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Ojiabo SN, Munsamy AJ. The Effect of Home-Based Dichoptic Therapy on Young Adults with Non-Strabismic Anisometropic Amblyopia on Stereo Acuity. CLINICAL OPTOMETRY 2022; 14:237-247. [PMID: 36466992 PMCID: PMC9718499 DOI: 10.2147/opto.s385845] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/18/2022] [Indexed: 06/17/2023]
Abstract
AIM To evaluate the effect of home-based dichoptic visual therapy using anaglyphic red-green filters on the stereo acuity in a sample of young adults with non-strabismic anisometropic amblyopia. METHODS The study was observational and cross-sectional in design. Two groups (experimental vs control) were sourced using purposive sampling of young adults with non-strabismic amblyopia (experimental group) in comparison to an age-match control group without amblyopia. For the purpose of refractive adaptation, all participants in both groups were asked to wear their spectacle correction constantly for at least 16 weeks prior to exposure to home-based dichoptic therapy. Stereo acuity measurements using the Stereo Fly test were obtained before and after 40 hours exposure to home-based dichoptic therapy. The changes in stereo acuity post eight weeks (40 hours) training from baseline measurements was obtained. The difference in medians between the experimental and control groups using the Mann-Whitney U-test was measured with significance set at P value of <0.05. RESULTS A total of 38 young adults (19 males, 19 females) with a mean age of 24.05 ± 5.66 years were enrolled in this study. Nineteen anisometropic amblyopes comprised the experimental group, fifteen of which were classified as moderate amblyopia (6/12-6/36) and 19 non-amblyopes comprised the control group. Home-based dichoptic therapy used on the experimental group after 8 weeks showed a significant improvement in stereo-acuity with a mean improvement of 345.26 ± 184.85 sec arc-1 [IQR:260;600; p<0.001] when compared to the control group. CONCLUSION Home-based dichoptic therapy improved stereo-acuity in non-strabismic anisometropic amblyopes (moderate) in young adults. Thus suggesting that binocularity can improve in anisometropic adult amblyopes with a treatment modality that may be a convenient option better suit the demanding lifestyle of economically active adults who may not be able to comply with clinic-based therapy.
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Affiliation(s)
- Sunday Nduka Ojiabo
- Department of Optometry, School of Health Science, University of KwaZulu-Natal, Westville Campus, Durban, South Africa
| | - Alvin J Munsamy
- Discipline of Optometry, School of Health Science, University of KwaZulu-Natal, Westville Campus, Durban, South Africa
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Roy S, Saxena R, Dhiman R, Phuljhele S, Sharma P. Comparison of Dichoptic Therapy Versus Occlusion Therapy in Children With Anisometropic Amblyopia: A Prospective Randomized Study. J Pediatr Ophthalmol Strabismus 2022; 60:210-217. [PMID: 35938643 DOI: 10.3928/01913913-20220627-02] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare a smartphone-based dichoptic video game with occlusion therapy in children with anisometropic amblyopia. METHODS In this prospective, randomized, interventional study, 55 children aged 5 to 15 years with anisometropic amblyopia were randomized into two groups: the video game group (n = 27) played a dichoptic video game with adjusted contrast for 2 hours/day and the patching group (n = 28) received occlusion therapy of the non-amblyopic eye for 6 hours/day. All patients were evaluated for best corrected visual acuity (BCVA), near vision, contrast sensitivity, and near and distance stereoacuity at baseline and 1, 2, and 3 months. RESULTS Mean distance BCVA improved from 0.74 ± 0.19 and 0.70 ± 0.18 logarithm of the minimum angle of resolution (logMAR) in the video game and patching groups, respectively, at baseline to 0.53 ± 0.19 and 0.49 ± 0.19 logMAR, respectively, at 3 months (P < .001 for both). Mean near vision was 0.82 ± 0.19 and 0.81 ± 0.17 logMAR in the video game and patching groups, respectively, at baseline and improved to 0.60 ± 0.16 and 0.63 ± 0.17 logMAR at 3 months (P < .001 for both). There was no significant difference in distance and near vision between the two groups at baseline and final follow-up visit. Contrast sensitivity was 1.41 ± 0.20 and 1.38 ± 0.20 in the video game and patching groups, respectively, at baseline and 1.74 ± 0.18 and 1.61 ± 0.21 at 3 months (P < .001 for both). At the final follow-up visit, contrast sensitivity was significantly better in the video game group compared to the patching group (P = .01). Near stereoacuity significantly improved only in the video game group (P = .006), whereas distance stereoacuity did not improve in either group. CONCLUSIONS Dichoptic video game therapy showed better results in terms of improvement in contrast sensitivity and near stereoacuity and similar outcomes for distance and near vision when compared to patching in children with anisometropic amblyopia. However, the availability of interesting games is essential to maintain children's interest. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XX-XX.].
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Gong L, Wei L, Yu X, Reynaud A, Hess RF, Zhou J. The Orientation Selectivity of Dichoptic Masking Suppression is Contrast Dependent in Amblyopia. Invest Ophthalmol Vis Sci 2022; 63:9. [PMID: 35675061 PMCID: PMC9187942 DOI: 10.1167/iovs.63.6.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Purpose We aimed to study the effect of stimulus contrast on the orientation selectivity of interocular interaction in amblyopia using a dichoptic masking paradigm. Methods Eight adults with anisometropic or mixed amblyopia and 10 control adults participated in our study. The contrast threshold in discriminating a target Gabor in the tested eye was measured with mean luminance in the untested eye, as well as with a bandpass oriented filtered noise in the other eye at low spatial frequency (0.25 c/d). Threshold elevation, which represents interocular suppression, was assessed using a the dichoptic masking paradigm (i.e. the contrast threshold difference between the target only and masked conditions), for each eye. Orientation selectivity of the interocular suppression as reflected by dichoptic masking was quantified by the difference between the parallel and orthogonal masking configurations. Two levels of mask's contrast (3 times or 10 times that of an individual's contrast threshold) were tested in this study. Results The strength of dichoptic masking suppression was stronger at high, rather than low mask contrast in both amblyopic and control subjects. Normal controls showed orientation-dependent dichoptic masking suppression both under high and low contrast levels. However, amblyopes showed orientation-tuned dichoptic masking suppression only under the high contrast level, but untuned under the low contrast level. Conclusions We demonstrate that interocular suppression assessed by dichoptic masking is contrast-dependent in amblyopia, being orientation-tuned only at high suprathreshold contrast levels of the mask.
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Affiliation(s)
- Ling Gong
- School of Ophthalmology and Optometry, Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Lili Wei
- School of Ophthalmology and Optometry, Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xi Yu
- School of Ophthalmology and Optometry, Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Alexandre Reynaud
- McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Robert F Hess
- McGill Vision Research, Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Jiawei Zhou
- School of Ophthalmology and Optometry, Eye Hospital, State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
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Kam KY, Chang DHF. Dichoptic Perceptual Training and Sensory Eye Dominance Plasticity in Normal Vision. Invest Ophthalmol Vis Sci 2021; 62:12. [PMID: 34106211 PMCID: PMC8196419 DOI: 10.1167/iovs.62.7.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We introduce a set of dichoptic training tasks that differ in terms of (1) the presence of external noise and (2) the visual feature implicated (motion, orientation), examining the generality of training effects between the different training and test cues and their capacity for driving changes in sensory eye dominance and stereoscopic depth perception. Methods We randomly assigned 116 normal-sighted observers to five groups (four training groups and one no training group). All groups completed both pre- and posttests, during which they were tested on dichoptic motion and orientation tasks under noisy and noise-free conditions, as well as a binocular phase combination task and two depth tasks to index sensory eye dominance and binocular function. Training groups received visual training on one of the four dichoptic tasks over 3 consecutive days. Results Training under noise-free conditions supported generalization of learning to noise-free tasks involving an untrained feature. By contrast, there was a symmetric learning transfer between the signal-noise and no-noise tasks within the same visual feature. Further, training on all tasks reduced sensory eye dominance but did not improve depth perception. Conclusions Training-driven changes in sensory eye balance do not depend on the stimulus feature or whether the training entails the presence of external noise. We conjecture that dichoptic visual training acts to balance interocular suppression before or at the site of binocular combination.
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Affiliation(s)
- Ka Yee Kam
- Department of Psychology, The University of Hong Kong, Hong Kong
| | - Dorita H F Chang
- Department of Psychology, The University of Hong Kong, Hong Kong.,The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong
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Donkor R, Silva AE, Teske C, Wallis-Duffy M, Johnson AP, Thompson B. Repetitive visual cortex transcranial random noise stimulation in adults with amblyopia. Sci Rep 2021; 11:3029. [PMID: 33542265 PMCID: PMC7862667 DOI: 10.1038/s41598-020-80843-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 12/10/2020] [Indexed: 11/09/2022] Open
Abstract
We tested the hypothesis that five daily sessions of visual cortex transcranial random noise stimulation would improve contrast sensitivity, crowded and uncrowded visual acuity in adults with amblyopia. Nineteen adults with amblyopia (44.2 ± 14.9 years, 10 female) were randomly allocated to active or sham tRNS of the visual cortex (active, n = 9; sham, n = 10). Sixteen participants completed the study (n = 8 per group). tRNS was delivered for 25 min across five consecutive days. Monocular contrast sensitivity, uncrowded and crowded visual acuity were measured before, during, 5 min and 30 min post stimulation on each day. Active tRNS significantly improved contrast sensitivity and uncrowded visual acuity for both amblyopic and fellow eyes whereas sham stimulation had no effect. An analysis of the day by day effects revealed large within session improvements on day 1 for the active group that waned across subsequent days. No long-lasting (multi-day) improvements were observed for contrast sensitivity, however a long-lasting improvement in amblyopic eye uncrowded visual acuity was observed for the active group. This improvement remained at 28 day follow up. However, between-group differences in baseline uncrowded visual acuity complicate the interpretation of this effect. No effect of tRNS was observed for amblyopic eye crowded visual acuity. In agreement with previous non-invasive brain stimulation studies using different techniques, tRNS induced short-term contrast sensitivity improvements in adult amblyopic eyes, however, repeated sessions of tRNS did not lead to enhanced or long-lasting effects for the majority of outcome measures.
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Affiliation(s)
- Richard Donkor
- Department of Optometry and Vision Science, University of Waterloo, 200 University Avenue West, Waterloo, ON, N0B 2T0, Canada
| | - Andrew E Silva
- Department of Optometry and Vision Science, University of Waterloo, 200 University Avenue West, Waterloo, ON, N0B 2T0, Canada
| | - Caroline Teske
- Department of Optometry and Vision Science, University of Waterloo, 200 University Avenue West, Waterloo, ON, N0B 2T0, Canada
| | - Margaret Wallis-Duffy
- Department of Optometry and Vision Science, University of Waterloo, 200 University Avenue West, Waterloo, ON, N0B 2T0, Canada
| | - Aaron P Johnson
- Department of Psychology, Concordia University, Montreal, Canada.,Réseau de Recherche en Santé de la Vision, Montreal, Canada.,CRIR/Lethbridge-Layton-Mackay Rehabilitation Centre du CIUSSS du Centre-Ouest-de-l'Île-de-Montréal, Montreal, Canada
| | - Benjamin Thompson
- Department of Optometry and Vision Science, University of Waterloo, 200 University Avenue West, Waterloo, ON, N0B 2T0, Canada. .,Center for Eye and Vision Research, Hong Kong, China. .,The Liggins Institute, University of Auckland, Auckland, New Zealand.
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Panachakel JT, Ramakrishnan AG, Manjunath KP. VR Glasses based Measurement of Responses to Dichoptic Stimuli: A Potential Tool for Quantifying Amblyopia? ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:5106-5110. [PMID: 33019135 DOI: 10.1109/embc44109.2020.9176510] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Amblyopia is a medical condition in which the visual inputs from one of the eyes is suppressed by the brain. This leads to reduced visual acuity and poor or complete loss of stereopsis. Conventional clinical tests such as Worth 4-dot test and Bagolini striated lens test can only detect the presence of suppression but cannot quantify the extent of suppression, which is important for identifying the effectiveness of treatments for amblyopia. A novel approach for quantifying the level of suppression in amblyopia is proposed in this paper. We hypothesize that the level of suppression in amblyopia can be measured by measuring the symmetry/asymmetry in the suppression experienced during a dichoptic image recognition task. Preliminary studies done on fifty one normal subjects prove that the differences between the accuracies of the left and right eyes can be used as a measure of asymmetry. Equivalence test performed using 'two-one-sided t-tests' procedure shows that the equivalence of the accuracies of left and right eyes for normal subjects is statistically significant (p = .03, symmetric equivalence margin of 5 percentage points). To validate this method, six amblyopic children underwent this test and the results obtained are promising. To the knowledge of the authors, this is the first work to make use of VR glasses and dichoptic image recognition task for quantifying the level of ocular suppression in amblyopic patients.
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Birch EE, Castañeda YS, Cheng-Patel CS, Morale SE, Kelly KR, Jost RM, Hudgins LA, Leske DA, Holmes JM. Associations of Eye-Related Quality of Life With Vision, Visuomotor Function, and Self-Perception in Children With Strabismus and Anisometropia. Invest Ophthalmol Vis Sci 2020; 61:22. [PMID: 32926105 PMCID: PMC7490229 DOI: 10.1167/iovs.61.11.22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/08/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate associations between eye-related quality of life (ER-QOL) assessed by the Child Pediatric Eye Questionnaire (Child PedEyeQ) and functional measures (vision, visuomotor function, self-perception) in children with strabismus, anisometropia, or both. Our hypothesis was that children with functional deficits would have lower ER-QOL, and if so, these associations would support the convergent construct validity of the Child PedEyeQ. Methods We evaluated 114 children (ages 5-11 years) with strabismus, anisometropia, or both. Each child completed the Child PedEyeQ to assess four Rasch-scored domains of ER-QOL: Functional Vision, Bothered by Eyes/Vision, Social, and Frustration/Worry. In addition, children completed one or more functional tests: visual acuity (n = 114), Randot Preschool Stereoacuity (n = 92), contrast balance index (suppression; n = 91), Readalyzer reading (n = 44), vergence instability (n = 50), Movement Assessment Battery for Children-2 manual dexterity (n = 57), and Pictorial Scale of Perceived Competence and Social Acceptance for Young Children (n = 44). Results Child PedEyeQ Functional Vision domain scores were correlated with self-perception of physical competence (rs = 0.65; 95% confidence interval [CI], 0.35-0.96) and reading speed (rs = 0.47; 95% CI, 0.16-0.77). Bothered by Eyes/Vision domain scores were correlated with self-perception of physical competence (rs = 0.52; 95% CI, 0.21-0.83). Moderate correlations were observed between Social domain scores and vergence instability (rs = -0.46; 95% CI, -0.76 to -0.15) and self-perception of physical competence (rs = 0.43; 95% CI, 0.12-0.73) and peer acceptance (rs = 0.49; 95% CI, 0.18-0.80). Frustration/Worry domain scores were moderately correlated with self-perception of physical competence (rs = 0.41; 95% CI, 0.10-0.71) and peer acceptance (rs = 0.47; 95% CI, 0.16-0.77). Conclusions Strong and moderate correlations were observed between functional measures and Child PedEyeQ domain scores. These associations provide supporting evidence that the Child PedEyeQ has convergent construct validity.
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Affiliation(s)
- Eileen E. Birch
- Retina Foundation of the Southwest, Dallas, Texas, United States
- Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | | | | | - Sarah E. Morale
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Krista R. Kelly
- Retina Foundation of the Southwest, Dallas, Texas, United States
- Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Reed M. Jost
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | | | - David A. Leske
- Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
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Martín S, Portela JA, Ding J, Ibarrondo O, Levi DM. Evaluation of a Virtual Reality implementation of a binocular imbalance test. PLoS One 2020; 15:e0238047. [PMID: 32822405 PMCID: PMC7446887 DOI: 10.1371/journal.pone.0238047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/07/2020] [Indexed: 01/12/2023] Open
Abstract
The purpose of this study was (1) to implement a test for binocular imbalance in a Virtual Reality headset, (2) to assess its testability, reliability and outcomes in a population of clinical patients and (3) to evaluate the relationships of interocular acuity difference, stereoacuity and binocular imbalance to amblyogenic risk factors. 100 volunteers (6 to 70 years old, mean 21.2 ± 16.2), 21 with no amblyogenic risk factors and 79 with amblyopia or a history of amblyopia participated. Participants were classified by amblyogenic risk factor (24 anisometropic, 25 strabismic and 30 mixed) and, for those with strabismus, also by refractive response (16 accommodative and 39 non-accommodative). We characterized our sample using three variables, called the ‘triplet’ henceforth: interocular acuity difference, stereoacuity and imbalance factor. Binocular imbalance showed high test-retest reliability (no significant difference between test and retest in a subgroup, n = 20, p = 0.831); was correlated with Worth 4 dots test (r = 0.538, p<0.0001); and correlated with both interocular acuity difference (r = 0.575, p<0.0001) and stereoacuity (r = 0.675, p<0.0001). The mean values of each variable of the triplet differed depending on group classification. Mixed and non-accommodative groups showed the worst mean values compared with the other groups. Among participants with strabismus, strabismic vs mixed subgroups did not show significant differences in any variable of the triplet, whereas the accommodative vs non-accommodative subgroups showed significant differences in all of them. According to a univariate logistic model, any variable of the triplet provides a good metric for differentiating patients from controls, except for binocular imbalance for anisometropic subgroup. The proposed binocular imbalance test is feasible and reliable. We recommend monitoring amblyopia clinically not only considering visual acuity, but also stereoacuity and interocular imbalance. Stereoacuity on its own fails because of the high percentage of patients with no measurable stereoacuity. Binocular imbalance may help to fill that gap.
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Affiliation(s)
| | | | - Jian Ding
- School of Optometry, University of California, Berkeley, CA, United States of America
| | | | - Dennis M. Levi
- School of Optometry, University of California, Berkeley, CA, United States of America
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Coco-Martin MB, Piñero DP, Leal-Vega L, Hernández-Rodríguez CJ, Adiego J, Molina-Martín A, de Fez D, Arenillas JF. The Potential of Virtual Reality for Inducing Neuroplasticity in Children with Amblyopia. J Ophthalmol 2020; 2020:7067846. [PMID: 32676202 PMCID: PMC7341422 DOI: 10.1155/2020/7067846] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/02/2020] [Accepted: 06/11/2020] [Indexed: 12/12/2022] Open
Abstract
In recent years, virtual reality (VR) has emerged as a new safe and effective tool for neurorehabilitation of different childhood and adulthood conditions. VR-based therapies can induce cortical reorganization and promote the activation of different neuronal connections over a wide range of ages, leading to contrasted improvements in motor and functional skills. The use of VR for the visual rehabilitation in amblyopia has been investigated in the last years, with the potential of using serious games combining perceptual learning and dichoptic stimulation. This combination of technologies allows the clinician to measure, treat, and control changes in interocular suppression, which is one of the factors leading to cortical alterations in amblyopia. Several clinical researches on this issue have been conducted, showing the potential of promoting visual acuity, contrast sensitivity, and stereopsis improvement. Indeed, several systems have been evaluated for amblyopia treatment including the use of different commercially available types of head mounted displays (HMDs). These HMDs are mostly well tolerated by patients during short exposures and do not cause significant long-term side effects, although their use has been occasionally associated with some visual discomfort and other complications in certain types of subjects. More studies are needed to confirm these promising therapies in controlled randomized clinical trials, with special emphasis on the definition of the most adequate planning for obtaining an effective recovery of the visual and binocular function.
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Affiliation(s)
- María B. Coco-Martin
- 1Group of Applied Clinical Neurosciences and Advanced Data Analysis, Neurology Department, Faculty of Medicine, University of Valladolid, Valladolid, Spain
| | - David P. Piñero
- 2Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
- 3Department of Ophthalmology, Vithas Medimar International Hospital, Alicante, Spain
| | - Luis Leal-Vega
- 1Group of Applied Clinical Neurosciences and Advanced Data Analysis, Neurology Department, Faculty of Medicine, University of Valladolid, Valladolid, Spain
| | - Carlos J. Hernández-Rodríguez
- 2Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
- 3Department of Ophthalmology, Vithas Medimar International Hospital, Alicante, Spain
| | - Joaquin Adiego
- 4Group of Applied Clinical Neurosciences and Advanced Data Analysis, Computer Science Department, School of Computing, University of Valladolid, Valladolid, Spain
| | - Ainhoa Molina-Martín
- 2Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Dolores de Fez
- 2Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Juan F. Arenillas
- 1Group of Applied Clinical Neurosciences and Advanced Data Analysis, Neurology Department, Faculty of Medicine, University of Valladolid, Valladolid, Spain
- 5Department of Neurology, Stroke Unit and Stroke Program, University Hospital, University of Valladolid, Valladolid, Spain
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Gao TY, Ledgeway T, Lie AL, Anstice N, Black J, McGraw PV, Thompson B. Orientation Tuning and Contrast Dependence of Continuous Flash Suppression in Amblyopia and Normal Vision. Invest Ophthalmol Vis Sci 2019; 59:5462-5472. [PMID: 30452600 DOI: 10.1167/iovs.18-23954] [Citation(s) in RCA: 7] [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 Suppression in amblyopia may be an unequal form of normal interocular suppression or a distinct pathophysiology. To explore this issue, we examined the orientation tuning and contrast dependence of continuous flash suppression (CFS) in adults with amblyopia and visually normal controls. Methods Nine patients (mean age, 26.9 ± SD 4.7 years) and 11 controls (mean age, 24.8 ± SD 5.3 years) participated. In the CFS paradigm, spatially one-dimensional noise refreshing at 10 Hz was displayed in one eye to induce suppression of the other eye, and suppression strength was measured by using a grating contrast increment detection task. In experiment 1, noise contrast was fixed and the orientation difference between the noise and the grating was varied. In experiment 2, noise and grating orientations were identical and noise contrast was varied. Results Suppression patterns varied in both groups. In experiment 1, controls showed consistently orientation-tuned CFS (mean half-height bandwidth, 35.8° ± SD 21.5°) with near-equal strength between eyes. Five of nine patients with amblyopia exhibited orientation-independent CFS. Eight patients had markedly unequal suppression between eyes. Experiment 2 found that increasing the noise contrast to the amblyopic eye may produce suppression of the fellow eye, but suppression remained unequal between eyes. Conclusions Our data revealed that orientation specificity in CFS was very broad or absent in some patients with amblyopia, which could not be predicted by clinical measures. Suppression was unbalanced across the entire contrast range for most patients. This suggests that abnormal early visual experience disrupts the development of interocular suppression mechanisms.
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Affiliation(s)
- Tina Y Gao
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Timothy Ledgeway
- School of Psychology, University of Nottingham, Nottingham, United Kingdom
| | - Alyssa L Lie
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Nicola Anstice
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.,Discipline of Optometry and Vision Science, University of Canberra, Australian Capital Territory, Australia
| | - Joanna Black
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
| | - Paul V McGraw
- School of Psychology, University of Nottingham, Nottingham, United Kingdom
| | - Benjamin Thompson
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.,School of Optometry and Vision Science, University of Waterloo, Ontario, Canada
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Charlesworth JM, Davidson MA. Undermining a common language: smartphone applications for eye emergencies. MEDICAL DEVICES-EVIDENCE AND RESEARCH 2019; 12:21-40. [PMID: 30697086 PMCID: PMC6339640 DOI: 10.2147/mder.s186529] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background Emergency room physicians are frequently called upon to assess eye injuries and vision problems in the absence of specialized ophthalmologic equipment. Technological applications that can be used on mobile devices are only now becoming available. Objective To review the literature on the evidence of clinical effectiveness of smartphone applications for visual acuity assessment marketed by two providers (Google Play and iTunes). Methods The websites of two mobile technology vendors (iTunes and Google Play) in Canada and Ireland were searched on three separate occasions using the terms “eye”, “ocular”, “ophthalmology”, “optometry”, “vision”, and “visual assessment” to determine what applications were currently available. Four medical databases (Cochrane, Embase, PubMed, Medline) were subsequently searched with the same terms AND mobile OR smart phone for papers in English published in years 2010–2017. Results A total of 5,024 Canadian and 2,571 Irish applications were initially identified. After screening, 44 were retained. Twelve relevant articles were identified from the health literature. After screening, only one validation study referred to one of our identified applications, and this one only partially validated the application as being useful for clinical purposes. Conclusion Mobile device applications in their current state are not suitable for emergency room ophthalmologic assessment, because systematic validation is lacking.
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Affiliation(s)
- Jennifer M Charlesworth
- School of Medicine, National University of Ireland, Galway, Ireland, .,AM Charlesworth & Associates Science and Technology Consultants, Ottawa, ON, Canada,
| | - Myriam A Davidson
- AM Charlesworth & Associates Science and Technology Consultants, Ottawa, ON, Canada,
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12
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Milleret C, Bui Quoc E. Beyond Rehabilitation of Acuity, Ocular Alignment, and Binocularity in Infantile Strabismus. Front Syst Neurosci 2018; 12:29. [PMID: 30072876 PMCID: PMC6058758 DOI: 10.3389/fnsys.2018.00029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 06/15/2018] [Indexed: 11/13/2022] Open
Abstract
Infantile strabismus impairs the perception of all attributes of the visual scene. High spatial frequency components are no longer visible, leading to amblyopia. Binocularity is altered, leading to the loss of stereopsis. Spatial perception is impaired as well as detection of vertical orientation, the fastest movements, directions of movement, the highest contrasts and colors. Infantile strabismus also affects other vision-dependent processes such as control of postural stability. But presently, rehabilitative therapies for infantile strabismus by ophthalmologists, orthoptists and optometrists are restricted to preventing or curing amblyopia of the deviated eye, aligning the eyes and, whenever possible, preserving or restoring binocular vision during the critical period of development, i.e., before ~10 years of age. All the other impairments are thus ignored; whether they may recover after strabismus treatment even remains unknown. We argue here that medical and paramedical professionals may extend their present treatments of the perceptual losses associated with infantile strabismus. This hypothesis is based on findings from fundamental research on visual system organization of higher mammals in particular at the cortical level. In strabismic subjects (as in normal-seeing ones), information about all of the visual attributes converge, interact and are thus inter-dependent at multiple levels of encoding ranging from the single neuron to neuronal assemblies in visual cortex. Thus if the perception of one attribute is restored this may help to rehabilitate the perception of other attributes. Concomitantly, vision-dependent processes may also improve. This could occur spontaneously, but still should be assessed and validated. If not, medical and paramedical staff, in collaboration with neuroscientists, will have to break new ground in the field of therapies to help reorganize brain circuitry and promote more comprehensive functional recovery. Findings from fundamental research studies in both young and adult patients already support our hypothesis and are reviewed here. For example, presenting different contrasts to each eye of a strabismic patient during training sessions facilitates recovery of acuity in the amblyopic eye as well as of 3D perception. Recent data also demonstrate that visual recoveries in strabismic subjects improve postural stability. These findings form the basis for a roadmap for future research and clinical development to extend presently applied rehabilitative therapies for infantile strabismus.
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Affiliation(s)
- Chantal Milleret
- Center for Interdisciplinary Research in Biology, Centre National de la Recherche Scientifique, College de France, INSERM, PSL Research University, Paris, France
| | - Emmanuel Bui Quoc
- Department of Ophthalmology, Robert Debré University Hospital, Assistance Publique - Hôpitaux de Paris Paris, France
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Virtual Interactive Environment for Low-Cost Treatment of Mechanical Strabismus and Amblyopia. INFORMATION 2018. [DOI: 10.3390/info9070175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This study presents a technique that uses an interactive virtual environment for the rehabilitation treatment of patients with mechanical strabismus and/or amblyopia who have lost eye movement. The relevant part of this treatment is the act of forcing the two eyes to cooperate with each other by increasing the level of adaptation of the brain and allowing the weak eye to see again. Accordingly, the game enables both eyes to work together, providing the patient with better visual comfort and life quality. In addition, the virtual environment is attractive and has the ability to overcome specific challenges with real-time feedback, coinciding with ideal approaches for use in ocular rehabilitation. The entire game was developed with free software and the 3D environment, which is made from low-cost virtual reality glasses, as well as Google Cardboard which uses a smartphone for the display of the game. The method presented was tested in 41 male and female patients, aged 8 to 39 years, and resulted in the success of 40 patients. The method proved to be feasible and accessible as a tool for the treatment of amblyopia and strabismus. The project was registered in the Brazil platform and approved by the ethics committee of the State University of Piaui—UESPI, with the CAAE identification code: 37802114.8.0000.5209.
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14
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Birch EE, Morale SE, Jost RM, De La Cruz A, Kelly KR, Wang YZ, Bex PJ. Assessing Suppression in Amblyopic Children With a Dichoptic Eye Chart. Invest Ophthalmol Vis Sci 2017; 57:5649-5654. [PMID: 27784068 PMCID: PMC5089215 DOI: 10.1167/iovs.16-19986] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Suppression has a key role in the etiology of amblyopia, and contrast-balanced binocular treatment can overcome suppression and improve visual acuity. Quantitative assessment of suppression could have a role in managing amblyopia. We describe a novel eye chart to assess suppression in children. Methods We enrolled 100 children (7–12 years; 63 amblyopic, 25 nonamblyopic with strabismus or anisometropia, 12 controls) in the primary cohort and 22 children (3–6 years; 13 amblyopic, 9 nonamblyopic) in a secondary cohort. Letters were presented on a dichoptic display (5 letters per line). Children wore polarized glasses so that each eye saw a different letter chart. At each position, the identity of the letter and its contrast on each eye's chart differed. Children read 8 lines of letters for each of 3 letter sizes. The contrast balance ratio was the ratio at which 50% of letters seen by the amblyopic eye were reported. Results Amblyopic children had significantly higher contrast balance ratios for all letter sizes compared to nonamblyopic children and controls, requiring 4.6 to 5.6 times more contrast in the amblyopic eye compared to the fellow eye (P < 0.0001). Amblyopic eye visual acuity was correlated with contrast balance ratio (r ranged from 0.49–0.57 for the 3 letter sizes). Change in visual acuity with amblyopia treatment was correlated with change in contrast balance ratio (r ranged from 0.43–0.62 for the 3 letter sizes). Conclusions Severity of suppression can be monitored as part of a routine clinical exam in the management of amblyopia in children.
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Affiliation(s)
- Eileen E Birch
- Crystal Charity Ball Pediatric Vision Laboratory, Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Sarah E Morale
- Crystal Charity Ball Pediatric Vision Laboratory, Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Reed M Jost
- Crystal Charity Ball Pediatric Vision Laboratory, Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Angie De La Cruz
- Crystal Charity Ball Pediatric Vision Laboratory, Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Krista R Kelly
- Crystal Charity Ball Pediatric Vision Laboratory, Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Yi-Zhong Wang
- Crystal Charity Ball Pediatric Vision Laboratory, Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Peter J Bex
- Department of Psychology, Northeastern University, Boston, Massachusetts, United States
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15
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Guo CX, Babu RJ, Black JM, Bobier WR, Lam CSY, Dai S, Gao TY, Hess RF, Jenkins M, Jiang Y, Kowal L, Parag V, South J, Staffieri SE, Walker N, Wadham A, Thompson B. Binocular treatment of amblyopia using videogames (BRAVO): study protocol for a randomised controlled trial. Trials 2016; 17:504. [PMID: 27756405 PMCID: PMC5069878 DOI: 10.1186/s13063-016-1635-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/30/2016] [Indexed: 12/02/2022] Open
Abstract
Background Amblyopia is a common neurodevelopmental disorder of vision that is characterised by visual impairment in one eye and compromised binocular visual function. Existing evidence-based treatments for children include patching the nonamblyopic eye to encourage use of the amblyopic eye. Currently there are no widely accepted treatments available for adults with amblyopia. The aim of this trial is to assess the efficacy of a new binocular, videogame-based treatment for amblyopia in older children and adults. We hypothesise that binocular treatment will significantly improve amblyopic eye visual acuity relative to placebo treatment. Methods/design The BRAVO study is a double-blind, randomised, placebo-controlled multicentre trial to assess the effectiveness of a novel videogame-based binocular treatment for amblyopia. One hundred and eight participants aged 7 years or older with anisometropic and/or strabismic amblyopia (defined as ≥0.2 LogMAR interocular visual acuity difference, ≥0.3 LogMAR amblyopic eye visual acuity and no ocular disease) will be recruited via ophthalmologists, optometrists, clinical record searches and public advertisements at five sites in New Zealand, Canada, Hong Kong and Australia. Eligible participants will be randomised by computer in a 1:1 ratio, with stratification by age group: 7–12, 13–17 and 18 years and older. Participants will be randomised to receive 6 weeks of active or placebo home-based binocular treatment. Treatment will be in the form of a modified interactive falling-blocks game, implemented on a 5th generation iPod touch device viewed through red/green anaglyphic glasses. Participants and those assessing outcomes will be blinded to group assignment. The primary outcome is the change in best-corrected distance visual acuity in the amblyopic eye from baseline to 6 weeks post randomisation. Secondary outcomes include distance and near visual acuity, stereopsis, interocular suppression, angle of strabismus (where applicable) measured at baseline, 3, 6, 12 and 24 weeks post randomisation. Treatment compliance and acceptability will also be assessed along with quality of life for adult participants. Discussion The BRAVO study is the first randomised controlled trial of a home-based videogame treatment for older children and adults with amblyopia. The results will indicate whether a binocular approach to amblyopia treatment conducted at home is effective for patients aged 7 years or older. Trial registration This trial was registered in Australia and New Zealand Clinical Trials Registry (ACTRN12613001004752) on 10 September 2013.
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Affiliation(s)
- Cindy X Guo
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Raiju J Babu
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Joanna M Black
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - William R Bobier
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Carly S Y Lam
- School of Optometry, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hong Kong, SAR, China
| | - Shuan Dai
- Department of Ophthalmology, Starship Children's Hospital, Auckland, New Zealand
| | - Tina Y Gao
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Robert F Hess
- Department of Ophthalmology, McGill Vision Research, McGill University, Montreal, QC, Canada
| | - Michelle Jenkins
- National Institute for Health Innovation, School of Population Health, The University of Auckland, Auckland, New Zealand
| | - Yannan Jiang
- National Institute for Health Innovation, School of Population Health, The University of Auckland, Auckland, New Zealand
| | - Lionel Kowal
- Department of Surgery, Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital; Ophthalmology, University of Melbourne, Melbourne, VIC, Australia
| | - Varsha Parag
- National Institute for Health Innovation, School of Population Health, The University of Auckland, Auckland, New Zealand
| | - Jayshree South
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Sandra Elfride Staffieri
- Department of Surgery, Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital; Ophthalmology, University of Melbourne, Melbourne, VIC, Australia
| | - Natalie Walker
- National Institute for Health Innovation, School of Population Health, The University of Auckland, Auckland, New Zealand
| | - Angela Wadham
- National Institute for Health Innovation, School of Population Health, The University of Auckland, Auckland, New Zealand
| | - Benjamin Thompson
- School of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand. .,School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada.
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16
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Tailor V, Bossi M, Bunce C, Greenwood JA, Dahlmann‐Noor A. Binocular versus standard occlusion or blurring treatment for unilateral amblyopia in children aged three to eight years. Cochrane Database Syst Rev 2015; 2015:CD011347. [PMID: 26263202 PMCID: PMC6718221 DOI: 10.1002/14651858.cd011347.pub2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Current treatments for amblyopia in children, occlusion and pharmacological blurring, have had limited success, with less than two-thirds of children achieving good visual acuity of at least 0.20 logMAR in the amblyopic eye, limited improvement of stereopsis, and poor compliance. A new treatment approach, based on the dichoptic presentation of movies or computer games (images presented separately to each eye), may yield better results, as it aims to balance the input of visual information from each eye to the brain. Compliance may also improve with these more child-friendly treatment procedures. OBJECTIVES To determine whether binocular treatments in children aged three to eight years with unilateral amblyopia result in better visual outcomes than conventional occlusion or pharmacological blurring treatment. SEARCH METHODS We searched the Cochrane Eyes and Vision Group Trials Register (last date of searches: 14 April 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 3), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to April 2015), EMBASE (January 1980 to April 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. SELECTION CRITERIA Two review authors independently screened the results of the search in order to identify studies that met the inclusion criteria of the review: randomised controlled trials (RCTs) that enrolled participants between the ages of three and eight years old with unilateral amblyopia, defined as best-corrected visual acuity (BCVA) worse than 0.200 logMAR in the amblyopic eye, and BCVA 0.200 logMAR or better in the fellow eye, in the presence of an amblyogenic risk factor such as anisometropia, strabismus, or both. Prior to enrolment, participants were to have undergone a cycloplegic refraction and comprehensive ophthalmic examination including fundal examination. In addition, participants had to have completed a period of optical treatment, if indicated, and BCVA in the amblyopic eye had to remain unchanged on two consecutive assessments despite reportedly good compliance with glasses wearing. Participants were not to have received any treatment other than optical treatment prior to enrolment. We planned to include any type of binocular viewing intervention; these could be delivered on different devices including computer monitors viewed with LCD shutter glasses or hand-held screens including mobile phone screens with lenticular prism overlay. Control groups were to have received standard amblyopia treatment; this could include occlusion or pharmacological blurring of the better-seeing eye. We planned to include full-time (all waking hours) and part-time (between 1 and 12 hours a day) occlusion regimens. DATA COLLECTION AND ANALYSIS We planned to use standard methodological procedures expected by The Cochrane Collaboration. We had planned to meta-analyse the primary outcome, that is mean distance BCVA in the amblyopic eye at 12 months after the cessation of treatment. MAIN RESULTS We could identify no RCTs in this subject area. AUTHORS' CONCLUSIONS Further research is required to allow decisions about implementation of binocular treatments for amblyopia in clinical practice. Currently there are no clinical trials offering standardised evidence of the safety and effectiveness of binocular treatments, but results from non-controlled cohort studies are encouraging. Future research should be conducted in the form of RCTs, using acknowledged methods of visual acuity and stereoacuity assessment with known reproducibility. Other important outcome measures include outcomes reported by users, compliance with treatment, and recurrence of amblyopia after cessation of treatment.
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Affiliation(s)
- Vijay Tailor
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology162 City RoadLondonUKEC1V 2PD
| | - Manuela Bossi
- UCL Institute of OphthalmologyDepartment of Visual NeurosciencesLondonUK
| | - Catey Bunce
- Moorfields Eye Hospital NHS Foundation TrustResearch and Development DepartmentCity RoadLondonUKEC1V 2PD
| | - John A Greenwood
- University College LondonExperimental Psychology26 Bedford WayLondonUKWC1H 0AP
| | - Annegret Dahlmann‐Noor
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology162 City RoadLondonUKEC1V 2PD
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17
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Bui Quoc E, Milleret C. Origins of strabismus and loss of binocular vision. Front Integr Neurosci 2014; 8:71. [PMID: 25309358 PMCID: PMC4174748 DOI: 10.3389/fnint.2014.00071] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 08/27/2014] [Indexed: 11/13/2022] Open
Abstract
Strabismus is a frequent ocular disorder that develops early in life in humans. As a general rule, it is characterized by a misalignment of the visual axes which most often appears during the critical period of visual development. However other characteristics of strabismus may vary greatly among subjects, for example, being convergent or divergent, horizontal or vertical, with variable angles of deviation. Binocular vision may also vary greatly. Our main goal here is to develop the idea that such “polymorphy” reflects a wide variety in the possible origins of strabismus. We propose that strabismus must be considered as possibly resulting from abnormal genetic and/or acquired factors, anatomical and/or functional abnormalities, in the sensory and/or the motor systems, both peripherally and/or in the brain itself. We shall particularly develop the possible “central” origins of strabismus. Indeed, we are convinced that it is time now to open this “black box” in order to move forward. All of this will be developed on the basis of both presently available data in literature (including most recent data) and our own experience. Both data in biology and medicine will be referred to. Our conclusions will hopefully help ophthalmologists to better understand strabismus and to develop new therapeutic strategies in the future. Presently, physicians eliminate or limit the negative effects of such pathology both on the development of the visual system and visual perception through the use of optical correction and, in some cases, extraocular muscle surgery. To better circumscribe the problem of the origins of strabismus, including at a cerebral level, may improve its management, in particular with respect to binocular vision, through innovating tools by treating the pathology at the source.
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Affiliation(s)
- Emmanuel Bui Quoc
- Ophthalmology Department, Hopital Robert Debre/Assistance Publique Hopitaux de Paris Paris, France
| | - Chantal Milleret
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB), Spatial Navigation and Memory Team Paris, France
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18
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Hamm LM, Black J, Dai S, Thompson B. Global processing in amblyopia: a review. Front Psychol 2014; 5:583. [PMID: 24987383 PMCID: PMC4060804 DOI: 10.3389/fpsyg.2014.00583] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 05/25/2014] [Indexed: 01/13/2023] Open
Abstract
Amblyopia is a neurodevelopmental disorder of the visual system that is associated with disrupted binocular vision during early childhood. There is evidence that the effects of amblyopia extend beyond the primary visual cortex to regions of the dorsal and ventral extra-striate visual cortex involved in visual integration. Here, we review the current literature on global processing deficits in observers with either strabismic, anisometropic, or deprivation amblyopia. A range of global processing tasks have been used to investigate the extent of the cortical deficit in amblyopia including: global motion perception, global form perception, face perception, and biological motion. These tasks appear to be differentially affected by amblyopia. In general, observers with unilateral amblyopia appear to show deficits for local spatial processing and global tasks that require the segregation of signal from noise. In bilateral cases, the global processing deficits are exaggerated, and appear to extend to specialized perceptual systems such as those involved in face processing.
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Affiliation(s)
- Lisa M Hamm
- Department of Optometry and Vision Science, University of Auckland Auckland, New Zealand
| | - Joanna Black
- Department of Optometry and Vision Science, University of Auckland Auckland, New Zealand
| | - Shuan Dai
- Department of Ophthalmology, Starship Children's Hospital Auckland, New Zealand ; Department of Ophthalmology, University of Auckland Auckland, New Zealand
| | - Benjamin Thompson
- Department of Optometry and Vision Science, University of Auckland Auckland, New Zealand ; Department of Optometry and Vision Science, University of Waterloo Waterloo, Canada
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19
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Xi J, Jia WL, Feng LX, Lu ZL, Huang CB. Perceptual learning improves stereoacuity in amblyopia. Invest Ophthalmol Vis Sci 2014; 55:2384-91. [PMID: 24508791 PMCID: PMC3989086 DOI: 10.1167/iovs.13-12627] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 01/23/2014] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Amblyopia is a developmental disorder that results in both monocular and binocular deficits. Although traditional treatment in clinical practice (i.e., refractive correction, or occlusion by patching and penalization of the fellow eye) is effective in restoring monocular visual acuity, there is little information on how binocular function, especially stereopsis, responds to traditional amblyopia treatment. We aim to evaluate the effects of perceptual learning on stereopsis in observers with amblyopia in the current study. METHODS Eleven observers (21.1 ± 5.1 years, six females) with anisometropic or ametropic amblyopia were trained to judge depth in 10 to 13 sessions. Red-green glasses were used to present three different texture anaglyphs with different disparities but a fixed exposure duration. Stereoacuity was assessed with the Fly Stereo Acuity Test and visual acuity was assessed with the Chinese Tumbling E Chart before and after training. RESULTS Averaged across observers, training significantly reduced disparity threshold from 776.7″ to 490.4″ (P < 0.01) and improved stereoacuity from 200.3″ to 81.6″ (P < 0.01). Interestingly, visual acuity also significantly improved from 0.44 to 0.35 logMAR (approximately 0.9 lines, P < 0.05) in the amblyopic eye after training. Moreover, the learning effects in two of the three retested observers were largely retained over a 5-month period. CONCLUSIONS Perceptual learning is effective in improving stereo vision in observers with amblyopia. These results, together with previous evidence, suggest that structured monocular and binocular training might be necessary to fully recover degraded visual functions in amblyopia. Chinese Abstract.
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Affiliation(s)
- Jie Xi
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Wu-Li Jia
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Li-Xia Feng
- Department of Ophthalmology, First Affiliated Hospital, Anhui Medical University, Hefei, Anhui, China
| | - Zhong-Lin Lu
- Laboratory of Brain Processes, Department of Psychology, The Ohio State University, Columbus, Ohio, United States
| | - Chang-Bing Huang
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
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20
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Barrett BT, Panesar GK, Scally AJ, Pacey IE. Binocular summation and other forms of non-dominant eye contribution in individuals with strabismic amblyopia during habitual viewing. PLoS One 2013; 8:e77871. [PMID: 24205005 PMCID: PMC3812153 DOI: 10.1371/journal.pone.0077871] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 09/05/2013] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Adults with amblyopia ('lazy eye'), long-standing strabismus (ocular misalignment) or both typically do not experience visual symptoms because the signal from weaker eye is given less weight than the signal from its fellow. Here we examine the contribution of the weaker eye of individuals with strabismus and amblyopia with both eyes open and with the deviating eye in its anomalous motor position. METHODOLOGY/RESULTS The task consisted of a blue-on-yellow detection task along a horizontal line across the central 50 degrees of the visual field. We compare the results obtained in ten individuals with strabismic amblyopia with ten visual normals. At each field location in each participant, we examined how the sensitivity exhibited under binocular conditions compared with sensitivity from four predictions, (i) a model of binocular summation, (ii) the average of the monocular sensitivities, (iii) dominant-eye sensitivity or (iv) non-dominant-eye sensitivity. The proportion of field locations for which the binocular summation model provided the best description of binocular sensitivity was similar in normals (50.6%) and amblyopes (48.2%). Average monocular sensitivity matched binocular sensitivity in 14.1% of amblyopes' field locations compared to 8.8% of normals'. Dominant-eye sensitivity explained sensitivity at 27.1% of field locations in amblyopes but 21.2% in normals. Non-dominant-eye sensitivity explained sensitivity at 10.6% of field locations in amblyopes but 19.4% in normals. Binocular summation provided the best description of the sensitivity profile in 6/10 amblyopes compared to 7/10 of normals. In three amblyopes, dominant-eye sensitivity most closely reflected binocular sensitivity (compared to two normals) and in the remaining amblyope, binocular sensitivity approximated to an average of the monocular sensitivities. CONCLUSIONS Our results suggest a strong positive contribution in habitual viewing from the non-dominant eye in strabismic amblyopes. This is consistent with evidence from other sources that binocular mechanisms are frequently intact in strabismic and amblyopic individuals.
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Affiliation(s)
- Brendan T. Barrett
- Bradford School of Optometry & Vision Science, University of Bradford, Bradford, West Yorkshire, United Kingdom
| | - Gurvinder K. Panesar
- Bradford School of Optometry & Vision Science, University of Bradford, Bradford, West Yorkshire, United Kingdom
| | - Andrew J. Scally
- School of Health Studies, University of Bradford, Bradford, West Yorkshire, United Kingdom
| | - Ian E. Pacey
- Bradford School of Optometry & Vision Science, University of Bradford, Bradford, West Yorkshire, United Kingdom
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Spiegel DP, Li J, Hess RF, Byblow WD, Deng D, Yu M, Thompson B. Transcranial direct current stimulation enhances recovery of stereopsis in adults with amblyopia. Neurotherapeutics 2013; 10:831-9. [PMID: 23857313 PMCID: PMC3805870 DOI: 10.1007/s13311-013-0200-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Amblyopia is a neurodevelopmental disorder of vision caused by abnormal visual experience during early childhood that is often considered to be untreatable in adulthood. Recently, it has been shown that a novel dichoptic videogame-based treatment for amblyopia can improve visual function in adult patients, at least in part, by reducing inhibition of inputs from the amblyopic eye to the visual cortex. Non-invasive anodal transcranial direct current stimulation has been shown to reduce the activity of inhibitory cortical interneurons when applied to the primary motor or visual cortex. In this double-blind, sham-controlled cross-over study we tested the hypothesis that anodal transcranial direct current stimulation of the visual cortex would enhance the therapeutic effects of dichoptic videogame-based treatment. A homogeneous group of 16 young adults (mean age 22.1 ± 1.1 years) with amblyopia were studied to compare the effect of dichoptic treatment alone and dichoptic treatment combined with visual cortex direct current stimulation on measures of binocular (stereopsis) and monocular (visual acuity) visual function. The combined treatment led to greater improvements in stereoacuity than dichoptic treatment alone, indicating that direct current stimulation of the visual cortex boosts the efficacy of dichoptic videogame-based treatment. This intervention warrants further evaluation as a novel therapeutic approach for adults with amblyopia.
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Affiliation(s)
- Daniel P. Spiegel
- />State Key Laboratory of Ophthalmology, Zhongshan, Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060 China
- />Department of Optometry and Vision Science, The University of Auckland, Auckland, 1142 New Zealand
- />Centre for Brain Research, The University of Auckland, Auckland, 1142 New Zealand
| | - Jinrong Li
- />State Key Laboratory of Ophthalmology, Zhongshan, Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060 China
| | - Robert F. Hess
- />Department of Ophthalmology, McGill University, Montreal, QC Canada
| | - Winston D. Byblow
- />Centre for Brain Research, The University of Auckland, Auckland, 1142 New Zealand
- />Department of Sport & Exercise Science, The University of Auckland, Auckland, 1142 New Zealand
| | - Daming Deng
- />State Key Laboratory of Ophthalmology, Zhongshan, Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060 China
| | - Minbin Yu
- />State Key Laboratory of Ophthalmology, Zhongshan, Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060 China
| | - Benjamin Thompson
- />Department of Optometry and Vision Science, The University of Auckland, Auckland, 1142 New Zealand
- />Centre for Brain Research, The University of Auckland, Auckland, 1142 New Zealand
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