Corneal sensation after topical anesthesia.
OBJECTIVE
To compare the topical effects of tetracaine, lidocaine, and bupivacaine on corneal sensitivity in normal eyes.


METHODS
Corneal touch sensitivity was measured with a Cochet-Bonnet anesthesiometer before and at 2.5-minute intervals after instillation of the anesthetic agent, until baseline levels had been reestablished. Seventeen healthy volunteers were randomized into five groups. Group 1 included 0.5% tetracaine (n = 6); group 2, 4% lidocaine (n = 8); group 3, 0.75% bupivacaine (n = 8); group 4, 0.5% tetracaine + 4% lidocaine (n = 5); and group 5, 0.5% tetracaine + 0.75% bupivacaine (n = 7).


RESULTS
The duration of anesthesia showed no differences between groups 1, 3, and 5. Although there was no difference between groups 2 and 4, both groups demonstrated significantly longer effects than groups 1, 3, and 5 (p < 0.005).


CONCLUSIONS
The application of 4% lidocaine results in a significantly prolonged topical anesthetic effect when compared with tetracaine and bupivacaine.
Nomura
K
K
Department of Ophthalmology, University of Rochester School of Medicine, New York, USA.
Singer
D E
DE
Aquavella
J V
JV
D000328:Adult; D000772:Anesthesia, Local / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage; D003315:Cornea / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation; D012677:Sensation / Q000187:drug effects / Q000502:physiology*; D013748:Tetracaine / Q000008:administration & dosage
D000779:Anesthetics, Local; D013748:Tetracaine; D008012:Lidocaine; D002045:Bupivacaine