Comparison of 4 topical anesthetic agents for effect and corneal toxicity in rabbits.

PURPOSE

To compare the onset time, duration of action, corneal toxicity, and corneal epithelial healing time of 4 topical anesthetic agents in rabbits.

SETTING

Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.

METHOD

Fifty-six rabbits were treated with 4 topical anesthetics (bupivacaine, lidocaine, procaine, and benzocaine) at different concentrations and different pH of solutions. Corneal sensation, corneal toxicity, and corneal epithelial healing time were measured.

RESULTS

The onset time of all 4 anesthetic agents was within 1 minute; however, bupivacaine and lidocaine produced significantly longer action than procaine or benzocaine (P < .05). Buffered bupivacaine and lidocaine had a significantly longer anesthetic effect than that of the nonbuffered solutions (P < .05). No significant effect on corneal epithelial healing time or corneal toxicity was observed.

CONCLUSION

Topical bupivacaine and lidocaine had a longer anesthetic effect, particularly in buffered solutions. No significant corneal toxicity was observed.