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

Objective To describe and to establish normative data for the foveae of diurnal birds of prey using spectral‐domain optical coherence tomography (SD‐OCT). Methods All animals (9 red‐tailed hawks, 3 Cooper's hawks, 3 American kestrels, 1 sharp‐shinned hawk, and 1 broad‐winged hawk) had an ophthalmic examination performed with slit lamp biomicroscopy and indirect ophthalmoscopy. Following ophthalmic examination, SD‐OCT was performed in each eye that had a visible fundus and normal fovea on SD‐OCT. Temporal foveae depth, central foveae depth, pecten‐temporal foveae distance, and pecten‐central foveae distance (PCFD) were measured using SD‐OCT. Differences in measured outcomes between species were determined using generalized linear mixed effects models. Results The central foveae (mean ± SD) displayed a small but significant depth variation between species (P = .002) and was deepest in red‐tailed hawks (293 ± 16 µm), followed by American kestrels (260 ± 12 µm), broad‐winged hawks (256 ± 16 µm), Cooper's hawks (250 ± 9 µm), and sharp‐shinned hawks (239 ± 16 µm). The temporal foveae were shallower than the central foveae in all species tested, and there was a significant variation between species (P < .001). The temporal foveae (mean ± SD) were deepest in American kestrels (137 ± 8 µm), followed by red‐tailed hawks (129 ± 3 µm), broad‐winged hawks (59.5 ± 3.5 µm), Cooper's hawks (20.3 ± 6.4 µm), and sharp‐shinned hawks (17.5 ± 0.7 µm). Pecten‐temporal foveae distance was approximately 30% shorter than PCFD in all species. There were no differences in the parameters tested between the eyes within each species (P ≥ .47). Conclusion Normative foveae SD‐OCT data were obtained in four species of diurnal birds of prey. Further studies are warranted to provide structural and functional information regarding normal and pathologic changes that can affect the foveae.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spectral‐domain optical coherence tomography imaging of normal foveae: A pilot study in 17 diurnal birds of prey

Gomes

Abou‐Madi

Ledbetter

et al. 2020

“…Reports of normative reference values for standard ophthalmic diagnostic tests in various avian species reveal wide species variation 10–36 . Normative measurements of the psittacine eye are limited to intraocular pressures of the budgerigar ( Melopsittacus undulatus ) and ring‐necked parakeet ( Psittacula krameri ) , while tear production and ocular ultrasound biometric values are reported for Amazon parrots ( Amazona aestiva ) 37,38 .…”

Section: Introductionmentioning

confidence: 99%

Clinical ophthalmic parameters of the Quaker parrot (Myiopsitta monachus)

Halsmer

Heatley

Scott

2022

PurposeOphthalmic 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.MethodsNinety‐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.ResultsMenace 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.ConclusionsThis work provides reference values and clinical findings to assist with monitoring the health of wild populations and maintaining the health of captive Quaker parrots.

“…The avian eye has several distinctive anatomical and physiologic features when compared to the eyes of other vertebrate taxa . A large variability in eye shape, mechanisms of both lenticular and corneal accommodation, variable numbers and positions of retinal specializations, and the presence of the pecten oculi are among the most conspicuous features . The pecten oculi is of particular interest as there is currently no consensus for its most important physiologic role .…”

Section: Introductionmentioning

confidence: 99%

“…1 A large variability in eye shape, mechanisms of both lenticular and corneal accommodation, variable numbers and positions of retinal specializations, and the presence of the pecten oculi are among the most conspicuous features. [1][2][3][4][5] The pecten oculi is of particular interest as there is currently no consensus for its most important physiologic role. [6][7][8] It is a pigmented and highly vascularized intraocular structure projecting anteriorly from the optic disk into the vitreous body.…”

Section: Introductionmentioning

confidence: 99%

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

Ferreira¹,

Fornazari²,

Saldanha³

et al. 2018

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