Prevalence of pre-iridal monocellular and fibrovascular membranes in canine globes affected with congenital glaucoma associated with anterior segment dysgenesis, primary glaucoma associated with goniodysgenesis, and secondary glaucoma.

Objectives: The objectives of this study were to (i) evaluate the prevalence of pre-iridal monocellular and fibrovascular membranes in canine globes affected with congenital glaucoma associated with anterior segment dysgenesis (ASD), primary glaucoma associated with goniodysgenesis (GD), and secondary glaucoma, and (ii) examine the associations between monocellular and fibrovascular membranes by breed, gender, age and histopathologic ocular changes on light microscopic examination. Methods: Records of dogs who had eyes enucleated due to blindness and uncontrolled glaucoma were reviewed. Glaucoma was categorized clinically and histologically into three groups: congenital/ASD, primary/GD, and secondary glaucoma. The presence or absence and type of pre-iridal membrane (monocellular or fibrovascular) and other intraocular histologic findings were reviewed and compared statistically for each group. Results: In total, 108 canine globes (101 dogs) were included. Pre-iridal monocellular membranes were identified with light microscopy in 10 out of 19 congenital/ASD, 29 out of 40 primary, and 23 out of 49 secondary glaucoma globes. Fibrovascular membranes were observed in 3 out of 19 congenital/ASD, 9 out of 40 in primary, and 24 out of 49 secondary glaucoma globes. There were no associations between the type of membrane and breed, gender, or age. Peripheral anterior synechiae were more common in globes with fibrovascular membranes, and uveal atrophy was more common in globes with monocellular membranes. Conclusion: Pre-iridal monocellular membranes are common in all types of canine glaucoma. They are identified with light microscopy most easily in cases of primary glaucoma, and they are masked by pre-iridal fibrovascular membranes in other forms of glaucoma.

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.

Congenital cataract and spherophakia leading to starvation in a free-ranging muskox neonate from the Northwest Territories, Canada.

A muskox neonate (Ovibos moschatus) that died of starvation was diagnosed with congenital lenticular anomalies that included spherophakia and hypermature cataract associated with probable lens-induced lymphocytic uveitis and neutrophilic keratitis. Impaired sight as a result of cataract and associated inflammation likely contributed to abandonment and starvation, although maternal death cannot be excluded definitively. Ocular lesions, such as congenital cataracts and spherophakia in neonates, may be important factors affecting survival in free-ranging animals.

Histologic, immunohistochemical, and scanning electron microscopic comparison of pre-iridal monocellular and fibrovascular membranes in normal and glaucomatous canine globes.

OBJECTIVES: (i) To evaluate immunohistochemical labeling of pre-iridal monocellular and fibrovascular membranes and (ii) describe the light and scanning electron microscopic (SEM) characteristics of these membranes in glaucomatous and normal/control canine globes. MATERIALS AND METHODS: All globes were evaluated with light microscopy. Immunohistochemical labeling for CD18, Smooth muscle actin (SMA), and CD117 was completed on 40 canine globes with congenital/anterior segment dysgenesis-associated glaucoma (n = 10), primary/goniodysgenesis-associated glaucoma (n = 10), secondary glaucoma (n = 10), and normal/control globes (n = 10). SEM was completed on 10 globes: 5 with monocellular membranes, 3 with fibrovascular membranes, and 2 without a histologically detectable membrane. RESULTS: Monocellular membranes were detected in all normal/control globes with light microscopy and appeared to be morphologically very similar to those in diseased globes. CD18 labeling was detected in 9/10 monocellular membranes in normal/control globes, 15/23 monocellular, and 7/8 fibrovascular membranes in globes with glaucoma. SMA and CD117 labeling was not detected in monocellular membranes of normal/control globes. SMA was expressed in 10/23 monocellular and 7/8 fibrovascular membranes of glaucomatous globes. CD117 was expressed in 7/23 monocellular and 5/8 fibrovascular membranes of glaucomatous globes. SEM of monocellular membranes revealed a continuous sheet of mostly spindle cells and few individual round cells that extended over the anterior iris face in normal/control and all glaucomatous globes. CONCLUSION: Pre-iridal monocellular membranes are a normal component of the anterior iris surface, and CD18 immunoreactivity suggests some cells within these are of leukocytic origin. SMA and CD117 labeling of monocellular membranes in glaucomatous, but not normal/control globes, suggest metaplastic cellular change secondary to intraocular pathology related to glaucoma.

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.

Peripheral cranial neuropathies consistent with cavernous sinus syndrome caused by extracranial nasopharyngeal lymphoma in a cat.

Cavernous sinus syndrome is a unique constellation of cranial nerve deficits occurring typically as a result of pathologic infiltration of the cavernous sinus, which is located in the lateral sellar compartment of the calvarium. This case report describes a polyneuropathy consistent with cavernous sinus syndrome as a result of a lesion outside of the cavernous sinus. The cat was presented with right internal and external ophthalmoplegia, loss of right corneal sensation, inspiratory stridor, dysphagia, dysphonia, tongue weakness, and weight loss. Magnetic resonance imaging identified a large nasopharyngeal mass along the base of, but without extension into, the calvarium. The histologic diagnosis was nasopharyngeal lymphoma. Focal extracranial masses should be considered as differential diagnoses for multiple cranial nerve deficits, including the constellation of clinical signs recognized as cavernous sinus syndrome.

Neuropathies crâniales périphériques compatibles avec un syndrome du sinus caverneux causé par un lymphome nasopharyngé extra-crânial chez un chat. Le syndrome du sinus caverneux est une constellation unique de déficits des nerfs crâniens se produisant typiquement comme le résultat d'une infiltration pathologique du sinus caverneux, qui est situé dans le compartiment sellaire latéral du calvarium. Le présent rapport de cas décrit une polyneuropathie compatible avec un syndrome du sinus caverneux résultant d'une lésion à l'extérieur du sinus caverneux. Le chat fut présenté avec une ophtalmoplégie interne et externe droit, perte de sensation au niveau de la cornée droite, stridor inspiratoire, dysphagie, dysphonie, faiblesse de la langue, et perte de poids. Un examen d'imagerie par résonnance magnétique permis d'identifier une large masse nasopharyngée suivant la base du calvarium, mais sans extension à l'intérieur. Le diagnostic histologique en fut un de lymphome nasopharyngé. Les masses focales extra-crâniales devraient être considérées dans le diagnostic différentiel lors de déficits de plusieurs nerfs crâniens, incluant la multitude de signes cliniques reconnus comme le syndrome du sinus caverneux.(Traduit par Dr Serge Messier).

A review of Horner's syndrome in small animals.

Horner's syndrome arises from dysfunction of the oculosympathetic pathway and is characterized by miosis, enophthalmos, protrusion of the third eyelid, and ptosis. It has been recognized in a wide variety of breeds and ages in small animal patients. The oculosympathetic pathway is a 3-neuron pathway. The central/first order neuron arises from the hypothalamus and extends down the spinal cord. The preganglionic/second order neuron arises from the first 3 thoracic spinal cord segments and travels through the thorax and cervical region until it synapses at the cranial cervical ganglion. The postganglionic/third order neuron travels from this ganglion to the orbit. Topical application of cocaine is the gold standard for differentiating Horner's syndrome from other causes of miosis. Topical 1% phenylephrine allows for identification of a post-ganglion Horner's syndrome. Numerous etiologies have been reported for Horner's syndrome, but idiopathic disease is most common. Ancillary diagnostics include otoscopic examination, thoracic radiographs, or advanced imaging. Treatment and prognosis are determined by the etiology.

Examen du syndrome de Horner chez les petits animaux. Le syndrome de Horner provient d'une dysfonction de la voie oculo-sympathique et est caractérisée par la miose, l'enophtalmie, la protrusion de la troisième paupière et la ptose. Elle a été reconnue chez une grande variété de races et d'âges chez les patients petits animaux. La voie oculo-sympathique est une voie à trois neurones. Le neurone central/de premier ordre provient de l'hypothalamus et s'étend vers le bas sur la colonne vertébrale. Le neurone préganglionnaire/de deuxième ordre provient des trois premiers segments thoraciques de la colonne vertébrale et se déplace dans le thorax et la région cervicale jusqu'à la synapse au ganglion cervical crânien. Le neurone postganglionnaire/de troisième ordre se déplace de ce ganglion jusqu'à l'orbite. L'application topique de cocaïne est le test de référence pour la différenciation du syndrome de Horner des autres causes de miose. La phényléphrine topique 1 % permet l'identification d'un syndrome de Horner postganglionnaire. Plusieurs étiologies ont été signalées pour le syndrome de Horner, mais la maladie idiopathique est la plus commune. Les diagnostics auxiliaires incluent l'examen otoscopique, des radiographies thoraciques ou une imagerie avancée. Le traitement et le pronostic sont déterminés par l'étiologie.(Traduit par Isabelle Vallières).

Evaluation of retinal morphology of canine sudden acquired retinal degeneration syndrome using optical coherence tomography and fluorescein angiography.

PURPOSE: To describe the optical coherence tomography (OCT) and fluorescein angiography changes in dogs with sudden acquired retinal degeneration syndrome (SARDS). METHODS: Retinal OCT was performed on 10 SARDS dogs and eight control dogs. Tomograms were collected in four quadrants around the optic nerve. Measurements were collected from the photoreceptor layer, the outer nuclear layer, the outer retina, the inner retina and the whole retina thickness in all quadrants. Sodium fluorescein was injected intravenously and serial fundic photographs were collected for a 5 minute period post-injection. RESULTS: In all quadrants, the outer nuclear layer (dorsal temporal P = 0.0000, dorsal nasal P = 0.0001, ventral temporal P = 0.0002, ventral nasal P = 0.000) and outer retina (dorsal temporal P = 0.0001, dorsal nasal P = 0.0002, ventral temporal P = 0.0054, ventral nasal P = 0.0084) measurements were significantly decreased in SARDS dogs. The whole retina thickness was significantly decreased in the dorsal temporal (P = 0.0082) and ventral temporal (P = 0.0428) retina. There were no significant differences in the photoreceptor layer thickness or inner retinal thickness between SARDS and control dogs. All SARDS dogs had a loss of definition of all of the photoreceptor bands on OCT. Two SARDS dogs had multifocal small retinal detachments and one of these dogs exhibited fluorescein leaking at the detachment sites. CONCLUSIONS: The significant reduction in the outer nuclear layer and the loss of band signals in the photoreceptor layers in dogs with SARDS identified on OCT support the previous histopathology findings. Small detachments may occasionally be detected on OCT and they may leak fluorescein.

Bilateral retinoschisis in a dog: A veterinary clinical application for optical coherence tomography.

A 11-year-old neutered male Labrador retriever-cross dog was presented to the University of Missouri-Columbia Veterinary Ophthalmology Service for subtle visual deficits. Indirect ophthalmoscopy revealed a smooth, bullous elevation in the superior-temporal retina OU. Optical coherence tomography (OCT) performed OU showed inner retinal separation consistent with retinoschisis. Electroretinography (ERG) revealed markedly reduced b-wave amplitudes in the more severely affected eye (OD) compared with the less severely affected eye (OS). The most notable reductions were in the rod response and 30-Hz flicker b-waves OD which were approximately 50% of the corresponding amplitudes OS. Implicit times, particularly the a-wave implicit times, were noticeably longer OD compared with OS. Lesions remained unchanged over 4 months at which time the dog was humanely euthanized for reasons unrelated to the ocular disease. Significant light microscopic ocular findings were bilateral superior temporal peripheral retinoschisis. The separation of the retinal tissue was similar between eyes and effectively divided the outer plexiform layer. In addition, thinning of the surrounding retinal layers was present. To the authors' knowledge, this is the first case of canine retinoschisis diagnosed with OCT, evaluated with electroretinography, and confirmed with light microscopic examination. History, clinical, and diagnostic findings, with the absence of disease progression over time, are analogous with cases of acquired senile retinoschisis in humans.

Odontogenic parakeratinized cyst resulting in exophthalmos and palatine, maxillary, and zygomatic bone erosion in a dog.

A novel case of a canine odontogenic parakeratinized cyst (COPC) that resulted in exophthalmos and palatine, maxillary, and zygomatic bone erosion in a 5-year-old Chihuahua dog is reported. Final diagnosis was aided by cross-sectional imaging (magnetic resonance imaging and computed tomography) and confirmed with histologic examination of the cyst wall.

Sudden acquired retinal degeneration syndrome in western Canada: 93 cases.

This study reviewed clinical data from dogs diagnosed with sudden acquired retinal degeneration syndrome (SARDS) in western Canada. Medical records from the Western College of Veterinary Medicine from 2002 to 2016 showed that 93 cases of SARDS were diagnosed based on presentation for sudden blindness and a bilaterally extinguished electroretinogram. The most common pure breeds were the miniature schnauzer, dachshund, and pug. The mean age at diagnosis was 8.1 years and males and females were equally affected. Most of the dogs were presented with normal non-chromatic, but abnormal chromatic pupillary light reflexes. The incidence of retinal degeneration as detected via ophthalmoscopy increased over time after SARDS diagnosis. Polyuria, polydipsia, polyphagia, weight gain, elevated liver enzyme values, isosthenuria, and proteinuria were common clinical and laboratory findings. Chromatic pupillary light reflex testing may be more valuable than non-chromatic pupillary light testing in detecting pupil response abnormalities in dogs with SARDS, although electroretinography remains the definitive diagnostic test.

Syndrome de la rétine silencieuse dans l'Ouest canadien : 93 cas. Cette étude a examiné les données cliniques provenant de chiens diagnostiqués avec le syndrome de la rétine silencieuse (syndrome de cécité soudaine acquise) dans l'Ouest canadien. Les dossiers médicaux du Western College of Veterinary Medicine de 2002 à 2016 ont montré que 93 cas du syndrome de la rétine silencieuse ont été diagnostiqués en se basant sur la présentation pour une cécité soudaine et un électrorétinogramme bilatéral sans incandescence. Les races les plus communes étaient le Schnauzer miniature, le Dachshund et le Pug. L'âge moyen au diagnostic était de 8,1 ans et les mâles et les femelles étaient également affectés. La plupart des chiens présentaient des réflexes pupillaires normaux à la lumière non chromatique mais des réflexes anormaux à la lumière chromatique. L'incidence de la dégénération rétinienne détectée par l'ophtalmoscopie a augmenté au fil du temps après le diagnostic du syndrome de la rétine silencieuse. La polyurie, la polydipsie, la polyphagie, le gain de poids, des valeurs d'enzymes hépatiques élevées, l'isosthénurie et la protéinurie étaient des résultats cliniques et de laboratoire communs. Le réflexe à la lumière pupillaire chromatique peut être plus utile que le test de la lumière pupillaire non chromatique pour détecter les anomalies de la réponse pupillaire chez les chiens atteints du syndrome de la rétine silencieuse, quoique l'électrorétinographie demeure le test diagnostique définitif.(Traduit par Isabelle Vallières).

Equine recurrent uveitis in western Canadian prairie provinces: A retrospective study (2002-2015).

The objectives of this study were to determine the demographics of horses with equine recurrent uveitis (ERU) presenting to the Western College of Veterinary Medicine and to describe and compare the prognosis of ERU in the Appaloosa with that in other breeds. Horses diagnosed with ERU by a veterinary ophthalmologist between 2002 and 2015 were included. Eye lesions were classified as mild, moderate, or severe based on clinical manifestations. Breed, age, severity, blindness, and final outcome were evaluated. Thirty-two horses fit the inclusion criteria; 62.5% were Appaloosas. Mean age at presentation was 12.13 ± 4.6 years. Equine recurrent uveitis was bilateral in 93.6% of horses and was severe in 59.4% of eyes at presentation. Bilateral blindness was present in 59.4% of horses at last follow-up. Of 27 horses available for follow-up, 63% were euthanized due to ERU. No significant differences in age, severity, blindness, or rate of euthanasia were noted between Appaloosas and other breeds. The Appaloosa is at increased risk for ERU, which is a devastating ocular disease.

Uvéite équine récurrente dans les provinces de l'Ouest canadien : étude rétrospective (2002­2015). L'objectif de cette étude consistait à déterminer les données démographiques des chevaux atteints d'uvéite équine récurrente (UER) présentés au Western College of Veterinary Medicine et de décrire et de comparer le pronostic de l'UER chez les chevaux Appaloosa avec celui des autres races. Les chevaux diagnostiqués entre 2002 et 2015 comme étant atteints de l'UER par un ophtalmologiste vétérinaire ont été inclus. Les lésions à l'œil étaient classées comme étant légères, modérées ou graves selon les manifestations cliniques. La race, l'âge, la gravité, la cécité et le résultat final ont été évalués. Trente-deux chevaux correspondaient aux critères d'inclusion : 62,5 % étaient des chevaux Appaloosa. L'âge moyen à la présentation était de 12,13 ans ± 4,6 années. L'uvéite équine récurrente était bilatérale chez 93,6 % des chevaux et était grave pour 59,4 % des yeux à la présentation. La cécité bilatérale était présente chez 59,4 % des chevaux au dernier suivi. Parmi les 27 chevaux disponibles pour le suivi, 63 % ont été euthanasiés en raison de l'UER. Aucune différence significative au niveau de l'âge, de la gravité, de la cécité ou du taux d'euthanasie n'a été signalée entre les chevaux Appaloosa et les autres races. Les chevaux Appaloosa présentent un risque accru d'UER, qui est une maladie oculaire dévastatrice.(Traduit par Isabelle Vallières).

Anophthalmia in a Wild Eastern Gray Squirrel (Sciurus carolinensis).

We describe bilateral true anophthalmia in a juvenile female eastern gray squirrel (Sciurus carolinensis) with histologic confirmation that orbital contents lacked ocular tissues. Additionally, the optic chiasm of the brain was absent and axon density in the optic tract adjacent to the lateral geniculate nucleus was reduced.

Effect of prolonged photoperiod on ocular tissues of domestic turkeys.

OBJECTIVE: The objective of this study is to investigate the structural and functional ocular changes that develop in turkeys exposed to a photoperiod of 23 h of light (23L) compared with a photoperiod of 14 h of light (14L). PROCEDURES: Ten-day-old Nicholas heavy strain poults were exposed to either a 14L or 23L photoperiod. Between 16 and 18 weeks of age, equal numbers of turkeys per treatment group underwent ophthalmic examination (biomicroscopy, indirect ophthalmoscopy) (n = 14), refractometry (n = 20), keratometry (n = 20), tonometry (n = 20), and full-field electroretinography (ERG) (n = 14). Postmortem analyses included orbital magnetic resonance imaging (MRI) (n = 10) and light microscopy (n = 24) at 18 weeks of age. RESULTS: Autorefraction revealed a median of -0.13 for sphere in both groups (P = 0.69), which is approximately emmetropia. The radius of curvature of the cornea was significantly higher (P = 0.0001) and the refractive power of the cornea was significantly lower (P = 0.0001) in the 23L group. The astigmatic power was significantly greater in the 23L group (P = 0.0001). Mean intraocular pressure did not differ between groups (P = 0.085). Turkeys from the 23L group had significantly larger globes in nasotemporal (P = 0.0007), dorsoventral (P = 0.015), and anterioposterior (P = 0.021) directions, and anterior chambers were more shallow (P = 0.0002). ERGs revealed the 23L group to have lower a- and b-wave amplitudes and significantly lower cone flicker amplitudes (P = 0.0008). Light microscopic examination revealed 23L turkeys to have significantly decreased numbers of nuclei in the outer nuclear layer (P = 0.0001) and inner nuclear layer (P = 0.0186), and decreased choroidal thickness (P = 0.0008). The prevalence of cataract in the 23L group was significantly higher (P = 0.001). CONCLUSIONS: Exposing turkeys to a prolonged photoperiod induces significant ocular disease.

Primary bilateral corneal nerve sheath neoplasm in a dog.

A 15-year-old, neutered male, Shih Tzu cross developed progressive corneal stromal thickening and vascularization of the right eye, and 5 months later, of the left eye. Both eyes became blind due to extensive corneal opacification and were enucleated. Light microscopic examination revealed a diffuse corneal infiltrate of neoplastic mesenchymal cells, and immunohistochemistry revealed diffuse cytoplasmic vimentin immunoreactivity and variable cytoplasmic and nuclear immunoreactivity for S100 in the neoplastic cells. Transmission electron microscopy revealed desmosomes between contiguous cells, thread-like cytoplasmic processes coated with basement membrane, extracellular bundles of collagen, and axonal degeneration consistent with features of a nerve sheath neoplasm. This is the first report of primary, bilateral corneal nerve sheath sarcoma in a canine.