Abstract
AIM: To investigate the effect of the Defocus Incorporated Soft Contact (DISC) lenses on myopia progression and choroidal thickness (ChT) of Chinese mainland children over a period of 12 months. METHODS: This was a prospective double-blind randomised controlled trial involving 84 myopic children. Subjects were randomly assigned to use of either DISC or single vision contact lens (SVL). Cycloplegic spherical equivalent refraction (SER), axial length (AL) and ChT were measured at 6 and 12 months. RESULTS: For 12 months, the average changes in SER and AL in the DISC group were (-0.50±0.41) D and (0.22±0.13) mm. Corresponding values in the SVL group were (-1.23±0.50) D and (0.49±0.15) mm. Myopia control efficacy in SER was 59% and 55% in AL. For those aged under 10, myopia control efficacy in SER is higher at 95% in 6 months and 71.4% in 12 months. ChT increased by 0.16±24.46 µm in the DISC group, while in contrast, it thinned in the SVL group (-9.11±32.25 µm) after 12 months. ChT changes demonstrated a significant negative association with AL over 12 months in the DISC group but not in the SVL group. In contrast, ChT change over 12 months was significantly negatively associated with initial ChT in the SVL group, but not in the DISC group. CONCLUSIONS: DISC lenses effectively slowed myopia progression and AL compared with SVL, especially for younger children. Myopia defocus treatment changes the original intrinsic relationship between ChT and myopia progression, providing strong evidence that myopia defocus design controls myopia progression by changing ChT.