
| | | | - Vasilios Diakonis
- 2nd Ophthalmology Department, Metropolitan Hospital, 185 47 Athens, Greece
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Dulaney CS, Murray J, Ghasia F. Contrast sensitivity, optotype acuity and fixation eye movement abnormalities in amblyopia under binocular viewing. J Neurol Sci 2023; 451:120721. [PMID: 37433244 DOI: 10.1016/j.jns.2023.120721] [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: 07/20/2022] [Revised: 06/20/2023] [Accepted: 06/24/2023] [Indexed: 07/13/2023]
Abstract
INTRODUCTION Visual function deficits are seen in amblyopic subjects during fellow and binocular viewing. The purpose of the study was to examine the relationship between Fixation Eye Movement (FEM) abnormalities and binocular contrast sensitivity and optotype acuity deficits in amblyopia. METHODS We recruited 10 controls and 25 amblyopic subjects [Anisometropic = 6, Strabismic = 10, Mixed = 9]. We measured binocular contrast sensitivity at spatial frequencies 1,2, 4, 8, 12 and 16 and binocular and monocular optotype acuity using a staircase procedure. We recorded FEMs using high-resolution video-oculography and classified subjects as having no nystagmus(None = 9) or nystagmus without FMN(n = 7) and with Fusion Maldevelopment Nystagmus (FMN)(n = 9). We computed the fixation instability, amplitude and velocity of the fast and slow FEMs. RESULTS Amblyopic subjects with and without nystagmus had worse binocular contrast sensitivity at spatial frequencies 12 and 16 and binocular optotype acuity than controls. The abnormalities were most pronounced in amblyopic subjects with FMN. Fixation instability of the Fellow Eye and Amblyopic Eye and vergence instability, amplitude of fast FEMs and velocity of slow FEMs were increased with reduced binocular contrast sensitivity and reduced optotype acuity in amblyopic subjects. CONCLUSIONS Fixation instability of Fellow Eye and Amblyopic Eye, optotype acuity and contrast sensitivity deficits are seen under binocular viewing in amblyopic subjects with and without nystagmus but are most pronounced in those with FMN. FEMs abnormalities correlate with both lower order (contrast sensitivity) and higher order (optotype acuity) visual function impairment in amblyopia.
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Affiliation(s)
- Cody S Dulaney
- Cleveland Clinic Cole Eye Institute, Visual Neurosciences and Ocular Motility Laboratory, Cleveland, OH, USA
| | - Jordan Murray
- Cleveland Clinic Cole Eye Institute, Visual Neurosciences and Ocular Motility Laboratory, Cleveland, OH, USA
| | - Fatema Ghasia
- Cleveland Clinic Cole Eye Institute, Visual Neurosciences and Ocular Motility Laboratory, Cleveland, OH, USA.
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Benhaim-Sitbon L, Lev M, Polat U. Extended perceptive field revealed in humans with binocular fusion disorders. Sci Rep 2023; 13:6584. [PMID: 37085571 PMCID: PMC10121568 DOI: 10.1038/s41598-023-33429-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/12/2023] [Indexed: 04/23/2023] Open
Abstract
Binocular vision disorders or dysfunctions have considerable impact on daily visual activities such as reading. Heterophoria (phoria) is a latent eye misalignment (with a prevalence of up to 35%) that appears in conditions that disrupt binocular vision and it may affect the quality of binocular fusion. Our recent study, which used lateral masking (LM), suggests that subjects with binocular fusion disorders (horizontal phoria) exhibit an asymmetry and an abnormal pattern of both binocular and monocular lateral interactions, but only for the horizontal meridian (HM). The perceptive field (PF) is the fundamental processing unit of human vision and both masking and crowding depend on its size. An increased PF size is found in amblyopic populations or in young children. We hypothesized that the PF's size would be asymmetric only for the phoric group (larger along the HM). We estimated the PF's size using two different methods (LM with equal-phase and opposite-phase flankers). Phoric subjects exhibited a larger binocular PF size, only for the HM, confirming our hypothesis of an asymmetric PF size. However, the monocular PF size of phoric and control subjects was similar. Phoria affects the PF's size similarly to meridional amblyopia but without being attributed to abnormal refraction. We suggest that these findings could help explain the inter-observer variability found in the masking literature and the reading difficulties often encountered in subjects with high heterophoria. Since perceptual learning can reduce the PF's size, further investigation of training may provide a novel therapy to reduce some symptoms related to heterophoria.
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Affiliation(s)
- Laura Benhaim-Sitbon
- School of Optometry and Vision Sciences, Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Maria Lev
- School of Optometry and Vision Sciences, Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Uri Polat
- School of Optometry and Vision Sciences, Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
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Birch EE, Kelly KR. Amblyopia and the whole child. Prog Retin Eye Res 2023; 93:101168. [PMID: 36736071 PMCID: PMC9998377 DOI: 10.1016/j.preteyeres.2023.101168] [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: 09/20/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 02/04/2023]
Abstract
Amblyopia is a disorder of neurodevelopment that occurs when there is discordant binocular visual experience during the first years of life. While treatments are effective in improving visual acuity, there are significant individual differences in response to treatment that cannot be attributed solely to difference in adherence. In this considerable variability in response to treatment, we argue that treatment outcomes might be optimized by utilizing deep phenotyping of amblyopic deficits to guide alternative treatment choices. In addition, an understanding of the broader knock-on effects of amblyopia on developing visually-guided skills, self-perception, and quality of life will facilitate a whole person healthcare approach to amblyopia.
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Affiliation(s)
- Eileen E Birch
- Pediatric Vision Laboratory, Retina Foundation of the Southwest, 9600 North Central Expressway #200, Dallas, TX, 75225, USA; Department of Ophthalmology, University of Texas Southwestern Medical Center, 5303 Harry Hines Boulevard, Dallas, TX, 75390, USA.
| | - Krista R Kelly
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5303 Harry Hines Boulevard, Dallas, TX, 75390, USA; Vision and Neurodevelopment Laboratory, Retina Foundation of the Southwest, 9600 North Central Expressway #200, Dallas, TX, 75225, USA.
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