The effect of defocus incorporated multiple segments (DIMS) spectacle lenses on astigmatism in children with myopia.

This study aims to explore the impact of wearing Defocus Incorporated Multiple Segments (DIMS) spectacle lenses on astigmatism in myopic children. This study included 396 myopic children and divided the participants into two groups:the DIMS group (n = 192) and a control group single vision lens (n = 204). The study analysed the effect of wearing DIMS on changes in spherical equivalent (SE),diopter sphere (DS),diopter cylinder (DC), axial length (AL) and corneal astigmatism (CA) after one year. Compared to the DIMS group (-0.30 ± 0.45D), the annual SE progression was faster in the control group (-0.95 ± 0.57D, P < 0.001). There is a slight difference in diopter cylinder between the DIMS group and the control group(-0.17 ± 0.28 VS -0.20 ± 0.38, P = 0.010).The change in corneal astigmatism in the DIMS group (-0.19 ± 0.57D) showed no statistically significant difference compared to that in the control group (-0.20 ± 0.66D, P = 0.624).These vector diagram analysis results indicate that the two types of lenses did not differentially affect the change in diopter cylinder and corneal astigmatism(R = 0.0237, P = 0.329;R = 0.0158, P = 0.594). There was no significant effect of spectacle lenses on astigmatism change in multivariate linear regression (P = 0.925) or mixed linear model (P = 0.464). Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression with no extra astigmatism progression.