The new edition of the international classification of retinopathy of premature. Part 1

Retinopathy of prematurity (ROP) is still one of the main causes of blindness and low vision from early childhood in developed countries and therefore remains the focus of attention of researchers and clinicians. The International Classification of Retinopathy of Prematurity (ICROP) was initially adopted in 1984, expanded in 1987, amended in 2005, and revised in 2021. Part 1 of this article discusses the new edition of the ICROP3. The reasons for updating the ICROP3 and the composition of the International Committee, which was specially organized for this purpose, are indicated. The new and third edition retains the current definitions (zone, stage, and extent of the disease). The main updates in ICROP3 include the improved classification of indicators, two of which, in the author’s opinion, are most significant for the acute stages of the disease. The definition of posterior zone II region and the recognition that retinal vascular changes in ROP represent a continuous spectrum from normal to preplus- and plus disease, with images demonstrating this range. In conclusion, the new edition of the ICROP3 requires a deep reading and discussion between domestic experts and must be introduced to clinical practices and the educational process. The next article will continue the discussion on the remaining additions/updates to ICROP3.