The purpose of this study is to determine whether bevacizumab 1-2 weeks before vitrectomy is effective in lowering the rate of early post-vitrectomy vitreous hemorrhage in diabetic patients.

Diabetes is the leading cause of blindness in the age range of 20-64 years. Pars plana vitrectomy may be indicated for the management of advanced proliferative diabetic retinopathy. Early post-vitrectomy hemorrhage in diabetic patients is relatively common; it occurs in 29% -75% of patients in the first month after surgery. This may cause delayed visual rehabilitation and detection of surgical complications such as retinal break or detachment. Preliminary reports such as case series reported by Spaide RF, et al showed beneficial effect of bevacizumab in proliferative diabetic retinopathy complicated by vitreous hemorrhage.

• Experimental: Intravitreal bevacizumab injection 1-2 weeks before surgery
• Sham Comparator: Sham injection (needleless syringe pressed against conjunctiva)

Inclusion Criteria:

• All eyes who are candidate for pars plana vitrectomy because of complications of diabetic retinopathy such as nonclearing vitreous hemorrhage, tractional retinal detachment threatening macula, active progressive PDR

Exclusion Criteria:

• One eye patient
• Best corrected visual acuity better than 20/50
• Pregnancy
• Use of internal tamponade such as silicone oil during surgery
• Concurrent ophthalmic surgery such as cataract extraction