in the retrospective investigation titled “risk factors evaluation of threshold retinopathy of prematurity” at a tertiary ophthalmic center in tehran, iran, the authors have studied 859 premature neonates during one year (2008-2009). 791 eyes have had retinopathy of prematurity (rop) and 7.4% of them presented threshold retinopathy (trop). the investigators aim has been to present and compare t...