Affiliation:
1. Department of Clinical Sciences, College of Veterinary Medicine Mississippi State University Mississippi State Mississippi USA
2. College of Veterinary Medicine Mississippi State University Mississippi State Mississippi USA
3. Department of Pathobiology and Population Medicine College of Veterinary Medicine, Mississippi State University Mississippi State Mississippi USA
Abstract
AbstractObjectiveTo evaluate corneal sensitivity and acute side effects following application of ropivacaine hydrochloride 0.5% and lidocaine hydrochloride 2% on the healthy equine cornea.Animals StudiedEight healthy adult horses.ProcedureA randomized, masked, crossover study design was utilized. Baseline Semiquantitative Preclinical Ocular Toxicology (SPOT) scores and corneal touch thresholds (CTT) using a Cochet‐Bonnet esthesiometer were recorded and measured, respectively, for eight healthy adult horses before medication application. Commercially available eyewash was used as a negative control. Ropivacaine hydrochloride 0.5% or lidocaine hydrochloride 2% solution was sprayed on a randomly selected eye, and the contralateral eye received eyewash. CTT was measured in both eyes at 1, 5, 15, 25, 35, 45, 55, 65, and 75 min post‐application. Post‐application SPOT scores were recorded immediately following the trial. Linear mixed model statistical analyses (mean ± standard error) were performed (p < .05).ResultsMean eyewash CTT (3.41 cm ± 0.464) was significantly different from ropivacaine‐treated (1.44 cm ± 0.562) (p = .008) and lidocaine‐treated eyes (1.75 cm ± 0.562) (p = .024); CTT was not significantly different between drug groups (p = .88). Time to maximum anesthesia was not significantly different between ropivacaine (13.25 min ± 3.353) and lidocaine (16.25 min ± 3.353) (p = .40). No side effects were appreciated as confirmed by SPOT.ConclusionsRopivacaine and lidocaine similarly decreased corneal sensitivity when applied topically without clinically evident short‐term ocular side effects. Lidocaine may be preferable in clinical settings due to its large, multi‐use vials and similar effects to ropivacaine.
Funder
ACVO Vision for Animals Foundation
College of Veterinary Medicine, Mississippi State University