Amaurosis and anesthesia technique.

摘要

In their report, which highlights orbital varix rupture as an unusual but potentially dangerous result of retrobulbar anesthesia, Yoshimoto and Matsumoto1 note that 1 reason for choosing injection anesthesia over topical or sub-Tenon's is the patient's aversion to seeing the surgical instruments. Although it is true that topical anesthesia provides no real amaurosis, the same cannot be said for sub-Tenon's. In a 1994 study, Griffiths and coauthors2 studied the effect of retrobulbar anesthesia on the optic nerve in 50 patients. They found that only 10% had no light perception after the injection while 8% had only light perception. The rest had hand motion (42%) or finger counting acuity (40%). These results demonstrate no advantage in terms of amaurosis over results with sub-Tenon's or parabulbar anesthesia.3 This finding is not surprising because magnetic resonance imaging has been used to show the flow of anesthetic agents delivered through a cannula in the anterior sub-Tenon's space to and around theoptic nerve.The low volume (1 to 2 mL) of anesthetic fluid used during parabulbar anesthesia, coupled with the use of a short, blunt cannula, makes the risk for orbital varix rupture unlikely. Because the use of retrobulbar anesthesia does not provide an advantage in terms of amaurosis, I would urge the authors to reconsider their anesthesia approach.