VEGFA and retinopathy of prematurity: Vitreous VEGF levels in type I ROP are unknown, but in vascularly active stage 4 ROP eyes, Sonmez et al. (35) found median (range) concentrations of 3.454 (0.774–8.882) ng/mL which were significantly higher than 0.316 (0.105–0.665) ng/mL in vascularly inactive stage four eyes and 0.059 (0.038–0.135) ng/mL in controls.