In this study, we evaluated the association of four SNPs in the genes encoding selenoprotein P (SelP, SELENOP gene), selenoprotein S (SelS, SELENOS gene), and glutathione peroxidase 4 (GPX4, GPX4 gene) with the development of ROP and its clinical course. The gene discussed is SELENOS; the disease is retinopathy of prematurity.