The purpose of the study is to explore the current incidence rate of retinopathy of prematurity (ROP) in China and to explore more appropriate screening criteria for ROP.

Inclusion Criteria:

From December 2024 to May 2025, preterm infants (gestational age <37 weeks) or low birth weight infants (birth weight <2500 g) who receive their first ROP screening at Xinhua Hospital or partner institutions will be included.

Exclusion Criteria:

1. Death before the first screening;
2. Death or loss to follow-up before complete retinal vascularization;
3. Presence of other diseases causing incomplete retinal vascularization, such as familial exudative vitreoretinopathy, incontinentia pigmenti, or Coats disease;
4. Coexisting conditions affecting the classification or staging of ROP, such as corneal opacity, congenital cataract, persistent fetal vasculature, retinoblastoma, anophthalmia, Terson syndrome, or other ocular infections or diseases;
5. Poor systemic condition preventing fundus examination;
6. History of ocular trauma or surgery (excluding treatments for ROP);
7. Poor-quality fundus images;
8. Other conditions deemed exclusionary by the investigators.

Tertiary hospital