[Macrophthalmos mimics microphthalmos in an 8-month-old Great Swiss Mountain Dog]

An 8-month-old Great Swiss Mountain dog was presented with a suspected right-sided microphthalmos, malformed and blind globe which was present since birth. On magnetic resonance imaging an ellipsoid macrophthalmos with absence of the normal retrobulbar tissue was detected. Histology revealed a dysplastic uvea with unilateral cyst formation associated with mild lymphohistiocytic inflammation. The ciliary body covered the posterior side of the lens unilaterally and showed focal metaplastic bone formation. Slight cataract formation as well as diffuse panretinal atrophy and intravitreal retinal detachment was evident. Preoperative diagnostic imaging procedure is recommended in eyes that clinically demonstrate as microphthalmos and are planned to be enucleated. As described in this case report the bulbus may be macrophthalmic which potentially complicates the enucleation. The performance of such a procedure at a site with ophthalmologic and soft tissue expertise is advisable. To the authors' knowledge this is the first report of a macrophthalmos with multiple ocular defects in a dog.

Self-limiting Orbital Emphysema Following Ocular Evisceration and Demonstration of Nasolacrimal-Oropharyngeal Communication in a South African Ostrich (Struthio camelus australis)

A 25-year-old, male, sanctuary-owned, South African ostrich (Struthio camelus australis) was evaluated for orbital emphysema after evisceration of a nonvisual and chronically irritated eye. On initial ophthalmic examination, the ostrich's left eye displayed severe corneal fibrosis, broad anterior synechia, and a shallow anterior chamber, all suggestive of a previous corneal perforation. Conjunctival hyperemia and eyelid crusts were also present, reportedly associated with chronic rubbing. Evisceration of the left eye was performed by excising the eyelid margins, conjunctiva, nictitans, cornea, and intraocular contents. Four weeks postoperatively, a nonpainful, fluctuant swelling of the surgical site was noted. Trocarization of the surgical site verified orbital emphysema and served to temporarily decompress the orbit. Orbital emphysema reoccurred within 48 hours but gradually regressed without intervention over the subsequent 9 months. A Jones test was performed in the healthy, right eye and demonstrated clear communication to the oropharynx. To our knowledge, this is the first reported case of an evisceration performed on an ostrich and the first reported case of orbital emphysema in any avian species. It is probable that the emphysema noted in this case was secondary to nasolacrimal duct-oropharynx communication.

Viability of in vitro preserved sperm of Harris's hawk (Parabuteo unicinctus)

Harris hawks (Parabuteo unicinctus) are the raptors with more anthropogenic use, which makes it necessary to improve their reproduction either natural or assisted for sustainable use even though they are not endangered. The aim of this study was to determine fresh and thawed P. unicinctus sperm capacitation and acrosome reaction parameters as indicators of sperm viability in ejaculates of birds with injuries. A total of 30 ejaculates were analyzed as fresh and thawed samples. Basic sperm evaluations as well as in vitro acrosomal reaction capability through the presence and distribution of Ca²⁺ and N-acetylglucosamine and sialic acid using chlortetracycline and agglutinin-fluorescein isothiocyanate Triticum vulgaris were performed, respectively. Tagged samples were observed using epifluorescence microscopy. The results indicated 30.00% decrease in sperm viability following freeze-thaw, while rate of capacitated sperms (10.00%) and the percentage of sperm with acrosomal reaction (40.00%) were increased. The results of the experiment demonstrated that the post-thaw viability of the obtained sperm may be an alternative for use in artificial insemination.

Ocular Iridociliary Adenoma in a Congo African Grey Parrot (Psittacus erithacus)

A 19-year-old female Congo African grey parrot (Psittacus erithacus) presented for an oval, solid, pigmented, suspected intraocular mass with extrascleral extension through the inferior cornea of the left eye. The eye was nonvisual, and intraocular portions of the mass significantly altered the posterior chamber. Neoplasia was confirmed by biopsy, and enucleation was performed because of the severity of ocular disease, loss of vision, enhancement of patient comfort, and potential metastasis. Histopathologic examination of the entire globe revealed a pigmented iridociliary adenoma. Iridociliary adenomas have been rarely reported in birds, and this case report details diagnosis and treatment. Iridociliary adenomas in other species are often benign, indicating this neoplasia can be successfully treated with no reoccurrence by complete excision.

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.

Successful chemical ablation of an intraorbital cyst caused by an eyelid injury and iatrogenic ankyloblepharon formation in a duck

CASE DESCRIPTION A client-owned 2-year-old 1.8-kg (4-lb) male pet Rouen duck (Anas platyrhynchos domesticus) was evaluated because of severe swelling around the left eye following traumatic injury to the upper and lower eyelids and 2 associated surgeries that resulted in the removal of the entire upper and lower eyelid margins. CLINICAL FINDINGS At initial evaluation, ankyloblepharon of the left eye was observed, with no upper or lower eyelid margins and a large, round, fluctuant subcutaneous mass over the left orbit. Orbital exploration and histologic examination revealed a benign cyst consisting of fibrous tissue, conjunctiva, and skeletal muscle bundles. Bacterial culture of cystic fluid yielded few Staphylococcus delphini. TREATMENT AND OUTCOME Excision of the cyst and evisceration of the left globe were performed, and once daily treatment with orally administered enrofloxacin suspension (12.6 mg/kg [5.7 mg/lb]) and meloxicam (1 mg/kg [0.45 mg/lb]) was initiated. Over the next 4 days, the cyst redeveloped and progressively enlarged. Accumulated fluid was aspirated from the cyst, and 20 mg of gentamicin was injected intraorbitally with ultrasound guidance. Over the subsequent 27-month period, no recurrence of clinical signs or adverse effects were reported by the owner. CLINICAL RELEVANCE To the authors' knowledge, this is the first report of cyst formation after adnexal injury and evisceration in birds and its successful treatment with intralesional gentamicin injection. Findings emphasized the importance of preserving lacrimal puncta during adnexal or eye removal surgeries in birds. Intralesional injection of gentamicin with the goal of destroying fluid-producing cells may be a safe and effective way to treat intraorbital cysts in birds and other species, although additional research would be required to confirm this.

Retinal transcriptome sequencing sheds light on the adaptation to nocturnal and diurnal lifestyles in raptors

Owls (Strigiformes) represent a fascinating group of birds that are the ecological night-time counterparts to diurnal raptors (Accipitriformes). The nocturnality of owls, unusual within birds, has favored an exceptional visual system that is highly tuned for hunting at night, yet the molecular basis for this adaptation is lacking. Here, using a comparative evolutionary analysis of 120 vision genes obtained by retinal transcriptome sequencing, we found strong positive selection for low-light vision genes in owls, which contributes to their remarkable nocturnal vision. Not surprisingly, we detected gene loss of the violet/ultraviolet-sensitive opsin (SWS1) in all owls we studied, but two other color vision genes, the red-sensitive LWS and the blue-sensitive SWS2, were found to be under strong positive selection, which may be linked to the spectral tunings of these genes toward maximizing photon absorption in crepuscular conditions. We also detected the only other positively selected genes associated with motion detection in falcons and positively selected genes associated with bright-light vision and eye protection in other diurnal raptors (Accipitriformes). Our results suggest the adaptive evolution of vision genes reflect differentiated activity time and distinct hunting behaviors.

Eye Removal Surgeries in Exotic Pets

This article covers considerations and techniques of eye removal surgeries in exotic pets. After issues including surgical indications, anesthesia, patient preparation, and instrumentation are explored, surgical techniques are described. Enucleation/exenteration and modified evisceration are discussed, with species-specific nuances of small mammals, birds, reptiles, snakes, amphibians, and fish highlighted.