Ocular diagnostics, ophthalmic findings, and conjunctival microbiome in the Chilean flamingo (Phoenicopterus chilensis).

OBJECTIVE: To establish normative data for selected ocular diagnostic tests and commensal conjunctival microflora and describe the incidence of ocular pathology in Chilean flamingos. ANIMALS STUDIED: A total of 41 Chilean flamingos were examined at the Blank Park Zoo in Des Moines, Iowa. PROCEDURES: In 20 flamingos, blink rate was assessed undisturbed in their exhibit, then gentle manual restraint was used to assess palpebral fissure length (PFL), aqueous tear production (phenol red thread test [PRTT] in one eye, endodontic absorbent paper point tear test [EAPPTT] in the other), intraocular pressure (IOP; rebound tonometry), and fluorescein staining. Twenty-one other flamingos were brought to a darkened area for neuro-ophthalmic examination, slit lamp biomicroscopy, and indirect ophthalmoscopy. Swabs from seven flamingos were used for ocular microbiome evaluation. RESULTS: Results are presented as mean ± standard deviation (range). Flamingos comprised 23 females/18 males, aged 11 ± 9.1 (0.7-40) years. Test results: blink rate, 3.7 ± 2 (1-9) blinks/min; PFL, 11.2 ± 1.2 (9-14) mm; IOP, 14 ± 3.2 (10-22) mmHg; EAPPT, 10.2 ± 2.8 (9-14) mm/min; PRTT, 6.8 ± 2.5 (3-13) mm/15 s. Dazzle reflex was positive in four birds examined. Pathologies included cataracts (n = 7 birds), corneal fibrosis (n = 3), endothelial pigment (n = 2), uveal cysts (n = 1), lens luxation (n = 1), and uveitis (n = 1). Ocular microbiome showed high diversity of taxa. CONCLUSIONS: Baseline ocular parameters and incidence of ophthalmic pathology assist veterinarians with disease screening for Chilean flamingos, while the ocular microbiome showed high diversity.

Relationship between the bacterial ocular surface microbiota and outcomes for cats with feline herpesvirus type 1 ocular surface disease.

OBJECTIVE: Feline herpesvirus 1 (FHV-1) causes ocular surface disease in domestic cats. The purpose of this study was to assess the relationship between bacterial ocular surface microbiota and outcomes for cats with FHV-1 ocular surface disease. ANIMALS STUDIED: Twenty-two shelter-housed cats with confirmed FHV-1 ocular surface disease. PROCEDURES: Animals were grouped according to FHV-1 shedding and ocular clinical scores following intervention: worsened outcome (WorOut, n = 11) or improved outcome (ImpOut, n = 11). Scoring and conjunctival sampling were completed on Days 1 and 8 of twice daily antiviral treatment. Bacterial DNA was extracted and submitted for 16S rRNA gene sequencing. Real-time polymerase chain reaction was performed for selected bacterial species. Overall DNA concentration between groups was assessed. RESULTS: Bacterial microbiota relative abundance composition was significantly different between ImpOut and WorOut groups (weighted UniFrac p = .006). Alpha diversity was significantly higher in the ImpOut group compared with the WorOut group (Shannon p = .042, Simpson's p = .022, Pielou's p = .037). Differences in the relative abundance of various phyla and species were detected between groups. Total DNA concentration was higher in the WorOut group compared with the ImpOut group (p = .04). Feline GAPDH (p = .001) and Bilophila wadsworthia (p = .024) copy number was significantly higher in the ImpOut group compared with the WorOut group. CONCLUSIONS: The results highlight the important relationship between the bacterial ocular surface microbiota and FHV-1 infection outcomes in cats treated with antiviral medications. Low bacterial species diversity, higher overall DNA (presumed predominantly bacterial) load, and certain bacterial phyla/species were associated with poor outcomes for cats with FHV-1 ocular disease.

Comparison of the effect of sedation and general anesthesia on pattern and flash visual evoked potentials in normal dogs.

BACKGROUND: Visual evoked potentials (VEPs) can provide objective functional assessment of the post-retinal visual pathway. This study compared the effects of sedation (butorphanol and dexmedetomidine) and general anesthesia (propofol and sevoflurane) on pattern and flash VEPs. Dogs (n = 13) underwent sedation or anesthesia and VEPs were obtained from 3 subcutaneous recording electrodes placed on the head (O1, Oz, O2). RESULTS: Pattern VEPs could only be recorded under sedation and a maximum of 3 peaks were identified (N75, P100, N135). Flash VEPs could be recorded under both sedation and anesthesia and a maximum of 5 peaks were identified (N1, P1, N2, P2, N3). The latency of the N1 peak and the baseline-N1 amplitude were significantly longer under general anesthesia. CONCLUSION: Visual evoked potentials should be preferentially recorded in dogs sedated with dexmedetomidine and butorphanol, regardless of the stimulus.

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).

Current ocular microbiome investigations limit reproducibility and reliability: Critical review and opportunities.

Enthusiasm for research describing microbial communities using next-generation sequencing (NGS) has outpaced efforts to standardize methodology. Without consistency in the way research is carried out in this field, the comparison of data between studies is near impossible and the utility of results remains limited. This holds true for bacterial microbiome research of the ocular surface, and other sites, in both humans and animals. In addition, the ocular surface remains under-explored when compared to other mucosal sites. Low bacterial biomass samples from the ocular surface lead to further technical challenges. Taken together, two major problems were identified: (1) Normalization of the workflow in studies utilizing NGS to investigate the ocular surface bacteriome is necessary in order to propel the field forward and improve research impact through cross-study comparisons. (2) Current microbiome profiling technology was developed for high bacterial biomass samples (such as feces or soil), posing a challenge for analyses of samples with low bacterial load such as the ocular surface. This article reviews the challenges and limitations currently facing ocular microbiome research and provides recommendations for minimum reporting standards for veterinary ophthalmologists and clinician scientists to limit inter-study variation, improve reproducibility, and ultimately render results from these studies more impactful. The move toward normalization of methodology will expedite and maximize the potential for microbiome research to translate into meaningful discovery and tangible clinical applications.

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.

Risk factors for equine recurrent uveitis in a population of Appaloosa horses in western Canada.

OBJECTIVE: To characterize clinical manifestations, measure frequency, and evaluate risk factors for equine recurrent uveitis (ERU) in Appaloosa horses in western Canada. ANIMALS: 145 Appaloosa horses. PROCEDURES: Ophthalmic examinations were completed and eyes were classified as having no or mild clinical signs, or moderate, or severe damage from ERU. Clinical signs, age, sex, base coat color, and pattern were recorded. Whole blood and/or mane hair follicles were collected for DNA extraction, and all horses were tested for the leopard complex (LP) spotting pattern allele. Pedigree analysis was completed on affected and unaffected horses, and coefficients of coancestry (CC) and inbreeding (COI) were determined. RESULTS: Equine recurrent uveitis was confirmed in 20 (14%) horses. The mean age of affected horses was 12.3 years (±5.3; range 3-25). Age was a significant risk factor for ERU diagnosis (ORyear  = 1.15) and classification (ORyear  = 1.19). The fewspot coat pattern was significantly associated with increased risk for ERU compared to horses that were minimally patterned or true solids. The LP/LP genotype was at a significantly greater risk for ERU compared to lp/lp (OR = 19.4) and LP/lp (OR = 6.37). Classification of ERU was greater in the LP/LP genotype compared to LP/lp. Affected horses had an average CC of 0.066, and there was a significant difference in the distribution of CC for affected horses versus the control group (P = .021). One affected horse was the sire or grandsire of nine other affected. CONCLUSIONS: Age, coat pattern, and genetics are major risk factors for the diagnosis and classification of ERU in the Appaloosa.

Initial description of the core ocular surface microbiome in dogs: Bacterial community diversity and composition in a defined canine population.

OBJECTIVE: To characterize the bacterial community residing on the conjunctiva of clinically healthy dogs. METHODS: Bacterial DNA from conjunctival swabs of 10 dogs with normal ocular examinations (both OD and OS, n = 20) was extracted, and 16S rRNA amplicons were sequenced using Illumina MiSeq 600. Resulting data were subjected to quality control steps, and analyzed for bacterial community richness and diversity, within- and between-group dissimilarity, and relative taxonomic composition. RESULTS: High-quality reads (2.22 million bp) resulted in a mean of 159 068 sequences per sample. Bacterial community evenness and diversity was high when compared to other species, and did not significantly differ when samples were grouped by dogs or eyes. As expected, within-dog samples were more similar than between-dog samples. Taxonomic classification revealed that >95% of the community consisted of Firmicutes (34.9 ± 8.8%), Actinobacteria (26.3 ± 7.1%), Proteobacteria (26.2 ± 6.6%), and Bacteroidetes (9.4 ± 2.4%). Key members of the dog ocular surface microbiome, found in all dogs and corresponding to >25% of all identified OTUs (operational taxonomic units), were part of the Bifidobacteriaceae, Lachnospiraceae, Moraxellaceae, Corynebacteriaceae families. Genera previously thought to account for the majority of the core ocular surface microbiome in the dog (Staphylococcus sp., Streptococcus sp., and Bacillus sp.) were associated with only 2.63% of overall reads. CONCLUSIONS: This study shows the feasibility of conjunctival swabs and high-throughput sequencing to profile the bacterial community structure of the canine ocular surface. A core ocular surface microbiome was identified for this canine population.

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.

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.