Veterinary clinical trial at AERC event

Intraocular Pressure Measurement in Equine Athletes during Endurance Competitions

In humans, continuous strenuous exercise has been shown to decrease pressure within the eye (intraocular pressure); however, no study has evaluated the effect of exercise on intraocular pressure in horses. With extensive documentation of normal equine intraocular pressure (15-30 mm Hg) and the knowledge of intraocular pressure changes in humans during exercise, we are evaluating elite equine athletes for similar changes. The objective of this investigation is to document the intraocular pressure of equine eyes prior to, during, and immediately after endurance competitions (50 miles) to determine the normal intraocular pressure of conditioned equine athletes and to document change during exercise. A second objective is to identify intraocular pressure differences between horses who successfully complete competition and those that are removed from competition due to exhaustion to determine if intraocular pressure is predictive of exhaustion. Our hypothesis is that continuous exercise will result in reduced intraocular pressure in the eyes of horses during endurance competitions, and the magnitude of change will represent an objective measure predictive of physical exhaustion.

Tonometry is the measurement of intraocular pressure and is a routine part of both human and animal ocular examinations. In this study, intraocular pressure will be measured with a portable TonoVet® rebound tonometer. This rapid, simple, noninvasive device allows reliable measurements to be obtained from horses in a normal standing position. Most horses are amenable to intraocular pressure measurement with this device due to the small probe size (1 mm) and brief corneal contact time. Following riders’ permission, cursory eye examinations will be performed on each horse participating in the study during the pre-ride examination and baseline intraocular pressure readings will be obtained. Intraocular pressure measurements will also be acquired at the intermediate vet checkpoints and at the post-ride examination. Measurements will not add significant time to the checkpoint as intraocular pressure can be measured while a horse and rider are waiting in line or immediately afterwards, as preferred by the rider. Veterinary cards will be scanned so that pertinent data from each horse can be logged with the intraocular pressure measurements for correlation between horses who complete competition and those who do not.

This investigation will generate data regarding the intraocular pressure status of horses participating in endurance competitions. The results may also identify intraocular pressure as an easily measured, objective measure of exhaustion that could change the way horses are assessed during competition and ultimately help to reduce the number of injuries during endurance rides, therefore benefitting endurance horses and endurance horse riding.

Please do not hesitate to contact us with any questions or concerns regarding this study!

Sincerely,
Rachel Allbaugh, DVM, MS
Board-Certified Veterinary Ophthalmologist
Assistant Professor, Kansas State University
mobile phone 785-410-5560

Susan Keil, DVM, MS,
Board-Certified Veterinary Ophthalmologist
AERC Board of Directors
mobile phone 913-233-9098
Board-Certified Veterinary Ophthalmologist