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Robert F. Hess - One of the best experts on this subject based on the ideXlab platform.
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can short term ocular dominance plasticity provide a general index to visual plasticity to personalize treatment in Amblyopia
Frontiers in Neuroscience, 2020Co-Authors: Chunwen Tao, Jiawei Zhou, Yiya Chen, Robert F. HessAbstract:Purpose: Recently, Lunghi et al showed that amblyopic eye’s visual acuity per se after 2 months of occlusion therapy could be predicted by a homeostatic plasticity, i.e., the temporary shift of perceptual eye dominance observed after a 2-hour monocular deprivation, in children with anisometropic Amblyopia(Lunghi et al., 2016). In this study, we assess whether the visual acuity improvement of the amblyopic eye measured after 2 months of occlusion therapy could be predicted by this plasticity. Methods: Seven children (6.86 ± 1.46 years old; SD) with anisometropic Amblyopia participated in this study. All patients were newly diagnosed and had no treatment history before participating our study. They finished 2 months of refractive adaptation and then received a 4-hour daily fellow eye patching therapy with an opaque patch for a 2-month period. Best-corrected visual acuity of the amblyopic eye was measured before and after the patching therapy. The homeostatic plasticity was assessed by measuring the temporary shift of perceptual eye dominance from 2-hour occlusion of the amblyopic eye before treatment. A binocular phase combination paradigm was used for this study. Results: We found that there was no significant correlation between the temporary shift of perceptual eye dominance observed after 2-hour occlusion of the amblyopic eye and the improvement in visual acuity in the amblyopic eye from 2-hour of classical patching therapy. This result, although in disagreements with the conclusions of Lunghi et al involving the short-term patching of the amblyopic eye, is in fact consistent with a reanalysis of Lunghi et al’ s data. Conclusions: The short-term changes in perceptual eye dominance as a result of short-term monocular deprivation do not provide an index of cortical plasticity in the general sense such that they are able to predict acuity outcomes from longer term classical patching.
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can short term ocular dominance plasticity provide a general index to visual plasticity to personalize treatment in Amblyopia
Frontiers in Neuroscience, 2020Co-Authors: Zhifen He, Yiya Chen, Jiawei Zhou, Robert F. HessAbstract:Purpose Recently, Lunghi et al. (2016) showed that amblyopic eye's visual acuity per se after 2 months of occlusion therapy could be predicted by a homeostatic plasticity, that is, the temporary shift of perceptual eye dominance observed after a 2-h monocular deprivation, in children with anisometropic Amblyopia. In this study, we assess whether the visual acuity improvement of the amblyopic eye measured after 2 months of occlusion therapy could be predicted by this plasticity. Methods Seven children (6.86 ± 1.46 years old; SD) with anisometropic Amblyopia participated in this study. All patients were newly diagnosed and had no treatment history before participating in our study. They finished 2 months of refractive adaptation and then received a 4-h daily fellow eye patching therapy with an opaque patch for a 2-month period. Best-corrected visual acuity of the amblyopic eye was measured before and after the patching therapy. The homeostatic plasticity was assessed by measuring the temporary shift of perceptual eye dominance from 2-h occlusion of the amblyopic eye before treatment. A binocular phase combination paradigm was used for this study. Results We found that there was no significant correlation between the temporary shift of perceptual eye dominance observed after 2-h occlusion of the amblyopic eye and the improvement in visual acuity in the amblyopic eye from 2 months of classical patching therapy. This result, although in disagreements with the conclusions of Lunghi et al. involving the short-term patching of the amblyopic eye, is in fact consistent with a reanalysis of Lunghi and colleagues' data. Conclusion The short-term changes in perceptual eye dominance as a result of short-term monocular deprivation do not provide an index of cortical plasticity in the general sense such that they are able to predict acuity outcomes from longer-term classical patching.
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can ocular dominance plasticity provide a general index to visual plasticity to personalize treatment in Amblyopia
medRxiv, 2020Co-Authors: Zhifen He, Yiya Chen, Jiawei Zhou, Robert F. HessAbstract:Purpose: Recently, Lunghi et al showed that amblyopic eye's visual acuity per se after 2 months of occlusion therapy could be predicted by a homeostatic plasticity, i.e., the temporary shift of ocular dominance observed after a 2-hour monocular deprivation, in children with anisometropic Amblyopia (Lunghi et al., 2016). In this study, we assess whether the visual acuity improvement of the amblyopic eye measured after 2 months of occlusion therapy could be predicted by this plasticity. Methods: Seven children (6.86 {+/-} 1.46 years old; SD) with anisometropic Amblyopia participated in this study. All patients were newly diagnosed and had no treatment history before participating in our study. They had finished 2 months of refractive adaptation and then received a 4-hour daily fellow eye patching therapy with an opaque patch for a 2-month period. Best-corrected visual acuity of the amblyopic eye was measured before and after the patching therapy. The homeostatic plasticity was assessed by measuring the temporary shift of ocular dominance observed after 2 hours of occlusion for the amblyopic eye before the treatment started. A binocular phase combination paradigm was used for this test. Results: We found that there was no significant correlation between the temporary shift of ocular dominance observed after 2 hours of occlusion for the amblyopic eye before the treatment started and the visual acuity gain obtained by the amblyopic eye from 2-month of classical patching therapy. This result involving the short-term patching of the amblyopic eye is consistent with a reanalysis of Lunghi et al's data. Conclusions: Ocular dominance plasticity does not provide an index of cortical plasticity in the general sense such that it could be used to predict acuity outcomes from longer term classical patching.
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contribution of short time occlusion of the amblyopic eye to a passive dichoptic video treatment for Amblyopia beyond the critical period
Neural Plasticity, 2019Co-Authors: Lauren Sauvan, Robert F. Hess, Natacha Stolowy, Daniele Denis, Frederic Matonti, Frederic Chavane, Alexandre ReynaudAbstract:Dichoptic movie viewing has been shown to significantly improve visual acuity in Amblyopia in children. Moreover, short-term occlusion of the amblyopic eye can transiently increase its contribution to binocular fusion in adults. In this study, we first asked whether dichoptic movie viewing could improve the visual function of amblyopic subjects beyond the critical period. Secondly, we tested if this effect could be enhanced by short-term monocular occlusion of the amblyopic eye. 17 subjects presenting stable functional Amblyopia participated in this study. 10 subjects followed 6 sessions of 1.5 hour of dichoptic movie viewing (nonpatched group), and 7 subjects, prior to each of these sessions, had to wear an occluding patch over the amblyopic eye for two hours (patched group). Best-corrected visual acuity, monocular contrast sensitivity, interocular balance, and stereoacuity were measured before and after the training. For the nonpatched group, mean amblyopic eye visual acuity significantly improved from 0.54 to 0.46 logMAR (p < 0.05). For the patched group, mean amblyopic eye visual acuity significantly improved from 0.62 to 0.43 logMAR (p < 0.05). Stereoacuity improved significantly when the data of both groups were combined. No significant improvement was observed for the other visual functions tested. Our training procedure combines modern video technologies and recent fundamental findings in human plasticity: (i) long-term plasticity induced by dichoptic movie viewing and (ii) short-term adaptation induced by temporary monocular occlusion. This passive dichoptic movie training approach is shown to significantly improve visual acuity of subjects beyond the critical period. The addition of a short-term monocular occlusion to the dichoptic training shows promising trends but was not significant for the sample size used here. The passive movie approach combined with interocular contrast balancing even over such a short period as 2 weeks has potential as a clinical therapy to treat Amblyopia in older children and adults.
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optical treatment of Amblyopia in older children and adults is essential prior to enrolment in a clinical trial
Ophthalmic and Physiological Optics, 2018Co-Authors: Nicola Anstice, Robert F. Hess, Joanna Black, Raiju J Babu, William R Bobier, Michelle Jenkins, Yannan Jiang, Lionel Kowal, Lisa S Kearns, Peter C K PangAbstract:PURPOSE: Optical treatment alone can improve visual acuity (VA) in children with Amblyopia, thus clinical trials investigating additional Amblyopia therapies (such as patching or videogames) for children require a preceding optical treatment phase. Emerging therapies for adult patients are entering clinical trials. It is unknown whether optical treatment is effective for adults with Amblyopia and whether an optical correction phase is required for trials involving adults. METHODS: We examined participants who underwent optical treatment in the Binocular Treatment for Amblyopia using Videogames (BRAVO) clinical trial (ANZCTR ID: ACTRN12613001004752). Participants were recruited in three age groups (7 to 12, 13 to 17, or ≥18 years), and had unilateral Amblyopia due to anisometropia and/or strabismus, with amblyopic eye VA of 0.30-1.00 logMAR (6/12 to 6/60, 20/40 to 20/200). Corrective lenses were prescribed based on cycloplegic refraction to fully correct any anisometropia. VA was assessed using the electronic visual acuity testing algorithm (e-ETDRS) test and near stereoacuity was assessed using the Randot Preschool Test. Participants were assessed every four weeks up to 16 weeks, until either VA was stable or until amblyopic eye VA improved to better than 0.30 logMAR, rendering the participant ineligible for the trial. RESULTS: Eighty participants (mean age 24.6 years, range 7.6-55.5 years) completed four to 16 weeks of optical treatment. A small but statistically significant mean improvement in amblyopic eye VA of 0.05 logMAR was observed (S.D. 0.08 logMAR; paired t-test p < 0.0001). Twenty-five participants (31%) improved by ≥1 logMAR line and of these, seven (9%) improved by ≥2 logMAR lines. Stereoacuity improved in 15 participants (19%). Visual improvements were not associated with age, presence of strabismus, or prior occlusion treatment. Two adult participants withdrew due to intolerance to anisometropic correction. Sixteen out of 80 participants (20%) achieved better than 0.30 logMAR VA in the amblyopic eye after optical treatment. Nine of these participants attended additional follow-up and four (44%) showed further VA improvements. CONCLUSIONS: Improvements from optical treatment resulted in one-fifth of participants becoming ineligible for the main clinical trial. Studies investigating additional Amblyopia therapies must include an appropriate optical treatment only phase and/or parallel treatment group regardless of patient age. Optical treatment of Amblyopia in adult patients warrants further investigation.
Benjamin Thompson - One of the best experts on this subject based on the ideXlab platform.
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the effect of transcranial direct current stimulation on contrast sensitivity and visual evoked potential amplitude in adults with Amblyopia
Scientific Reports, 2016Co-Authors: Zhaofeng Ding, Daniel P Spiegel, Zidong Chen, Lily Y L Chan, Guangwei Luo, Junpeng Yuan, Daming Deng, Benjamin ThompsonAbstract:Amblyopia is a neurodevelopmental disorder of vision that occurs when the visual cortex receives decorrelated inputs from the two eyes during an early critical period of development. Amblyopic eyes are subject to suppression from the fellow eye, generate weaker visual evoked potentials (VEPs) than fellow eyes and have multiple visual deficits including impairments in visual acuity and contrast sensitivity. Primate models and human psychophysics indicate that stronger suppression is associated with greater deficits in amblyopic eye contrast sensitivity and visual acuity. We tested whether transcranial direct current stimulation (tDCS) of the visual cortex would modulate VEP amplitude and contrast sensitivity in adults with Amblyopia. tDCS can transiently alter cortical excitability and may influence suppressive neural interactions. Twenty-one patients with Amblyopia and twenty-seven controls completed separate sessions of anodal (a-), cathodal (c-) and sham (s-) visual cortex tDCS. A-tDCS transiently and significantly increased VEP amplitudes for amblyopic, fellow and control eyes and contrast sensitivity for amblyopic and control eyes. C-tDCS decreased VEP amplitude and contrast sensitivity and s-tDCS had no effect. These results suggest that tDCS can modulate visual cortex responses to information from adult amblyopic eyes and provide a foundation for future clinical studies of tDCS in adults with Amblyopia.
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Amblyopia and the binocular approach to its therapy
Vision Research, 2015Co-Authors: Robert F. Hess, Benjamin ThompsonAbstract:There is growing evidence that abnormal binocular interactions play a key role in Amblyopia. In particular, stronger suppression of the amblyopic eye has been associated with poorer amblyopic eye visual acuity and a new therapy has been described that directly targets binocular function and has been found to improve both monocular and binocular vision in adults and children with Amblyopia. Furthermore, non-invasive brain stimulation techniques that alter excitation and inhibition within the visual cortex have been shown to improve vision in the amblyopic eye. The aim of this review is to summarize this previous work and interpret the therapeutic effects of binocular therapy and non-invasive brain stimulation in the context of three potential neural mechanisms; active inhibition of signals from the amblyopic eye, attenuation of information from the amblyopic eye and metaplasticity of synaptic long term potentiation and long term depression.
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the measurement and treatment of suppression in Amblyopia
Journal of Visualized Experiments, 2012Co-Authors: Joanna Black, Robert F. Hess, Jeremy R Cooperstock, Long To, Benjamin ThompsonAbstract:Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current estimates put the prevalence of Amblyopia at approximately 1-3%1-3, the majority of cases being monocular2. Amblyopia is most frequently caused by ocular misalignment (strabismus), blur induced by unequal refractive error (anisometropia), and in some cases by form deprivation. Although Amblyopia is initially caused by abnormal visual input in infancy, once established, the visual deficit often remains when normal visual input has been restored using surgery and/or refractive correction. This is because Amblyopia is the result of abnormal visual cortex development rather than a problem with the amblyopic eye itself4,5 . Amblyopia is characterized by both monocular and binocular deficits6,7 which include impaired visual acuity and poor or absent stereopsis respectively. The visual dysfunction in Amblyopia is often associated with a strong suppression of the inputs from the amblyopic eye under binocular viewing conditions8. Recent work has indicated that suppression may play a central role in both the monocular and binocular deficits associated with Amblyopia9,10 . Current clinical tests for suppression tend to verify the presence or absence of suppression rather than giving a quantitative measurement of the degree of suppression. Here we describe a technique for measuring amblyopic suppression with a compact, portable device11,12 . The device consists of a laptop computer connected to a pair of virtual reality goggles. The novelty of the technique lies in the way we present visual stimuli to measure suppression. Stimuli are shown to the amblyopic eye at high contrast while the contrast of the stimuli shown to the non-amblyopic eye are varied. Patients perform a simple signal/noise task that allows for a precise measurement of the strength of excitatory binocular interactions. The contrast offset at which neither eye has a performance advantage is a measure of the "balance point" and is a direct measure of suppression. This technique has been validated psychophysically both in control13,14 and patient6,9,11 populations. In addition to measuring suppression this technique also forms the basis of a novel form of treatment to decrease suppression over time and improve binocular and often monocular function in adult patients with Amblyopia12,15,16 . This new treatment approach can be deployed either on the goggle system described above or on a specially modified iPod touch device15.
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abnormal cortical processing of pattern motion in Amblyopia evidence from fmri
NeuroImage, 2012Co-Authors: Benjamin Thompson, Martin Y Villeneuve, Christian Casanova, Robert F. HessAbstract:Abstract Converging evidence from human psychophysics and animal neurophysiology indicates that Amblyopia is associated with abnormal function of area MT, a motion sensitive region of the extrastriate visual cortex. In this context, the recent finding that amblyopic eyes mediate normal perception of dynamic plaid stimuli was surprising, as neural processing and perception of plaids has been closely linked to MT function. One intriguing potential explanation for this discrepancy is that the amblyopic eye recruits alternative visual brain areas to support plaid perception. This is the hypothesis that we tested. We used functional magnetic resonance imaging (fMRI) to measure the response of the amblyopic visual cortex and thalamus to incoherent and coherent motion of plaid stimuli that were perceived normally by the amblyopic eye. We found a different pattern of responses within the visual cortex when plaids were viewed by amblyopic as opposed to non-amblyopic eyes. The non-amblyopic eyes of amblyopes and control eyes differentially activated the hMT + complex when viewing incoherent vs. coherent plaid motion, consistent with the notion that this region is centrally involved in plaid perception. However, for amblyopic eye viewing, hMT + activation did not vary reliably with motion type. In a sub-set of our participants with Amblyopia we were able to localize MT and MST within the larger hMT + complex and found a lack of plaid motion selectivity in both sub-regions. The response of the pulvinar and ventral V3 to plaid stimuli also differed under amblyopic vs. non-amblyopic eye viewing conditions, however the response of these areas did vary according to motion type. These results indicate that while the perception of the plaid stimuli was constant for both amblyopic and non-amblyopic viewing, the network of neural areas that supported this perception was different.
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restoration of binocular vision in Amblyopia
Strabismus, 2011Co-Authors: Robert F. Hess, Behzad Mansouri, Benjamin ThompsonAbstract:Purpose: To develop a treatment for Amblyopia based on re-establishing binocular vision.Methods: A novel procedure is outlined for measuring and reducing the extent to which the fixing eye suppresses the fellow amblyopic eye in adults with Amblyopia. We hypothesize that suppression renders a structurally binocular system, functionally monocular.Results: We demonstrate that strabismic amblyopes can combine information normally between their eyes under viewing conditions where suppression is reduced by presenting stimuli of different contrast to each eye. Furthermore we show that prolonged periods of binocular combination leads to a strengthening of binocular vision in strabismic amblyopes and eventual combination of binocular information under natural viewing conditions (stimuli of the same contrast in each eye). Concomitant improvement in monocular acuity of the amblyopic eye occurs with this reduction in suppression and strengthening of binocular fusion. Additionally, stereoscopic function was establishe...
Roy W Beck - One of the best experts on this subject based on the ideXlab platform.
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a randomized trial of levodopa as treatment for residual Amblyopia in older children
Ophthalmology, 2015Co-Authors: Michael X Repka, Roy W Beck, Jonathan M Holmes, Cynthia L Beauchamp, Raymond T Kraker, Trevano W Dean, Michael R Siatkowski, Richard P Golden, Aaron M Miller, Lisa C VerderberAbstract:Objective To assess the efficacy and short-term safety of levodopa as adjunctive treatment to patching for Amblyopia. Design Randomized, placebo-controlled trial. Participants One hundred thirty-nine children 7 to 12 years of age with residual Amblyopia resulting from strabismus, anisometropia, or both combined (visual acuity [VA], 20/50–20/400) after patching. Methods Sixteen weeks of oral levodopa or placebo administered 3 times daily while patching the fellow eye 2 hours daily. Main Outcome Measures Mean change in best-corrected amblyopic-eye VA at 18 weeks. Results At 18 weeks, amblyopic-eye VA improved from randomization by an average of 5.2 letters in the levodopa group and by 3.8 letters in the placebo group (difference adjusted for baseline VA, +1.4 letters; 1-sided P = 0.06; 2-sided 95% confidence interval, −0.4 to 3.3 letters). No serious adverse effects from levodopa were reported during treatment. Conclusions For children 7 to 12 years of age with residual Amblyopia after patching therapy, oral levodopa while continuing to patch 2 hours daily does not produce a clinically or statistically meaningful improvement in VA compared with placebo and patching.
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optical treatment of strabismic and combined strabismic anisometropic Amblyopia
Ophthalmology, 2012Co-Authors: Susan A Cotter, Michele B Melia, Michael X Repka, Roy W Beck, Jonathan M Holmes, Nicole C Foster, David K Wallace, Susanna M Tamkins, Raymond T Kraker, Darren L HooverAbstract:Objective To determine visual acuity improvement in children with strabismic and combined strabismic–anisometropic (combined-mechanism) Amblyopia treated with optical correction alone and to explore factors associated with improvement. Design Prospective, multicenter, cohort study. Participants We included 146 children 3 to Methods Optical treatment was provided as spectacles (prescription based on a cycloplegic refraction) that were worn for the first time at the baseline visit. Visual acuity with spectacles was measured using the Amblyopia Treatment Study HOTV visual acuity protocol at baseline and every 9 weeks thereafter until no further improvement in visual acuity. Ocular alignment was assessed at each visit. Main Outcome Measures Visual acuity 18 weeks after baseline. Results Overall, amblyopic eye visual acuity improved a mean of 2.6 lines (95% confidence interval [CI], 2.3–3.0), with 75% of children improving ≥2 lines and 54% improving ≥3 lines. Resolution of Amblyopia occurred in 32% (95% CI, 24%–41%) of the children. The treatment effect was greater for strabismic Amblyopia than for combined-mechanism Amblyopia (3.2 vs 2.3 lines; adjusted P = 0.003). Visual acuity improved regardless of whether eye alignment improved. Conclusions Optical treatment alone of strabismic and combined-mechanism Amblyopia results in clinically meaningful improvement in amblyopic eye visual acuity for most 3- to Financial Disclosure(s) The authors have no proprietary or commercial interest in any of the materials discussed in this article.
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a randomized trial comparing bangerter filters and patching for the treatment of moderate Amblyopia in children
Ophthalmology, 2010Co-Authors: Robert P Rutstein, Elizabeth L. Lazar, Graham E. Quinn, Roy W Beck, Jonathan M Holmes, Susan A Cotter, Darren L Hoover, Dean J Bonsall, Eric R Crouch, David A LeskeAbstract:OBJECTIVE: To determine whether visual acuity improvement with Bangerter filters is similar to improvement with patching as initial therapy for children with moderate Amblyopia. DESIGN: Randomized, clinical trial. PARTICIPANTS: We enrolled 186 children, 3 to or =3 lines (Bangerter group 38% vs patching group 35%; P = 0.61) or had > or =20/25 amblyopic eye acuity (36% vs 31%, respectively; P = 0.86). There was a lower treatment burden in the Bangerter group as measured with the Amblyopia Treatment Index. With Bangerter filters, neither a fixation switch to the amblyopic eye nor induced blurring in the fellow eye to worse than that of the amblyopic eye was required for visual acuity improvement. CONCLUSIONS: Because the average difference in visual acuity improvement between Bangerter filters and patching was less than half a line, and there was lower burden of treatment on the child and family, Bangerter filter treatment is a reasonable option to consider for initial treatment of moderate Amblyopia.
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a randomized trial comparing bangerter filters and patching for the treatment of moderate Amblyopia in children
Ophthalmology, 2010Co-Authors: Robert P Rutstein, Elizabeth L. Lazar, Graham E. Quinn, Roy W Beck, Jonathan M Holmes, Susan A Cotter, Darren L Hoover, Dean J Bonsall, Eric R Crouch, David A LeskeAbstract:Objective To determine whether visual acuity improvement with Bangerter filters is similar to improvement with patching as initial therapy for children with moderate Amblyopia. Design Randomized, clinical trial. Participants We enrolled 186 children, 3 to Methods Children were randomly assigned to receive either daily patching or to use a Bangerter filter on the spectacle lens in front of the fellow eye. Study visits were scheduled at 6, 12, 18, and 24 weeks. Main outcome measures Visual acuity in amblyopic eyes at 24 weeks. Results At 24 weeks, amblyopic eye improvement averaged 1.9 lines in the Bangerter group and 2.3 lines in the patching group (difference in mean visual acuities between groups adjusted for baseline acuity = 0.38 line). The upper limit of a 1-sided 95% confidence interval was 0.76 line, which slightly exceeded a prespecified noninferiority limit of or =3 lines (Bangerter group 38% vs patching group 35%; P = 0.61) or had > or =20/25 amblyopic eye acuity (36% vs 31%, respectively; P = 0.86). There was a lower treatment burden in the Bangerter group as measured with the Amblyopia Treatment Index. With Bangerter filters, neither a fixation switch to the amblyopic eye nor induced blurring in the fellow eye to worse than that of the amblyopic eye was required for visual acuity improvement. Conclusions Because the average difference in visual acuity improvement between Bangerter filters and patching was less than half a line, and there was lower burden of treatment on the child and family, Bangerter filter treatment is a reasonable option to consider for initial treatment of moderate Amblyopia.
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comparison of the Amblyopia treatment study hotv and the electronic early treatment of diabetic retinopathy study visual acuity protocols in amblyopic children aged 5 to 11 years
Journal of Aapos, 2009Co-Authors: Eileen E Birch, Samara F Strauber, Roy W Beck, Jonathan M HolmesAbstract:As part of the long-term follow-up of amblyopic children who were enrolled in the Amblyopia Treatment Study, we tested visual acuity in both eyes of 142 patients by using 2 established visual acuity protocols, the Amblyopia Treatment Study HOTV (ATS HOTV) visual acuity protocol and the Electronic-Early Treatment of Diabetic Retinopathy Study (E-ETDRS) protocol, at one of the annual visits. Mean age at the time of testing was 9.0 years (range, 5.6-11.9 years). The ATS-HOTV protocol resulted in a slight mean overestimate of visual acuity relative to the E-ETDRS protocol (0.68 lines for amblyopic eyes; 0.25 lines for fellow eyes). The overestimation occurred primarily when the E-ETDRS visual acuity was poorer than 0.3 logMAR. ATS-HOTV acuity also underestimated interocular visual acuity differences by 0.42 lines. When one uses the ATS-HOTV protocol, it may be wise to exercise caution when interpreting "near-normal" visual acuity or interocular differences as "within normal" because the ATS-HOTV method may have a slight bias toward better performance of amblyopic eyes than E-ETDRS.
Michael X Repka - One of the best experts on this subject based on the ideXlab platform.
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a randomized trial of levodopa as treatment for residual Amblyopia in older children
Ophthalmology, 2015Co-Authors: Michael X Repka, Roy W Beck, Jonathan M Holmes, Cynthia L Beauchamp, Raymond T Kraker, Trevano W Dean, Michael R Siatkowski, Richard P Golden, Aaron M Miller, Lisa C VerderberAbstract:Objective To assess the efficacy and short-term safety of levodopa as adjunctive treatment to patching for Amblyopia. Design Randomized, placebo-controlled trial. Participants One hundred thirty-nine children 7 to 12 years of age with residual Amblyopia resulting from strabismus, anisometropia, or both combined (visual acuity [VA], 20/50–20/400) after patching. Methods Sixteen weeks of oral levodopa or placebo administered 3 times daily while patching the fellow eye 2 hours daily. Main Outcome Measures Mean change in best-corrected amblyopic-eye VA at 18 weeks. Results At 18 weeks, amblyopic-eye VA improved from randomization by an average of 5.2 letters in the levodopa group and by 3.8 letters in the placebo group (difference adjusted for baseline VA, +1.4 letters; 1-sided P = 0.06; 2-sided 95% confidence interval, −0.4 to 3.3 letters). No serious adverse effects from levodopa were reported during treatment. Conclusions For children 7 to 12 years of age with residual Amblyopia after patching therapy, oral levodopa while continuing to patch 2 hours daily does not produce a clinically or statistically meaningful improvement in VA compared with placebo and patching.
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atropine vs patching for treatment of moderate Amblyopia follow up at 15 years of age of a randomized clinical trial
JAMA Ophthalmology, 2014Co-Authors: Michael X Repka, Jonathan M Holmes, Raymond T Kraker, Allison Summers, Stephen R Glaser, Carmen Barnhardt, David Robbins TienAbstract:Importance Initial treatment for Amblyopia of the fellow eye with patching and atropine sulfate eyedrops improves visual acuity. Long-term data on the durability of treatment benefit are needed. Objective To report visual acuity at 15 years of age among patients who were younger than 7 years when enrolled in a treatment trial for moderate Amblyopia. Design, Setting, and Participants In a multicenter clinical trial, 419 children with Amblyopia (visual acuity, 20/40 to 20/100) were randomly assigned to patching (minimum of 6 h/d) or atropine sulfate eyedrops, 1% (1 drop daily), for 6 months. Treatment after 6 months was at the discretion of the investigator. Two years after enrollment, an unselected subgroup of 188 children were enrolled into long-term follow-up. Intervention Initial treatment with patching or atropine with subsequent treatment at investigator discretion. Main Outcomes and Measures Visual acuity at 15 years of age with the electronic Early Treatment Diabetic Retinopathy Study test in amblyopic and fellow eyes. Results Mean visual acuity in the amblyopic eye measured in 147 participants at 15 years of age was 0.14 logMAR (approximately 20/25); 59.9% of amblyopic eyes had visual acuity of 20/25 or better and 33.3%, 20/20 or better. Mean interocular acuity difference (IOD) at 15 years of age was 0.21 logMAR (2.1 lines); 48.3% had an IOD of 2 or more lines and 71.4%, 1 or more lines. Treatment (other than spectacles) was prescribed for 9 participants (6.1%) aged 10 to 15 years. Mean IOD was similar at examinations at 10 and 15 years of age (2.0 and 2.1 logMAR lines, respectively; P = .39). Better visual acuity at the 15-year examination was achieved in those who were younger than 5 years at the time of entry into the randomized clinical trial (mean logMAR, 0.09) compared with those aged 5 to 6 years (mean logMAR, 0.18; P P = .44 and P = .43, respectively). Conclusions and Relevance At 15 years of age, most children treated for moderate Amblyopia when younger than 7 years have good visual acuity, although mild residual Amblyopia is common. The outcome is similar regardless of initial treatment with atropine or patching. The results indicate that improvement occurring with Amblyopia treatment is maintained until at least 15 years of age. Trial Registration clinicaltrials.gov Identifier:NCT00000170
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optical treatment of strabismic and combined strabismic anisometropic Amblyopia
Ophthalmology, 2012Co-Authors: Susan A Cotter, Michele B Melia, Michael X Repka, Roy W Beck, Jonathan M Holmes, Nicole C Foster, David K Wallace, Susanna M Tamkins, Raymond T Kraker, Darren L HooverAbstract:Objective To determine visual acuity improvement in children with strabismic and combined strabismic–anisometropic (combined-mechanism) Amblyopia treated with optical correction alone and to explore factors associated with improvement. Design Prospective, multicenter, cohort study. Participants We included 146 children 3 to Methods Optical treatment was provided as spectacles (prescription based on a cycloplegic refraction) that were worn for the first time at the baseline visit. Visual acuity with spectacles was measured using the Amblyopia Treatment Study HOTV visual acuity protocol at baseline and every 9 weeks thereafter until no further improvement in visual acuity. Ocular alignment was assessed at each visit. Main Outcome Measures Visual acuity 18 weeks after baseline. Results Overall, amblyopic eye visual acuity improved a mean of 2.6 lines (95% confidence interval [CI], 2.3–3.0), with 75% of children improving ≥2 lines and 54% improving ≥3 lines. Resolution of Amblyopia occurred in 32% (95% CI, 24%–41%) of the children. The treatment effect was greater for strabismic Amblyopia than for combined-mechanism Amblyopia (3.2 vs 2.3 lines; adjusted P = 0.003). Visual acuity improved regardless of whether eye alignment improved. Conclusions Optical treatment alone of strabismic and combined-mechanism Amblyopia results in clinically meaningful improvement in amblyopic eye visual acuity for most 3- to Financial Disclosure(s) The authors have no proprietary or commercial interest in any of the materials discussed in this article.
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effect of age on response to Amblyopia treatment in children
Archives of Ophthalmology, 2011Co-Authors: Jonathan M Holmes, Elizabeth L. Lazar, William F Astle, Linda R Dagi, Michele B Melia, Marcela Frazier, Michael X Repka, Richard W Hertle, Sean P Donahue, Graham E. QuinnAbstract:Objective To determine whether age at initiation of treatment for Amblyopia influences the response among children 3 to less than 13 years of age with unilateral Amblyopia who have 20/40 to 20/400 amblyopic eye visual acuity. Methods A meta-analysis of individual subject data from 4 recently completed randomized Amblyopia treatment trials was performed to evaluate the relationship between age and improvement in logMAR amblyopic eye visual acuity. Analyses were adjusted for baseline amblyopic eye visual acuity, spherical equivalent refractive error in the amblyopic eye, type of Amblyopia, prior Amblyopia treatment, study treatment, and protocol. Age was categorized (3 to Results Children from 7 to less than 13 years of age were significantly less responsive to treatment than were younger age groups (children from 3 to Conclusions Amblyopia is more responsive to treatment among children younger than 7 years of age. Although the average treatment response is smaller in children 7 to less than 13 years of age, some children show a marked response to treatment.
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stereoacuity in children with anisometropic Amblyopia
Journal of Aapos, 2011Co-Authors: David K Wallace, Elizabeth L. Lazar, Yi Pang, Eileen E Birch, Jonathan M Holmes, Raymond T Kraker, Michele Melia, K Hopkins, Marjean Taylor Kulp, Michael X RepkaAbstract:Purpose To determine factors associated with pretreatment and posttreatment stereoacuity in subjects with moderate anisometropic Amblyopia. Methods Data for subjects enrolled in seven studies conducted by the Pediatric Eye Disease Investigator Group were pooled. The sample included 633 subjects aged 3 to Results Better baseline stereoacuity was associated with better baseline amblyopic eye acuity (P Conclusions In children with anisometropic Amblyopia of 20/40 to 20/100 inclusive, better posttreatment stereoacuity is associated with better baseline stereoacuity and better posttreatment amblyopic eye acuity. Even if their visual acuity deficit resolves, many children with anisometropic Amblyopia have stereoacuity worse than that of nonamblyopic children of the same age.
Ziad F Bashshur - One of the best experts on this subject based on the ideXlab platform.
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macular ultrastructural features in Amblyopia using high definition optical coherence tomography
British Journal of Ophthalmology, 2013Co-Authors: Christiane Alhaddad, Georges El Mollayess, Dalida Jaafar, Ziyad Mahfoud, Ziad F BashshurAbstract:Purpose To study macular morphology in amblyopic eyes using high-definition spectral domain optical coherence tomography (SD-OCT) and to compare the findings with fellow eyes. Methods This was a prospective institutional study of patients ≥6 years of age with unilateral Amblyopia. Enhanced high-definition single line macular scans of amblyopic eyes were obtained using SD-OCT and compared with fellow eyes. Scans were evaluated qualitatively for structural differences. Central foveal thickness was measured and areas of the different retinal layers were computed within 500 µm from the foveal centre nasally and temporally. Results Forty-five patients with unilateral Amblyopia were included: 25 with strabismic and 20 with anisometropic Amblyopia with a mean age of 24.8 years. Qualitatively, the bulge in the inner segment/outer segment junction of the central fovea was noted to be attenuated or absent in 60% of amblyopic eyes compared with 29% of normal eyes, p=0.02. Also, amblyopic eyes demonstrated a shallow foveal pit compared with normal fellow eyes. Mean foveal thickness was significantly increased in amblyopic (228.56 µm) versus fellow eyes (221.72 µm), p=0.03. Upon exploring different retinal layers, the temporal inner nuclear layer area was increased (p=0.04) while the outer nuclear layer area was decreased (p=0.04) in amblyopic eyes compared with fellow eyes. Conclusions Using enhanced high-definition SD-OCT, amblyopic eyes demonstrated qualitative and quantitative differences in macular features, possibly representing signs of immaturity compared with normal fellow eyes.
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retinal nerve fibre layer and macular thickness in Amblyopia as measured by spectral domain optical coherence tomography
British Journal of Ophthalmology, 2011Co-Authors: Christiane Alhaddad, Georges El Mollayess, Carol G Cherfan, Dalida Jaafar, Ziad F BashshurAbstract:Background/aims To study peripapillary retinal nerve fibre layer (RNFL) and macular thickness in Amblyopia using high-definition spectral-domain optical coherence tomography (SD-OCT) and to compare the results with available literature using the time-domain modality. Methods This was a prospective institutional study of patients ≥6 years of age with unilateral Amblyopia (strabismic or anisometropic) and non-amblyopic anisometropia. RNFL and macular thicknesses were measured using SD-OCT and compared between fellow eyes. Results The mean age was 20 (±12) years; 45 patients had Amblyopia: 14 strabismic and 31 anisometropic. 20 patients had non-amblyopic anisometropia. The mean macular thickness was significantly increased in the amblyopic (273.8 μm) vs fellow eyes (257.9 μm), p=0.001. This difference remained significant in the anisometropic group (p=0.002) but not the strabismic group. The mean RNFL thickness was similar in amblyopic (95.4 μm) and fellow eyes (94.0 μm). Similar results were obtained regardless of the level of visual acuity, age or refractive error. In the control group of non-amblyopic anisometropia, the interocular difference did not reach statistical significance. Conclusions Central macular thickness was significantly increased in anisometropic Amblyopia using SD-OCT. Anisometropia alone did not produce such a difference, which points to a possible correlation between Amblyopia and the development of the retinal layers.