Severe orbital hematoma with third eyelid swelling and prolapse following a blind maxillary nerve block in a horse.

A 20-year-old quarter horse gelding was presented for routine dental examination. Periodontal disease and luxation of tooth 108 was diagnosed and oral extraction was planned. After an unsuccessful blind maxillary nerve block, it was elected to perform the procedure under total intravenous anesthesia. Following recovery, a focal superficial corneal ulcer, severe retrobulbar swelling, mild exophthalmos, and marked swelling and prolapse of the third eyelid (nictitating membrane) were observed. Clinical signs persisted beyond 48 h despite the use of systemic anti-inflammatories and topical ocular anti-inflammatories and antibiotics. A temporary tarsorrhaphy was subsequently done at 48 h and the horse was discharged after 5 d of hospitalization and regression of clinical signs. Although it is very useful for easing dental extractions, the blind maxillary nerve block is associated with potential complications due to inadvertent vascular puncture. This case report describes a rare complication of prolapse of the third eyelid in a horse after a maxillary nerve block and successful treatment with a temporary tarsorrhaphy. Key clinical message: This case report explains how nictitating membrane swelling and prolapse can occur following a blind maxillary nerve block in the horse and describes treatment with a temporary tarsorrhaphy.

Hématome orbitaire sévère avec gonflement de la troisième paupière et prolapsus à la suite d'un bloc du nerf maxillaire à l'aveugle chez un cheval. Un hongre quarter horse de 20 ans a été présenté pour un examen dentaire de routine. Une maladie parodontale et une luxation de la dent 108 ont été diagnostiquées et une extraction orale a été planifiée. Après l'échec d'un bloc du nerf maxillaire à l'aveugle, il a été décidé d'effectuer la procédure sous anesthésie intraveineuse. Après la guérison, un ulcère cornéen superficiel focal, un gonflement rétrobulbaire sévère, une légère exophtalmie ainsi qu'un gonflement et un prolapsus marqués de la troisième paupière (membrane nictitante) ont été observés. Les signes cliniques ont persisté au-delà de 48 heures malgré l'utilisation d'anti-inflammatoires systémiques et d'anti-inflammatoires oculaires topiques et d'antibiotiques. Une tarsorraphie temporaire a ensuite été réalisée à 48 heures et le cheval est sorti après 5 jours d'hospitalisation et de régression des signes cliniques. Bien qu'il soit très utile pour faciliter les extractions dentaires, le bloc du nerf maxillaire à l'aveugle est associé à des complications potentielles dues à une ponction vasculaire involontaire. Ce rapport de cas décrit une complication rare de prolapsus de la troisième paupière chez un cheval après un bloc nerveux maxillaire et un traitement réussi par tarsorraphie temporaire.Message clinique clé:Ce rapport de cas explique comment un gonflement et un prolapsus de la membrane nictitante peuvent survenir à la suite d'un bloc du nerf maxillaire à l'aveugle chez le cheval et décrit le traitement par tarsorraphie temporaire.(Traduit par Dr Serge Messier).

Evaluation of Uveitis Induced in Rats by a Type I Collagen Peptide as a Model for Childhood Arthritis-associated Uveitis.

Chronic asymptomatic and acute symptomatic anterior uveitis are forms of ocular inflammation associated with juvenile idiopathic arthritis (JIA) Chronic JIA-associated uveitis is characterized by young age of onset, female predilection, oligoarthritis, and antinuclear antibody (ANA) positivity. Acute JIA-associated uveitis predominantly affects older male juveniles who also develop enthesitis. A type I collagen-derived peptide (melanin-associated antigen [MAA]) induces anterior uveitis in rodents. In this study, we evaluated MAA-induced uveitis in rats as a potential model for JIA-uveitis. We characterized MAA-induced uveitis by assessing its relationship to age and sex; tracking the occurrence of arthritis, enthesitis, and ANA positivity; and measuring vitreous fluid inflammatory biomarkers. Juvenile and adult and male and female Lewis rats (Rattus norvegicus) were inoculated with MAA. Slit-lamp biomicroscopy, indirect ophthalmoscopy, and joint examinations were performed 3 times weekly. Rats were euthanized at 4 wk after MAA inoculation, and plasma ANA testing, vitreous inflammatory biomarker assays, and globe histopathology assessments were conducted. Uveitis, arthritis, ANA status, levels of inflammatory biomarkers, histopathology, and joint tomographic images were assessed in relation to age and sex and compared with nonuveitic controls. All MAA-immunized rats developed uveitis characterized by anterior chamber fibrin, iridal vessel dilation, and miosis, and uveal and choroidal lymphocytic infiltration. Levels of the vitreous fluid biomarker CCL5 were higher in uveitic rats compared with control rats. Time to uveitis onset, clinical uveitis scores, and biomarker levels did not differ based on age or sex. None of the MAA-exposed rats had arthritis, enthesitis, or ANA. None of the rats inoculated with MAA that had been treated with matrix metallopeptidase 1 had clinical, histologic, or immunohistochemical evidence of ocular inflammation. In contrast to JIA-associated uveitis in humans, MAA-induced uveitis in rats is not associated with age or sex predilections and MAA is not arthritogenic.

Contouring in the optic plane improves the accuracy of computed tomography-based segmentation of the optic pathway.

Canine optic pathway structures are often contoured on CT images, despite the difficulty of visualizing the optic pathway with CT using standard planes. The purpose of this prospective, analytical, diagnostic accuracy study was to examine the accuracy of optic pathway contouring by veterinary radiation oncologists (ROs) before and after training on optic plane contouring. Optic pathway contours used as the gold standard for comparison were created based on expert consensus from registered CT and MRI for eight dogs. Twenty-one ROs contoured the optic pathway on CT using their preferred method, and again following atlas and video training demonstrating contouring on the optic plane. The Dice similarity coefficient (DSC) was used to assess contour accuracy. A multilevel mixed model with random effects to account for repeated measures was used to examine DSC differences. The median DSC (5th and 95th percentile) before and after training was 0.31 (0.06, 0.48) and 0.41 (0.18, 0.53), respectively. The mean DSC was significantly higher after training compared with before training (mean difference = 0.10; 95% CI, 0.08-0.12; P < 0.001) across all observers and patients. DSC values were comparable to those reported (0.4-0.5) for segmentation of the optic chiasm and nerves in human patients. Contour accuracy improved after training but remained low, potentially due to the small optic pathway volumes. When registered CT-MRI images are not available, our study supports routine addition of an optic plane with specific window settings to improve segmentation accuracy in mesaticephalic dogs ≥11 kg.

Evaluation of conjunctival graft procedures and factors that lead to graft complications in canine cases.

PURPOSE: To describe the complications of conjunctival graft surgery occurring in cases at a referral ophthalmic service and evaluate factors that lead to occurrence of complications in canine cases. METHODS: A retrospective case-control study was completed using data from the Veterinary Medical Center at the Western College of Veterinary Medicine, Saskatoon, Canada, between May 2015 and March 2020. Case records from dogs that underwent conjunctival pedicle graft surgery and subsequently either did or did not develop a conjunctival graft complication were reviewed. RESULTS: One hundred and six dogs undergoing conjunctival graft surgeries were identified. Sixteen conjunctival graft complications occurred, of which, eight led to negative outcomes. Univariable analysis comparing canine eyes that developed complications to control eyes revealed potential (p ≤ .05) differences between the groups in post-operative fluoroquinolone use, Streptococcus canis isolation, intraoperative intravenous cefazolin use, corneal stromal white cell infiltrate, and mean ulcer diameter. The use of intraoperative cefazolin could not be effectively evaluated with available data; however, no dogs (n = 22) receiving intraoperative cefazolin developed complications. Multivariable analysis revealed that dogs that were treated with a second-generation fluoroquinolone and that had S. canis isolated had higher odds of experiencing complications than dogs that were not treated with a second-generation fluoroquinolone and that were S. canis negative (Odds ratio = 64.7 [95% CI 6.3-669], p < .0001). CONCLUSIONS: Streptococcus species played a role in conjunctival graft complications in our study. Empiric selection of second-generation fluoroquinolone monotherapy may need reconsideration given the frequent isolation of Streptococcus spp. from canine ulcers. The use of intraoperative cefazolin may be associated with a lower complication rate.

Ophthalmic Parameters and Ophthalmoscopy of Burrowing Owls (Athene cunicularia).

Twelve adult burrowing owls (Athene cunicularia) maintained in a managed environment underwent complete bilateral ophthalmic examinations to assess ocular parameters and, if present, describe lesions (n = 24 eyes). Tear production was measured with a Schirmer tear test (STT), and intraocular pressure (IOP) was measured with rebound tonometry using established calibration settings (D = dog/cat, P = other species). Retinography was performed for all birds after application of topical rocuronium bromide, and corneal diameter was measured. Menace response was absent bilaterally in 7 of 12 (58.3%) owls; however, this did not appear to be related to the presence of fundic lesions. Ocular lesions were visualized in 6 of 12 (50%) owls. The most common ophthalmic abnormality noted was mild multifocal fundic pigment clumping, suggestive of chorioretinal scarring. Other ocular lesions included 1 retinal tear and 1 incipient cataract. Mean tear production was 6.1 ± 3.0 mm/min. Mean IOPs were 11.6 ± 1.8 mm Hg and 7.1 ± 1.3 mm Hg for the D and P settings, respectively, and these were significantly different (P < 0.001). The IOP results did not differ significantly based on patient age or between the right and left eyes, but a higher mean was obtained from males versus females using the D setting (P < 0.039; male mean 12.1 ± 1.9 mm Hg; female mean 10.9 ± 1.2 mm Hg). Measurements obtained from the STT were not affected by either age or sex. Corneal height was 11 mm and width was 12 mm, regardless of age or sex. The rebound tonometer D setting is recommended for measuring IOP values in this species. Burrowing owls had inconsistent mydriasis following topical rocuronium bromide application to the eye; however, a complete fundic examination was possible with or without complete mydriasis.

Phacoemulsification and intraocular lens implantation in a Canada lynx with phacoclastic uveitis.

A 4-year-old male Canada lynx (Lynx canadensis) was referred to the ophthalmology service at the University of Saskatchewan with a 7-month history of cataract and chronic phacoclastic uveitis secondary to penetrating trauma from a lynx claw. Ophthalmic examination of the right eye revealed a corneal scar, marked aqueous flare, extensive fibrovascular membranes extending from the iris to the lens, anterior and posterior synechiae, immature cataract, and anterior vitritis; the fundus was not visible. Phacoemulsification surgery and intraocular lens implantation using a custom lens of D+46 and 14 mm (An-vision, West Jordan, Utah, USA) was performed. Post-operative medications included sub-conjunctival injections of atropine, cefazolin, and triamcinolone, and oral doxycycline and prednisolone. At the 5-month follow-up, the uveitis was controlled, and a normal fundus was visualized; at 21 mo, the eye remained comfortable and visual. This is the first case report to describe phacoemulsification in a wild felid as a treatment for a traumatic cataract and severe phacoclastic uveitis. Key clinical message: Despite chronic phacoclastic uveitis, phacoemulsification surgery can provide a positive outcome for mature wild felids with traumatic lens rupture, even when topical treatment cannot be administered.

Phacoémulsification et implantation de lentilles intraoculaires chez un lynx du Canada atteint d'uvéite phacoclastique. Un lynx du Canada mâle de 4 ans (Lynx canadensis) a été référé au service d'ophtalmologie de l'University of Saskatchewan avec une histoire de 7 mois de cataracte et d'uvéite phacoclastique chronique secondaire à un traumatisme pénétrant d'une griffe de lynx. L'examen ophtalmique de l'oeil droit a révélé une cicatrice cornéenne, un phénomène de Tyndall marqué, des membranes fibrovasculaires étendues s'étendant de l'iris au cristallin, des synéchies antérieure et postérieure, une cataracte immature et une vitreite antérieure; le fond d'oeil n'était pas visible. Une chirurgie de phacoémulsification et une implantation de lentille intraoculaire à l'aide d'une lentille personnalisée de D+46 et 14 mm (An-vision, West Jordan, Utah, USA) ont été réalisées. Les médicaments postopératoires comprenaient des injections sous-conjonctivales d'atropine, de céfazoline et de triamcinolone, ainsi que de la doxycycline et de la prednisolone par voie orale. Au suivi à 5 mois, l'uvéite était contrôlée et un fond d'oeil normal était visualisé; à 21 mois, l'oeil restait confortable et visuel. Il s'agit du premier rapport de cas décrivant la phacoémulsification chez un félin sauvage comme traitement d'une cataracte traumatique et d'une uvéite phacoclastique sévère.Message clinique clé:Malgré l'uvéite phacoclastique chronique, la chirurgie de phacoémulsification peut donner un résultat positif pour les félins sauvages matures présentant une rupture traumatique du cristallin, même lorsqu'un traitement topique ne peut pas être administré.(Traduit par Dr Serge Messier).

Relationship between the ratio of optic nerve sheath diameter to eyeball transverse diameter and morphological characteristics of dogs.

OBJECTIVE: To assess the feasibility of ocular ultrasonography for measurement of the ratio of optic nerve sheath diameter (ONSD) to eyeball transverse diameter (ETD) in dogs with various morphologies and to evaluate the interobserver reliability of the ONSD/ETD ratio and its correlation with various morphological variables. ANIMALS: 45 healthy dogs of various breeds. PROCEDURES: Height, head circumference, body weight, body condition score, intraocular pressure, and blood pressure were recorded for each dog. Unsedated dogs underwent bilateral ocular ultrasonography once. A veterinarian and board-certified ophthalmologist who were unaware of subject signalment independently reviewed the ultrasonographic videos and selected 1 image for each eye on which the ETD and ONSD were measured. The ONSD/ETD ratio was calculated and compared between the 2 observers. Correlations between the ONSD/ETD ratio and various physiologic and morphological variables were assessed. RESULTS: 172 ONSD/ETD ratios were recorded. The ONSD/ETD ratio was calculated for at least 1 eye for 44 of the 45 (98%) dogs. Mean ± SD time required to complete the ultrasonographic examination was 90 ± 30 seconds (range, 15 seconds to 3 minutes). The mean ± SD ONSD/ETD ratio was 0.17 ± 0.01 (range, 0.15 to 0.20). The ONSD/ETD ratio did not differ significantly between the left and right eyes or the 2 observers and was not correlated with any of the variables assessed. CONCLUSIONS AND CLINICAL RELEVANCE: Ocular ultrasonography was a rapid, noninvasive, and reliable method for measurement of the ONSD/ETD ratio. The ONSD/ETD ratio did not appear to be influenced by dog morphology.

Bacterial isolates of indolent ulcers in 43 dogs.

PURPOSE: To determine whether bacteria are isolated from canine indolent ulcers and evaluate their influence on clinical outcomes. METHODS: Swabs for anaerobic and aerobic culture were collected from indolent ulcers of 43 client-owned dogs presenting to the University of Saskatchewan Veterinary Medical Centre. Outcomes were compared between ulcers with bacterial isolates and those without. Medical therapy was reviewed. RESULTS: Bacteria were isolated in 8/43 ulcers: Three cultured two isolates and five cultured single isolates. Staphylococcus was the most common genus isolated and was present in six ulcers: Species included unspecified [2], pseudintermedius [2], schleiferi [1], and hominis [1]. Streptococcus was the second most common isolate present in two ulcers: Species included canis and agalactiae. Tobramycin was the most common antibiotic used in ulcers with bacterial isolates prior to referral (n = 3). One case did not have conclusive follow-up data from the referring veterinarian and was therefore excluded from further analysis. All seven culture-positive ulcers were recorded as healed without complication: six healing after one procedure and one healing after two procedures. Thirty-five ulcers were culture-negative. There was no difference in outcome between indolent ulcers with bacterial isolates and those with negative cultures (P = .7475). CONCLUSIONS: Bacteria were isolated from 19% of indolent ulcers, and Staphylococcus was the most common isolate. Bacterial isolation did not influence outcome.

In vivo imaging comparison of unilateral circular retinal plaques in retriever dogs to dysplasia and detachment in the English Springer Spaniel.

PURPOSE: To compare the scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), and fluorescein angiography (FA) findings in retrievers with a single unilateral circular retinal plaque to those of an English springer spaniel with bilateral retinal dysplasia. PROCEDURES: A retrospective record review identified three dogs with circular retinal plaques that underwent SLO and OCT; in two of the three dogs, FA was also completed. Morphologic changes, lesion measurements, and angiogram characteristics were documented. An English springer spaniel with bilateral retinal dysplasia that had undergone SLO, OCT, and FA was used for comparison. RESULTS: Scanning laser ophthalmoscopy of the retriever dogs revealed circular retinal plaques with a dark periphery located in the tapetal retina. OCT revealed a thickening of the nerve fiber layer corresponding to the circular pattern observed on SLO. Within the circular plaque, the retina was predominantly of normal architecture. FA revealed variable hypofluorescence of both the rim and the center of the circular lesion throughout the early angiogram phases. In the late recirculation phase, small multifocal areas of hyperfluorescence were observed. OCT of geographic retinal dysplasia in the English springer spaniel revealed disorganization of both inner and outer retinal layers, and retinal detachment. CONCLUSIONS: Circular plaques observed in the tapetal retina are predominantly formed by a thickening of inner retina, while retinal dysplasia has disorganization of both inner and outer retinal layers. Further etiologic research is needed, including pedigree mapping to determine whether retinal plaques are an acquired or inherited condition.

Effect of intracameral epinephrine on heart rate, post-operative ocular hypertension, and long-term outcome following canine phacoemulsification.

PURPOSE: To determine the effect of intrsacameral epinephrine on heart rate, blood pressure, post-operative ocular hypertension, and complications following canine phacoemulsification. PROCEDURES: A prospective, double-blinded, controlled trial was carried out using 30 client-owned dogs undergoing phacoemulsification. Eyes were randomly assigned to a treatment group receiving intracameral (IC) epinephrine (n = 31) or balanced salt solution (n = 25) at the beginning of surgery. Heart rate, post-operative intraocular pressures, and outcomes were compared between treatment groups. RESULTS: No adverse reactions to IC epinephrine or saline were observed. Post-operative ocular hypertension developed at the 2 and/or 4 hours pressure reading in 35% and 46% in the epinephrine and saline groups, respectively (P = .5072). There were 9.7% and 23.1% eyes that developed complications in the IC epinephrine and saline groups, respectively (P = .2373). CONCLUSIONS: Intracameral epinephrine is safe to use, and non-significant decreases in post-operative ocular hypertension and long-term complications were observed.