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

Abstract

To perform a descriptive investigation of the red-eared slider turtle (Trachemys scripta elegans) eye, performing selected ophthalmic diagnostic tests with the aim of establishing normal reference values for this species. Thirty adult healthy red-eared slider turtles were used to establish normal ophthalmic test values in this investigation. Selected ophthalmic tests included: collection of material for bacterial culture analysis, esthesiometry, intraocular pressure (IOP), A- and B-mode ultrasonic biometry, fundus photography, and central corneal thickness (CCT). Normal parameters found for the ocular diagnostic tests were: esthesiometry: 5.84±0.48cm; IOP: 5.42±1.70mmHg; CCT: 154.5±0.14μm; palpebral fissure length: 9.71±0.55mm; modified Schirmer tear test: 2.55±3.4mm; globe axial length: 7.60±0.23mm; anterior chamber depth: 0.76±0.23mm; lens axial length: 2.45±0.28mm; vitreous chamber depth: 4.31±0.42mm. An avascular retinal pattern with nerve fibers radiating from the small white circular optic disk was observed. None of the animals had a conus papillaris. The most frequent bacteria found were Bacillus spp. (33.33%) followed by Proteus vulgaris (20.69%) and Staphylococcus aureus (18.39%). No significant differences between left and right eyes or genders were found for any of the results. Reference data and morphologic observations obtained in this investigation might help veterinary ophthalmologists to diagnose ocular diseases in the red-eared slider turtle.