AIM: To observe the clinical outcome of non-vascularization area after laser photocoagulation in the patients with retinopathy of prematurity(ROP)to lay the foundation for the clinical treatment of ROP.

METHODS: For a prospective follow-up observation from June 2014 to June 2016, 186 cases(372 eyes)underwent retinal laser photocoagulation were screened out in the ROP screening clinic and neonatal intensive care unit(NICU)bedside screening by the cooperative group of screening for ROP in our hospital. Non-vascularization area were exist in 26 cases(32 eyes). There were 17 male patients(18 eyes)and 9 females(14 eyes), the gestational age at birth was 29.4±0.4wk, and the average birth weight was 1222.8±70.3g. Among these cases, 10 patients(12 eyes)developed pre-threshold type 1 ROP, 12 patients(14 eyes)developed threshold ROP, and 4 cases(6 eyes)developed aggressive posterior-ROP. The Retcam fundus photography was performed at 1, 3, 8 and 12wk after laser surgery respectively. The changes of the non-vascularization area, the lesions and the additional lesions were observed. During following-up, if the lesions were found to increase, retinal laser photocoagulation or intravitreal injection of anti- vascular endothelial growth factor(VEGF)would be performed, until the lesions were completely under control.

RESULTS: In the all 26 patients, non-vascularization areas were found in 1wk after laser resection, but the lesions ridge dissipated from the stage 3 to stage 2 and stage 1. The dissipation were more obviously in patients with ROP of pre-threshold type 1. The range of non-vascularization areas was narrowed at 3wk in 27 eyes(84%), and the retinal vessels continued to develop to the surrounding areas,but in the other 5 eyes(16%),the non-vascularization areas were not significantly narrowed, the lesion ridge developed stage 3-4, with bleeding and proliferation phenomenon, then we timely to gave additional retinal laser photocoagulation. In these 5 eyes, 3(9%)developed threshold ROP, and 2 developed aggressive posterior-ROP. At the 8th week, 3 eyes(9%)of the 5 eyes were found with additional photocoagulation, the condition was controlled and stable. In 2 eyes(6%), the neovascularization disappeared in the ridge and the lesion was not found, then intravitreal injection of anti-VEGF were given. At the 12th week, the additional lesions in the 2 eyes had subsided, the ridge subsided, and the retinal blood vessels to the temporal shaped slightly stiff.

CONCLUSION: Retinal laser photocoagulation is an effective method for the treatment of retinopathy in premature infants. Most retinal blood vessels would develope in missing areas after the laser photocoagulation. A small proportion of patients need timely replenishment of laser photocoagulation treatment, if necessary, combined with intravitreal injection of anti-VEGF.