Severe allergic reactions to peribulbar local anesthesia are extremely rare. A 70-year-old woman presented with acute orbital swelling and optic nerve dysfunction after a peribulbar local anesthetic injection. The patient was treated with acute orbital decompression as well as intravenous antibiotics and methylprednisolone; she made a good recovery. An allergy, probably to lignocaine, was the most likely cause. Urgent recognition and treatment of this condition may prevent potentially serious visual consequences.