Anesthetic dose and analgesic effects of sub-Tenon's anesthesia in cataract surgery

To compare the analgesic effects of different doses of sub-Tenon's anesthesia in cataract surgery by assessing patient response to visceral stimulus.

Inouye Eye Hospital, Tokyo, Japan.

A prospective study was done of 1019 eyes of 1019 patients having phacoemulsification and posterior chamber intraocular lens implantation. They received a 1.0 mL (391 eyes), 2.0 mL (366 eyes), or 3.0 mL (262 eyes) anesthetic infiltration into the sub-Tenon's space. Pain scores were recorded when the anterior chamber was irrigated with an acetylcholine chloride solution to attain miosis after lens implantation.

The distribution of pain scores was significantly different among the 3 groups (P < .0001, Kruskal-Wallis test). Multiple comparison revealed that the 3.0 mL anesthetic infiltration offered significantly higher analgesic effects than the 2 lower doses. The 3.0 mL sub-Tenon's anesthesia effectively blocked the visceral stimulus.

For cataract surgery, 3 mL is the optimal dose of anesthetic solution in sub-Tenon's anesthesia.