Endothelial nitric oxide synthase (e-NOS) can lead to relaxation in the endothelial cells of blood vessels, but at high oxygen concentrations, NOX can transform into nitro-oxidative forms such as peroxynitrite, which result in microvascular degeneration in phase 1 oxygen-induced retinopathy (OIR) models [10]. Here, NOS3 is linked to retinal disorder.