This has largely been accomplished by analyzing the levels of erythropoietin, VEGF, and cytokines like interleukins (IL-6, IL-7, IL-10, and IL-15), Eotaxin, FGF basic, G-CSF, GM-CSF, IP-10, and RANTES in the vitreous to identify their potential as biomarkers for ROP progression (14–16). This evidence concerns the gene IL7 and retinopathy of prematurity.