Inclusion Criteria:  - Infants with a birth weight of ≤ 1500 g or geststional age of ≤ 30 weeks and selected infants with birth weight between 1500 and 2000 g or gestational age of more than 30 weeks with an unstable clinical course, including those requiring cardiorespiratory support. Patients with bilateral disease who will receive bilateral injections, are only included. Type 1 ROP according to ETROP study which is defined as, Zone I ROP with plus disease, Zone I, stage 3 ROP without plus disease and Zone II, stage 2 or 3 ROP with plus disease.  Exclusion Criteria:  Eyes with previous intravitreal injections. Eyes with previous laser therapy. Eyes with any other pathology, other than ROP. Eyes with ROP stage 4 or 5. Eyes with mucopurulent or purulent conjunctivitis. Infants who will not be able to comply to the follow-up schedule.