Some clinical biological markers, such as circRNAs expression profile changes in peripheral blood mononuclear cells (PBMCs)4, serum fructosamine5, complete blood count (CBC) in the first week after birth6, critical levels of interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and vascular endothelial growth factor-A in cord blood7, serum IL-33 and endorphin levels8, etc., revealed some value in the early detection of ROP. The gene discussed is IL6; the disease is retinopathy of prematurity.