Ophthalmic parameters of Blue-and-yellow Macaws (Ara ararauna) and Lear's Macaws (Anodorhynchus leari)

Our aim was to determine the ophthalmic parameters and describe the eye histology of Blue-and-yellow Macaws (Ara ararauna) and Lear's Macaws (Anodorhynchus leari) kept at the Triage Center for Wild Animals (CETAS) and in Getulio Vargas Zoobotanic Park (Salvador, northeastern Brazil), respectively. Thirty four clinically healthy macaws (28 Blue-and-yellow Macaws and six Lear's Macaws) were studied. The investigation included culture of the conjunctival bacterial flora, evaluation of tear production by endodontic absorbent paper point tear test (EAPPTT) and phenol red thread test (PRTT), measurement of palpebral fissure length (PFL), corneal touch threshold (CTT) and intraocular pressure (IOP), as well as characterisation of conjunctival cytology samples, B-mode ultrasonography, and eye histology of one Blue-and-yellow Macaw. There was a predominance of Gram-positive bacteria in the samples analysed and the microorganism colonies were resistant to tetracycline and oxacillin. Blue-and-yellow Macaws had significantly higher EAPPTT than Lear's Macaws, but there were no differences in PFL and IOP. Conjunctival cytology revealed predominance of squamous and columnar epithelial cells. The pecten, a pleated structure located on the optic nerve and projecting into the vitreous, was composed of several large blood vessels and capillaries. The ophthalmic parameters determined in this study may help in the diagnosis of ocular diseases in Blue-and-yellow and Lear's Macaws.