Degree and duration of corneal anesthesia after topical application of 0.4% oxybuprocaine hydrochloride ophthalmic solution in ophthalmically normal dogs.
OBJECTIVE
To assess the anesthetic efficacy and local tolerance of topically applied 0.4% oxybuprocaine ophthalmic solution to in dogs and compare its effects with those of 1% tetracaine solution.


METHODS
34 ophthalmically normal Beagles.


METHODS
Dogs were assigned to 2 groups, and baseline corneal touch threshold (CTT) was measured bilaterally with a Cochet-Bonnet aesthesiometer. Dogs of group 1 (n = 22) received a single drop of 0.4% oxybuprocaine ophthalmic solution in one eye and saline (0.9% NaCl) solution (control treatment) in the contralateral eye. Dogs of group 2 (n = 12) received a single drop of 0.4% oxybuprocaine ophthalmic solution in one eye and 1% tetracaine ophthalmic solution in the contralateral eye. The CTT of each eye was measured 1 and 5 minutes after topical application and then at 5-minute intervals until 75 minutes after topical application.


RESULTS
CTT changes over time differed significantly between oxybuprocaine-treated and control eyes. After instillation of oxybuprocaine, maximal corneal anesthesia (CTT = 0) was achieved within 1 minute, and CTT was significantly decreased from 1 to 45 minutes, compared with the baseline value. No significant difference in onset, depth, and duration of corneal anesthesia was found between oxybuprocaine-treated and tetracaine-treated eyes. Conjunctival hyperemia and chemosis were detected more frequently in tetracaine-treated eyes than in oxybuprocaine-treated eyes.


CONCLUSIONS
Topical application of oxybuprocaine and tetracaine similarly reduced corneal sensitivity in dogs, but oxybuprocaine was less irritating to the conjunctiva than was tetracaine.
Département des sciences cliniques, INP-Ecole nationale vétérinaire, 31076 Toulouse Cedex 3, France.
Jean-Yves
JY
Douet
Julien
J
Michel
Alain
A
Regnier
D000287:Administration, Topical; D000704:Analysis of Variance; D000772:Anesthesia, Local / Q000379:methods / Q000662:veterinary*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D000818:Animals; D003315:Cornea / Q000187:drug effects* / Q000601:surgery; D004285:Dogs; D009883:Ophthalmic Solutions / Q000008:administration & dosage; D017288:Pain Threshold / Q000187:drug effects; D011343:Procaine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology; D013748:Tetracaine / Q000494:pharmacology; D013997:Time Factors
D000779:Anesthetics, Local; D009883:Ophthalmic Solutions; D013748:Tetracaine; D011343:Procaine; C005298:benoxinate