OCULAR HEALTH ASSESSMENT, TEAR PRODUCTION, AND INTRAOCULAR PRESSURE IN THE ANDROS ISLAND IGUANA (CYCLURA CYCHLURA CYCHLURA)

Abstract

The purpose of this study was to assess the ocular health of a wild population of Andros Island iguanas (Cyclura cychlura cychlura) and determine reference values for tear production and intraocular pressure (IOP) for this species. Fifty-two iguanas, 20 males and 32 females, ranging in size from 11.1- to 51.0-cm snout-to-vent length (SVL), were included in the sample set, with measurements obtained from each eye. No abnormalities were found on ophthalmic examination, with the exception of mild, focal chemosis in one individual and periocular ticks in 52% of iguanas. Tear production was measured using the phenol red thread test, and IOP was measured using the TonoVet rebound tonometer set on the P (undefined species) setting. No significant difference was found between males and females for either measurement. No significant difference was found between right and left eyes for intraocular pressure; however, a significant difference was found between eyes for tear production values. The mean (+/- SD) of IOP in the left and right eyes were 4.77 +/- 1.88 mm Hg and 5.12 +/- 2.52 mm Hg, respectively, with a range of 1-11 mm Hg. The mean (+/- SD) of tear production in the left and right eyes were 10.63 +/- 6.89 mm/15 sec (range 1-28 mm/15 sec) and 12.44 +/- 7.52 mm/15 sec (range 1-23 mm/15 sec), respectively. A positive correlation was found between SVL and all ocular parameters measured. This study provides an assessment of ocular health, as well as baseline values for IOP and tear production, in the Andros Island iguana.

Modified Schirmer tear test and rebound tonometry in blue-fronted Amazon parrot (Amazona aestiva)

“…Fluctuations in tear production are documented to be influenced by age, time of year, time of day and environmen-tal conditions (Wojick et al 2013). In this study, tests were performed under the same conditions and time of year.…”

“…Studies comparing rebound tonometry and a manometer showed that, in some birds, IOP was overestimated, while it was underestimated in others. However, even with these variations, the values obtained are considered useful for clinical application (Jeong et al 2007, Reuter et al 2010, Wojick et al 2013. To minimize such oscillations, it is suggested that a single method be used for a particular species (Meekins et al 2015).…”