The consequences of avian ocular trauma: histopathological evidence and implications of acute and chronic disease

Abstract

Ocular trauma can lead to profound acute and chronic lesions within the eye. Here, we provide insight into understanding ocular damage caused by trauma, which may help future studies suggest new therapeutic options and provide insight regarding the releasability of avian wildlife.

Clinical findings and normative ocular data for free‐living Anna's (Calypte anna) and Black‐chinned (Archilochus alexandri) Hummingbirds

“…Traumatic ocular pathology is most commonly reported in raptors, comprising up to 90% of ocular lesions seen in wild raptors. [25][26][27]39 Reports of ocular trauma have also included waterfowl, parrots, songbirds, chickens, hornbills, bustards, herons, roadrunners, and penguins. 27 The large size of the avian eye relative to body mass and size of the head with much of its outline lying outside the bony orbit likely predisposes it to involvement during many incidents of head trauma.…”

“…Although an important tool for studying naturally occurring ocular disease, clinical surveys of ocular disease in free-living avian populations are rarely reported. 22,23 More frequently, reports of ophthalmic findings in wild birds describe those presented to veterinary clinics and rehabilitation centers, [24][25][26][27] or selected so as to describe specific disease conditions. 28 However, findings of such studies are likely not representative of ocular disease prevalence in free-living avian populations.…”

Presumed Photoreceptor Dysplasias in Peregrine Falcons (Falco Peregrinus) and Peregrine Falcon Hybrids

“…Retinas with lateonset primary photoreceptor retinopathies (e.g., some forms of progressive retinal atrophy) have developmental abnormalities but have variable onsets of visual deficits and rates of progression. In contrast, secondary retinopathies are typically characterized by photoreceptor degeneration following normal or apparently normal photoreceptor development and differentiation (e.g., trauma, toxins, systemic disease; Narfstrom and Peterson-Jones 2013; Moore et al 2017). In contrast to primary retinopathies, there are numerous reports of secondary retinopathies across multiple avian species, including in several species of raptors (Buyukmihci et al 1988;El-Sayyad et al 2014).…”

The use of sulfur hexafluoride microbubbles for contrast‐enhanced ocular ultrasonography of the pecten oculi in birds

“…Structural detail of the pecten oculi has been elucidated in anatomical studies using scanning electron and light microscopy . However, advanced diagnostic imaging investigations (ie, optical coherence tomography—OCT) may better help to understand the precise role of the pecten oculi in normal ocular health and in disease pathogenesis . Ultrasonography (US) is a widely available, quick, and noninvasive imaging technique with multiple modalities (eg, color and pulsed Doppler ultrasonography; D‐US) that has been successfully used to investigate the pecten oculi .…”

“…10,15,22,23 However, advanced diagnostic imaging investigations (ie, optical coherence tomography-OCT) may better help to understand the precise role of the pecten oculi in normal ocular health and in disease pathogenesis. [24][25][26][27] Ultrasonography (US) is a widely available, quick, and noninvasive imaging technique with multiple modalities (eg, color and pulsed Doppler ultrasonography; D-US) that has been successfully used to investigate the pecten oculi. 7,8,28 Physiologic parameters for resistive and pulsatility indexes of the pectinate artery have been investigated using D-US in both American Pekin ducks (Anas platyrhynchos domestica) and harpy eagles (Harpia harpyja).…”