With the advent of new treatments and improved precision in the timing of treatment, retinopathy of prematurity (ROP) is slowly morphing into a chronic illness. To be sure, blindness in infancy from ROP remains a possible outcome, even with the best surgical management. Nevertheless, problems of reduced visual acuity, high myopia, nystagmus, strabismus, late retinal detachments, and glaucoma, occur in children who had severe ROP. These problems last a lifetime, even though they do not cause blindness in infancy.

What causes these chronic problems, and what causes the disease in the first place? We know a lot about some of the risk factors for ROP, such as low birth weight and gestational age. Is it simply peradventure that two similar infants, side by side in the same nursery, with the same general hospital course, could have highly discrepant outcomes? Why does one child with advanced ROP develop myopia, and another not? What are the factors …