The Eye of the Largest Forest Raptor, the Harpy Eagle (Harpia harpyja): Morphologic Observations and Reference Values for Selected Ophthalmic Tests.

Abstract

OBJECTIVE: To carry out a descriptive investigation of the most relevant morphological features of the harpy eagle eye and to provide normative data for selected ophthalmic diagnostic tests. ANIMALS STUDIED: Twenty-nine clinically normal harpy eagles (Harpia harpyja). PROCEDURES: Selected morphological ocular observations were made in live animals under physical restraint: Schirmer tear test (STT), culture of normal conjunctival flora, slit lamp biomicroscopic examination of adnexa and anterior segment, rebound tonometry, applanation tonometry, central corneal thickness (CCT), palpebral fissure length (PFL), B-mode ultrasound, and ocular biometry. Eyelid histology was evaluated from previously deceased individuals. RESULTS: STT type I 17.48 ± 5.476 mm/min; Rebound tonometry 14.00 IQR 4.00 mmHg; Applanation tonometry 15.00 IQR 6.00 mmHg; CCT 0.563 ± 0.041 mm; PFL 26.42 ± 2.13 mm; Axial globe length 29.43 IQR 0.42 mm; Anterior chamber depth 5.00 IQR 0.22 mm; Axial length of the lens 6.60 IQR 0.97 mm; Vitreous chamber depth 16.50 IQR 0.80 mm, and pecten length 8.80 IQR 1.47 mm. The conjunctiva of the lower eyelid has a distinct cartilaginous plate adjacent to the conjunctival epithelium. The most frequent conjunctival bacterial isolates were E. coli (32.76%) followed by Enterobacter spp. (15.52%) and Streptococcus spp. (10.34%). CONCLUSION: Reference data and morphologic observations obtained in this investigation might aid in the understanding and diagnosis of eye diseases in harpy eagles and improve the clinical management of ocular disease.