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Objective: To evaluate the postoperative visual outcome and complications of 25-gauge pars plana vitrectomy (PPV) via a lateral approach without proptosis of the globe in dogs., Procedures: We reviewed the medical records of dogs diagnosed with giant rhegmatogenous retinal detachment (RRD) at Yokohama Animal Eye Clinic from 2016 to 2019 and treated by 25-gauge PPV. Medical records included signalment, follow-up time, etiology and duration of RRD, angle between the outermost trocar ports, immediate postoperative anatomic success rate, pre- and postoperative visual status, and postoperative complications., Results: Seventy-two dogs (78 eyes, 13 breeds) were included. The most common breed was the Toy Poodle (48.6%), and the mean follow-up time was 690.6 days. The most common etiology of RRD was cataract surgery (46.2%). The mean angle between the outermost trocar ports was 71.4º. Immediate postoperative anatomic success was noted in all eyes. Vision was regained or maintained in 87.2% of eyes, and the mean time to return of vision was 28.5 days. Maintenance of vision until the last known follow-up was noted in 73.5% of eyes. The most common postoperative complication was glaucoma (40.3%), and glaucoma was the most common etiology of postoperative vision loss (88.9%)., Conclusion: Twenty-five gauge PPV via a lateral approach without proptosis of the globe is a successful method for treating canine giant RRD., (© 2021 American College of Veterinary Ophthalmologists.)

Purpose: Retrospectively evaluate prognostic indicators and outcome in dogs undergoing temporary tarsorrhaphy following traumatic proptosis., Methods: Medical records (2004-2017) were reviewed for signalment, cause and duration of proptosis, and clinical findings on admission. The operating faculty member, post-operative medications, and ophthalmic findings at last recheck were recorded. Owners of dogs with blinded eyes were surveyed regarding final outcome and satisfaction. Data were analyzed using Fisher's exact, Likelihood ratio, and Mann-Whitney tests., Results: At last recheck, 17.5 ± 7.3 (mean ± SD) days post-operatively, vision was present in 12/43 eyes (28%). Vision at last recheck was not correlated with breed, cause or duration of proptosis, or post-operative medications (P > .05), but was correlated with presence of direct and indirect pupillary light reflexes (PLRs) on admission (P = .001 and .02, respectively), and with assessment and surgery performed by veterinary ophthalmologists rather than surgery or emergency personnel (P = .015). Mean satisfaction scores (graded 0-10) of 22 owners contacted 59.6 ± 48.2 months after last recheck were 7.8 ± 2.6 (n = 6), 5.7 ± 4.9 (n = 3), and 8.8 ± 1.3 (n = 13) for dogs with phthisical eyes, eyes requiring long-term medications, and blind but otherwise normal eyes, respectively (P = .284)., Conclusions: Contrary to previous studies, breed, and cause and duration of proptosis, did not significantly affect outcome. Testing of direct and indirect PLR is a simple and significant prognostic indicator. Patients assessed and operated by a veterinary ophthalmologist have better prognosis., (© 2019 American College of Veterinary Ophthalmologists.)

Case Description: A 5.5-year-old neutered male mixed-breed dog was presented for evaluation of a 5-month history of deviation of the right globe upon opening the mouth and a 1-month history of conjunctivitis in the same eye. Clinical findings, diagnostic imaging results, treatment and follow-up are described., Clinical Findings: When the mouth was opened, the right globe deviated rostrally and laterally. There was no pain or resistance to opening the mouth, or resistance to retropulsion of the globe. No other abnormalities were observed. Computed tomography was performed, revealing a contrast-enhancing region associated with the right masseter muscle impinging into the right orbit; this was more pronounced with the mouth open. Cytology revealed a small number of mildly to moderately atypical mesenchymal cells. Histopathology was consistent with polyphasic myositis, with a predominance of lymphocytes and plasma cells. No infectious agents were identified. Serum antibody titers for Toxoplasma gondii and Neospora caninum were negative. Serum titers for 2 M antibody were positive at 1:500, consistent with a diagnosis of masticatory muscle myositis., Treatment and Outcome: Therapy with prednisone was initiated. During a follow-up period of 5 months, there was no recurrence of clinical signs, and the dose of prednisone was reduced by 25%., Clinical Significance: To the authors' knowledge, this is the first reported case of masticatory muscle myositis causing dynamic exophthalmos and strabismus in a dog., (© 2015 American College of Veterinary Ophthalmologists.)

A 13-year-old cob mare was presented with exophthalmos and periocular swelling of the left eye. The diagnostic work-up included ocular ultrasound, sonographic examination through the thinned frontal bone, radiography, standing computed tomography of the skull and exploratory osteoplastic surgery. Histopathology was consistent with an organized hematoma. An intradiploic hematoma of the frontal bone was diagnosed 5 years after head trauma, with progressive expansion and deformation of the skull resulting in exophthalmos. Exophthalmos with facial bone deformation was the only clinical finding of intradiploic hematoma. Standing computed tomography (CT) aided the diagnosis to differentiate intradiploic hematoma from other, more common causes of facial bone distortion associated with paranasal sinus diseases. Intradiploic hematoma of possible traumatic origin is a differential diagnosis for sinonasal disease and exophthalmos in the horse., (© 2013 American College of Veterinary Ophthalmologists.)

A 4-month-old intact female English Springer Spaniel presented to the University of Georgia Veterinary Teaching Hospital for evaluation of unilateral, progressive exophthalmos oculus sinister (OS) of 2 weeks' duration. Complete ophthalmic examination revealed moderate OS exophthalmos and lateral globe deviation. No other abnormalities were noted on physical or ophthalmic examination, ocular ultrasound, complete bloodwork, or thoracic radiography. Skull computed tomography (CT) revealed a large, focal, smoothly irregular, cavitated, expansile bony lesion involving the left caudal maxillary and left frontal bones. Biopsies, obtained through a frontal sinusotomy approach to preserve the left globe integrity, demonstrated normal reactive trabecular bone with locally extensive fibrosis. Calvarial hyperostosis was diagnosed based upon appearance on imaging, lesion unilaterality, absence of mandibular involvement, and histopathology. Six months after initial presentation, skull CT was repeated and marked reduction in the degree of frontal bone thickening was demonstrated with complete resolution of cavitations. There was marked clinical improvement with mild, nonpainful exophthalmos, and lateral globe deviation OS on ophthalmic examination. Eleven months after initial presentation, there was complete resolution of the frontal bone lesion with mild thickening of the left calvarial bones on repeat skull CT. There was no exophthalmos or globe deviation present on clinical ophthalmic examination. The proliferative osteopathic lesion was self-resolving with resolution of the exophthalmos and has not recurred to date. To the authors' knowledge, this is the first report of calvarial hyperostosis in a previously unreported breed presenting as unilateral exophthalmos., (© 2011 American College of Veterinary Ophthalmologists.)

Purpose: To describe the clinical, histological, and immunohistochemical manifestations of canine necrotizing scleritis., Methods: A retrospective examination of the clinical records and samples of ocular tissues from five dogs with a histological diagnosis 'necrotizing scleritis' was completed. Archived, formalin-fixed, paraffin-embedded samples and two control globes were stained with hematoxylin and eosin, Gram, periodic acid-Schiff (PAS) and Masson trichrome stains, and they were immunohistochemically labeled for CD3, CD18, and CD20., Results: Of the five cases reviewed, only two could be confirmed as idiopathic necrotizing scleritis. The other three cases were retrospectively diagnosed as unilateral focal, non-necrotizing scleritis, one as episcleritis and the third was scleritis secondary to a proptosed globe based on our retrospective clinical, histological, and immunohistochemical evaluations. In these two cases, idiopathic necrotizing scleritis manifested as a bilateral, progressive, inflammatory disease of the sclera and cornea that induces significant uveitis. Light microscopic examination confirmed collagen degeneration and granulomatous inflammation. There was no evidence for an infectious etiology based on Gram's and PAS stainings. Immunohistochemical labeling revealed a predominance of B cells in idiopathic, bilateral necrotizing scleritis. Tinctorial staining abnormalities with Masson's trichrome stain were present in scleral collagen of the two cases with idiopathic necrotizing scleritis as well as a case of secondary traumatic scleritis., Conclusions: Based on a limited number of cases, idiopathic canine necrotizing scleritis shares similar histopathological features with non-necrotizing scleritis and episcleritis; however, necrotizing scleritis is B-cell-dominated and bilateral, and significant collagen alterations manifest with Masson's trichrome stain., (© 2011 American College of Veterinary Ophthalmologists.)

A 4-year-old Andalusian horse was presented for examination following a 3-month history of exophthalmos of the right eye and a soft swelling of the right supraorbital fossa noted after blunt head trauma. Ultrasonographic examination of the swelling showed an anecogenic mass of 5 cm in diameter involving the retrobulbar space. Centesis of the mass through the supraorbital fossa was performed and yielded a serous fluid with 7.2 g/dL of total protein and density of 1040. No cells were seen in the sample. A tentative diagnosis of cyst was made. The cyst was surgically removed and the definitive histologic diagnosis was retrobulbar dermoid cyst. No recurrence has developed 18 months following the complete removal of the cyst capsule. To the authors' knowledge, there are no previous reports of retrobulbar dermoid cysts in horses. Localization, causes and success of surgical treatment of dermoid cysts are discussed.

A 1-year-old Shar Pei presented for recent-onset exophthalmos and right peri-ocular facial swelling. Physical examination revealed the facial mass was of soft-tissue consistency and nonpainful to the dog. Due to inability to retropulse the globe during ophthalmologic examination, it was suspected the mass had impinged into the orbit, resulting in rostral displacement of the globe. Anatomic location suggested the lesion was probably associated with the zygomatic salivary gland. Fine-needle aspiration and subsequent cytological evaluation of fluid extracted from the facial mass was consistent with a diagnosis of zygomatic mucocele. Computed tomography imaging confirmed a single fluid-filled mass was resulting in both the facial distention and the exophthalmos. A modified, lateral orbitotomy surgical approach was selected for excision of the lesion to provide ventral exposure to the orbit, while minimizing trauma to the globe and supporting structures. Histopathology of the excised lesion confirmed a diagnosis of zygomatic mucocele. This case demonstrates utilization of a modified lateral orbitotomy for effective surgical management of a zygomatic mucocele in a dog, with preservation of vision and absence of any significant postoperative complications.

A 4-year old, male intact, captive-bred chinchilla (Chinchilla lanigera) was presented due to progressive exophthalmos of the right eye over a 5-month period. Ophthalmic examination revealed exophthalmos with dorsal displacement of the right globe. Retropulsion was decreased and a fluctuant, subcutaneous mass could be palpated posterior and dorsal to the central aspect of the zygomatic bone. Transdermal ultrasonography revealed a fluid-filled mass consistent with a cyst located within the ventral right orbit. Computed tomography demonstrated dorsal displacement of the globe, lateral displacement of the zygomatic arch, and numerous mineral-dense foci within the lumen of the cyst. The cyst was removed en bloc by ventral transpalpebral orbitotomy. Histopathology revealed a single capsulated cyst with multiple invaginated protoscolices, characterized by a prominent scolex with refractile hooklets, suckers, and abundant calcareous corpuscles consistent with a Taenia coenurus. Exophthalmos resolved with surgical therapy and there was no evidence of recurrence or postoperative complications over a period of 2 years. To the authors' knowledge, this is the first reported case of an orbital cyst of parasitic origin in a chinchilla.

A retrobulbar malignant fibrous histiocytoma was diagnosed in a 12-year-old castrated male Keeshond dog. The mass was excised with a lateral orbitotomy and zygomatic arch resection. Vision was preserved in the affected eye, and no recurrence was noted up to 10 months postoperatively. Malignant fibrous histiocytoma originates from primitive mesenchymal stem cells. The malignant fibrous histiocytoma seen in our patient was most consistent with the storiform-pleomorphic variant, given the storiform arrangement of spindle cells, the presence of histiocytoid cells, and a mixed inflammatory infiltrate, without giant cells. The metastatic potential of malignant fibrous histiocytoma in general, and the storiform variant in particular, is unknown. Seventeen months later the dog was presented to the referring veterinarian with anorexia, diarrhea, weight loss and bilateral purulent nasal exudates. The dog was euthanized without necropsy.

Six Holstein calves were evaluated for progressive exophthalmos. The affected calves were receiving daily injections of dexamethasone (30 microg/kg subcutaneously twice daily) as part of a metabolic study. The control calves did not exhibit exophthalmos. The ocular examinations were normal except for the exophthalmos, which ranged from mild to marked in severity. Upon postmortem examination, marked deposition of retrobulbar adipose tissue was noted in the affected calves. Dexamethasone administration appears to increase deposition of retrobulbar adipose tissue resulting in a progressive exophthalmos.

A 5-year-old European hedgehog was examined because of exophthalmos of the left eye. A retrobulbar mass in the ventromedial orbit was suspected and confirmed by a computed tomography scan. Exophthalmos progressed despite systemic broad-spectrum antibiotic therapy. The left orbit was exenterated and the mass was partially removed. The histopathologic diagnosis was lacrimal ductal carcinoma. Lacrimal ductal carcinoma is rare in humans and animals. The long-term prognosis is guarded to poor.

Clinical and histologic findings of an orbital lacrimal cyst (dacryops) in a 23-year-old-female red-eared slider (Chrysemys scripta elegans) are described. Main ophthalmologic findings included unilateral exophthalmus, engorged episcleral vessels, periocular swelling superior to the globe, incomplete lid closure, and reduced ocular motility. Based on sonographic and cytologic examination of the tissue, the preliminary diagnosis of an orbital cyst was established. After surgical resection of the cystic structure, the eye remained visual but enophthalmic. Histopathologic diagnosis of the resected tissue was interstitial dacryoadenitis.

A 16-month-old, male, neuter Dwarf Lop rabbit presented with exophthalmos of the right eye of 3 weeks duration. Under sedation an ultrasound of the right eye was performed and showed an orbital hypo-echoic area posterior and ventrolateral to the right globe, which was presumed to be a cyst. Fine needle aspirate removed 5.5 mLs of straw-colored fluid from the cyst, which allowed the globe to return to its normal position. Two months later the rabbit re-presented with exophthalmos of the right eye. Exploratory surgery was performed and a large cystic structure was removed from the ventro-lateral conjunctival fornix. Histology confirmed the cyst to be a coenurus of Taenia serialis.