PurposeThe treatment with anti-VEGF for Retinopathy of prematurity (ROP) has already been widely applied in clinics even though there are still many concerns about this treatment. In this project we investigated the clinical outcomes of intra-vitreous conbercept (IVC) and ranibizumab (IVR) injection for treating type 1 prethreshold ROP in Zone II.MethodsThe data of ROP infants receiving IVR or IVC from January 2017 to March 2020 who were followed up for at least 12 months in our hospital was studied in the present retrospective study. Regression, reactivation, complications, and ocular biological parameters were evaluated.ResultsOne hundred twenty-five eyes (64 infants) in IVC group and 229 eyes (117 infants) in IVR group were observed in the study. All infants showed good response to the two anti-VEGF agents. No eyes deteriorated during the observation. No significant difference was found between the two groups as to the regression within one week and one month, the reactivation rate, and the retreatment interval (p > 0.05) whereas retinal complete vascularization rate at 6 mons after the initial treatment and mean completion time of retinal vascularization after initial injection showed significant difference (p < 0.05). At 12 mons PMA the ocular parameters also presented no statistical difference between the two treated groups (p > 0.05). However, the ocular showed slight myopic tendency with the anti-VEGF treatment when compared to the control group (p < 0.05) whereas there was no statistical difference revealed between the two treated groups (p > 0.05).ConclusionsBoth conbercept and ranibizumab for treating type 1 prethreshold ROP in Zone II are safe and effective. They had little effect on the development of ocular whereas there was a slight tendency of myopia after the treatment.