Effect of topical cyclopentolate alone or combined with phenylephrine in healthy horses

Abstract

Objective Evaluate the effect of repeated doses of topical 1% cyclopentolate hydrochloride alone and in combination with topical 2.5% phenylephrine on pupil diameter (PD), tear production (STT‐1), intraocular pressure (IOP), digestive function (gut motility and feces production), and heart rate (HR). Animal studied: Six healthy mares. Procedures In a prospective, randomized, controlled, and crossover design study, the left eye of six healthy mares was administered 0.2 mL of cyclopentolate alone and in combination with 0.2 mL of phenylephrine. The drugs were administered 3 times a day for 1 day, twice a day for 1 day, and then once a day for 2 days, as commonly used in practice. Daily and two days after the last topical drug administration, HR, digestive auscultation, feces production, STT‐1, IOP, and PD were recorded. Results The cyclopentolate alone significantly increased the horizontal and vertical PD of the treated eye from day 2 to day 6 (p < .0001) compared with the baseline value. The combination with topical phenylephrine did not have any additional effect on mydriasis compare with the cyclopentolate alone. The other ocular and digestive parameters were not affected by repeated doses of cyclopentolate alone or combined. Conclusions Repeated administration of cyclopentolate alone or combined with phenylephrine induce a significant mydriasis for at least 48 h after the last administration in normal horses’ eyes, and do not affect STT‐1, IOP, digestive function, and HR. The phenylephrine combined with the cyclopentolate did not potentiate the pupil dilation when compared with cyclopentolate alone in healthy horses.

Medical Management versus PACK-CXL in Dogs with Infectious Keratitis: A Randomized Controlled Trial Protocol

“…Based on this study design, a cause-and-effect relationship between an intervention and disease outcome can be established [ 44 ]. According to a literature search (all publication abstracts and titles were screened), five randomized controlled trials [ 45 , 46 , 47 , 48 ] were published in the Journal of Veterinary Ophthalmology in 2021, out of 80 clinical studies (short reports and reviews were excluded). Information regarding study design, such as sample size calculation or masking, was missing in some publications.…”