MMP2 and myopia: The results showed that the expression levels of the Col1a1 and Mmp2 genes were significantly increased (P < 0.05) in the retinal tissues of the FD-Inj-Br group, and the expression level of Slc39a5 was significantly decreased (P < 0.05), while there were no significant differences in the expression of other myopia-related genes between the two groups (Fig. 6a).