Significantly higher expressions of IL-1ra (p = 0.014), MMP2 (p = 0.0085), and MMP-9 (p = 0.03) were detected in severe ROP cases compared to mild ROP and no-ROP tear samples that was further confirmed by zymography (Figures 3C–E). This evidence concerns the gene MMP9 and retinopathy of prematurity.