Ophthalmic findings and parameters in Western tiger salamanders (Ambystoma mavortium) from northern Colorado.

OBJECTIVE: The aim of this study was to document ophthalmic examination findings and provide reference values for ocular examinations and diagnostics in clinically normal Western tiger salamanders (Ambystoma mavortium) and to evaluate the mydriatic effect of a topical rocuronium bromide and identify any adverse effects. ANIMALS STUDIED: Sixteen Western tiger salamanders. PROCEDURE: A complete ophthalmic examination, including intraocular pressure via rebound tonometry [iCare® TonoVet (dog-setting) or iCare® TonoVet Plus (dog-setting)], and fluorescein and Rose Bengal stains, was performed. Ocular surface flora culture swabs were collected for microbiology in four salamanders. Rocuronium bromide (50 µL; 0.01 mg) was administered into each eye in three salamanders. Pupil size and constriction ability were evaluated up to 60 min following administration of rocuronium bromide. Distant visual examination and Doppler heart rate were used to monitor for potential adverse effects of rocuronium bromide. RESULTS: Observed ocular abnormalities included lipid keratopathy/keratitis (19%; 3/16), parasitic ophthalmitis (19%; 3/16), and cataracts (6.3%; 1/16). A significant difference was found between tonometry with iCare® TonoVet (11.5 ± 2.7 mmHg) versus TonoVet Plus (15.4 ± 3.7 mmHg) (p = .025). Fluorescein and Rose Bengal stains were negative in all salamanders. Ocular surface microbiology revealed a high incidence of contamination from environmental flora, with the most common isolate being unidentified as Gram-negative nonfermenters (75%; 3/4). No significant change in pupil size or constriction ability was observed with rocuronium bromide. CONCLUSION: This is the first study to document ocular examination findings and diagnostics in captive and wild urodeles and may serve as a reference for clinical assessment and future studies of the Western tiger salamander.

Long-term effect of oral cannabidiol administration to healthy adult dogs on tear production, intraocular pressure, and tear concentrations.

OBJECTIVE: To determine the chronic effects of oral cannabidiol (CBD) use on tear production, intraocular pressure (IOP), and concentration of CBD in tears of healthy dogs. ANIMALS STUDIED: Eighteen healthy research Beagles. PROCEDURES: This was a masked, placebo-controlled, randomized prospective study. Eighteen dogs were randomly assigned to three groups (six dogs per group) based on daily dosage of oral MCT oil (placebo), CBD 5 mg/kg, and CBD 10 mg/kg. Schirmer tear test (STT-1) and IOP were measured twice daily (7 am and 7 pm) every 4 weeks for 36 weeks. Week 36 tears were collected and analyzed for CBD concentrations (ng/mL) using liquid chromatography/mass spectrometry. A mixed linear model was used as the statistical method and p-value <.05 was considered significant. RESULTS: No significant differences were found between placebo vs. 5 mg/kg vs. 10 mg/kg for STT-1 or IOP (AM and PM). CBD was detected in 10 out of 11 (91%) viable tear samples receiving 5 mg/kg or 10 mg/kg dosages. One sample in the 5 mg/kg group had inadequate tear volume for analysis. The CBD concentration in tears was at or below the lower limit of quantification in placebo group, 4.12-11.2 ng/mL for the 5 mg/kg group, and 6.22-152 ng/mL for the 10 mg/kg group. CONCLUSIONS: Long-term administration of oral CBD in healthy research beagles demonstrates a favorable safety profile regarding ocular tolerability. Oral CBD administration does not appear to affect tear production or IOP over a 36-week period. This is the first canine study positively identifying concentrations of CBD in tears following oral administration.

Iridial melanocytoma in a ferruginous hawk (Buteo regalis): A case report and review of avian melanocytic neoplasia.

A 21-year-old, suspected female captive ferruginous hawk (Buteo regalis) was followed for 3 years due to an iridial mass of the left eye (OS) that progressively increased in size. Enucleation of OS was eventually recommended due to the iridial mass taking up approximately 75% of the anterior chamber, and the bird seemed less active. A complete physical examination, complete blood cell count, biochemistry, and survey radiographs were performed pre-surgery with no findings indicating metastasis. A subconjunctival enucleation was performed and the globe was submitted for histopathology through the Comparative Ocular Pathology Lab of Wisconsin. The histopathologic evaluation determined the mass to be consistent with an iris melanocytoma, which has not been previously reported in this species. The patient recovered well from surgery and has remained comfortable and active for 117 days post-surgery. This case report aimed to review the current available information on avian ocular neoplasms as well as describe the clinical presentation, medical management and surgical procedure, and long-term follow-up for this patient to enhance clinical understanding of the behavior of iris melanocytic tumors in avian species.

Increase in infected corneal ulcerations in dogs during the northern Colorado's 2020 wildfire season.

OBJECTIVE: In the fall of 2020, Colorado experienced the two largest wildfires in state history. The smoke blanketed the college town of Fort Collins, Colorado, the location of the Veterinary Teaching Hospital at Colorado State University (CSU-VTH). The objective for this cross-sectional observational study was to evaluate how these wildfires and the corresponding elevated air quality index (AQI)) was associated with infected corneal ulcerations in dogs when compared to the two previous years. ANIMALS: Seventeen dogs were included in this study. PROCEDURES: Medical records from dogs presented to the CSU-VTH ophthalmology service with infected corneal ulcerations in August, September, and October of 2020, 2019, and 2018 were evaluated. Only corneal ulcerations with growth on their microbial cultures were included in this study. RESULTS: The study revealed a significant increase in prevalence of infected corneal ulcerations in dogs presented to the CSU-VTH during the three wildfire months of 2020 that is, 3.5% (9/255) when compared with the two previous years, 2019: 1.0% (4/383, p = 0.04), and 2018: 0.9% (4/457) (p = .01). The AQI (mean ± standard error) was also significantly elevated for dogs that presented with infected corneal ulcerations in 2020 (70.2 ± 5.8) compared with 2019 (19.7 ± 8.7) and 2018 (45.6 ± 8.7) (p < .01). CONCLUSIONS AND CLINICAL RELEVANCE: Elevation of AQI from wildfires seems to be correlated with an increased prevalence of infected corneal ulceration in dogs. As the duration and frequency of wildfires continues to rise globally, the effects of these wildfires on animal health should be investigated further.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Ocular anatomy and correlation with histopathologic findings in two common octopuses (Octopus vulgaris) and one giant Pacific octopus (Enteroctopus dofleini) diagnosed with inflammatory phakitis and retinitis.

PURPOSE: Review octopus ocular anatomy and describe the histopathologic findings in three octopuses diagnosed with phakitis and retinitis. ANIMALS: Two common octopuses (Octopus vulgaris) and one giant Pacific octopus (Enteroctopus dofleini) with a history of ophthalmic disease. METHODS: A literature search was performed for the ocular anatomy section. Both eyes from all three octopuses, and two control eyes, were submitted for histopathologic evaluation. Hematoxylin and eosin stain was used for standard histopathologic evaluation; GMS stain was used to screen for fungi, gram stain for bacteria; and Fite's acid fast stain for acid fast bacteria. RESULTS: Anatomically, the anterior chamber of the octopus has direct contact with ambient water due to an opening in the dorsal aspect of a pseudocornea. The octopus lens is divided into anterior and posterior segments. The anterior half is exposed to the environment through the opening into the anterior chamber. Neither part of the lens has a lens capsule. The retina is everted, unlike the inverted vertebrate retina, and consists of just two layers. Histopathology revealed inflammatory phakitis and retinitis of varying severity in all six eyes of the study animals. No intraocular infectious organisms were recognized but one common octopus eye had clusters of coccidian parasites, identified as Aggregata sp., in extraocular tissues and blood vessels. CONCLUSION: We describe inflammatory phakitis and retinitis in two species of octopuses. The underlying cause for the severe intraocular response may be direct intraocular infection, water quality, an ocular manifestation of a systemic disease, or natural senescence.

Unfolding the diagnosis of subspectacular fluid opacity in a corn snake (Pantherophis guttatus).

OBJECTIVE: To present the results of clinical, surgical, and histopathologic procedures and how these were compared with the initial presumptive clinical diagnosis in a corn snake (Pantherophis guttatus) presenting with subspectacular fluid opacity; and to improve upon currently established surgical enucleation techniques in the snake. ANIMAL STUDIED: An 8-month-old corn snake was presented for enlarged globe OD. PROCEDURES: The following diagnostics were performed: systemic and ophthalmic examinations, complete blood count, cytology and culture of subspectacular fluid, and histopathology of enucleated globe and spectacle. Enucleation was performed in a routine fashion with the addition of a porcine small intestinal submucosa bioscaffold graft (SISplus™; Avalon Medical, Stillwater, MN), sutured over the orbit. RESULTS: Systemic examination revealed signs of maxillary stomatitis. Ophthalmic examination revealed semitransparent fluid in the subspectacular space. Complete blood count was unremarkable. Cytology of fluid obtained via subspectacular centesis was acellular, and culture grew Clostridium perfringens, which was consistent with the clinical suspicion of right maxillary stomatitis. Histopathology of the enucleated globe revealed spectaculitis, characterized by regional heterophilic inflammation, and no evidence of lymph dissection in the (peri)ocular tissues. The final diagnosis was a subspectacular abscess. Follow-up revealed that the SIS graft provided excellent healing and cosmesis of the surgical site. CONCLUSIONS: While there are reports of lymphatic fluid dissection between skin layers during ecdysis, which can result in an opaque spectacle, the fluid opacity in this case was attributed to a subspectacular abscess secondary to an ascending oral infection. Addition of biological wound dressing may contribute to positive post-enucleation outcome in the snake.

Ocular findings and selected ophthalmic diagnostic tests in a group of young commercially available Guinea and Skinny pigs (Cavia porcellus).

OBJECTIVE: The purpose of this study is to evaluate a group of young commercially available Skinny pigs, to gain information regarding ocular findings in this breed of guinea pig. Comparisons of ocular findings are to be made between Skinny pigs and haired guinea pigs. ANIMAL STUDIED: Ten haired guinea pigs and ten Skinny pigs were examined. PROCEDURE: A complete ophthalmic examination including Schirmer tear test-II (STT-II), phenol red thread test (PRTT), rebound tonometry with TonoVet PLUS, Fluorescein and Rose Bengal stain was performed. Microbiology swabs for aerobic bacterial growth were collected from conjunctiva of both eyes prior to the ophthalmic examination. RESULTS: The ophthalmic examination revealed seven abnormal ocular findings: trichiasis, mucopurulent discharge, hyperemia/chemosis of the conjunctiva, corneal fibrosis, corneal vascularization, and foreign body on the cornea or conjunctiva. Skinny pigs had a significantly higher amount of mucopurulent discharge (P = .0133) and a significantly higher STT-II (P < .001) than haired guinea pigs. Although not significant, trichiasis, keratitis with corneal vascularization, and foreign body presence were more common in Skinny pigs. Significantly more Skinny pigs had Pasteurellaceae isolated from their conjunctiva than haired guinea pigs (P = .0112). Antimicrobial susceptibility for the five Pasteurellaceae organisms isolated revealed susceptibility toward oxytetracycline, tobramycin, ciprofloxacin, and ofloxacin, whereas resistance was found toward erythromycin, trimethoprim-sulfamethoxazole, and moxifloxacin. CONCLUSION: Young Skinny pigs have a higher risk of Pasteurellaceae-associated conjunctivitis. Oxytetracycline, tobramycin, ciprofloxacin, and ofloxacin were identified as topical antibiotics that may be useful for Pasteurellaceae-associated conjunctivitis in Skinny pigs.

Treatment of canine postoperative ocular hypertension with combined latanoprost 0.005% and atropine 1% ophthalmic solutions.

OBJECTIVE: To compare the effects of topical 0.005% latanoprost (L) vs combined 0.005% latanoprost and 1% atropine (LA) on control of postoperative ocular hypertension (POH), development of posterior synechiae formation, pupil size, and blindness after phacoemulsification surgery in dogs. ANIMAL STUDIED: Dogs with postoperative ocular hypertension were included in the study: L-group, latanoprost (eight dogs, 14 eyes) and LA-group, latanoprost and atropine (nine dogs, 15 eyes). PROCEDURES: Complete ophthalmic examinations including tonometry were performed at 1, 7, and 21 days following phacoemulsification. RESULTS: No significant differences were found between the measured intraocular pressure (IOP) at days 1 and 7 postphacoemulsification surgery in the L-group and the LA-group (P = 0.26 [14.12 ± 1.76 mmHg vs 16.96 ± 1.68 mmHg] and P = 0.71 [15.45 ± 1.43 mmHg vs 16.20 ± 1.36 mmHg], respectively). No significant differences were found between pupil sizes at day 7 for the two groups (P = 0.25 [13.83% vs 24.77%]). No significant differences were found between odds of posterior synechiae formation at day 21 (P = 0.92) with a probability ± SE for L-group vs LA-group at 0.27 ± 0.14 vs 0.25 ± 0.13. No significant differences were found in odds of postoperative blindness between groups (P = 0.58) with a probability ± SE of 0.21 ± 0.11 vs 0.13 ± 0.09, respectively for L and LA. CONCLUSIONS: Combined topical latanoprost and atropine in dogs maintains normal postoperative IOPs but does not seem to cause increased mydriasis compared to latanoprost alone.

Standing ophthalmic surgeries in horses.

Standing ophthalmic surgery without general anesthesia allows for several routine ophthalmic procedures including eyelid lacerations and enucleations to be performed in the horse, but does contain increased risk of causing tissue damage arising from the inability to eliminate eye and head movements. Heavy sedation and local nerve blocks of the involved motor and sensory nerves are essential in achieving a good outcome from ophthalmic surgery in the nonanesthetized horse. The inability to use an operating microscope in standing surgery in horses prevents performing precise corneal and intraocular microsurgeries.

Equine deep stromal abscesses (51 cases - 2004-2009)--Part 2: the histopathology and immunohistochemical aspect with attention to the histopathologic diagnosis, vascular response, and infectious agents.

PURPOSE: To investigate histopathologic and immunohistochemical aspects of equine deep stromal abscesses (DSA) with a focus on the histopathologic diagnosis, presumptive etiology, and the immunohistochemical expression of three angiogenesis-related factors: vascular endothelial growth factor-A (VEGF-A), pigment epithelium-derived factor (PEDF), and interleukin-1 receptor antagonist (IL-1ra). SAMPLE POPULATION: Paraffin-embedded biopsy samples from 51 DSA. The biopsies were collected from full-thickness penetrating keratoplasty or split-thickness lamellar keratoplasty surgeries at the University of Florida Veterinary Medical Center in the period from 2004 to 2009. PROCEDURE: The histopathologic and immunohistochemical findings were tested for association between each other. Prevalence calculation and test for association with qualitative data analysis was used for data evaluation. RESULTS: Fungal hyphae were found histologically in 47.1% (n = 24) of the DSA cases. Histopathologically, most fungal DSA showed suppurative keratitis (n = 34; 66.7%) and little to no stromal vascularization infiltrating the abscess (negative association, P = 0.005). All three angiogenesis-related factors were expressed to some degree in DSA tissue. A negative association between VEGF-A and PEDF when compared to the presence of fungal hyphae (P < 0.001, P = 0.023) indicated that cases positive for these two factors will most probably not have fungal hyphae present. CONCLUSION: Abnormally decreased VEGF-A expression is suggested as the reason for the slow vascularization and delayed resolution of fungal DSA, whereas PEDF and IL-ra did not seem to have any influence on the vascularization process. Clinical and histopathologic characteristics of DSA make it possible to suggest an etiology for an equine DSA with an unknown etiology.

Equine deep stromal abscesses (51 cases - 2004-2009)--Part 1: the clinical aspects with attention to the duration of the corneal disease, treatment history, clinical appearance, and microbiology results.

OBJECTIVE: To study the equine deep stromal abscesses (DSA) with focus on the duration of the corneal disease, medical treatment, season of presentation, clinical appearance, and the degree of corneal vascularization. MATERIAL AND METHODS: Equine DSA diagnosed, biopsied, and surgically treated at the University of Florida Veterinary Medical Center (UFVMC) from 2004 to 2009 were identified. The medical record, clinical photographic images, and microbiology results for each case were evaluated. Frequency and prevalence calculation as well as qualitative data analysis was performed for clinical and microbiological data. RESULTS: Fifty-one equine DSA were included in the study. Spring (March, April, May; 33.4%) and winter (December, January, February; 31.4%) were the most common seasons for DSA presentation. The 51 cases were divided into four categories of focal opacity from their clinical appearance: focal yellow (45.2%), focal white (23.5%), diffuse yellow/white (23.5%), and focal pink (7.8%). 5.9% of the DSA (n = 3) were culture positive for fungal growth, whereas 17.6% were positive for bacterial growth (n = 9). No association between short-/long-term systemically administered NSAID treatment and the corneal vascular response to the corneal lesion could be appreciated. CONCLUSION: Equine DSA most often present in the spring and winter in the subtropical environment of the state of Florida (USA). The clinical appearance may have a connection with the etiology and pathogenesis of the equine DSA. No connection between short- or long-term systemically administered NSAID and the degree of corneal vascularization of the DSA was noted.