An international classification of retinopathy of prematurity.

The unifying principle underlying this classification system is: The more posterior the disease and the greater the amount of involved retinal vascular tissue, the more serious the disease. The staging of the disease at any given location expresses the natural history and evolution of events at the border between vascularized and avascular retina. The classification system is designed to permit the examiner full latitude in transcribing his observations so that they will be immediately intelligible to another examiner who may not have had the opportunity to examine the specific infant.