The new international classification of retinopathy of prematurity.

The international classification of acute retinopathy of prematurity (ROP) appearing in this issue 1 is a timely and important contribution to the ocular examination and management of the retinopathy in these premature infants. See also p 1130. During the epidemic period of ROP, generally designated then as retrolental fibroplasia, the survival rate of small premature neonates with birthweights under 1,000 g was less than 10%. By the 1980s, due to improved neonatal care, that survival rate has increased by fourfold or greater. These low-birthweight infants, who are at the highest risk of ROP, are surviving today, but in the early 1950s would not have lived long enough for the disease to develop. Cases of ROP are occurring today despite the most meticulous monitoring of arterial blood gases. The extreme prematurity, combined with factors other than excess oxygen, may be responsible for current cases. With a substantial number of new cases