Three example images from eyes of patients with and without AP-ROP. A) Left eye of an infant with type 2 ROP. On ophthalmoscopy, this patient had zone II, stage 2 disease with pre-plus and a severity score of 4.1. B) Right eye of an infant with treatment-requiring (TR) ROP. On ophthalmoscopy, this infant was diagnosed with zone 2, stage 3 disease with plus disease. C) Left eye of an infant diagnosed with TR-ROP with AP-ROP. On ophthalmoscopy, this patient was diagnosed with zone 1, stage 3 with plus disease. Compared to the baby in B, the baby in C demonstrated extensive flat stage 3 disease rather than the more typical stage configuration seen in B.