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Romanian Journal of Ophthalmology 2017For many years, amblyopia was regarded as a disorder of the visual system in which an organic cause could not be identified. Optical Coherence Tomography opens new... (Review)
Review
For many years, amblyopia was regarded as a disorder of the visual system in which an organic cause could not be identified. Optical Coherence Tomography opens new horizons in understanding the etiopathology of amblyopia and seems to highlight morphologic anomalies in the retina of the amblyopic eye. The objective of this paper is to analyze the macular thickness, optic nerve changes, and choroidal thickness found in patients diagnosed with amblyopia based on trials reported in the literature. This study analyzes 30 clinical trials regarding amblyopia evaluation with Optical Coherence Tomography. The research articles analyzed were published between 2006 - 2016 and were identified on PubMed database. 19 research studies focused on macular and nerve optic changes, 7 on choroidal changes and 6 on retinal changes after occlusion. The results were discussed according to the type of amblyopia, alteration of macular thickness, optic nerve changes, ganglion cell layer changes, and alteration of choroidal thickness. The results are of great variability, and it seems that macula and choroid involvement is more frequently suggested compared with optic nerve involvement. OCT = Optical Coherence Tomography, RNFL = Retinal Nerve Fiber Layer, GCC = Ganglion Cell Complex, ACD = Anterior Chamber Depth, BCVA = Best Corrected Visual Acuity.
Topics: Amblyopia; Animals; Humans; Macula Lutea; Nerve Fibers; Retinal Ganglion Cells; Tomography, Optical Coherence
PubMed: 29450380
DOI: 10.22336/rjo.2017.18 -
Current Biology : CB Sep 2014Over the last 50 years, research into the developmental plasticity of the visual cortex has led to a growing understanding of first the causes and then of the underlying... (Review)
Review
Over the last 50 years, research into the developmental plasticity of the visual cortex has led to a growing understanding of first the causes and then of the underlying cellular mechanisms of amblyopia or 'lazy eye', the commonest childhood disorder of vision. While it is widely believed that amblyopia cannot be treated successfully after the age of about 7, recent animal studies have demonstrated that visual cortex plasticity can be restored or enhanced later in life, paving the way for new strategies for the treatment of amblyopia that attempt to remove molecular brakes on plasticity. In addition, both animal and human work has established that amblyopia is not simply a monocular deficit, and therefore the most promising new non-invasive approaches force the two eyes to cooperate as opposed to conventional procedures that severely penalise the good eye.
Topics: Amblyopia; Animals; Humans; Neuronal Plasticity; Visual Cortex
PubMed: 25247373
DOI: 10.1016/j.cub.2014.05.063 -
Journal of Optometry 2020To determine the national and subnational prevalence of amblyopia and the respective provincial distribution and trend during 1990-2018 in Iran.
PURPOSE
To determine the national and subnational prevalence of amblyopia and the respective provincial distribution and trend during 1990-2018 in Iran.
METHODS
Amblyopia data retrieved from 26 original studies, systematic reviews, Data has been cleaned by STATA and a linear mixed effect spatio-temporal model was used to calculate Gaussian process regression mean functions. Using a Bayesian approach, by pooling empirical data based on the assumed prior, a posterior distribution obtained for age and sex specific prevalence prediction nationally during the study time and provincially.
RESULTS
The overall age-adjusted prevalence of Amblyopia was 0.03 (95% CI, 0.022-0.035). The prevalence was comparable in boys and girls (p = 0.85), highest prevalence was in >30 years old (p = 0.038). Our extrapolation revealed a stable trend of prevalence of Amblyopia in Iran during 1990-2018 (national screening program has been active from 1990 onwards). While Amblyopia prevalence suggested a declining trend in three provinces of Hormozgan, Qom and Tehran and it went up in 13 other provinces.
CONCLUSION
Amblyopia prevalence seems unchanged despite the concurrent screening program. It is noteworthy that the coverage of the program has been improved and has reached more than 85% in 2018. Our finding mandates a formal evaluation on the program.
Topics: Adolescent; Adult; Amblyopia; Child; Child, Preschool; Female; Geography; Humans; Iran; Male; Prevalence; Visual Acuity; Young Adult
PubMed: 32321688
DOI: 10.1016/j.optom.2019.12.001 -
Scientific Reports Jul 2020Amblyopia is a neurodevelopmental disorder of the visual cortex arising from abnormal visual experience early in life which is a major cause of impaired vision in...
Amblyopia is a neurodevelopmental disorder of the visual cortex arising from abnormal visual experience early in life which is a major cause of impaired vision in infants and young children (prevalence around 3.5%). Current treatments such as eye patching are ineffective in a large number of patients, especially when applied after the juvenile critical period. Physical exercise has been recently shown to enhance adult visual cortical plasticity and to promote visual acuity recovery. With the aim to understand the potentialities for translational applications, we investigated the effects of voluntary physical activity on recovery of depth perception in adult amblyopic rats with unrestricted binocular vision; visual acuity recovery was also assessed. We report that three weeks of voluntary physical activity (free running) induced a marked and long-lasting recovery of both depth perception and visual acuity. In the primary visual cortex, ocular dominance recovered both for excitatory and inhibitory cells and was linked to activation of a specific intracortical GABAergic circuit.
Topics: Amblyopia; Animals; Depth Perception; Disease Models, Animal; Exercise Therapy; GABAergic Neurons; Humans; Rats; Running; Treatment Outcome; Visual Acuity; Visual Cortex
PubMed: 32728106
DOI: 10.1038/s41598-020-69630-7 -
Ophthalmology Dec 1997The purpose of the study is to evaluate the monocular and binocular outcome of three types of "penalization" (blurring of the sound eye) treatment of amblyopia:...
OBJECTIVE
The purpose of the study is to evaluate the monocular and binocular outcome of three types of "penalization" (blurring of the sound eye) treatment of amblyopia: traditional full-time atropine or optical penalization and a new intermittent atropine regimen involving atropine instillation 1 to 3 days a week.
DESIGN
The study design was a retrospective study.
PARTICIPANTS
A total of 163 patients with strabismic amblyopia treated by full-time atropine (n = 38), intermittent atropine (n = 73), or optical (n = 52) penalization participated.
MAIN OUTCOME MEASURES
Logarithm of the minimum angle of resolution (logMAR) visual acuity, and binocularity index were determined.
RESULTS
All three forms of penalization produced statistically significant mean reduction in amblyopia (1.7-2.7 logMAR lines) and mean improvement in binocularity by the end-of-treatment or long-term follow-up visit or both, with minimal mean loss after discontinuation or slight mean improvement on these measures at long-term mean follow-up of 1.9 to 4 years across groups. Few patients achieved high-grade stereoacuity. Compliance was high. Comparable efficacy was found for all three treatment groups after controlling for age, depth of amblyopia, and binocularity at the initial visit. Initial-visit amblyopia depth was strongly and significantly associated with amblyopia depth at both post-treatment visits. Pretreatment and post-treatment binocularity showed a similar strong relationship. Surprisingly, however, there was no consistent or significant association found between depth of amblyopia and binocularity in any visit combination. Post-treatment measures of these two variables also were not associated with initial-visit age or refractive error at any clinically significant level. Mean treatment duration was 1.1 to 2.9 years and was not found to be associated with visual outcome. Amblyopia reversal was found in one (full-time atropine) case at a clinically important level.
CONCLUSIONS
The authors confirmed previous reports of penalization's efficacy as a primary treatment of moderate amblyopia (20/100 or better acuity) and, in some cases, relatively severe amblyopia (>20/100) and also confirmed its ability to significantly improve mean binocularity. Amblyopia and binocularity appear to respond to treatment independently and, within the postinfancy age range of the sample studied, the responses appear to be independent of initial-visit age. The high acceptability to patients and parents of atropine penalization, and particularly of the intermittent regimen introduced here, suggests the need for prospective-study-based re-evaluation of the relative merits of penalization and occlusion as the standard of care for mild-to-moderate amblyopia.
Topics: Accommodation, Ocular; Amblyopia; Atropine; Child; Child, Preschool; Follow-Up Studies; Humans; Mydriatics; Optics and Photonics; Retrospective Studies; Sensory Deprivation; Strabismus; Treatment Outcome; Vision, Binocular; Vision, Monocular; Visual Acuity
PubMed: 9400777
DOI: 10.1016/s0161-6420(97)30048-7 -
Clinical & Experimental Optometry Sep 2010Treatment for amblyopia commonly involves passive methods such as occlusion of the non-amblyopic eye. An evidence base for these methods is provided by animal models of... (Review)
Review
Treatment for amblyopia commonly involves passive methods such as occlusion of the non-amblyopic eye. An evidence base for these methods is provided by animal models of visual deprivation and plasticity in early life and randomised controlled studies in humans with amblyopia. Other treatments of amblyopia, intended to be used instead of or in conjunction with passive methods, are known as 'active' because they require some activity on the part of the patient. Active methods are intended to enhance treatment of amblyopia in a number of ways, including increased compliance and attention during the treatment periods (due to activities that are interesting for the patient) and the use of stimuli designed to activate and to encourage connectivity between certain cortical cell types. Active methods of amblyopia treatment are widely available and are discussed to some extent in the literature, but in many cases the evidence base is unclear, and effectiveness has not been thoroughly tested. This review looks at the techniques and evidence base for a range of these methods and discusses the need for an evidence-based approach to the acceptance and use of active amblyopia treatments.
Topics: Amblyopia; Animals; Atropine; Humans; Orthoptics; Phototherapy
PubMed: 20533925
DOI: 10.1111/j.1444-0938.2010.00486.x -
Seminars in Ophthalmology May 2021Traditional therapies to treat amblyopia, such as optical correction or occlusion/penalization of the non-amblyopic eye, are efficacious but are not without limitations...
Traditional therapies to treat amblyopia, such as optical correction or occlusion/penalization of the non-amblyopic eye, are efficacious but are not without limitations such as poor adherence and decreased success with increasing age. Recently, there has been an interest in new amblyopia therapies, some using binocular techniques, through a variety of platforms including video games, movies, and virtual reality. Overall, available efficacy results for these treatments are highly variable.
Topics: Amblyopia; Humans; Video Games; Vision, Binocular; Visual Acuity
PubMed: 33656963
DOI: 10.1080/08820538.2021.1893765 -
Indian Journal of Ophthalmology Sep 2019Amblyopia is the most common cause of monocular visual impairment affecting 2-5% of the general population. Amblyopia is a developmental cortical disorder of the visual... (Review)
Review
Amblyopia is the most common cause of monocular visual impairment affecting 2-5% of the general population. Amblyopia is a developmental cortical disorder of the visual pathway essentially due to abnormal visual stimulus, reaching the binocular cortical cells, which may be multivariate. Ganglion cells are of two types: parvocellular (P cells) and magnocellular (M cells); they are the first step where the light energy is converted in to neural impulse. P cells are involved in fine visual acuity, fine stereopsis, and color vision and M cells are involved in gross stereopsis and movement recognition. Strabismus, refractive error, cataract, and ptosis, occurring during critical period are highly amblyogenic. The critical period extends from birth to 7--8 years. The earlier the clinically significant refractive error and strabismus are detected and treated, the greater the likelihood of preventing amblyopia. Treatment for amblyopia in children includes: optical correction of significant refractive errors, patching, pharmacological treatment, and alternative therapies which include: vision therapy, binocular therapy, and liquid crystal display eyeglasses are newer treatment modalities for amblyopia. Age of starting the treatment is not predictive of outcome, instituting treatment on detection and early detection plays a role in achieving better outcomes. This review aims to give a simplified update on amblyopia, which will be of use to a clinician, in understanding the pathophysiology of the complex condition. We also share the cortical aspects of amblyopia and give recent developments in the treatment of amblyopia.
Topics: Amblyopia; Atropine; Eyeglasses; Humans; Mydriatics; Ophthalmic Solutions; Sensory Deprivation; Visual Acuity
PubMed: 31436180
DOI: 10.4103/ijo.IJO_11_19 -
Ophthalmic Research 2021Amblyopia is an important public health problem and standard screening is quite necessary for early diagnosis and treatment especially for the remote areas. As the place...
INTRODUCTION
Amblyopia is an important public health problem and standard screening is quite necessary for early diagnosis and treatment especially for the remote areas. As the place of the largest Tibetan population, the Tibetan Plateau has special geographical characteristics such as high altitude, time zone, and ethnic composition, where very little information is available about the prevalence of amblyopia and other ocular diseases. The article aims to determine the prevalence of amblyopia and associated factors in grade 1 Tibetan children, living in Lhasa, Tibet Autonomous Region.
METHODS
A cross-sectional study was conducted. All the participants were scheduled for comprehensive eye examinations including visual acuity testing, ocular deviation and movement evaluation, cycloplegic refraction and examinations of the external eye, anterior segment, media, and fundus. Amblyopia was assessed in the children according to the standard definition.
RESULTS
A total of 1,856 students participated in the examinations (97.58% response rate). 1,852 students completed all the related examinations, and 34 of them were diagnosed as amblyopia with the prevalence of 1.84% (95% confidence interval [CI]: 1.22-2.45%). Unilateral amblyopia was diagnosed in 23 students (1.24%, 95% CI: 0.74-1.75%), including 16 anisometropic, 4 strabismic, 1 visual deprivational, and 2 mixed. Other 11 students were diagnosed as bilateral amblyopia (0.59%, 95% CI: 0.24-0.94%), including 9 ametropic, 1 deprivational, and 1 with nystagmus. The mean cylinder refraction and absolute value of the spherical equivalent refraction of amblyopic eyes was respectively -2.15 ± 1.52 D and 2.70 ± 2.33 D. Amblyopia was significantly associated with hyperopia (≥+2.00 D, odds ratio [OR] 8.22, 95% CI 3.42-19.72), astigmatism (≤-2.00 D, OR 6.76, 95% CI 2.56-17.85), and anisometropia (≥+0.50 to <+1.00 D, OR 3.95, 95% CI 1.44-10.79; ≥+1.00 D, OR 21.90, 95% CI 8.24-58.18).
CONCLUSIONS
The prevalence of amblyopia in grade 1 students of Lhasa is relatively higher than that of many other ethnic populations in China previously reported. Refractive errors including anisometropia, hyperopia, and astigmatism are the major risk factors of amblyopia.
Topics: Amblyopia; Child; Child, Preschool; China; Cross-Sectional Studies; Ethnicity; Female; Humans; Male; Prevalence; Refraction, Ocular; Retrospective Studies; Risk Factors; Schools; Tibet; Visual Acuity
PubMed: 33279900
DOI: 10.1159/000511264 -
Optometry and Vision Science : Official... Jun 2009Blur induced by uncorrected astigmatism during early development can result in amblyopia, as evidenced by reduced best-corrected vision relative to normal, in measures... (Review)
Review
Blur induced by uncorrected astigmatism during early development can result in amblyopia, as evidenced by reduced best-corrected vision relative to normal, in measures of grating acuity, vernier acuity, contrast sensitivity across a range of spatial frequencies, recognition acuity, and stereoacuity. In addition, uncorrected astigmatism during early development can result in meridional amblyopia, or best-corrected visual deficits that are greater for, or are present only for, specific stimulus orientations. Astigmatism-related amblyopia can be successfully treated with optical correction in children as old as school age, but the amblyopia may not be completely eliminated with optical treatment alone, and the age at which optical treatment is most effective has yet to be determined. Future research on determining the period of susceptibility of the visual system to negative effects of uncorrected astigmatism and exploration of alternative or complimentary treatment methods, in addition to optical correction, are warranted.
Topics: Amblyopia; Astigmatism; Contrast Sensitivity; Depth Perception; Eyeglasses; Humans; Visual Acuity
PubMed: 19430327
DOI: 10.1097/OPX.0b013e3181a6165f