Ordinal regression showed an association between NfL and ROP; however, adjustment negated significance (mean NfL/day first month: no-, mild/moderate [stage 1–2], and severe ROP [stage 3 or treated]) (OR [95% CI] 2.57 [1.59–4.14], p < 0.001). This evidence concerns the gene NEFL and retinopathy of prematurity.