A Preliminary Study Of Positive Defocus Of Toroidal Multi Optical-microlens Spectacle Lenses To Delay Myopia In School-age Children

Objective: The effectiveness of two different designs of defocused spectacle lenses in delaying myopia in school-age myopic children was assessed by observing the development of myopia in school-age myopic children wearing two different positive Defocus of Toroidal Multi Optical-microlens designs of defocused spectacle lenses and single vision lenses.Methods: A prospective clinical observation was used.A total of 246 myopic children aged 6-14 years in our hospital were collected and divided into 3 groups,82 cases in each group,including group A(defocused spectacle lenses center optical area 10 mm in diameter),group B(defocused spectacle lenses center optical area 6mm for day and10 mm for night),and group C(single vision lenses).Using the pre-lens-wearing axial length(AL),spherical equivalent refraction(SER)and subfoveal choroidal thickness(SFChT)as the baseline and recording examination data were recorded at 3 and 6 months after wearing glasses,and the changes of AL,SER and SFChT over time in the three groups of myopic children were observed.The change values of Al,SER and SFChT in three groups of myopia children were compared at 3 and 6 months after wearing glasses,to determine the effect of two types of defocused spectacle lenses on the progression of myopia and to evaluate their effectiveness.The correlation between SFChT change and Al change,and between SFChT change and SER change were also analyzed.Results:1.The comparison of the AL before and after wearing the glasses among the three groups of myopic children was statistically significant(P < 0.05);the comparison of the SER before and after wearing the glasses was statistically significant in group A and group C(P<0.05),while the SER of group B was not statistically different over time(P > 0.05);the comparison of the SFChT before and after wearing the glasses was statistically significant in group A and group B(P < 0.05).2.The increase of AL and SER in group A and group B was lower than those in group C(P<0.05),and the increase of SFChT was higher than that in group C(P<0.05).The increase of AL and SER in group B were lower than those in group A(P<0.05).3.There was a moderately negative correlation between change of SFChT and AL(r=-0.621,P=0.000、r=-0.653,P=0.000),the change of SFChT was moderately positively correlated with the change of SER in group A and B(r = 0.541,P = 0.000,r = 0.556,P=0.000).The change of SFChT was negatively correlated with the change of AL(r =-0.296,P = 0.007),there was a positive correlation between the change of SFChT and the change of SER(r = 0.276,P = 0.012),but to a weaker extent.Conclusions:1.Positive Defocus of Toroidal Multi Optical-microlens spectacle lenses are effective in controlling the progression of myopia in school-age children.2.Lens designs that reduce the diameter of the central optical area can significantly enhance the effectiveness of myopia control.3.By wearing defocused spectacle lenses,myopic children can effectively slow down the growth of the axial length and myopic refraction and increase the thickness of subfoveal choroidal thickness,so as to exert the effect of myopia control.