Lipoidal corneal degeneration in aged falcons

Clinical ophthalmic parameters of the Quaker parrot (Myiopsitta monachus)

PURPOSE

Ophthalmic diagnosis in many avian species remains hindered by a lack of normative values. This study aimed to establish normal ophthalmic parameters for select diagnostic tests in clinically normal Quaker parrots.

METHODS

Ninety-six captive Quaker parrots aged 8-18 years underwent ophthalmic examination to include assessment of neuro-ophthalmic reflexes, phenol red thread test, rebound tonometry, fluorescein staining, palpebral fissure length measurements, slit lamp biomicroscopy, indirect ophthalmoscopy, and ocular ultrasound biometry.

RESULTS

Menace response, dazzle reflex, and direct pupillary light reflex were present for all Quaker parrots. Tear production (mean ± SD) was 13.3 ± 4.0 mm/15 s and intraocular pressure (IOP, mean ± SD) was 10.6 ± 1.4 and 6.0 ± 1.3 mmHg in the D and P rebound tonometer calibration settings, respectively. For IOP measurement, D and P calibration settings were not interchangeable, with the lesser variation of the D setting preferred in the absence of a gold standard. Ultrasound measurement of the anterior chamber depth increased with age and males had longer axial globe and vitreous lengths. Incidental adnexal and ocular lesions, identified in 36/96 (37.5%) of Quaker parrots, did not statistically affect the created reference data.

CONCLUSIONS

This work provides reference values and clinical findings to assist with monitoring the health of wild populations and maintaining the health of captive Quaker parrots.

Transformation of electrospun Keratin/PVA nanofiber membranes into multilayered 3D Scaffolds: Physiochemical studies and corneal implant applications

In this study, we engineered an electrospun keratin/polyvinyl alcohol (PVA) nanofiber membrane with a three-dimensional (3D) fiber network. Both keratin and PVA are known as biocompatible materials, and the 3D assembly of these two led to a transparent membrane with superior mechanical properties. The as-prepared three-dimensionally assembled keratin/PVA nanofiber (3D keratin/PVA NFs) membrane was characterized by state-of-the-art techniques and used as a corneal implant in rabbit eyes. The transparency, mechanical properties, and biocompatibility of the electrospun keratin/PVA NFs were highly enhanced after 3D modification which is mainly attributed to its unique three-dimensional morphology. The performance of 3D keratin/PVA NFs membrane was compared with horse amniotic membrane (AM), and the results obtained from the clinical and histological evaluations showed that it could be considered as an alternative material to the AM. Furthermore, this study provides an emerging approach for converting a two-dimensional electrospun nanofiber membrane to three-dimensional fiber networks that resemble the structure of the extracellular matrix (ECM).

The ocular pyogranulomatous lesion in a Gentoo penguin (Pygoscelis papua) from the Antarctic Peninsula: evaluation of microbiological and histopathological analysis outcomes

In this study, it was aimed to present the results of microbiological, cytological, histopathological, and immunohistochemical analyses of ocular samples from an Antarctic (Ardley Island, King George Island) Gentoo penguin chick (Pygoscelis papua) with a pyogranulomatous lesion in the right eye. Samples were taken from both the healthy left eye and the lesion in the right eye. Conventional culture methods and phenotypic and molecular tests were used for bacterial isolation and identification, respectively. None of the isolates could be identified phenotypically. As a result, four of the five isolates obtained from the right eye were considered to belong to putative novel bacterial species and taxa as their similarity to GenBank data was below 98.75%. The isolates were considered to be Pasteurellaceae bacterium, Corynebacterium ciconiae, Cardiobacteriaceae bacterium, Actinomyces sp., and Dermabacteraceae bacterium. The only isolate from the left eye was identified as Psychrobacter pygoscelis. The cytological analysis demonstrated cell infiltrates composed mostly of degenerate heterophils, reactive macrophages, plasma cells, lymphocytes, and eosinophils. Based on histopathological findings, the lesion was defined as a typical pyogranulomatous lesion. Immunohistochemistry demonstrated that the granuloma was positive for TNF-α, IL-4, MMP-9, IL-1β, and IL-6. This is the first documented report of the unilateral pyogranulomatous ocular lesion in a Gentoo penguin chick, living in its natural habitat in Antarctica. This report also describes the isolation of four bacteria from the infected eye, which are considered to belong to novel Genus, species, or taxa. The primary bacterial pathogen that caused the ocular lesion was not able to be detected and remains unclear.

Ophthalmic Evaluation of Raptors Suffering From Ocular Trauma

Ocular problems are often associated with traumatic injury in raptors. A comprehensive evaluation, including a complete ophthalmic examination, is vital in determining the patient's overall health and suitability for release. Steps for conducting ocular examination and diagnostic testing in raptors is discussed. Additionally, common clinical findings after trauma, as well as the mechanisms by which ocular injury occurs, are outlined. An overview of medical treatments recommended for commonly diagnosed ocular diseases and the utility of ancillary diagnostic procedures is also presented.

Once in a blue moon: Lipid keratopathy and intrastromal hemorrhage in a Mission golden-eyed tree frog (Trachycephalus resinifictrix)

Mimicking natural anuran biology is a major challenge faced in the husbandry management of frogs, and the quandary of lipid keratopathy in frogs under human care has plagued keepers and practitioners for decades. Unlike corneal lipid dystrophy or lipidosis secondary to degeneration, where there is limited or no vascular in-growth or inflammatory response, lipid keratopathies are associated with vascularization, most often following the appearance of lipid. Hemorrhage from stromal neovascularization has not been described in a frog; however, the presence of vessels in lipid keratopathy certainly heralds the possibility. We report a rather unique case of lipid keratopathy in a 6-year-old female Mission golden-eyed tree frog (Trachycephalus resinifictrix) that not only had concurrent intrastromal hemorrhage, but blue plasmoid staining of the corneal stroma. Current views on both the function of blue plasma in several species and lipid keratopathy are briefly discussed. Overall, evidence suggests that the cause of lipid keratopathy is probably multifactorial and will not successfully be rectified until anuran biology and husbandry are better understood.

Ocular Surface Disease in Birds

Avian ocular disease may be primary or a manifestation of systemic disease. Various infectious and noninfectious diseases have been reported to cause ocular pathology. Thorough physical examination and diagnostic testing are necessary to determine a treatment plan.