Tear production and intraocular pressure values in captive lizards Pogona Vitticeps

Purpose: To determine reference values for tear production and intraocular pressure (IOP) in Pogona vitticeps. Methods: Eighteen healthy, captive Pogona vitticeps of both sexes, average age of 30.6 months (range 20–49 months) were enrolled in the study. All animals underwent a physical examination. Slit-lamp biomicroscopy and indirect ophthalmoscopy with 78-diopter lens were performed in both eyes. Tear production was measured by the Phenol Red Thread test (PRTt) OU. IOP was bilaterally assessed by rebound tonometry (Tonovet"). Ophthalmic parameters were evaluated immediately after each animal was pulled out of the terrarium. Snout-to-vent length (SVL) was measured for each animal. To test for differences between sexes, and left and right eye, a Mann-Whitney test and a two-sample t-test were used in PRTt and IOP, respectively. A Spearman test was used to verify correlations between SVL and PRTt, and Pearson test to verify IOP. Data were expressed as mean+/-SEM. Results: no ocular abnormalities were observed. SVL was 19.75 +/- 0.44 cm (range 16–24 cm). PRTt values in the left and right eyes were 5.61 +/- 0.52 mm/15 s (range 3–10 mm/15 s) and 5.50 +/- 0.51 mm/15 s (range 2–10 mm/15 s), respectively. IOP values in the left and right eyes were 3.29 mmHg +/-0.15 mmHg (range 2–4.33 mmHg) and 3.50 +/- 0.14 mmHg (range 2.66– 4.66 mmHg), respectively. No significant differences were detected between sexes, left and right eyes for both intraocular pressure and tear production. No correlation was found between SVL and the two ocular parameters measured. Conclusions: This study provides reference values for tear production and IOP in the Pogona Vitticeps.