The effects of topical diclofenac, topical flurbiprofen, and humidity on corneal sensitivity in normal dogs.
OBJECTIVE
To determine the immediate and chronic effects of topical 0.1% diclofenac and 0.03% flurbiprofen on corneal sensitivity in normal canine eyes.


METHODS
Eighteen normal, nonbrachycephalic dogs.


METHODS
A prospective, randomized, masked, crossover study was performed. To determine the immediate effects associated with treatment, the study drug was instilled into the eye every 5 min for five doses, and corneal sensitivity of treated and untreated eyes was obtained prior to treatment and every 15 min post-treatment for 60 min. To determine the chronic effects, the study drug was instilled every 12 h for 30 days, and corneal sensitivity of treated and untreated eyes was obtained prior to treatment on days 0 and 30. A washout period of at least 30 days occurred between drug crossover. Ambient temperature and humidity were measured throughout the study.


RESULTS
After multiple instillations, there was no difference in corneal sensitivity between eyes over time for diclofenac (P = 0.67) or flurbiprofen (P = 0.54), with a median sensitivity of 25 mm (1.8 g/mm2). After chronic dosing, there was no difference in corneal sensitivity between eyes over time for diclofenac (P = 0.82) or flurbiprofen (P = 0.56), with a median sensitivity of 35 mm (1.0 g/mm2). Decreasing ambient humidity was associated with an increase in sensitivity measurements (P = 0.0001).


CONCLUSIONS
Neither diclofenac nor flurbiprofen had an effect on corneal sensitivity after multiple-drops or twice-daily dosing for 30 days. Ambient humidity may have an effect on corneal sensitivity measurements, with a longer filament length eliciting a blink response at lower humidity.
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, 1008 W. Hazelwood Drive, Urbana, IL, 61802, USA.
Daniel M
DM
Dorbandt
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, 1008 W. Hazelwood Drive, Urbana, IL, 61802, USA.
Amber L
http://orcid.org/0000-0003-3677-9434
AL
Labelle
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, 1008 W. Hazelwood Drive, Urbana, IL, 61802, USA.
Mark A
MA
Mitchell
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, 1008 W. Hazelwood Drive, Urbana, IL, 61802, USA.
Ralph E
RE
Hamor
D060433:Administration, Ophthalmic; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D001767:Blinking / Q000187:drug effects; D003315:Cornea / Q000187:drug effects*; D018592:Cross-Over Studies; D004008:Diclofenac / Q000008:administration & dosage / Q000494:pharmacology*; D004285:Dogs; D004311:Double-Blind Method; D005480:Flurbiprofen / Q000008:administration & dosage / Q000494:pharmacology*; D006813:Humidity; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000494:pharmacology; D011446:Prospective Studies
D000894:Anti-Inflammatory Agents, Non-Steroidal; D009883:Ophthalmic Solutions; D004008:Diclofenac; D005480:Flurbiprofen
corneal esthesiometry; corneal sensitivity; diclofenac; flurbiprofen; humidity; topical NSAID