Efficacy of ultra-low-dose (0.1 mg) ranibizumab intravitreal injection for treatment of prethreshold type 1 retinopathy of prematurity: A case series.

To report the results of treatment of type 1 prethreshold retinopathy of prematurity using intravitreal injection of ultra-low dose of ranibizumab (0.1 mg in 0.01 mL). A retrospective observational case series study. Review of files of eligible infants who received this form of treatment to determine the outcome of treatment and any associated ocular or systemic side effects. The study included 24 eyes of 12 preterm infants with mean gestational age of 29.75 ± 1.54 weeks and mean birth weight of 1074.58 ± 320.59 g. A total of 22 eyes (91.67%) had zone II disease while 2 eyes of one infant (8.33%) had zone I disease. All cases showed regression of the signs of the active retinopathy of prematurity with complete retinal vascularization. None of the cases required retreatment. Three eyes developed ocular complications. Apart from mild feeding intolerance that lasted for 24 h after injection in one infant, none of the cases developed systemic side effects. Intravitreal injection of ultra-low-dose ranibizumab showed promising efficacy and good ocular safety. However, further large-scale studies are required to give stronger evidence about the efficacy and safety of ultra-low-dose ranibizumab.