Retinopathy of prematurity (ROP), previously known as retrolental fibroplasia (RLF), is a isease of the eye that affects prematurely born babies. It is thought to be caused by disorganised growth of retinal blood vessels which may result in scarring and retinal detachment. ROP can be mild and may resolve spontaneously, but may lead to blindness in serious cases. As such, all preterm babies are at risk for ROP, and very low birth weight is an additional risk factor. Both oxygen toxicity and relative hypoxia can contribute to the development of ROP.