ObjectiveTo evaluate the factors that may influence the possibility of early hemorrhage after vitrectomy with silicon oil tamponade for proliferative diabetic retinopathy (PDR).MethodsSixty-seven eyes of 60 patients of PDR who received vitrectomy and silicon oil filled in Department of Ophthalmology, China-Japan Friendship Hospital during January 2014 and May 2017 were included in this study. There were 34 males and 26 females, with the mean age of 51.3±12.5 years. Groups were divided depending on the degree of postoperative hemorrhage in 3 days: non-hemorrhage group (NH group) and hemorrhage Group (H group) composed of two sub-group that were called slight hemorrhage (SH) and massive hemorrhage (MH) group. The treatment was conventional 25G or 27G pars plana vitrectomy combined with silicon oil tamponade. Forty eyes received phacoemulsification. The follow-up ranged from 8 to 16 months, with the mean follow-up of 11.2±5.6 months. The possible related factors of early hemorrhage after vitrectomy with silicon oil tamponade were analyzed. Independent t test, χ2 test and Fisher test were used in this study.Results55 eyes of 48 patients were in the NH group, while 12 eyes of 12 patients were in the H Group. There were statistical significances on the difference of age (t=−3.552, P=0.001), gender (P=0.052), hypertension (P=0.021), HbA1c (t=2.187, P=0.033) and presence of neovascularization of iris (χ2= 6.414, P=0.011), but there was no difference on diabetes duration (t=−0.451, P=0.654). Of the 12 patients in the H group, 7 were in the SH group and 5 were in the MH group. The MH group had a significantly higher HbA1c level (7.8±1.1)% compared with the SH Group (9.7±0.7)%, the difference was statistical significant (t=−3.256, P=0.009). Higher systolic blood pressure of MH group 186±7 mmHg (1 mmHg=0.133 kPa) acquired during operation was observed compared with SH Group 153±18 mmHg, the difference was statistical significant (t=−3.894, P=0.003). There was no statistical significances on the difference of age (t=1.954), gender, hypertension duration (t=−1.787), diabetes duration (t=−1.079), fasting blood-glucose (t=−0.361), diastolic blood pressure during operation (t=−0.811) between the two groups (P＞0.05).ConclusionsYounger age, history of hypertension, presence of neovascularization of iris, higher level of HbA1c may predict greater possibility to cause early hemorrhage after vitrectomy with silicon oil tamponade for PDR. The patients with high level of HbA1c and high systolic pressure during the operation are more likely to undergo massive hemorrhage and secondary glaucoma.