AIM: To study the efficacy of laser combined with ranibizumab in the treatment of proliferative diabetic retinopathy(PDR)and its effects on levels of plasminogen activator inhibitor(PAI), tissue plasminogen activator(t-PA)and vascular endothelial growth factor(VEGF)in aqueous humor.

METHODS: Totally 76 cases of patients(76 eyes)with PDR were divided into observation group(n=41)and control group(n=35)according to the use of ranibizumab or not. Control group was given routine laser surgery, and observation group was added with ranibizumab for adjuvant treatment. The laser energy and density used in treatment, and the best corrected visual acuity(BCVA), central macular thickness(CMT)and levels of PAI, t-PA and VEGF in aqueous humor after treatment, postoperative complications and prognosis were compared between the two groups.

RESULTS: The sunfleck quantity, laser energy and energy density in observation group were lower than those in control group(P<0.05). After treatment, the BCVA in the two groups was gradually increased while the CMT was gradually decreased, and the difference within-groups at different times was statistically significant(P<0.05), and the BCVA in observation group was higher than that in control group at the same time while the CMT was lower than that in control group(P<0.05). After treatment, the levels of VEGF, t-PA and PAI in aqueous humor were gradually increased, and were significantly lower than preoperative levels(P<0.05), and there was a statistically significant difference at different time points within-groups(P<0.05), and the levels of VEGF, t-PA and PAI in aqueous humor in observation group were lower than those in control group at the same time(P<0.05). The incidence rates of postoperative macular edema in the two groups were 17% and 37% respectively(P<0.05). The PDR recurrence rates at 1a after operation were 6% and 16% respectively(P>0.05).

CONCLUSION: Laser combined with ranibizumab for PDR can significantly reduce the expression levels of serum VEGF, t-PA and PAI in aqueous humor, decrease the CMT, and improve the BCVA. And combined therapy is beneficial to reduce the sunfleck quantity, laser energy and energy density during treatment, and lower the laser damage towards the retina.