Degree and duration of corneal anesthesia after topical application of 0.4% oxybuprocaine hydrochloride ophthalmic solution in ophthalmically normal dogs

Abstract

Topical application of oxybuprocaine and tetracaine similarly reduced corneal sensitivity in dogs, but oxybuprocaine was less irritating to the conjunctiva than was tetracaine.

Corneal anesthesia following application of 0.4% oxybuprocaine hydrochloride ophthalmic solution to normal feline eyes

“…The time interval until the touch sensitivity was restored to its baseline value was found to vary widely due to intersubject variation, with a range of 35–50 min and an average of 45 min. Using Cochet–Bonnet aesthesiometry, recovery of corneal sensitivity was reported to range from 30 to 60 min and 25 to 70 min in human and in canine eyes treated with 0.4% oxybuprocaine . In our sample population of healthy cats, the overall effect of oxybuprocaine in reducing corneal sensitivity was not significantly different between males and females and between subjects older and younger than the median age (5 years) of the group.…”

“…With the Cochet–Bonnet aesthesiometry, the threshold for corneal sensitivity can be expressed as the length of the nylon filament (in cm), or the pressure applied (in g/mm 2 ) to the cornea by the tip of the filament that varies depending on the filament diameter . In previous reports on corneal analgesia achieved with topical anesthetics currently used in veterinary ophthalmology, the CTT readings have been reported as filament lengths . To facilitate comparison of these data with those of the present study, our results on CTT values were given as filament length.…”

“…Complete corneal desensitization (corresponding to a CTT of 0) was evident at 1 and 5 min in 100% of the treated eyes, but duration of maximal effect ranged from 5 to 30 min among the cats, with an average value of about 21 min. By comparison, duration of complete corneal anesthesia assessed with the Cochet–Bonnet aesthesiometer after instillation of one drop of 0.4% oxybuprocaine has been found to range from 5 to 20 min in human eyes and 15–50 min in canine eyes . The time interval until the touch sensitivity was restored to its baseline value was found to vary widely due to intersubject variation, with a range of 35–50 min and an average of 45 min.…”

“…Tetracaine eye drops are available in form of a 0.5% and 1.0% aqueous solutions or a 0.5% viscous formulation . The depth and duration of their pharmacological effects on corneal sensitivity have been assessed in clinically normal dogs and horses . Oxybuprocaine (benoxinate) is a para‐aminobenzoic acid ester developed in the early 50s to serve as a topical anesthetic in human, and which analgesic effects on human cornea have been known since 1955 .…”

Retrobulbar vs peribulbar regional anesthesia techniques using bupivacaine in dogs

“…Decreased filament length required to stimulate a blink reflex reflected decreased corneal sensitivity. The longest filament length in centimeters that induced a blink reflex on at least 3 of 5 stimulations was recorded as the corneal sensitivity, and a lack of blink reflex using a 0.5‐cm filament was defined as complete loss of corneal sensation (ie, corneal sensitivity of zero) . Environmental conditions were kept the same between measurements in an effort to standardize the aesthesiometer data collection.…”