Asymmetrical accommodation in hyperopic anisometropic amblyopia.
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ABSTRACT:
SUBMITTER: Toor S
PROVIDER: S-EPMC5787021 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:To determine factors associated with pretreatment and posttreatment stereoacuity in subjects with moderate anisometropic amblyopia.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 <18 years with anisometropic amblyopia, no heterotropia observed by cover test, and baseline amblyopic eye acuity of 20/100 or better. A subset included 248 subjects who were treated with patching or Bangerter filters and had stereoacuity testing at both the baseline and outcome examinations. Multivariate regression models identified factors associated with baseline stereoacuity and with outcome stereoacuity as measured by the Randot Preschool Stereoacuity test.Better baseline stereoacuity was associated with better baseline amblyopic eye acuity (P < 0.001), less anisometropia (P = 0.03), and anisometropia due to astigmatism alone (P < 0.001). Better outcome stereoacuity was associated with better baseline stereoacuity (P < 0.001) and better amblyopic eye acuity at outcome (P < 0.001). Among 48 subjects whose amblyopic eye visual acuity at outcome was 20/25 or better and within one line of the fellow eye, stereoacuity was worse than that of children with normal vision of the same age.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.
| S-EPMC3223370 | biostudies-literature
Project description:Cognition is very important in our daily life. However, amblyopia has abnormal visual cognition. Physiological changes of the brain during processes of cognition could be reflected with ERPs. So the purpose of this study was to investigate the speed and the capacity of resource allocation in visual cognitive processing in orientation discrimination task during monocular and binocular viewing conditions of amblyopia and normal control as well as the corresponding eyes of the two groups with ERPs. We also sought to investigate whether the speed and the capacity of resource allocation in visual cognitive processing vary with target stimuli at different spatial frequencies (3, 6 and 9 cpd) in amblyopia and normal control as well as between the corresponding eyes of the two groups. Fifteen mild to moderate anisometropic amblyopes and ten normal controls were recruited. Three-stimulus oddball paradigms of three different spatial frequency orientation discrimination tasks were used in monocular and binocular conditions in amblyopes and normal controls to elicit event-related potentials (ERPs). Accuracy (ACC), reaction time (RT), the latency of novelty P300 and P3b, and the amplitude of novelty P300 and P3b were measured. Results showed that RT was longer in the amblyopic eye than in both eyes of amblyopia and non-dominant eye in control. Novelty P300 amplitude was largest in the amblyopic eye, followed by the fellow eye, and smallest in both eyes of amblyopia. Novelty P300 amplitude was larger in the amblyopic eye than non-dominant eye and was larger in fellow eye than dominant eye. P3b latency was longer in the amblyopic eye than in the fellow eye, both eyes of amblyopia and non-dominant eye of control. P3b latency was not associated with RT in amblyopia. Neural responses of the amblyopic eye are abnormal at the middle and late stages of cognitive processing, indicating that the amblyopic eye needs to spend more time or integrate more resources to process the same visual task. Fellow eye and both eyes in amblyopia are slightly different from the dominant eye and both eyes in normal control at the middle and late stages of cognitive processing. Meanwhile, abnormal extents of amblyopic eye do not vary with three different spatial frequencies used in our study.
| S-EPMC5638445 | biostudies-literature
Project description:ObjectiveTo 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.DesignProspective, multicenter, cohort study.ParticipantsWe included 146 children 3 to <7 years old with previously untreated strabismic amblyopia (n = 52) or combined-mechanism amblyopia (n = 94).MethodsOptical 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 measuresVisual acuity 18 weeks after baseline.ResultsOverall, 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.ConclusionsOptical treatment alone of strabismic and combined-mechanism amblyopia results in clinically meaningful improvement in amblyopic eye visual acuity for most 3- to <7-year-old children, resolving in at least one quarter without the need for additional treatment. Consideration should be given to prescribing refractive correction as the sole initial treatment for children with strabismic or combined-mechanism amblyopia before initiating other therapies.Financial disclosure(s)The authors have no proprietary or commercial interest in any of the materials discussed in this article.
| S-EPMC3250558 | biostudies-literature
Project description:Treatment of grating stimulation has been used in amblyopia for decades, but high dropout rate and inconvenience for daily practice occur in previous studies. We developed a home-based portable system with rotating grating stimulation on a tablet. Thirty anisometropic amblyopic children were randomly allocated into the control or Grating group. They drew contour of the picture under patch of a better eye for 6 months. Best-corrected visual acuity (BCVA), grating acuity (GA), and contrast sensitivity (CS) were assessed at the baseline, 1st, 2nd, 3rd, and 6th months of training. All participants completed the 6-month training. Patched eyes of both groups exhibited no difference. Trained eyes of the control group had significantly slight improvement in BCVA and GA. In particular, the Grating group exhibited significantly higher BCVA, GA, and CS compared with those of the control group at the 3rd and 6th months of training. Moreover, percentage of the Grating group with great improvement (BCVA ≥ 0.3 or CS ≥ 0.3) was significantly larger than those of the control group at the 3rd or 6th months of training. The portable grating stimulation system demonstrates its trainability by no dropout and effectiveness by significant improvements in all assessments through a well experimental design.Trial Registration: ClinicalTrials.gov NCT04213066, registered 30/12/2019, https://clinicaltrials.gov/ct2/show/NCT04213066 .
| S-EPMC8169940 | biostudies-literature
Project description:Amblyopia, also known as lazy eye, usually occurs during early childhood and results in poor or blurred vision. Recent neuroimaging studies have found cortical structural/functional abnormalities in amblyopia. However, until now, it was still not known whether the spontaneous activity of the brain changes in amblyopia subjects. In the present study, regional homogeneity (ReHo), a measure of the homogeneity of functional magnetic resonance imaging signals, was used for the first time to investigate changes in resting-state local spontaneous brain activity in individuals with anisometropic amblyopia. Compared with age- and gender-matched subjects with normal vision, the anisometropic amblyopia subjects showed decreased ReHo of spontaneous brain activity in the right precuneus, the left medial prefrontal cortex, the left inferior frontal gyrus, and the left cerebellum, and increased ReHo of spontaneous brain activity was found in the bilateral conjunction area of the postcentral and precentral gyri, the left paracentral lobule, the left superior temporal gyrus, the left fusiform gyrus, the conjunction area of the right insula, putamen and the right middle occipital gyrus. The observed decreases in ReHo may reflect decreased visuo-motor processing ability, and the increases in ReHo in the somatosensory cortices, the motor areas and the auditory area may indicate compensatory plasticity in amblyopia.
| S-EPMC3427333 | biostudies-literature
Project description:Purpose:We measure neural responses associated with form and motion processing in children with anisometropia before and after treatment with spectacles and occlusion. Methods:In this prospective, case-control treatment study, 10 children with anisometropia and amblyopia and 16 age-matched visually normal children participated. Steady-state visual evoked potentials (VEP) were recorded from electrodes over the occipital cortex. The visual stimulus comprised a horizontal bar grating into which Vernier offsets were introduced and withdrawn periodically at 3.75 Hz. The VEP amplitude at 3.75 Hz (first harmonic [1F]) and 7.5 Hz (second harmonic [2F]) were recorded to index the sensitivity of form/position-sensitive versus motion/transient-sensitive neural populations, respectively. Response amplitude at 1F and 2F were recorded over a series of 10 logarithmically spaced offset sizes before and after treatment. Main outcome measures are VEP amplitude versus displacement functions, interocular response amplitude differences. Results:After relaxing into spectacles (minimally-treated state), form/position-sensitive responses in the dominant/less ametropic eye of the children with anisometropia were larger and responses in the more ametropic eye were smaller than those of controls. Motion-transient responses were equal to those of controls in the less ametropic eye, but were smaller than controls in the more ametropic eye. After treatment, responses did not differ from those of controls. Conclusions:Form and motion responses are differentially susceptible to neural deprivation via optical blur. Form responses are more plastic than motion responses in minimally-treated children with anisometropic amblyopia. Most treatment effects occurred above threshold range, suggesting some treatment effects are not detected clinically.
| S-EPMC6779065 | biostudies-literature
Project description:Amblyopia is a developmental disorder that results in deficits of monocular and binocular vision. It is presently unclear whether these deficits result from attenuation of signals in the amblyopic eye, inhibition by signals in the fellow eye, or both. In this study, we characterize mechanisms underlying anisometropic amblyopia using a binocular phase and contrast combination paradigm and a contrast gain control model. Subjects dichoptically viewed two slightly different images and reported the perceived contrast and phase of the resulting cyclopean percept. We found that the properties of binocular combination were abnormal in many aspects in amblyopic vision. The observed abnormalities can be explained by a combination of (1) attenuated monocular signal in the amblyopic eye, (2) stronger interocular contrast gain control from the fellow eye to the signal in the amblyopic eye (direct interocular inhibition), and (3) stronger interocular contrast gain control from the fellow eye to the contrast gain control signal from the amblyopic eye (indirect interocular inhibition). We conclude that anisometropic amblyopia led to both monocular and interocular deficits. A complete understanding of the mechanisms underlying amblyopia requires studies of both monocular deficits and binocular interactions.
| S-EPMC3324098 | biostudies-literature
Project description:Perceptual learning in contrast detection improves monocular visual function in adults with anisometropic amblyopia; however, its effect on binocular combination remains unknown. Given that the amblyopic visual system suffers from pronounced binocular functional loss, it is important to address how the amblyopic visual system responds to such training strategies under binocular viewing conditions. Anisometropic amblyopes (n?=?13) were asked to complete two psychophysical supra-threshold binocular summation tasks: (1) binocular phase combination and (2) dichoptic global motion coherence before and after monocular training to investigate this question. We showed that these participants benefited from monocular training in terms of binocular combination. More importantly, the improvements observed with the area under log CSF (AULCSF) were found to be correlated with the improvements in binocular phase combination.
| S-EPMC4735338 | biostudies-literature
Project description:IntroductionAmblyopia always presents with monocular and binocular dysfunction. In this study, we aim to investigate the efficacy of alternative occlusion using liquid crystal glasses versus continuous occlusion therapy using traditional patches for treating amblyopia.MethodsEligible subjects with anisometropic amblyopia were randomized into 2 groups: alternative flicker glass (AFG) or patching group. In the AFG group, subjects were instructed to wear the flicker glasses for 1 h a day. The AFG is a lightweight spectacle frame with liquid crystal lenses that provide direct square-wave alternating occlusion, which were preprogrammed at a temporal frequency of 7 Hz. In the patching group, the patients were prescribed to wear traditional patches for 2 h a day. The best-corrected visual acuity (BCVA), contrast sensitivity function (CSF), and stereoacuity were measured at the baseline and 3 and 12 weeks.ResultsIn this pilot study, a total of 40 children were recruited, with 20 in the AFG group. Mean BCVA improved by 0.17 ± 0.14 logMAR (95% CI = 0.10-0.23) in the AFG group and 0.18 ± 0.18 logMAR (95% CI = 0.09-0.26) in the patching group from baseline to 12 weeks. The improvement in BCVA in both groups was significant (both p < 0.01), while there was no significant difference between the groups (p = 0.82). The CSF of both low and high spatial frequencies exhibited significant improvement at 12 weeks in the AFG group (p < 0.01, respectively) and just had a significant improvement at low spatial frequency in the patching group (p < 0.01). The stereoacuity significantly improved by 504.00 ± 848.00 (95% CI = 107.12 to 900.88) arc seconds in the AFG group (p < 0.05), while it was 263.50 ± 639.55 (95% CI = -35.82 to 562.82) arc seconds in the patching group (p > 0.05).ConclusionAlternative flicker glass was effective in improving both monocular and binocular function, which was most likely achieved by reducing suppression and promoting binocular fusion. This therapy exhibited promise as an alternative method for amblyopia treatment.
| S-EPMC8743914 | biostudies-literature
Project description:Previous studies have indicated regional abnormalities of both gray and white matter in amblyopia. However, alterations of cortical thickness associated with changes in white matter integrity have rarely been reported. In this study, structural magnetic resonance imaging and diffusion tensor imaging (DTI) data were obtained from 15 children with anisometropic amblyopia and 15 age- and gender-matched children with normal sight. Combining DTI and surface-based morphometry, we examined a potential linkage between disrupted white matter integrity and altered cortical thickness. The fractional anisotropy (FA) values in the optic radiations (ORs) of children with anisometropic amblyopia were lower than in controls (P < 0.05). The cortical thickness in amblyopic children was lower than controls in the following subregions: lingual cortex, lateral occipitotemporal gyrus, cuneus, occipital lobe, inferior parietal lobe, and temporal lobe (P < 0.05, corrected), but was higher in the calcarine gyrus (P < 0.05, corrected). Node-by-node correlation analysis of changes in cortical thickness revealed a significant association between a lower FA value in the OR and diminished cortical thickness in the following subregions: medial lingual cortex, lateral occipitotemporal gyrus, lateral, superior, and medial occipital cortex, and lunate cortex. We also found a relationship between changes of cortical thickness and white matter OR integrity in amblyopia. These findings indicate that developmental changes occur simultaneously in the OR and visual cortex in amblyopia, and provide key information on complex damage of brain networks in anisometropic amblyopia. Our results also support the hypothesis that the pathogenesis of anisometropic amblyopia is neurodevelopmental.
| S-EPMC5563750 | biostudies-other