Case report: Management and long-term ophthalmic sequelae of monogenean ocular infestation in cownose rays (Rhinoptera bonasus).

Monogenean ectoparasitic flatworm infestations, particularly in closely confined populations, can result in severe epizootic disease that is often devastating and occasionally fatal. This case series describes a population of cownose rays (Rhinoptera bonasus) (n = 52) housed in an aquarium touch-tank exhibit that presented with severe ocular disease due to infestation with monogeneans, presumably Benedeniella posterocolpa of the Capsilidae family. The most severely affected individuals (n = 9), including several cases with bilaterally ruptured corneas, underwent serial examinations prior to and following treatment with praziquantel, systemic antibiotics, and corticosteroids. The entire population underwent frequent therapeutic water changes with a scheduled decrease in salinity, increase in temperature, and a series of seven praziquantel tank treatments. At the last follow up examination (3.75 years), the most common ocular findings were corneal fibrosis (18/18 eyes; 100%), cataract formation (13/18 eyes; 72.2%), synechia (8/18 eyes; 44.4%), and dyscoria (5/18 eyes; 27.8%). Despite severe corneal disease, including corneal rupture, all examined eyes (18/18; 100%) showed remarkable corneal remodeling and a largely clear visual axis. There are very few reports describing corneal disease in aquarium housed elasmobranchs, and no reports describe ophthalmic implications of monogenean infestation in these animals. This further underscores the importance of this case series in demonstrating the capacity for healing of elasmobranch eyes and can provide further guidance regarding prognosis and treatment in cases of severe corneal disease.

Efficacy of the topical antihistamine olopatadine in dogs with experimentally induced allergic conjunctivitis.

OBJECTIVE: The objective of the study was to evaluate the efficacy of a once a day, over the counter antihistamine eye drop, 0.7% olopatadine hydrochloride, in treating or preventing experimentally induced allergic conjunctivitis in dogs. ANIMALS STUDIED: Twelve systemically healthy pet dogs with no known history of allergies or atopic dermatitis, and in the past 12 months had no known ocular abnormalities. PROCEDURES: Dogs were randomly assigned to two groups: "Treatment" which received topical 0.7% olopatadine hydrochloride and "Control" which received artificial tears. Dogs received the antihistamine eye drops before (Phase 1) or after (Phase 2) receiving a compounded ophthalmic histamine solution to induce clinical signs of allergic conjunctivitis. Conjunctival hyperemia, chemosis, follicles, ocular discharge, and ocular pruritus were graded, and photographs were used to document changes. Schirmer tear test values, fluorescein staining, and intraocular pressures were monitored throughout. RESULTS: In both Phase 1 and Phase 2, conjunctival scores increased 10 min after histamine administration (p < .05). There was no difference between maximum overall conjunctival scores between treatment and control groups in either phase or when comparing treatment groups of Phase 1 to Phase 2 (p > .05). However, treatment groups in Phase 2 did have a higher maximum conjunctival chemosis score and spent more time at their maximum chemosis score when compared to Phase 1 (p < .05). CONCLUSION: Olopatadine may be beneficial as prophylaxis to reduce the degree and duration of clinical signs of allergic conjunctivitis.

Evaluation of a commercial NGS service for detection of bacterial and fungal pathogens in infectious ulcerative keratitis.

OBJECTIVES: To compare results from a commercial next-generation sequencing (NGS) service to corneal cytology and culture for identification of causative organisms in veterinary patients presenting for infectious ulcerative keratitis (IUK). PROCEDURE: Swabs for corneal aerobic and fungal cultures and DNA swabs for NGS were submitted for canine and equine normal controls (n = 11 and n = 4, respectively) and IUK patients (n = 22 and n = 8, respectively) for which microbrush cytology specimens confirmed the presence of infectious organisms. The sensitivity of the NGS results was compared with bacterial and fungal culture results. Concordance between the NGS and culture results was determined. RESULTS: The NGS results were positive for bacterial and fungal organisms in 5 and 1 normal and 18 and 1 IUK cases, respectively. Bacterial and fungal cultures were positive for 7 and 2 normal and 20 and 5 IUK cases, respectively. Sensitivity of NGS was 82.14% (95% confidence interval (CI), 63.11% to 93.94%) and specificity was 76.47% (95% CI, 50.10% to 93.19%). Concordance (complete and partial) between identified bacterial and fungal organisms was found in 79% and 100% of cases, respectively. NGS identified organisms in 3 culture-negative IUK samples. CONCLUSION: A commercial NGS service may be useful in the identification of causative agents in IUK cases with a sensitivity greater than the sensitivity previously reported for aerobic culture. Further testing is needed to determine the clinical significance of additional organisms isolated by NGS from infected cases, as well as organisms isolated from normal corneas.

Effects of gabapentin and trazodone on electroretinographic responses in clinically normal dogs.

OBJECTIVE: To compare electroretinographic (ERG) responses obtained in dogs before and after oral administration of gabapentin, trazodone, and a combination of both medications. ANIMALS: 12 clinically normal dogs. PROCEDURES: A short-protocol ERG with 20 minutes of dark adaption was recorded for all dogs to establish baseline ERG responses. Dogs then received gabapentin (approx 30 mg/kg), trazadone (approx 20 mg/kg or approx 5 mg/kg), or a combination of gabapentin (approx 20 mg/kg) and trazodone (approx 5 mg/kg) orally, and the same ERG protocol was repeated 2 hours later. Dogs were given a washout period of at least 1 week between treatments. RESULTS: a-Wave amplitudes were significantly (P = 0.018) decreased after administration of the combination of gabapentin and trazodone. b-Wave amplitudes were significantly decreased after administration of the 20-mg/kg dose of trazodone (P = 0.006) and after administration of the combination of gabapentin and trazodone (P = 0.002). Heavier dogs that received higher total doses of trazodone had decreases in a-wave amplitude after administration of the 20-mg/kg dose of trazodone and in b-wave amplitude after administration of the 5-mg/kg dose of trazodone. CLINICAL RELEVANCE: High doses of trazodone and the combination of gabapentin and trazodone significantly decreased a-wave and b-wave amplitudes in clinically normal dogs. However, the effects on retinal responses had little clinical importance. Therefore, these medications can be used safely in a clinical setting; however, further studies are needed in dogs with retinal disease.

Canine endotheliitis: Clinical characteristics, advanced imaging features, and treatment.

OBJECTIVE: To describe the clinical findings, multimodal corneal imaging features and treatment in canine patients diagnosed with endotheliitis. ANIMALS STUDIED: Four canine patients met inclusion criteria for bilateral corneal disease with endothelial inflammation and secondary corneal edema that responded to topical anti-inflammatory treatment. METHODS: The patients selected underwent a complete ophthalmic examination with emphasis on the cornea including ultrasound pachymetry (USP), Fourier-domain optical coherence tomography (FD-OCT), in vivo confocal microscopy (IVCM), and digital slit lamp photography. RESULTS: All patients in this study demonstrated thickened corneas due to edema with USP and FD-OCT. With IVCM, mild to severe polymegathism and pleomorphism of corneal endothelial cells, reduced endothelial cell density, hyperreflective keratic precipitates (KPs), and extracellular debris as well as hyporeflective pseudoguttata were observed. With FD-OCT, hyperreflective KPs were commonly observed on the inferior cornea. Clinical examination and advanced imaging results were consistent with a diagnosis of endotheliitis. All patients initially responded to topical anti-inflammatory treatment and required continued therapy; two patients also received topical netarsudil, a rho-associated coiled-coil kinase inhibitor. CONCLUSION: Endotheliitis should be considered for canine patients with bilateral edema that is most severe in the inferior cornea. Careful inspection of Descemet's membrane-endothelial complex should be performed for KPs or inflammatory debris. Chronic administration of topical anti-inflammatories may be necessary to prevent flare-ups of endotheliitis.

An unusual case of eosinophilic uveitis in a cat.

An 8-year-old female spayed domestic short-haired cat was examined for recurrent unilateral anterior uveitis of 5 month's duration. No underlying cause was found on infectious disease screening. The cat also had a 4-year history of allergic or immune-mediated skin disease that was controlled with corticosteroid injections followed by long-term oral cyclosporine therapy. Medical management with frequent topical anti-inflammatory drugs (prednisolone acetate 1% suspension, diclofenac 0.1% solution) controlled the intraocular inflammation; however, the uveitis would relapse when therapy was discontinued. Eventually, secondary glaucoma developed OD and the eye was enucleated. At the time of surgery, a complete blood count showed a mild eosinophilia. Histopathology revealed a marked panuveitis characterized by an abundant accumulation of mixed inflammatory cells, with a predominantly eosinophilic infiltrate in the anterior chamber, iris, ciliary body, and choroid. No etiologic agents were found on serial sections, and there were no cellular criteria for malignancy noted. Nine months after enucleation, the chronic dermatitis appeared to be in remission despite no further medical management. This is the first known report of a primarily eosinophilic uveitis in a cat with chronic allergic skin disease and may be considered an ocular variant of feline eosinophilic granuloma complex.

The effect of central corneal thickness on intraocular pressure values using various tonometers in the dog.

OBJECTIVE: To compare intraocular pressure readings from three different tonometers, the Tono-Pen AVIA® (TP), TonoVet® (TV) and TonoVet Plus® (TV+) and to determine how measurements from each tonometer are affected by central corneal thickness (CCT). ANIMALS: Ninety dogs. PROCEDURES: Normal dogs and dogs with ocular disease were selected for study inclusion. Central corneal thickness measurements were gathered with the Pachette 4 ultrasonic pachymeter, and IOP measurements were gathered with the three tonometers in random order. ANOVA or Wilcoxon tests were utilized for overall group comparisons. Linear regression analyses were utilized to determine the association between IOP and CCT. RESULTS: When comparing tonometers to each other, for all dogs, readings from the TV+were significantly different compared to the TV (p = <.0001) and TP (p = <.0001); however, there was no significant difference between the TV and the TP (p = .999). Linear regression did not find any significant correlation between corneal thickness and IOP readings with any tonometer when looking at normal dogs or when including dogs with ocular abnormalities. DISCUSSION: This study did not find a significant correlation between an increase in CCT and increase in IOP reading in any tonometer comparison amongst normal and dogs with ocular abnormalities. The TV+produced consistently and significantly higher readings, but measurements did not exceed the expected IOP range in normal dogs. For consistency, the same tonometer should be used when monitoring IOP over time.

Using minimum inhibitory concentration values of common topical antibiotics to investigate emerging antibiotic resistance: A retrospective study of 134 dogs and 20 horses with ulcerative keratitis.

OBJECTIVES: To identify the minimum inhibitory concentration (MIC) distribution for commonly used topical antibiotics from isolates of dogs and horses with ulcerative bacterial keratitis, and to investigate changes in MIC values over time and following treatment with topical fluoroquinolones. ANIMALS STUDIED: One hundred thirty-four client-owned dogs and 20 client-owned horses with bacterial ulcerative keratitis. PROCEDURE: Minimum inhibitory concentration values for 14 topical antibiotics were reported for canine and equine cases of bacterial ulcerative keratitis between 2013 and 2018. Changes in MIC values over time and after treatment with topical fluoroquinolones were reported. RESULTS: The three most common bacterial genera isolated were Staphylococcus, Streptococcus, and Pseudomonas. Together, these represented 79.4% of canine cases and 77.4% of equine cases. Overall, isolates from horses tended to have lower MIC values, as did Pseudomonas isolates from both dogs and horses, compared to other bacterial genera, especially Staphylococcus spp. The MIC values of erythromycin and trimethoprim sulfa for Staphylococcus spp., and the MIC value of moxifloxacin for Pseudomonas significantly increased over time. Previous topical fluoroquinolone use was associated with a significant increase in the MIC value of ofloxacin in canine and equine Staphylococcus isolates and current topical fluoroquinolone use was associated with significant increases in the MIC values of ciprofloxacin, moxifloxacin, and ofloxacin in canine Staphylococcus isolates. CONCLUSION: Patients previously or currently treated with topical fluoroquinolones, particularly in Staphylococcus infections, may require alternative antibiotics or additional antibiotic classes other than fluoroquinolones. Bacterial culture with MIC susceptibility testing should be highly recommended when a Staphylococcal infection is suspected.

Efficacy of long-term topical flurbiprofen in limiting lens capsule opacities following phacoemulsification in dogs.

OBJECTIVE: To assess lens capsule opacity (LCO) following phacoemulsification in dogs receiving long-term topical ophthalmic flurbiprofen sodium 0.03%. ANIMAL STUDIED: Twenty-five client owned dogs undergoing phacoemulsification surgery for either diabetic or nondiabetic cataracts. METHODS: Prospective, randomized, masked clinical study assessing two groups of dogs for twelve months following phacoemulsification. All dogs underwent a complete eye examination and were photographed at each visit, beginning three weeks post-surgery, and repeated at 2, 3, 6, and 12 months post-surgery. Post-operative treatment protocols were similar for both groups, except that Group F received topical flurbiprofen once daily for 12 months and Group A received artificial tears once daily for 12 months. Digital photographs were analyzed for LCO using a subjective grading scale (0-4). The change in capsular opacities from 3 weeks to 12 months post-surgery was evaluated for each dog, and the groups were compared. RESULTS: There were 25 dogs evaluated post-phacoemulsification at each designated time point of the study. There were 12 dogs in Group A and 13 dogs in Group F. There was no significant statistical difference in LCO score between Groups A and F at baseline (3 weeks post-surgery), 6 months post-surgery, or 12 months post-surgery. Scores did not change significantly from baseline to 12 months within or between groups. CONCLUSIONS: Topical ophthalmic flurbiprofen sodium 0.03% solution applied once daily for 12 months following phacoemulsification does not appear to lead to a decrease in LCO formation as compared to artificial tears control.

Phacoemulsification outcomes in Boston terriers as compared to non-Boston terriers: a retrospective study (2002-2015).

OBJECTIVES: To compare visual outcome and cause of blindness between two groups of dogs undergoing phacoemulsification. ANIMALS STUDIED: Study population consisted of 35 Boston terriers (BT; 70 eyes) and 77 non-Boston terriers (NBT; 154 eyes) that underwent bilateral phacoemulsification surgery. PROCEDURES: Medical records were reviewed to determine visual outcome, complications leading to blindness and follow-up. A Kaplan-Meier survival curve was used to estimate surgical success at 1 and 2 years postoperatively. RESULTS: Eleven of 35 BT developed known vision loss, with 12 of 70 (17.1%) eyes becoming blind within one year of surgery, and 17 of 77 NBT developed known vision loss, with 19 of 154 (12.3%) eyes becoming blind within 1 year of surgery. No further vision loss was reported among those BT with a 2-year follow-up. In the NBT group, seven additional dogs, a total of 24 of 77 NBT developed vision loss, with a known total of 31 of 154 (20.1%) eyes becoming blind within two years of surgery. These results were not significantly different. The overall surgical success in both groups based on individual eyes was estimated to be between 80 and 90% at 1 year postsurgery and between 65 and 80% at 2 years postsurgery. Glaucoma was the leading cause of vision loss in both groups. CONCLUSIONS: There was no significant difference in visual outcomes between a group of BT and a group of NBT undergoing bilateral phacoemulsification at the University of Tennessee between 2002 and 2015. Glaucoma was the leading cause of vision loss in both groups.

Plasma bupivacaine concentrations following orbital injections in cats.

OBJECTIVE: To determine plasma bupivacaine concentrations after retrobulbar or peribulbar injection of bupivacaine in cats. STUDY DESIGN: Randomized, crossover, experimental trial with a 2 week washout period. ANIMALS: Six adult healthy cats, aged 1-2 years, weighing 4.6 ± 0.7 kg. METHODS: Cats were sedated by intramuscular injection of dexmedetomidine (36-56 µg kg-1) and were administered a retrobulbar injection of bupivacaine (0.75 mL, 0.5%; 3.75 mg) and iopamidol (0.25 mL), or a peribulbar injection of bupivacaine (1.5 mL, 0.5%; 7.5 mg), iopamidol (0.5 mL) and 0.9% saline (1 mL) via a dorsomedial approach. Blood (2 mL) was collected before and at 5, 10, 15, 22, 30, 45, 60, 120, 240 and 480 minutes after bupivacaine injection. Atipamezole was administered approximately 30 minutes after bupivacaine injection. Plasma bupivacaine and 3-hydroxybupivacaine concentrations were determined using liquid chromatography-mass spectrometry. Bupivacaine maximum plasma concentration (Cmax) and time to Cmax (Tmax) were determined from the data. RESULTS: The bupivacaine median (range) Cmax and Tmax were 1.4 (0.9-2.5) µg mL-1 and 17 (4-60) minutes, and 1.7 (1.0-2.4) µg mL-1, and 28 (8-49) minutes, for retrobulbar and peribulbar injections, respectively. In both treatments the 3-hydroxybupivacaine peak concentration was 0.05-0.21 µg mL-1. CONCLUSIONS AND CLINICAL RELEVANCE: In healthy cats, at doses up to 2 mg kg-1, bupivacaine peak plasma concentrations were approximately half that reported to cause arrhythmias or convulsive electroencephalogram (EEG) activity in cats, and about one-sixth of that required to produce hypotension.

Malassezia spp on the periocular skin of dogs and their association with blepharitis, ocular discharge, and the application of ophthalmic medications.

OBJECTIVE: To determine how frequently Malassezia spp were identified on the periocular skin of dogs and assess the respective associations between the presence of Malassezia spp on the periocular skin and blepharitis, ocular discharge, and the application of ophthalmic medications. DESIGN: Prospective clinical study. ANIMALS: 167 eyelids of 84 dogs. PROCEDURES: Samples obtained from the surface of the eyelid skin by use of adhesive tape were evaluated cytologically for the presence of Malassezia spp. Dogs were grouped on the basis of the presence of blepharitis, nature of ocular discharge, and whether ophthalmic medications were applied, and the proportion of samples with Malassezia spp was compared among the groups. RESULTS: Malassezia spp were detected in 19 samples, of which 15 were obtained from eyes without blepharitis and 14 were obtained from eyes treated with topical ophthalmic medications. The proportion of samples with Malassezia spp was significantly higher for eyes with ocular discharge than for eyes without ocular discharge, especially if that discharge was mucoid or mucopurulent, and for eyes that were treated with aqueous-based medications only or a combination of oil- and aqueous-based medications than for eyes that were not treated. CONCLUSIONS AND CLINICAL RELEVANCE: Malassezia organisms were detected on the periocular skin of 3 of 56 (5%) clinically normal dogs. Malassezia organisms were also frequently found on the periocular skin of dogs that had mucoid or mucopurulent ocular discharge or that were administered topical aqueous-based ophthalmic medications, and the periocular skin of these dogs should be cytologically evaluated for Malassezia organisms.