Electrodiagnosis and Treatment Monitoring of Children with Refractive Amblyopia

Yap, Tiong Peng; Boon, Mei Ying

doi:10.1016/j.yaoo.2020.04.001

Cited by 6 publications

(10 citation statements)

References 112 publications

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“…Secondary treatments, such as occlusion therapy and vision therapy, may be prescribed in situations where the patients are less responsive to spectacle treatment. 5 , 14 The critical period for efficacious treatment of astigmatism, as it relates to and produces amblyopia, has not been established. The depth of amblyopia may certainly be affected by the severity of anisoastigmatism and degree of anisometropia in pediatric patients.…”

Section: Introductionmentioning

confidence: 99%

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The effect of amblyopia on clinical outcomes of children with astigmatism

et al. 2021

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Background: Amblyopia is more common in children with high astigmatism, but factors contributing to development of amblyopia and visual outcomes are not fully understood. Objective: To evaluate the effect of amblyopia on the clinical outcomes in children with ⩾1.75 diopter (D) astigmatism. Methods: We reviewed the medical records of children with ⩾1.75 D astigmatism with and without amblyopia (amblyopes group and non-amblyopes group). The mean age, gender, amount and type of ocular deviation, presence of convergence insufficiency (CI), stereopsis, time of initial spectacle use and follow-up time, differences in best-corrected visual acuity (VoD) and spherical equivalent (SE) between eyes were assessed and compared between the groups. Best-corrected visual acuity (BCVA), mean SE, astigmatism measurements were assessed and compared between amblyopic, fellow, and non-amblyopic eyes. Results: The records included 68 eyes of 34 children with amblyopia and 56 eyes of 28 children without amblyopia. The mean age, gender, amount and type of ocular deviation, presence of CI, stereopsis, time of initial spectacle use, follow-up time, and the difference in SE did not differ between groups. In amblyopes, exodeviation was more common and statistically greater in near (33 cm) than at distance (6 m) (p = 0.005). The mean BCVA and astigmatism values were statistically different between amblyopic, fellow, and non-amblyopic eyes. Conclusion: A greater near than distance exodeviation and higher mean astigmatism value were found in amblyopic children with astigmatism.

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Section: Introductionmentioning

confidence: 99%

“… 17 Yap and Boon reported that a proportion of amblyopic children may need more time to respond to spectacle treatment. 14 …”

Section: Introductionmentioning

confidence: 99%

The effect of amblyopia on clinical outcomes of children with astigmatism

et al. 2021

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“…Besides, the horizontal effect was only observed in children (3–7 years old) in Yap’s study, and the meridional disparity was observed in subjects of older age range (7–26 years old) in our study. According to recent studies ( Yap et al, 2019 , 2020b ; Yap and Boon, 2020 ), the horizontal effect is an indicator of normality. It is important to separate the meridian-specific deficit from the normal physiological phenomenon (i.e., horizontal effect), thus future study could include newly diagnosed amblyopes and meridional amblyopes with other types of regular astigmatism to further clarify it.…”

Section: Discussionmentioning

confidence: 99%

Meridian-Specific and Post-Optical Deficits of Spatial Vision in Human Astigmatism: Evidences From Psycho-Physical and EEG Scalings

Wang

Feng

et al. 2021

Front. Psychol.

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Previous studies have demonstrated that orientation-specific deprivation in early life can lead to neural deficits of spatial vision in certain space, and can even result in meridional amblyopia (MA). Individuals with astigmatism are the optimal and natural models for exploring this asymmetric development of spatial vision in the human visual system. This study aims to assess the contrast sensitivity function (CSF) and EEG signals along two principal meridians in participants with regular astigmatism when being optimal optical corrected. Twelve participants with astigmatism (AST group, 20 eyes) and thirteen participants with (MA group, 19 eyes) were recruited in the current study. CSFs and spatial sweep visual evoked potentials (sVEP) were measured with vertical and horizontal sinewave gratings along two principal meridians monocularly. Area under log CSF (AULCSF), spatial frequency threshold corresponding to 80% contrast gratings (SF threshold at 80% ctr), and CSF acuity were calculated from CSF test. In addition, sVEP amplitudes and thresholds were calculated with the recursive least square method. Participants with astigmatism exhibited marked vertical-horizontal resolution disparities even after they were corrected with optimal optical corrections. CSF tests showed that AULCSF along weak meridian (measured with horizontal gratings) was lower than that along strong meridian (measured with vertical gratings) in both groups. Significant meridional disparity of CSF acuity was also found in both groups. In addition, the MA group showed larger meridional disparity compared to the AST group. Spatial sVEP thresholds also supported the existence of marked meridional disparity. Our results suggest that meridian-specific partial deprivation in early life might lead to monocularly asymmetric development of spatial vision in the human visual system. In terms of application, we tested the feasibility and reliability of adopting psychophysical and EEG scalings to investigate the asymmetric development of spatial vision related to astigmatism. These paradigms are potentially applicable to reduce and even eliminate the meridional disparity in the primary visual cortex by adopting perceptual learning or other vision-related interventions.

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“…refraction, ophthalmoscopy and cover test) to identify potential amblyogenic factors and to exclude ocular pathologies. [9] In situations of unexplained loss of vision, electrophysiological testing may be used to assist clinicians in the differential diagnosis.…”

Section: Introductionmentioning

confidence: 99%

“…In clinical practice, electrophysiological techniques are rarely used to monitor amblyopia treatments even though VEPs may be used to assess neural deficits non-invasively and objectively. [9][10][11][12][13][14][15][16][17][18][19][20][21] Previous studies have demonstrated reduced peak amplitudes (P100) and delayed peak latencies in amblyopic eyes. [16][17][18][19][20][21][22][23][24][25][26][27] The attenuation in the P100 amplitude has been attributed to passive signal degradation, [28] undersampling [29] and reduced activity of neurons due to poor quality signals from the amblyopic eye, [30] whereas delayed latencies have been attributed to poor integration within V1 and the extrastriate cortex, [31][32][33], perhaps reflecting neuronal connectivity that is slower or less efficient than expected.…”

Section: Introductionmentioning

confidence: 99%