Inclusion Criteria:  male or female patients aged over 18 years diagnosed with type 1 or 2 diabetic mellitus (DM) confirmed by experienced endocrinologists. Active PDR and NVG was clinically evident across these patients. The indications to perform surgery included vitreous hemorrhage or fibrous proliferation in the macular area, together with uncontrolled intraocular pressure.  Exclusion Criteria:  (i) coexistent ocular disease that may interfere with visual outcome; (ii) previous history of vitrectomy or anti-VEGF pharmacotherapy in either eye; (iii) a macula-involving retinal detachment for >6 months in the study eye; (iv) severe external ocular infection; (v) usage of anticoagulant or antiplatelet therapy; (vi) preoperative or postoperative poor diabetes control [serum hemoglobin A1c (HbA1c) >11.0%]; (vii) uncontrolled systemic diseases, such as hypertension, cardiac diseases or presenting abnormal coagulation-associated blood diseases.