We study optical localized waves on a plane-wave background in negative-index materials governed by the defocusing nonlinear Schr6dinger equation with self-steepening effect. Important characteristics of localized wav...We study optical localized waves on a plane-wave background in negative-index materials governed by the defocusing nonlinear Schr6dinger equation with self-steepening effect. Important characteristics of localized waves, such as the excitations, transitions, propagation stability, and mechanism, are revealed in detail. An intrigu- ing sequential transition that involves the rogue wave, antidark-dark soliton pair, antidark soliton and antidark soliton pair can be triggered as the self-steepening effect attenuates. The corresponding phase diagram is estab- lished in the defocusing regime of negative-index materials. The propagation stability of the localized waves is confirmed numerically. In particular, our results illuminate the transition mechanism by establishing the exact correspondence between the transition and the modulation instability analysis.展开更多
Background Myopia control interventions,such as defocus incorporated multiple segments(DIMS)spectacle lenses,have been adopted in school-aged children to reduce the prevalence of myopia and its complications.This stud...Background Myopia control interventions,such as defocus incorporated multiple segments(DIMS)spectacle lenses,have been adopted in school-aged children to reduce the prevalence of myopia and its complications.This study aimed to investigate the effect of DIMS spectacle lenses on subfoveal choroidal thickness(SfChT)over a period of two years,as the choroidal response to myopic control is a crucial factor in exploring its potential effect on predict-ingmyopiaprogression.Methods This study involved a secondary analysis of our previous randomized clinical trial.Myopic school-aged children aged 8-13 years were recruited in a two-year study investigating the effect of DIMS spectacle lenses on myo-pia progression.The treated group received DIMS spectacle lenses(n=78),while the control group was treated with a pair of single vision(SV)spectacle lenses(n=80).SfChT was monitored at 1 week,1,3,6,12,18 and 24 months post lens wear using spectral-domain optical coherence tomography and a custom made auto-segmentation algo-rithm utilizing convolutional neural networks.Results SfChT increased significantly after 1 week of DIMS spectacle lens wear compared to those wearing SV spectacle lenses(adjusted mean change relative to baseline±SEM at 1 week;DIMS vs.SV,6.75±1.52μum vs.-3.17±1.48μm;P<0.0001,general linear model).The thickness of choroid increased to 13.64±2.62μm after 12 months of DiMS lens wear while the choroid thinned in SV group(-9.46±2.55μm).Choroidal changes demonstrated a significant negative association with axial elongation over two years in both the DIMS and SV groups.Choroidal change at 3 months significantly predicted the changes in AL at 12 months after controlling the effect of age and gender.Conclusions Our study demonstrated a significant choroidal thickening in response to myopic defocus incorpo-rated in a spectacle lens after 1 week of lens wear,sustained over the two-year study period.The results suggested that choroidal changes at 3 months may help predict changes in axial length after one year.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11475135,11547302,11434013 and 11425522
文摘We study optical localized waves on a plane-wave background in negative-index materials governed by the defocusing nonlinear Schr6dinger equation with self-steepening effect. Important characteristics of localized waves, such as the excitations, transitions, propagation stability, and mechanism, are revealed in detail. An intrigu- ing sequential transition that involves the rogue wave, antidark-dark soliton pair, antidark soliton and antidark soliton pair can be triggered as the self-steepening effect attenuates. The corresponding phase diagram is estab- lished in the defocusing regime of negative-index materials. The propagation stability of the localized waves is confirmed numerically. In particular, our results illuminate the transition mechanism by establishing the exact correspondence between the transition and the modulation instability analysis.
基金support as the collabora-tive research(PolyU Grant No.H-ZG3B and 1-87LK)the spectacles and lenses for the study+4 种基金supported by other PolyU Grants(Grant Nos.BD90,ZVS5,ZVN1)Research Impact Fund(Grant No.R5032-18)Research Center for SHARP Vision(Grant No.1-BBCO)Henry G.Leong Endowed Professorship in Elderly Vision Health(Grant No.8-847)The Hong Kong Special Administrative Region Government(InnoHK initiative).
文摘Background Myopia control interventions,such as defocus incorporated multiple segments(DIMS)spectacle lenses,have been adopted in school-aged children to reduce the prevalence of myopia and its complications.This study aimed to investigate the effect of DIMS spectacle lenses on subfoveal choroidal thickness(SfChT)over a period of two years,as the choroidal response to myopic control is a crucial factor in exploring its potential effect on predict-ingmyopiaprogression.Methods This study involved a secondary analysis of our previous randomized clinical trial.Myopic school-aged children aged 8-13 years were recruited in a two-year study investigating the effect of DIMS spectacle lenses on myo-pia progression.The treated group received DIMS spectacle lenses(n=78),while the control group was treated with a pair of single vision(SV)spectacle lenses(n=80).SfChT was monitored at 1 week,1,3,6,12,18 and 24 months post lens wear using spectral-domain optical coherence tomography and a custom made auto-segmentation algo-rithm utilizing convolutional neural networks.Results SfChT increased significantly after 1 week of DIMS spectacle lens wear compared to those wearing SV spectacle lenses(adjusted mean change relative to baseline±SEM at 1 week;DIMS vs.SV,6.75±1.52μum vs.-3.17±1.48μm;P<0.0001,general linear model).The thickness of choroid increased to 13.64±2.62μm after 12 months of DiMS lens wear while the choroid thinned in SV group(-9.46±2.55μm).Choroidal changes demonstrated a significant negative association with axial elongation over two years in both the DIMS and SV groups.Choroidal change at 3 months significantly predicted the changes in AL at 12 months after controlling the effect of age and gender.Conclusions Our study demonstrated a significant choroidal thickening in response to myopic defocus incorpo-rated in a spectacle lens after 1 week of lens wear,sustained over the two-year study period.The results suggested that choroidal changes at 3 months may help predict changes in axial length after one year.
