To the Editor.
—We enjoyed reading the article by Friedberg et al1 describing their experience with local anesthesia in sub-Tenon's space for vitreoretinal surgery. They reported successful anesthesia in 98 of 100 patients with no associated morbidity. We expect that as more surgeons use this technique, there will be a decrease in the incidence of retrobulbar hemorrhage, optic nerve injection, and perforation of the globe.We have also used anesthesia in sub-Tenon's space both primarily and as a supplement to incomplete retrobulbar and peribulbar blocks. A single injection in sub-Tenon's space of 3 mL of anesthetic (2% lidocaine hydrochloride and 0.75% bupivacaine hydrochloride) is adequate supplementation for most patients with failed primary blocks. However, it is particularly distressing for both the surgeon and the patient when incomplete anesthesia is achieved despite repeated supplementations in sub-Tenon's space. Friedberg et al reported two cases with failed block. In our experience these