The i-ROP ASSIST app is designed to allow clinicians to compare beside images of infants at risk for retinopathy of prematurity (ROP) with a published set of reference standard images. Users are able to upload fundus images and determine the relative severity of their image among the set of reference images by finding the image that most closely matches the relative degree of vascular abnormality. Published reference data for the spread of expert classifications (plus, pre-plus, or normal) and reference standard diagnosis (consensus diagnosis of multiple independent image gradings & ophthalmoscopic diagnosis) is provided for the selected reference image.