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Wu C, Gaier ED, Nihalani BR, Whitecross S, Hensch TK, Hunter DG. Durable recovery from amblyopia with donepezil. Sci Rep 2023; 13:10161. [PMID: 37349338 PMCID: PMC10287641 DOI: 10.1038/s41598-023-34891-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 05/09/2023] [Indexed: 06/24/2023] Open
Abstract
An elevated threshold for neuroplasticity limits visual gains with treatment of residual amblyopia in older children and adults. Acetylcholinesterase inhibitors (AChEI) can enable visual neuroplasticity and promote recovery from amblyopia in adult mice. Motivated by these promising findings, we sought to determine whether donepezil, a commercially available AChEI, can enable recovery in older children and adults with residual amblyopia. In this open-label pilot efficacy study, 16 participants (mean age 16 years; range 9-37 years) with residual anisometropic and/or strabismic amblyopia were treated with daily oral donepezil for 12 weeks. Donepezil dosage was started at 2.5 or 5.0 mg based on age and increased by 2.5 mg if the amblyopic eye visual acuity did not improve by 1 line from the visit 4 weeks prior for a maximum dosage of 7.5 or 10 mg. Participants < 18 years of age further patched the dominant eye. The primary outcome was visual acuity in the amblyopic eye at 22 weeks, 10 weeks after treatment was discontinued. Mean amblyopic eye visual acuity improved 1.2 lines (range 0.0-3.0), and 4/16 (25%) improved by ≥ 2 lines after 12 weeks of treatment. Gains were maintained 10 weeks after cessation of donepezil and were similar for children and adults. Adverse events were mild and self-limited. Residual amblyopia improves in older children and adults treated with donepezil, supporting the concept that the critical window of visual cortical plasticity can be pharmacologically manipulated to treat amblyopia. Placebo-controlled studies are needed.
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Affiliation(s)
- Carolyn Wu
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA.
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
| | - Eric D Gaier
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Bharti R Nihalani
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Sarah Whitecross
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA
| | - Takao K Hensch
- Center for Brain Science, Department of Molecular Cellular Biology, Harvard University, Cambridge, MA, USA
- International Research Center for Neurointelligence, University of Tokyo Institutes for Advanced Study, Tokyo, Japan
- FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - David G Hunter
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- International Research Center for Neurointelligence, University of Tokyo Institutes for Advanced Study, Tokyo, Japan
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Wang G, Liu L. Amblyopia: progress and promise of functional magnetic resonance imaging. Graefes Arch Clin Exp Ophthalmol 2022; 261:1229-1246. [PMID: 36282454 DOI: 10.1007/s00417-022-05826-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 08/14/2022] [Accepted: 09/02/2022] [Indexed: 11/28/2022] Open
Abstract
Amblyopia is a neurodevelopmental disorder characterized by functional deficits in the visual cortex. Functional magnetic resonance imaging (fMRI) is the most commonly used neuroimaging technique for investigating amblyopia. Herein, we systematically searched a PubMed database from inception to December 2021 to highlight the current progress and promises about fMRI technology in amblyopia; amblyopia's neural mechanism, the comparison of different types of amblyopia, and the evaluation of the therapeutic effect were explored. Relevant articles published in English and appropriate cross-references were considered for inclusion, including basic studies, imaging techniques, clinical diagnostic and therapeutic studies, case series, and reviews.
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Affiliation(s)
- Guiqu Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Longqian Liu
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China.
- Department of Optometry and Visual Science, West China Hospital, Sichuan University, Chengdu, 610041, China.
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Miller NP, Aldred B, Schmitt MA, Rokers B. Impact of Amblyopia on the Central Nervous System. J Binocul Vis Ocul Motil 2020; 70:182-192. [PMID: 33206009 DOI: 10.1080/2576117x.2020.1841710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Amblyopia is a common perceptual disorder resulting from abnormal visual input during development. The clinical presentation and visual deficits associated with amblyopia are well characterized. Less is known however, about amblyopia's impact on the central nervous system (CNS). While early insights into the neuropathophysiology of amblyopia have been based on findings from animal models and postmortem human studies, recent advances in noninvasive magnetic resonance imaging (MRI) techniques have enabled the study of amblyopia's effects in vivo. We review recent retinal and neuroimaging research documenting amblyopia's structural and functional impact on the CNS. Clinical imaging provides some evidence for retinal and optic nerve abnormalities in amblyopic eyes, although the overall picture remains inconclusive. Neuroimaging studies report clearer changes in both structure and function of the visual pathways. In the optic nerves, optic tracts, and optic radiations of individuals with amblyopia, white-matter integrity is decreased. In the lateral geniculate nuclei, gray matter volume is decreased and neural activity is reduced. Reduced responses are also seen in the amblyopic primary visual cortex and extrastriate areas. Overall, amblyopia impacts structure and function at multiple sites along the visual processing hierarchy. Moreover, there is some evidence that amblyopia's impact on the CNS depends on its etiology, with different patterns of results for strabismic and anisometropic amblyopia. To clarify the impact of amblyopia on the CNS, simultaneous collection of retinal, neural, and perceptual measures should be employed. Such an approach will help (1) distinguish cause and effect of amblyopic impairments, (2) separate the impact of amblyopia from other superimposed conditions, and (3) identify the importance of amblyopic etiology to specific neural and perceptual deficits.
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Affiliation(s)
- Nathaniel P Miller
- Department of Psychology, University of Wisconsin-Madison , Madison, Wisconsin.,Psychology, New York University Abu Dhabi , Abu Dhabi, UAE
| | - Breanna Aldred
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison , Madison, Wisconsin
| | - Melanie A Schmitt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison , Madison, Wisconsin
| | - Bas Rokers
- Psychology, New York University Abu Dhabi , Abu Dhabi, UAE
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Farvardin M, Khalili MR, Behnia M. Levodopa Plus Occlusion Therapy versus Occlusion Therapy Alone for Children with Anisometropic Amblyopia. J Ophthalmic Vis Res 2019; 14:457-464. [PMID: 31875101 PMCID: PMC6825694 DOI: 10.18502/jovr.v14i4.5451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 04/09/2019] [Indexed: 11/30/2022] Open
Abstract
Purpose This study aimed to compare the effects of short-term administration of levodopa plus occlusion therapy versus occlusion therapy alone in preschool children with hyperopic anisometropic amblyopia. Methods This comparative interventional study included 40 eligible preschool children aged 6 to 7 years with hyperopic anisometropic amblyopia. The primary outcome measure was the logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity recorded at baseline, 3 weeks after the treatment initiation and 12 weeks after the treatment termination. The results were compared between the two groups. Results No statistically significant intergroup difference was observed in baseline logMAR visual acuities (P = 0.92). The mean logMAR visual acuities of the amblyopic eyes were significantly better in both groups three weeks after the treatment initiation than the baseline (P< 0.01 in both groups). At 12 weeks after treatment termination, the logMAR visual acuities of the amblyopic eyes were significantly better than the baseline values (P< 0.001 in the placebo group and P = 0.09 in the levodopa group). Intergroup comparisons revealed no statistically significant difference in visual acuities 3 weeks after the treatment initiation (P = 0.11) and 12 weeks after the treatment termination (P=0.10). Twelve weeks after the treatment termination, visual acuities regressed 0.037 logMAR in the placebo group and 0.042 logMAR in the levodopa group. These regression rates were not significantly different (P = 0.89). Conclusion The results of this study provide evidence that adding short-term administration of levodopa to occlusion therapy in hyperopic anisometropic amblyopia offers no additional benefit in visual outcomes and provides no advantage in terms of the regression rate.
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Affiliation(s)
- Majid Farvardin
- Poostchi Ophthalmology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Reza Khalili
- Poostchi Ophthalmology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mehdi Behnia
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
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Roper-Hall G. Current Concepts of Amblyopia: A Neuro-Ophthalmology Perspective. ACTA ACUST UNITED AC 2017. [DOI: 10.3368/aoj.57.1.2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Brown HDH, Woodall RL, Kitching RE, Baseler HA, Morland AB. Using magnetic resonance imaging to assess visual deficits: a review. Ophthalmic Physiol Opt 2017; 36:240-65. [PMID: 27112223 PMCID: PMC4855621 DOI: 10.1111/opo.12293] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 02/15/2016] [Indexed: 01/25/2023]
Abstract
Purpose Over the last two decades, magnetic resonance imaging (MRI) has been widely used in neuroscience research to assess both structure and function in the brain in health and disease. With regard to vision research, prior to the advent of MRI, researchers relied on animal physiology and human post‐mortem work to assess the impact of eye disease on visual cortex and connecting structures. Using MRI, researchers can non‐invasively examine the effects of eye disease on the whole visual pathway, including the lateral geniculate nucleus, striate and extrastriate cortex. This review aims to summarise research using MRI to investigate structural, chemical and functional effects of eye diseases, including: macular degeneration, retinitis pigmentosa, glaucoma, albinism, and amblyopia. Recent Findings Structural MRI has demonstrated significant abnormalities within both grey and white matter densities across both visual and non‐visual areas. Functional MRI studies have also provided extensive evidence of functional changes throughout the whole of the visual pathway following visual loss, particularly in amblyopia. MR spectroscopy techniques have also revealed several abnormalities in metabolite concentrations in both glaucoma and age‐related macular degeneration. GABA‐edited MR spectroscopy on the other hand has identified possible evidence of plasticity within visual cortex. Summary Collectively, using MRI to investigate the effects on the visual pathway following disease and dysfunction has revealed a rich pattern of results allowing for better characterisation of disease. In the future MRI will likely play an important role in assessing the impact of eye disease on the visual pathway and how it progresses over time.
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Affiliation(s)
| | | | | | - Heidi A Baseler
- Department of Psychology, University of York, York, UK.,Hull York Medical School, University of York, York, UK
| | - Antony B Morland
- Department of Psychology, University of York, York, UK.,Hull York Medical School, University of York, York, UK
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Summers CG, Connett JE, Holleschau AM, Anderson JL, De Becker I, McKay BS, Brilliant MH. Does levodopa improve vision in albinism? Results of a randomized, controlled clinical trial. Clin Exp Ophthalmol 2014; 42:713-21. [PMID: 24641678 DOI: 10.1111/ceo.12325] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 02/20/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Dopamine is an intermediate product in the biosynthesis of melanin pigment, which is absent or reduced in albinism. Animal research has shown that supplying a precursor to dopamine, levodopa, may improve visual acuity in albinism by enhancing neural networks. This study examines the safety and effectiveness of levodopa on best-corrected visual acuity in human subjects with albinism. DESIGN Prospective, randomized, placebo-controlled, double-masked clinical trial conducted at the University of Minnesota. PARTICIPANTS Forty-five subjects with albinism. METHODS Subjects with albinism were randomly assigned to one of three treatment arms: levodopa 0.76 mg/kg with 25% carbidopa, levodopa 0.51 mg/kg with 25% carbidopa, or placebo and followed for 20 weeks, with best-corrected visual acuity measured at enrollment, and at weeks 5, 10, 15, and 20 after enrollment. Side-effects were recorded with a symptom survey. Blood was drawn for genotyping. MAIN OUTCOME MEASURES Side-effects and best-corrected visual acuity 20 weeks after enrolment. RESULTS All subjects had at least one mutation found in a gene known to cause albinism. Mean age was 14.5 years (range: 3.5 to 57.8 years). Follow up was 100% and compliance was good. Minor side-effects were reported; there were no serious adverse events. There was no statistically significant improvement in best-corrected visual acuity after 20 weeks with either dose of levodopa. CONCLUSIONS Levodopa, in the doses used in this trial and for the time course of administration, did not improve visual acuity in subjects with albinism.
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Affiliation(s)
- C Gail Summers
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, USA; Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
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Wong AM. New concepts concerning the neural mechanisms of amblyopia and their clinical implications. Can J Ophthalmol 2012; 47:399-409. [DOI: 10.1016/j.jcjo.2012.05.002] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Revised: 05/09/2012] [Accepted: 05/22/2012] [Indexed: 11/29/2022]
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Maurer D, Hensch TK. Amblyopia: background to the special issue on stroke recovery. Dev Psychobiol 2012; 54:224-38. [PMID: 22415912 DOI: 10.1002/dev.21022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this introductory article, we summarize the evidence from humans and animal models on the shaping of postnatal visual development by focused binocular input. When balanced input is missing during a sensitive period, deficits emerge, including seemingly permanent impairments in visual acuity that are labeled amblyopia. Rodent models have identified neurochemical changes that control the onset of such sensitive periods and molecular and structural brakes that lead to the diminution of the plasticity thereafter. Both animal and human studies of amblyopia have recently identified exciting ways to remediate vision in adulthood that bear some similarity to the interventions that have proved successful in promoting recovery from stroke.
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Effects of l-dopa methyl ester on visual cortex injury induced by amblyopia and its underlying mechanism. Neurosci Lett 2012; 508:95-100. [DOI: 10.1016/j.neulet.2011.12.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 12/12/2011] [Accepted: 12/14/2011] [Indexed: 11/20/2022]
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Abstract
Functional magnetic resonance imaging (fMRI), positron emission tomography (PET) and magnetoencephalography (MEG) have been the principal neuroimaging tools used to assess the site and nature of cortical deficits in human amblyopia. A review of this growing body of work is presented here with particular reference to various controversial issues, including whether or not the primary visual cortex is dysfunctional, the involvement of higher-order visual areas, neural differences between strabismic and anisometropic amblyopes, and the effects of modern-day drug treatments. We also present our own recent MEG work in which we used the analysis technique of synthetic aperture magnetometry (SAM) to examine the effects of strabismic amblyopia on cortical function. Our results provide evidence that the neuronal assembly associated with form perception in the extrastriate cortex may be dysfunctional in amblyopia, and that the nature of this dysfunction may relate to a change in the normal temporal pattern of neuronal discharges. Based on these results and existing literature, we conclude that a number of cortical areas show reduced levels of activation in amblyopia, including primary and secondary visual areas and regions within the parieto-occipital cortex and ventral temporal cortex.
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Affiliation(s)
- Stephen J Anderson
- The Wellcome Trust Laboratory for MEG Studies, School of Life and Health Sciences, Aston University, Birmingham, UK.
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