Normal variation in, and effect of 2% pilocarpine on, intraocular pressure and pupil size in female horses.
Abstract: To determine normal variation in, and effect of 2% pilocarpine hydrochloride on, intraocular pressure (IOP) and pupil size in female horses during a specified period. Methods: 10 female horses with normotensive eyes. Methods: IOP and horizontal and vertical pupil size were measured on a single day between 8 AM and 8 PM at hours 0, 0.5, 1, 2, 4, 6, 8, 10, and 12. Measurements were repeated after single- dose application of 2% pilocarpine to both eyes. IOP and pupil size were measured at 8 AM and noon in a 5-day experiment of twice-daily application of 2% pilocarpine. Results: Variation in IOP and pupil size was not significant between 8 AM and 8 PM. Change in IOP or pupil size after a single dose of 2% pilocarpine also was not significant. In the multiple-dose experiment, the IOP at noon on the fifth day was significantly higher than the IOP in the morning on the first and second days. The IOP in the morning on the fifth day was significantly higher than the IOP in the morning and at noon on the first and second days. The IOP at noon on the fourth day was significantly higher than the morning IOP on the first and second days and at noon on the first day. The decrease in vertical pupil size was significant. Conclusions: Between 8 AM and 8 PM, variation in IOP and pupil size in normotensive eyes of horses is not significant. Two percent pilocarpine does not significantly change IOP between 8 AM and 8 PM in clinically normal horses after a single dose or multiple twice-daily applications. After multiple twice-daily applications, a trend toward an increase in IOP was seen, and the decrease in vertical pupil size was significant.
Publication Date: 1998-11-26 PubMed ID: 9829407
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- Journal Article
Summary
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This research paper investigates the variation in intraocular pressure (IOP) and pupil size in normal female horses, as well as the effect of 2% pilocarpine hydrochloride on these parameters. It was found that the variation in IOP and pupil size was not significant during a set time frame and that a single dose of 2% pilocarpine did not significantly change these parameters. However, after multiple daily applications of 2% pilocarpine, a trend towards increased IOP was observed while the decrease in the vertical size of the pupil was significant.
Study Methodology
- The study involved 10 female horses with normotensive eyes (regular eye pressure).
- Intraocular Pressure (IOP) and horizontal and vertical pupil sizes were measured in these horses from 8 AM to 8 PM at specific time intervals (0, 0.5, 1, 2, 4, 6, 8, 10, and 12 hours).
- This set of measurements was then repeated after introducing a single dose application of 2% pilocarpine hydrochloride into both eyes.
- A second experiment involved the application of 2% pilocarpine twice daily for five days. Measurements of IOP and pupil size were taken at 8 AM and noon during this phase of the study.
Findings of the Study
- The natural variation in IOP and pupil size between 8 AM and 8 PM was found to be insignificant.
- This regularity was not significantly affected after the application of a single dose of 2% pilocarpine.
- In the multiple-dose experiment, the IOP at noon on the fifth day was significantly higher than the IOP in the morning on the first and second days.
- The IOP in the morning on the fifth day was significantly higher than the IOP in the morning and at noon on the first and second days.
- The IOP at noon on the fourth day was also significantly higher than the morning IOP on the first and second days and at noon on the first day.
- The decrease in the vertical size of the pupil after multiple applications of 2% pilocarpine was significant.
Conclusion
- The natural variation in IOP and pupil size in horses between 8 AM and 8 PM is not significant.
- A single dose of 2% pilocarpine does not significantly change these parameters during the same time frame.
- However, after multiple twice-daily applications of 2% pilocarpine, an increasing trend was seen in IOP and a significant decrease was noted in the vertical size of the pupil.
Cite This Article
APA
van der Woerdt A, Gilger BC, Wilkie DA, Strauch SM, Orczeck SM.
(1998).
Normal variation in, and effect of 2% pilocarpine on, intraocular pressure and pupil size in female horses.
Am J Vet Res, 59(11), 1459-1462.
Publication
Researcher Affiliations
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210, USA.
MeSH Terms
- Animals
- Circadian Rhythm
- Drug Administration Schedule / veterinary
- Drug Evaluation / veterinary
- Female
- Horses / physiology
- Intraocular Pressure / drug effects
- Parasympathomimetics / administration & dosage
- Parasympathomimetics / pharmacology
- Pilocarpine / administration & dosage
- Pilocarpine / pharmacology
- Pupil / drug effects
Citations
This article has been cited 1 times.- Von Zup M, Lassaline M, Kass PH, Miller PE, Thomasy SM. Effects of 0.2% brimonidine and 0.2% brimonidine-0.5% timolol on intraocular pressure and pupil size in normal equine eyes.. Equine Vet J 2017 Nov;49(6):810-814.
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