Evaluation of intraocular pressure in conscious Hermann's tortoises (Testudo hermanni) by means of rebound tonometry

Abstract

Rebound tonometry was a practical and rapid means of determining IOP in small- to medium-sized tortoises that required minimal manual restraint of the animals. Establishing IOP values in healthy Hermann's tortoises will provide a reference frame for use during complete ophthalmic examinations, thus allowing clinicians to diagnose a broader spectrum of ocular pathological conditions in tortoises.

The eye of the red‐eared slider turtle: morphologic observations and reference values for selected ophthalmic diagnostic tests

“…Intraocular pressure in wild animals has previously been evaluated using indentation tonometry and applanation tonometry and rebound tonometry . Few studies about IOP in reptiles, especially testudine species, were reported in the literature . Specifically, in red‐eared slider turtles, there is only one study reporting this parameter .…”

“…The available literature focuses on ocular diseases, pathophysiologic mechanisms and clinical treatments . Some available studies with reptile species also report normal ophthalmic parameters and selected clinical tests . Normal values for rebound tonometry and tear production have been reported for red‐eared slider turtles.…”

Evaluation of rebound tonometry in red‐eared slider turtles (Trachemys scripta elegans)

“…The other needle was connected to a pressure transducer (NL108T2 Disposable Physiological Pressure Transducer, Warner Instruments, Hamden, CT) and continuous physiologic recorder (Dash â 4000 Pro, GE Healthcare, Milwaukee, WI) allowing IOP to be verified and continuously recorded. Triplicate TonoLab â followed by TonoVet â readings were acquired as described below, by the same observer (CD) at 5,10,15,20,25,30,35,40,50,60,70, and 80 mmHg for each eye.…”

“…[11, 12, 14, 19] Although TonoVet® rebound tonometry was recently described in tortoises,[10] the accuracy of these readings, when compared to true IOP as measured by a manometer and the effects of manual and chemical restraint on IOP, have not been evaluated in any reptile species. The purpose of this study was to evaluate the ability of two rebound tonometers, the TonoVet® and TonoLab®, to estimate IOP in adult red-eared slider turtles using different methods of manual and chemical restraint and to compare IOP estimates obtained with these two devices to a manometer.…”

“…[1][2][3][4] Normal mean intraocular pressure (IOP) values have been reported for a number of healthy, conscious and chemically restrained exotic and wild animal species. [5][6][7][8][9] While limited information is available on IOP in some terrestrial reptile species, 10 in aquatic freshwater turtles, such as red-eared slider turtles, normal IOP values have not been reported [11][12][13][14] and ocular anatomy and normal ophthalmic reference data for this species are scarce. However, the establishment of normal physiological ophthalmic parameters, such as IOP, is critical for accurately diagnosing ophthalmic disease in any species.…”