65 years old scheduled for Rt cataract surgery, she received 1mg of midazolam preoperative. Retrobulbar block was performed. Pt becomes obtunded and apneic. BP and HR was normal, pt intubated and send to ICU for observation. What is the most likely Cause:
A. Midazolam overdose
B. Retrobulbar hemorrhage
C. Intravascular injection of local anesthesia
D. Local anesthesia spread to subarachnoid space