Retrobulbar block is commonly performed under monitored anesthesia prior to cataract surgery. Known complications associated with retrobulbar block include cranial nerve palsies, seizures, and cardiorespiratory arrest. We report a case of severe shivering following a retrobulbar block. Two minutes after the block was administered, the patient experienced severe shivering, which subsided after injection of pethidine 25 mg. The likely etiology of the shivering was inadvertent dural puncture of the optic nerve sheath and local anesthetic spread into the cerebrospinal fluid space. Shivering may be a warning sign of brain stem anesthesia, and in such a scenario the clinician should direct special attention to possible life-threatening complications.