Hong GJ, Koerner JC, Weinert MC, et al. - Using ROPtool analysis of narrow-field retinal images, researchers conducted this longitudinal study to quantitatively compare retinal vascular characteristics over time in eyes eventually treated vs not treated for retinopathy of prematurity (ROP). Seven hundred forty-five images (89.5%) had 3-4 quadrants analyzable by ROPtool out of 832 examinations (99 infants). Using ROPtool, a quantitative analysis of retinal vascular characteristics will help to predict the eventual need for ROP therapy as early as 32 weeks postmenstrual age. In order to determine eyes that would potentially require care for ROP, ROPtool index values were more beneficial than changes in these indices.