Retinopathy of prematurity was the main cause of blindness in children after the second world war. It was observed in very premature babies who had been administered with gas oxygen in high concentrations for prolonged periods. The discovery of this correlation has led to premature retinopathy now being a rare illness.

The retinal blood vessels leave from the optic nerve in the direction of the circumference. They are one of the last sections of the eye to develop in the embryo and reaches completion around the end of the last trimester. Hence, if a child is born prematurely, these vessels will not have had time to reach the circumference of the retina, rendering these areas lacking adequate blood flow causing ischemia.

The rapid administration of high oxygen concentration to newborns inhibits further growth of blood vessels and results in the creation of new pathological vessels and connective tissue. In serious cases these pull the retina and can even lead to its detachment.

Infants that are more likely to be affected are those that weigh less than 1500 grams at birth and those who were given high dosage of oxygen and for long periods.

Fortunately, most cases have a good outcome up to full restoration. In severe cases very premature babies may require cryotherapy or photocoagulation with lasers to stop the growth of abnormal blood vessels.

Most of these children have myopia and, therefore, must be administered with appropriate glasses.

Generally, children with retinopathy of prematurity should be closely monitored because they have an increased chance of developing strabismus and amblyopia.