Measurement of tear production using phenol red thread and standardized endodontic absorbent paper points in European pond turtles (Emys orbicularis).

Abstract

The objective of this study was to determine the aqueous fraction of the tear film using the phenol red thread test (PRTT) and paper point tear test (PPTT) in healthy adult European pond turtles (Emys orbicularis). Twenty-four healthy adult European pond turtles were studied. Measurement of tear secretion was performed using the PRTT and standardized endodontic absorbent PPTT. Horizontal palpebral fissure length (HPFL) was measured using digital calipers and was correlated with the weight of the animal. The mean ± SD PRTT, PPTT, and HPFL values for the left and right eyes were 5.12 ± 1.54 mm/15 sec and 4.62 ± 1.76 mm/15 sec; 4.50 ± 1.25 mm/1 min and 4.20 ± 1.53 mm/1 min; and 8.4 ± 0.6 mm and 8.3 ± 0.6 mm, respectively. No significant differences were detected between right and left eyes of individual turtles or between males and females in all tests. This study represents reference values of tear production in European pond turtles obtained from PRTT and PPTT methods and forms an important baseline study in defining the healthy chelonian ocular surface.