Ophthalmic parameters in adult lowland paca (Cuniculus paca) raised in captivity

Objective To investigate the ophthalmic parameters of lowland pacas, including the anatomic features, tear production, intraocular pressure, central corneal thickness, and morphology of the corneal endothelium. Animals studied Thirteen adult, anesthetized Cuniculus paca. Procedure Eyes were evaluated using slit-lamp biomicroscopy, the Schirmer tear test I, digital applanation tonometry, binocular indirect ophthalmoscopy, and noncontact specular microscopy. Results The biomicroscopy findings showed blue/brown pigmented bulbar conjunctivae, well-developed cilia (only in the upper eyelid margin), superior and inferior lacrimal puncta, brown irides, round pupils, and vestiges of the nictitating membrane. The results of the Schirmer tear test I revealed (mean +/- SD) a lacrimation rate of 4.10 +/- 0.44 mm/min. The intraocular pressure was 6.34 +/- 0.43 mmHg. Central corneal thickness measured by specular microscopy was 0.35 +/- 0.01 mm. The mean values of density, hexagonality, and the area of the endothelial cells were 2083.15 +/- 42.47 cells/mm(2), 67.07 +/- 3.30%, and 486.30 +/- 9.56 m(2), respectively. Conclusions The ocular parameters defined in this study may be used for reference in future studies and might also contribute to therapeutic approaches appropriate to this species.