AIM: To investigate the clinical effects of laser photocoagulation combined with anti-vascular endothelial growth factor(VEGF)drugs at different time in the treatment of diabetic retinopathy(DR).

METHODS: A prospective study was conducted. Totally 120 patients(191 diseased eyes)with DR who were admitted to the hospital between January 2018 and January 2019 were divided into group A(treated with simple laser photocoagulation, 30 cases, 44 diseased eyes), group B(treated with intravitreal injection of ranibizumab, 30 cases, 46 diseased eyes), group C(treated with intravitreal injection of ranibizumab after laser photocoagulation, 30 cases, 49 diseased eyes)and group D(treated with laser photocoagulation after intravitreal injection of ranibizumab, 30 cases, 52 diseased eyes). Patients in each group were followed up for 6mo after the end of treatment. The best corrected visual acuity(BCVA), intraocular pressure and central foveal thickness(CMT)of each group were compared before and after treatment. The situation of laser photocoagulation and anti-VEGF treatment, complications and recurrence of diabetic macular edema were observed.

RESULTS: There was no significant difference in BCVA or CMT among the four groups before treatment(P>0.05). The two indexes were improved at 1wk, 1mo, 3mo and 6mo after treatment(P<0.05). Besides, they were better in group C and group D than in group A and group B at different time after treatment(P<0.05). The BCVA and CMT in group D were better than those in group C at 1wk, 1mo and 3mo after surgery(P<0.05). There was no significant difference in intraocular pressure among the four groups before or after treatment(P>0.05). The laser parameters and frequency of laser treatment were lower or fewer in group C and group D than in group A, and lower in group D than in group C(P<0.05). The frequencies of intravitreal injection in group C and group D were fewer than that in group B(P<0.05). There was no significant difference in the frequency of laser treatment or drug injection between groups C and group D(P>0.05). There was no significant difference in the incidence of complications or the incidence of diabetic macular edema among the four groups during follow up(P>0.05).

CONCLUSION: The effect of laser photocoagulation after intravitreal injection of anti-VEGF drug is better than simple photocoagulation, simple intravitreal injection or intravitreal injection of ranibizumab after laser photocoagulation in the treatment of DR. It can improve the BCVA, relieve macular edema, reduce laser energy, frequency of laser treatment and injection frequency of anti-VEGF drug, with safety.