To investigate the association between changes in astigmatism and retinal thickness in adolescents wearing myopic defocus spectacle lenses, a total of 60 adolescents with low to moderate myopia from June to December 2023 were selected, with the dominant eye (60 eyes) chosen for observation. They were randomly divided into Defocus Incorporated Multiple Segments (DIMS) lenses group, Highly Aspherical Lenslets (HAL) group, and Single Vision Lenses (SVL) control group. Follow-ups were conducted at 3 months and 6 months to observe changes in astigmatism and retinal thickness. Intergroup differences and the interaction effects between follow-up time and group were analyzed. The results showed the increase in astigmatism in the DIMS group was significantly higher than that in the HAL and SVL groups (P < 0.05). Retinal thickness in the 1 mm, 3 mm, and 6 mm macular central fovea regions increased significantly in all three groups (P < 0.05). The DIMS group showed uneven growth, the HAL group exhibited uniform growth, and the SVL group demonstrated uniform growth outside the 1 mm central fovea. A significant interaction effect was observed between follow-up time and group (P < 0.05). DIMS lenses may lead to increased astigmatism and uneven changes in retinal thickness, while HAL and SVL lenses have a more uniform impact on astigmatism and retinal thickness. This study provides clinical evidence for the personalized selection of myopic defocus spectacle lenses.