Background  Retinopathy of prematurity (ROP) is a retinal vasoproliferative disorder that affects exclusively in premature infants and is one of the main reasons for blindness in children worldwide. Laser or drug treatment is often used in the early stage, and surgery is mainly used in the late stage.

  Objective  To observe the efficacy of intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) combined with laser in treatment of stage 4a plus (+) retinopathy of prematurity (ROP).

  Methods  Totally 10 consecutive ROP patients (12 eyes) in 4a plus (+) who received initial anti-VEGF combined laser treatment in our hospital from January 2014 to December 2020 were collected in our study. All patients were examined by indirect ophthalmoscopy and documented with fundus photography using a RetCam II to evaluate the vascular activity. The mean birth weight was (1015.00 ± 410.59) g, with the mean gestational age of (28.30 ± 1.83) weeks. The mean post menstrual age at intervention was (41.67 ± 3.33) weeks, and the mean follow-up period was (868.36 ± 804.85) days. All treated eyes received laser photocoagulation within one week after 0.025mL of Ranibizumab (10 mg/mL) was intravitreally injected. Patients were followed up every 1 to 3 weeks until the retinal vascular fully developed. When the disease deteriorated during the follow-up period, surgery was needed. The main outcome observation were the regression of ROP and the local and systemic complications associated with the treatment.

  Results  After receiving the treatment, all eyes exhibited decreased vascular activity and partial recession of retinal ridge and retinal neovascularization. At the final visit, 9 eyes became stable and 3 eyes deteriorated and further surgery was performed. No local or systemic adverse events associated with the treatment were observed during the following period.

  Conclusion  Anti-VEGF combined with laser treatment is an effective and well-tolerated method for 4a plus (+) ROP, which can preserve the eyesight for more advanced ROP patients.