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Objective: To determine the impact of chronic dental disease on the nasolacrimal duct of chinchillas using contrast CT dacryocystorhinography., Animals Studied: Two 12-year-old female chinchillas with uni- or bilateral ocular discharge and a history of chronic, moderate (Chinchilla 1, one-year) or severe (Chinchilla 2, three-years) dental disease., Procedures: Contrast CT dacryocystorhinography was performed to identify abnormalities in the nasolacrimal duct and dentition, and to correlate those changes., Results: Chinchilla 1 had a focal soft tissue attenuating expansion of the maxillary bone rostral to the first left premolar interpreted as possible abscessation causing deviation of the nasolacrimal duct over its dorsomedial margin. The right nasolacrimal duct appeared normal. Chinchilla 2 had periapical abscessation of a retained subgingival left maxillary incisor fragment which extended into the nasal cavity causing focal narrowing and distal dilation of the left nasolacrimal duct. Complete contrast infusion of the right nasolacrimal duct could not be completed on Chinchilla 2. A focal area of superficial corneal fibrosis ipsilateral to the obstructed nasolacrimal duct was also identified in Chinchilla 2. Treatment consisted of occlusal adjustments to correct the coronal elongation, systemic antibiotics (metronidazole and either marbofloxacin or azithromycin), and topical tear replacement therapy and diclofenac as needed. Ocular discharge decreased in both chinchillas but did not resolve long-term in either animal., Conclusions: Chronic dental disease including periapical abscessation in chinchillas can obstruct the nasolacrimal duct, leading to impaired tear drainage. Management of dental disease is crucial to maintain patency of the nasolacrimal duct., (© 2024 The Author(s). Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists.)

Objective: To describe normative ocular surface and aqueous tear testing data for cats of various cephalic conformation., Animals Studied: Fifty-three healthy adult cats (11 British Shorthair, 11 Burmese, 10 Devon Rex, 10 Scottish Fold, and 11 Sphynx)., Procedures: Blink rate, corneal tactile sensation (CTS), and Schirmer tear test with or without topical anesthesia (STT-1, STT-2) and with nasolacrimal stimulation (NL-STT1, NL-STT2) were assessed. Palpebral fissure length (PFL) and skull morphology were measured, and cephalic index (CI) and craniofacial ratio (CFR) calculated., Results: Mean ± SD test results were as follows: blink rate (5.0 ± 2.3 blinks/min), CTS (3.2 ± 0.7 cm), STT-1 (11.2 ± 4.3 mm/min), STT-2 (6.7 ± 3.6 mm/min), NL-STT1 (13.4 ± 5.7 mm/min), NL-STT2 (13.5 ± 5.2 mm/min), and PFL (2.0 ± 0.2 cm). Corneal sensitivity did not differ significantly among breeds (p = .152) but was negatively correlated with body weight (r = -.32, p = .019). STT-1 significantly differed among breeds (p < .001) and was lowest in Sphynx cats (8.7 ± 4.3 mm/min). A positive correlation was detected between STT-1 values at 30 and 60 s (r = .98; p < .001). The nasolacrimal reflex significantly increased STT in anesthetized and unanesthetized eyes (approximately +100% and +20%, respectively; p ≤ .002). STT-1 tended to be higher in intact versus neutered cats (p = .062). Age did not impact any test result (p ≥ .085)., Conclusions: Normative data described here serve as a baseline for future studies assessing ocular surface disease in multiple feline breeds. Unlike dogs, brachycephalic cats did not have lower CTS or STT-1 than non-brachycephalic cats., (© 2022 The Authors. Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists.)

Objective: To assess correlations between clinical and cytological features of feline eosinophilic keratoconjunctivitis at the time of cytological diagnosis., Animals Studied: Fifteen client-owned, domestic breed cats (18 eyes) examined between 2007 and 2019., Procedures: An electronic search and medical record review of cats diagnosed with feline eosinophilic keratitis or keratoconjunctivitis (FEK) based on clinical examination findings and eosinophils detected on corneal cytology were conducted. Clinical severity was graded using a modified version of a previously validated semiquantitative preclinical ocular toxicology scoring (SPOTS) system. Clinical grades were assigned following review of clinical images and medical record descriptions, and cytological grades were assigned following review of archived corneal cytology slides. Correlations were analyzed for significance using Spearman's rank correlation coefficient., Results: Higher total corneal scores correlated with higher total conjunctival scores, but not with total fluorescein scores. Small lymphocyte scores correlated negatively with scores for collagen degeneration or mineralization. Globule leukocytes, a unique cell type not previously described in ocular cytology, were identified in 4 of 18 cytological samples. Higher globule leukocyte scores were correlated with higher scores for mast cells or plasma cells. Specimens with lower eosinophil scores had higher globule leukocyte scores., Conclusions: Large variability was detected in the cytological characteristics and clinical features of FEK-affected cats. This is the first report of globule leukocytes being identified in ocular cytology from any species. The role of globule leukocytes in the etiopathogenesis and progression of FEK remains unknown and warrants further investigation., (© 2021 The Authors. Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists.)

Objective: To compare complication rates and visual outcomes following phacoemulsification in Pugs versus dogs of other breeds., Animals Studied: Thirty-two pure-bred Pugs (55 eyes) and 32 dogs of other breeds (56 eyes) undergoing phacoemulsification., Procedures: Multi-institutional retrospective medical record review of perioperative factors, postoperative complications, and visual outcomes. The reference population of dogs of varying breeds included surgical cases following each Pug case at the same institutions. Perioperative risk factors and postoperative complication rates were compared between the two populations., Results: Pigmentary keratitis and diabetes mellitus were the most common preoperative comorbidities, found in 75% (P < .001) and 72% (P = .12) of Pugs, respectively. No perioperative factors were significantly associated with postoperative complications in Pugs. Postoperative complication rates were similar between groups; however, the most common complication in Pugs was corneal ulceration (15% of operated eyes), whereas glaucoma was most common in the reference population (13% of operated eyes). Three months postoperatively, vision was preserved in 91% of eyes of Pugs (50/55) and 95% of the reference population (53/56). One year postoperatively, 80% (32/40) of Pug eyes and 82% (28/34) of eyes in the reference population remained sighted., Conclusions: Comorbidities and complications of cataract surgery in Pugs of this study demonstrate a predisposition for corneal disease. This highlights the importance of preoperative evaluation of factors associated with PK and corneal clarity, and postoperative monitoring for corneal ulceration in this breed., (© 2020 American College of Veterinary Ophthalmologists.)

Objective: Sudden acquired retinal degeneration syndrome (SARDS) is one of the leading causes of acute blindness in dogs, with an unknown etiology and no effective treatment. Certain breeds such as Dachshunds are overrepresented among SARDS patients, and therefore, the syndrome is suspected to have a genetic component. The objective of this study was to determine if a genetic locus associated with SARDS in Dachshunds could be identified using a genome-wide association study (GWAS)., Procedures: Genome-wide association mapping was performed in 15 SARDS-affected and 16 unaffected Dachshunds. Genotyping of three classical DLA class II genes (DLA-DRB1, DLA-DQA1, and DLA-DQB1) was performed in 34 SARDS-affected and 66 unaffected Dachshunds to evaluate for an association in this region., Results: Although no single nucleotide polymorphisms (SNPs) were of genome-wide statistical significance (P Bonferroni  < 0.05), 5 of the top 9 SNPs were in the major histocompatibility complex (MHC). Using DLA typing, the allele DLA-DRB1*09401 was identified as a risk factor for the development of SARDS (P = 0.0032, OR = 4.0). The alleles DLA-DQB1*00101 (P = 0.0050, OR = 0.31), DLA-DQA1*00901 (P = 0.0087, OR = 0.33), and a previously identified DLA-DRB1allele described as "DRB1-T" (P = 0.0284, OR = 0.37) were identified as protective factors., Conclusions: Although far from definitive, association of SARDS with alleles of immunologic importance further supports the hypothesis that autoimmunity may play a role in the pathogenesis of SARDS., (© 2019 The Authors. Veterinary Ophthalmology published by Wiley Periodicals, Inc. on behalf of American College of Veterinary Ophthalmologists.)

Objective: To investigate the effect of topically applied proparacaine on bacterial and fungal culture results and to compare cytologic and culture results in patients with ulcerative keratitis., Procedure: Corneal samples were collected from 33 dogs, 19 horses, and 12 cats with spontaneously arising ulcerative keratitis. Samples for bacterial (dogs, cats, horses) and fungal (horses) cultures were collected prior to and following application of 0.5% proparacaine or saline. All patients then received a topical anesthetic, and samples were collected for cytology. Frequency of cultivatable bacteria before (Swab 1) and after (Swab 2) application of proparacaine or saline was compared using Fisher's exact test. Homogeneity of culture and cytology results was assessed using McNemar's test., Results: No difference was detected in number of animals from which bacteria were isolated from Swab 1 or Swab 2 for proparacaine (21/37 and 17/37, respectively) or saline (10/27 and 12/27, respectively). Small numbers prevented analysis of fungal culture results in horses between Swab 1 and Swab 2 for proparacaine (2/12 and 1/12, respectively) or saline (both, 1/8). Bacteria were isolated from 10 of 20 horses and detected cytologically in 3 of these; fungi were isolated from 3 of 20 horses and detected cytologically in 2 of these. Bacteria were detected more frequently using culture (31/64) than cytology (19/64)., Conclusion: Proparacaine did not significantly alter bacterial or fungal culture results in cats, dogs, or horses; however, clinical significance warrants investigation. Culture and cytology provided complementary data; both should be performed to maximize organism detection in patients with ulcerative keratitis., (© 2018 American College of Veterinary Ophthalmologists.)

Objective: To compare the effectiveness of retrobulbar anesthesia (RBA) and peribulbar anesthesia (PBA) in dogs., Animal Studied: Six adult mixed-breed dogs (18-24 kg)., Procedures: In a randomized, masked, crossover trial with a 10-day washout period, each dog was sedated with intravenously administered dexmedetomidine and administered 0.5% bupivacaine:iopamidol (4:1) as RBA (2 mL via a ventrolateral site) or PBA (5 mL divided equally between ventrolateral and dorsomedial sites). The contralateral eye acted as control. Injectate distribution was evaluated by computed tomography. Following intramuscularly administered atipamezole, corneal and periocular skin sensation, intraocular pressure (IOP), and ocular reflexes, and appearance were evaluated for 24 hours. Comparisons were performed with mixed-effects linear regression (IOP) or the exact Wilcoxon signed rank test (scores). Significance was set at P ≤ .05., Results: Injectate distribution was intraconal in 2/6 RBA- and 4/6 PBA-injected eyes. Eyes undergoing PBA had significantly reduced lateral, ventral, and dorsal periocular skin sensation for 2-3 hours, and significantly reduced corneal sensitivity for 4 hours, relative to control eyes. Chemosis and exophthalmos occurred in 33%-40% of eyes undergoing RBA and 83%-100% eyes undergoing PBA but resolved within 14 hours. Anterior uveitis developed in 2/6 and 1/6 eyes of RBA and PBA, respectively, of them corneal ulcer developed in one eye of each treatment. Both resolved 1-3 days following medical treatment., Conclusions: Peribulbar injection produced notable anesthesia more reliably than did retrobulbar injection. Both techniques may produce adverse effects, although the uveitis/ulcer could have resulted from the contrast agent used., (© 2018 American College of Veterinary Ophthalmologists.)

Objective: To estimate the prevalence of ocular disease and obtain normative ocular data for free-living hummingbirds., Animals Studied: Two hundred and sixty-three free-living, adult Hummingbirds from coastal and inland central California were studied, including Anna's (Calypte anna, n = 186) and Black-chinned (Archilochus alexandri; n = 77) hummingbirds., Procedures: Slit lamp biomicroscopy and indirect ophthalmoscopy were performed on all individuals. Rebound tonometry, measurement of horizontal palpebral fissure length, and streak retinoscopy were performed on select individuals. Five conscious Anna's Hummingbirds underwent ocular imaging including fundus photography, digital slit lamp photography, and anterior segment and retinal optical coherence tomography., Results: The prevalence of ocular disease in this population was 2.28%. Ocular imaging revealed a thin cornea, shallow anterior chamber, large lens, and a single central, deep convexiclivate fovea. Mean ± SD intraocular pressure was 11.21 ± 2.23 mm Hg. Mean ± SD eyelid length was 2.59 ± 0.19 mm. All eyes were emmetropic or mildly hyperopic with a mean (range) ± SD refractive error of +0.32 (-0.25 to +1) ± 0.33 diopters., Conclusions: Consistent with previous reports, these data suggest that hummingbirds have visual characteristics found in predatory and prey species, as well as a low prevalence of spontaneous ocular disease. This work provides a set of reference values and clinical findings that can be used in the future research on hummingbird vision and ocular disease. It also provides representative diagnostic images of normal birds and demonstrates that advanced ocular imaging can be performed on manually restrained hummingbirds without pharmacologic dilation., (© 2018 American College of Veterinary Ophthalmologists.)

Objective: To determine factors associated with sudden acquired retinal degeneration syndrome (SARDS) diagnosed within one referral population., Animals Studied: 151 dogs diagnosed with SARDS., Procedures: Breed, age, sex, and body weight were compared between dogs with electroretinogram-confirmed SARDS and dogs presented to the UC Davis Veterinary Medical Teaching Hospital (UCD-VMTH) from 1991 to 2014., Results: SARDS was diagnosed in 151 dogs, representing 1.3% of dogs presented to the UCD-VMTH for ophthalmic disease. Although dogs of 36 breeds were affected, the Dachshund (n = 31, 21%), Schnauzer (16, 11%), Pug (11, 7%), and Brittany (5, 3%) were significantly overrepresented, and the Labrador Retriever (3, 2%) was significantly underrepresented vs. the reference population (P < 0.001). Median (range) age and body weight of affected vs. reference dogs were 8.9 (3-20) vs. 6.8 (0.1-26) years and 12.4 (2.8-52.7) vs. 22.3 (0.1-60) kg, respectively. Dogs 6-10 years of age and between 10-20 kg in body weight were significantly overrepresented in the SARDS population, while dogs <6 years of age were significantly underrepresented (P < 0.01). Spayed females (59% of affected dogs) were significantly overrepresented compared to the reference population, whereas intact females (1% of affected dogs) were significantly underrepresented., Conclusions: Consistent with previous studies, smaller, middle-aged, spayed female dogs may be at increased risk of developing SARDS. Unlike previous studies, this is the first study comparing a variety of SARDS-affected breeds to a reference population. Potentially increased risk of SARDS in several breeds, particularly Dachshunds, suggests a familial factor that warrants further investigation using genetic techniques., (© 2017 American College of Veterinary Ophthalmologists.)

Objective: To evaluate repeatability and reproducibility of tear osmolarity measured using the TearLab ™ osmometer in normal dogs and to assess its diagnostic potential in dogs with keratoconjunctivitis sicca (KCS)., Animals Studied: Beagle dogs; six normal and five with KCS., Procedures: Tear osmolarity and Schirmer tear test-1 (STT-1) values were obtained at various times. Normal dogs were assessed for diurnal variation and repeatability and reproducibility of measurements. Dogs with KCS were evaluated before and after 5 months' topical twice-daily therapy with 2% cyclosporine., Results: Mean ± SD tear osmolarity (mOsm/L) was significantly higher in normal dogs (337.4 ± 16.2) than in dogs with KCS before therapy (306.2 ± 18.0; P < 0.0001), but not following therapy with 2% cyclosporine (330.5 ± 13.7; P = 1.00). Osmolarity readings lower than 325.5 mOsm/L were suggestive of KCS (84.8% sensitivity and 87.1% specificity). In normal dogs, tear osmolarity readings were stable during the daytime (P = 0.99). Repeated measurements revealed high variability and typically poor-to-moderate repeatability and reproducibility, although this was improved by taking three successive measurements at each session. Considering combined data from all dogs, a positive correlation existed between STT-1 and tear osmolarity measurements (Pearson's correlation test, P = 0.04, r = 0.62)., Conclusions: Canine tear osmolarity as determined by TearLab ™ osmometer was variable, required multiple readings to be informative, and differed from values reported for humans. Dogs with KCS had a lower tear osmolarity than did normal dogs, and this increased following cyclosporine therapy., (© 2016 American College of Veterinary Ophthalmologists.)

Objective: To characterize grossly, histologically, and via computed tomography (CT) the appearance of intrascleral cartilage, bone, or both in domestic goats with otherwise normal eyes and to correlate this with age, sex, and breed., Animals Studied: Sixty-eight domestic goats (89 eyes)., Procedures: Forty-nine formalin-fixed globes from 38 goats underwent high-resolution CT, and gross and light microscopic examination. An additional 40 eyes from 30 goats underwent light microscopy only. Age, breed, and sex of affected goats were retrieved from medical records., Results: Considering all methods of evaluation collectively, cartilage was detected in 42% of eyes (44% of goats) and bone in 11% of eyes (12% of goats); bone was never seen without cartilage. Goats in which bone, cartilage, or both were detected ranged from 0.25 to 13 (median = 3.5) years of age, represented 11 of 12 breeds of the study population, and had a male:female ratio of 11:19. Bone was detected in the eyes of significantly more males (n = 8) than females (n = 2). No sex predilection was noted for cartilage alone. Histology revealed intrascleral chondrocyte-like cells, hyaline cartilage, and islands of lamellar bone. Some regions of bone had central, adipose-rich, marrow-like cavities. CT localized mineralized tissue as adjacent to or partially surrounding the optic nerve head., Conclusions: This is the first report of intrascleral bone or cartilage in a normal goat and of intrascleral bone in an otherwise normal mammal. The high prevalence of intrascleral cartilage and bone in this study suggests that this finding is normal and likely represents an adaptation in goats., (© 2016 American College of Veterinary Ophthalmologists.)

Objective: To compare signalment, presentation, treatment, and outcome in horses diagnosed with corneal degeneration (CD) or calcific band keratopathy (CBK) at a referral hospital., Animals Studied: Sixty-nine horses (87 eyes) diagnosed with either CD or CBK., Procedures: Medical records of horses diagnosed with CD or CBK at the University of California-Davis Veterinary Medical Teaching Hospital (UCD-VMTH) between 2000 and 2013 were reviewed. Signalment, concurrent ophthalmic diagnoses, previous therapies, diagnostic tests, systemic diagnoses, treatment, follow-up, and outcomes were compared between horses diagnosed with CD or CBK. Age, breed, and gender were compared between the CD/CBK and UCD-VMTH populations., Results: Thirty-three horses (42 eyes) and 36 horses (45 eyes) were diagnosed with CD and CBK, respectively. Horses with CD or CBK were significantly older (P < 0.001) than the UCD-VMTH population with a median age of 16 or 18 years, respectively. Appaloosas were significantly overrepresented in the CD/CBK population (33%) in comparison with the UCD-VMTH population (1.8%, P < 0.001). Equine recurrent uveitis was concurrently diagnosed in 67% and 84% of horses with CD or CBK, respectively. Pituitary pars intermedia dysfunction (PPID) was diagnosed significantly less often in horses with CD vs. CBK (P = 0.03). Chemical chelation with ethylenediaminetetraacetic acid was performed significantly less frequently in horses diagnosed with CD (7.1%) vs. CBK (31.1% of eyes) (P = 0.012)., Conclusions: Despite some differences, equine CD and CBK are relatively similar conditions and may represent a continuum of disease severity. Horses with PPID should be monitored closely for corneal disease including CBK., (© 2016 American College of Veterinary Ophthalmologists.)

Objective: To determine histologic and immunohistochemical predictors of metastasis of feline diffuse iris melanoma (FDIM)., Animals: Globes from 47 client-owned cats enucleated for FDIM between January 1985 and December 2013., Procedures: Hematoxylin and eosin-stained sections were evaluated for neoplastic invasiveness and cell morphology, necrosis within the neoplasm, inflammation, and glaucoma. Sections were immunolabeled with antibodies against melan-A, PNL2, E-cadherin, or B-Raf, and label intensity, percentage of labeled cells, and label homogeneity were semi-quantitatively graded. Medical records were evaluated, and referring veterinarians and clients were contacted to determine whether cats developed metastasis following enucleation. The log-rank test or Cox proportional hazards model was used to determine associations between histologic or immunohistochemical parameters and metastasis., Results: Metastasis was suspected or confirmed in 9/47 (19%) cats. Extrascleral extension, necrosis within the neoplasm, a mitotic index of >7 mitoses in 10 high-power (×400) fields, choroidal invasion, and increased E-cadherin and melan-A label intensity were each associated with increased rate of metastasis. PNL2 label homogeneity was associated with decreased rate of metastasis. Decreased PNL2 label intensity and an increasing percentage of neoplastic cells labeled for melan-A each approached significance for increased rate of metastasis., Conclusions: We report four histologic and three immunohistochemical parameters helpful in determining cats at risk of metastasis of FDIM. Further studies should determine if B-Raf mutations identified in human malignant melanomas are found in cats with FDIM and assess benefits of adjunctive therapy following enucleation of eyes with FDIM bearing poor prognostic indicators., (© 2016 American College of Veterinary Ophthalmologists.)

Objective: The aim of this study was to evaluate goblet cell density (GCD) and distribution in cats without clinical evidence of ocular surface disease and without histologic evidence of conjunctival disease., Animals Studied: Fourteen Domestic Shorthair cats euthanized for reasons unrelated to this study., Procedures: Before euthanasia, cats were verified using slit-lamp biomicroscopy and fluorescein staining to be free of eyelid or ocular surface abnormalities. Immediately after euthanasia, bilateral conjunctival specimens including third eyelid (TEL) were collected, routinely processed, and stained with periodic acid-Schiff and hematoxylin and eosin. Thirteen conjunctival regions were identified. For each region, GCD was expressed as the percentage of goblet cells/200 basal epithelial cells., Results: Mean GCD ranged widely by region: anterior surface of the TEL = 48.8%, fornicial regions = 47.0%, palpebral regions = 38.5%, bulbar regions = 19.6%, and posterior surface of the TEL = 12.6%. The anterior surface of the TEL had significantly higher GCD than did the bulbar and the palpebral regions, but not the fornicial regions. Bulbar conjunctiva had significantly lower GCD than did all other conjunctival regions except the posterior surface of the TEL. No significant difference was noted between GCD of male versus female cats, dorsal versus ventral regions, or lateral versus medial regions., Conclusions: Although conjunctival GCD ranged widely by region, the anterior surface of the TEL appears to be an excellent location for assessing conjunctival goblet cells in cats because this area has high GCD and is more readily accessible than is the palpebral, fornicial, or bulbar conjunctiva., (© 2016 American College of Veterinary Ophthalmologists.)

Sudden acquired retinal degeneration syndrome (SARDS) is one of the leading causes of currently incurable canine vision loss diagnosed by veterinary ophthalmologists. The disease is characterized by acute onset of blindness due to loss of photoreceptor function, extinguished electroretinogram with an initially normal appearing ocular fundus, and mydriatic pupils which are slowly responsive to bright white light, unresponsive to red, but responsive to blue light stimulation. In addition to blindness, the majority of affected dogs also show systemic abnormalities suggestive of hyperadrenocorticism, such as polyphagia with resulting obesity, polyuria, polydipsia, and a subclinical hepatopathy. The pathogenesis of SARDS is unknown, but neuroendocrine and autoimmune mechanisms have been suggested. Therapies that target these disease pathways have been proposed to reverse or prevent further vision loss in SARDS-affected dogs, but these treatments are controversial. In November 2014, the American College of Veterinary Ophthalmologists' Vision for Animals Foundation organized and funded a Think Tank to review the current knowledge and recently proposed ideas about disease mechanisms and treatment of SARDS. These panel discussions resulted in recommendations for future research strategies toward a better understanding of pathogenesis, early diagnosis, and potential therapy for this condition., (© 2015 American College of Veterinary Ophthalmologists.)

Feline herpesvirus type 1 (FHV-1) is a common and important cause of ocular surface disease, dermatitis, respiratory disease, and potentially intraocular disease in cats. Many antiviral drugs developed for the treatment of humans infected with herpesviruses have been used to treat cats infected with FHV-1. Translational use of drugs in this manner ideally requires methodical investigation of their in vitro efficacy against FHV-1 followed by pharmacokinetic and safety trials in normal cats. Subsequently, placebo-controlled efficacy studies in experimentally inoculated animals should be performed followed, finally, by carefully designed and monitored clinical trials in client-owned animals. This review is intended to provide a concise overview of the available literature regarding the efficacy of antiviral drugs and other compounds with proven or putative activity against FHV-1, as well as a discussion of their safety in cats., (© 2016 American College of Veterinary Ophthalmologists.)

Objectives: To determine the role of equine herpesvirus (EHV) in idiopathic keratoconjunctivitis in horses and to determine whether sample collection method affects detection of EHV DNA by quantitative polymerase chain reaction (qPCR)., Animals Studied: Twelve horses with idiopathic keratoconjunctivitis and six horses without signs of ophthalmic disease., Procedures: Conjunctival swabs, corneal scrapings, and conjunctival biopsies were collected from 18 horses: 12 clinical cases with idiopathic keratoconjunctivitis and six euthanized controls. In horses with both eyes involved, the samples were taken from the eye judged to be more severely affected. Samples were tested with qPCR for EHV-1, EHV-2, EHV-4, and EHV-5 DNA. Quantity of EHV DNA and viral replicative activity were compared between the two populations and among the different sampling techniques; relative sensitivities of the sampling techniques were determined., Results: Prevalence of EHV DNA as assessed by qPCR did not differ significantly between control horses and those with idiopathic keratoconjunctivitis. Sampling by conjunctival swab was more likely to yield viral DNA as assessed by qPCR than was conjunctival biopsy. EHV-1 and EHV-4 DNA were not detected in either normal or IKC-affected horses; EHV-2 DNA was detected in two of 12 affected horses but not in normal horses. EHV-5 DNA was commonly found in ophthalmically normal horses and horses with idiopathic keratoconjunctivitis., Conclusions: Because EHV-5 DNA was commonly found in control horses and in horses with idiopathic keratoconjunctivitis, qPCR was not useful for the etiological diagnosis of equine keratoconjunctivitis. Conjunctival swabs were significantly better at obtaining viral DNA samples than conjunctival biopsy in horses in which EHV-5 DNA was found., (© 2015 American College of Veterinary Ophthalmologists.)

Objective: To describe the lacrimal system of snakes using contrast micro-computed tomography (micro-CT) with 3-dimensional reconstruction, fluorescein passage ('Jones') testing, histology, and gross dissection., Animals Studied: One royal python and 19 snake cadavers representing 10 species., Procedures: Direct observation following injection of fluorescein into the subspectacular space, micro-CT following injection of three contrast agents into the subspectacular space, gross dissection following injection of latex into the subspectacular space, and histopathology., Results: Injection of fluorescein confirmed patency, but not course of the lacrimal duct. Barium enabled clear visualization of the lacrimal duct, whereas two iodinated contrast agents proved inadequate. Collectively, micro-CT, anatomic dissections, and histology suggest tears are produced by a single, large, serous, retrobulbar gland, released into the subspectacular space via several ductules, and drained through a single punctum originating in the ventronasal subspectacular space, and the lacrimal duct, which takes one of three routes of variable tortuosity before opening into the oral cavity in close association with the opening of the duct of the vomeronasal organ., Conclusions: The ophidian lacrimal duct has a generally tortuous course, and the details of its anatomy are species-variable. The tortuous course of the duct likely predisposes snakes to duct occlusion and must be considered when planning medical and surgical interventions in snakes with pseudobuphthalmos and subspectacular abscessation., (© 2014 American College of Veterinary Ophthalmologists.)

Objective: To describe using spectral domain optical coherence tomography (SD-OCT), digital slit-lamp biomicroscopy, and external photography, changes in the ophidian cuticle, spectacle, and cornea during ecdysis., Animals Studied: Four normal royal pythons (Python regius)., Procedures: Snakes were assessed once daily throughout a complete shed cycle using nasal, axial, and temporal SD-OCT images, digital slit-lamp biomicroscopy, and external photography., Results: Spectral domain optical coherence tomography (SD-OCT) images reliably showed the spectacular cuticle and stroma, subcuticular space (SCS), cornea, anterior chamber, iris, and Schlemm's canal. When visible, the subspectacular space (SSS) was more distended peripherally than axially. Ocular surface changes throughout ecdysis were relatively conserved among snakes at all three regions imaged. From baseline (7 days following completion of a full cycle), the spectacle gradually thickened before separating into superficial cuticular and deep, hyper-reflective stromal components, thereby creating the SCS. During spectacular separation, the stroma regained original reflectivity, and multiple hyper-reflective foci (likely fragments from the cuticular-stromal interface) were noted within the SCS. The cornea was relatively unchanged in character or thickness throughout all stages of ecdysis. Slit-lamp images did not permit observation of these changes., Conclusions: Spectral domain optical coherence tomography (SD-OCT) provided excellent high-resolution images of the snake anterior segment, and especially the cuticle, spectacle, and cornea of manually restrained normal snakes at all stages of ecdysis and warrants investigation in snakes with anterior segment disease. The peripheral spectacle may be the preferred entry point for diagnostic or therapeutic injections into the SSS and for initiating spectacular surgery., (© 2014 American College of Veterinary Ophthalmologists.)

Objectives: To assess in vitro the antiviral efficacy against feline herpesvirus (FHV-1) and cytotoxicity for cultured feline cells of famciclovir and its metabolites, BRL 42359 and penciclovir. To investigate the effect of timing of penciclovir application on in vitro antiviral activity., Procedures: Plaque reduction assays were used to estimate antiviral efficacy of all compounds and the effect of penciclovir exposure before or after exposure to a FHV-1 field isolate. Cytotoxicity was evaluated by assessing cell morphology and viable cell number for 72 h following exposure to each compound., Results: The penciclovir concentration that inhibited FHV-1-induced plaque formation by 50% (IC50 ) was 0.86 μg/mL (3.4 μm). Famciclovir and BRL 42359 had no antiviral effect against FHV-1 at any concentration assessed. Antiviral activity was significantly enhanced when cells were exposed to 4 μm penciclovir (approximate IC50 ) for 1 h but not for 24 h before viral adsorption. Delaying exposure of cells to penciclovir for 1, 2, or 4 h after viral adsorption significantly enhanced antiviral activity. Relative to untreated control wells, >88% of cells remained viable when exposed to famciclovir (100 μm), BRL 42359 (1.06 mm), or penciclovir (40 μm) for 72 h. No morphologic evidence of cytotoxicity was noted., Conclusions: Penciclovir demonstrates potent antiviral activity against FHV-1 and may be effective at lower tissue, tear, and plasma concentrations than previously targeted. The duration of in vitro antiviral effect of penciclovir suggests that frequent famciclovir administration may be necessary in vivo. Famciclovir and BRL 42359 showed no signs of in vitro cytotoxicity., (© 2013 American College of Veterinary Ophthalmologists.)

Objective: To evaluate diagnostic utility of aqueous humor analysis in animals with anterior uveitis., Animals: Client-owned dogs (n = 12) and cats (n = 10)., Procedures: Examination findings and diagnostic test results including aqueous humor cytology were compared., Results: Disease duration prior to aqueocentesis was not significantly different between dogs with idiopathic anterior uveitis and those with an etiologic diagnosis, but was shorter in cats with feline infectious peritonitis (FIP) than those with idiopathic uveitis. Microbial nucleic acids, antigens, or antibodies against them were seldom found in blood/serum; however, serum feline coronavirus titers ≥1:6400 were detected only in cats with FIP. Aqueous humor cytology was diagnostic in no cats and two dogs, both with neoplasia. Although aqueous humor contained predominantly neutrophils in cats with FIP and large reactive lymphocytes and plasma cells appeared more frequent in cats with idiopathic uveitis, neither clinical nor cytologic assessment of anterior chamber contents differed significantly between cats with idiopathic or FIP-associated uveitis. Cytologically assessed plasma cell number was correlated with keratic precipitates and disease duration. Clinically detectable hyphema and cytologic erythrocyte number were correlated. However, cytologic cell grades and clinical grade of flare or cell numbers within the anterior chamber were not correlated., Conclusions: Aqueous humor cytology permitted diagnosis of neoplasia in dogs with anterior uveitis but was generally not helpful in cats. Poor correlation between clinical and cytologic assessment of cell numbers and type within the anterior chamber dictates that clinical grading should not be the sole criterion for electing to perform aqueocentesis., (© 2013 American College of Veterinary Ophthalmologists.)

A 22-year-old Australian stockhorse gelding was presented with anterior uveitis in the right eye which was nonresponsive to anti-inflammatory therapy. Clinical examination revealed corneal edema and vascularization, marked hypopyon, and thickening of the dorsal iris, which was confirmed by ultrasonography. Hematologic and biochemical analyses, abdominal and thoracic ultrasonography, and abdominocentesis with cytologic and biochemical analysis revealed no significant abnormalities. Cytological examination of an aqueous humor sample revealed a population of predominantly large lymphoblasts with high nuclear-to-cytoplasmic ratio, round or irregular nuclei, clumped nuclear chromatin, multiple large prominent nucleoli, and a small volume of basophilic cytoplasm. The cytologic diagnosis was intraocular lymphoma. Biopsy of the right submandibular lymph node revealed no evidence of neoplastic invasion. Euthanasia and a complete necropsy were performed and revealed no evidence of neoplasia in any tissue other than the right eye, which had an extensive, well-defined infiltrate of neoplastic lymphocytes expanding the ciliary body and iris, infiltrating the ciliary epithelium, and extending into the pars plana and peripheral choroid. Immunohistochemistry confirmed that neoplastic cells expressed the T-cell marker CD3. To the authors' knowledge, this is the first description of primary, solitary uveal T-cell lymphoma in a horse. Although apparently rare, lymphoma should be considered in horses with uveitis, even when inflammation is unilateral and in the absence of extraocular signs of neoplasia. Aqueocentesis and cytological examination provided an antemortem diagnosis in this case and should be considered as a diagnostic tool for investigation of uveal thickening and hypopyon., (© 2013 American College of Veterinary Ophthalmologists.)

A 9-year-old male castrated Scottish terrier was referred to the Radiation Oncology Service at the William R. Pritchard Veterinary Medical Teaching Hospital for palliative radiation therapy of an incompletely excised, recurrent subcutaneous mast cell tumor (MCT) located over the right scapula, and surgical removal of a perianal MCT. Three weeks after initial presentation and prior to the fifth radiation treatment, the patient was presented with cloudiness of the left eye of 3-7 days duration. Ophthalmic consultation revealed 3+ aqueous flare with a dependent, swirling component filling approximately one-third of the anterior chamber. Aqueocentesis was performed under general anesthesia. Cytology revealed mast cells with highly atypical morphology and considered most consistent with neoplasia. The patient died 7 months after pathologic diagnosis of MCT on the right shoulder and 2 months after the cytologic diagnosis of malignant mast cells in the left anterior chamber. To the authors' knowledge, this is the first report of intraocular involvement in a mammal with MCTs, described here as intraocular mastocytosis., (© 2013 American College of Veterinary Ophthalmologists.)

A 16-year-old spayed female cat was evaluated for lagophthalmos and chronic exposure keratitis in both eyes. Ophthalmic examination revealed upper and lower eyelid entropion of the left eye (OS) and markedly decreased retropulsion, restricted eye movement, marked episcleral congestion, and severe keratitis of both eyes (OU). Magnetic resonance imaging of both orbits revealed extensive, irregular, contrast-enhancing tissue without evidence of osteolysis considered compatible with diffuse inflammatory tissue. Feline herpesvirus DNA was not detected in conjunctival samples. Partial temporary tarsorrhaphies were placed OU, and the cat was treated with topically administered erythromycin ointment OU, orally administered famciclovir and prednisolone, and sublingually administered buprenorphine. Little improvement was noted after 2 weeks. Six weeks after initial presentation, a left exenteration was performed and histopathology was consistent with idiopathic sclerosing orbital pseudotumor (ISOP). Ten weeks after initial presentation, the patient represented for weight loss and jaw pain. Computed tomography demonstrated disease progression in the right orbit and the patient was euthanized. Histopathology of the decalcified skull revealed an aggressive and highly infiltrative mass involving the right orbit with extension to the maxilla, hard palate, nasal cavity and gingiva most consistent with feline restrictive orbital myofibroblastic sarcoma (FROMS). Clinical data from this patient support the reclassification of ISOP as FROMS. MRI and CT may provide supportive evidence for FROMS, but histopathology is necessary for definitive diagnosis. Aggressive and early surgical treatment, including bilateral exenteration, with adjunctive radiotherapy and/or chemotherapy should be considered for patients with FROMS., (© 2013 American College of Veterinary Ophthalmologists.)

Objective: To validate a means of collecting tears from cats, develop an assay for quantifying famciclovir and penciclovir in tears, and to assess famciclovir and penciclovir concentrations and pharmacokinetics in the tears of cats being treated orally with famciclovir for suspected herpetic disease., Animals: Seven client-owned cats., Procedures: Cats were treated orally with a median (range) dose of 40 (39-72) mg of famciclovir/kg three times daily for at least 24 h. At various time points following famciclovir administration, tear samples were collected using Schirmer tear test strips. Tear famciclovir and penciclovir concentrations were measured using liquid chromatography-mass spectrometry, and concentration-time profiles were analyzed noncompartmentally. The relationship between famciclovir dose and tear penciclovir concentration near its maximum was evaluated using least squares linear regression., Results: Maximum tear famciclovir concentration of 0.305 μg/mL occurred at 2.64 h; elimination half-life was 2.28 h. Maximum tear penciclovir concentration (0.981 μg/mL) occurred 2.25 h following oral administration of famciclovir; elimination half-life was 2.77 h. A significant positive correlation was noted between famciclovir dose and tear penciclovir concentration at various time points between 0.5 and 3.75 h following drug administration (P = 0.025). Tear penciclovir concentration exceeded the concentration shown to have in vitro efficacy against feline herpesvirus (FHV-1) (0.304 μg/mL) in about half of samples collected., Conclusions: Oral administration of 40 mg of famciclovir/kg to cats resulted in a tear penciclovir concentration-time profile that approximated the plasma penciclovir concentration-time profile and frequently achieved a penciclovir concentration at the ocular surface likely to be effective against FHV-1., (© 2012 American College of Veterinary Ophthalmologists.)

Objective: To investigate the effects of bovine lactoferrin on in vitro replication of feline herpes virus (FHV-1) and to determine at what points during viral replication these effects occur., Sample Population: Cultured Crandell-Reese feline kidney (CRFK) cells and FHV-1 strain 727., Procedure: Five concentrations of bovine lactoferrin (0.5, 1, 2, 5, and 10 mg/mL) were added at one or more of three time points during conventional plaque reduction assays: (a) uninfected CRFK cells were incubated in lactoferrin-containing medium for 30 min prior to viral adsorption; (b) virus was suspended in lactoferrin-containing medium prior to and during adsorption, or (c) CRFK cells were incubated with lactoferrin-containing medium for 48 h following viral adsorption. Plaques were counted and antiviral effect expressed as percent inhibition relative to control medium that contained no lactoferrin., Results: Exposure of CRFK cells to lactoferrin prior to or during viral adsorption inhibited FHV-1 replication by 87-96% (mean: 91%). Application of lactoferrin following viral adsorption had no appreciable effect on FHV-1 replication. No additive or synergistic effects were noted when lactoferrin was added at multiple steps. These effects were similar at all concentrations of lactoferrin tested. Cytotoxic effects of lactoferrin on CRFK cells were not observed at any concentration tested., Conclusions and Clinical Relevance: Bovine lactoferrin has a notable inhibitory effect on the in vitro replication of FHV-1 prior to and during, but not following viral adsorption. These findings strongly suggest that lactoferrin inhibits FHV-1 adsorption to the cell surface and/or penetration of the virus into the cell. Clinical effects of topical lactoferrin in acute or recrudescent herpetic episodes in cats warrant investigation.

The objective of this study was to describe method of placement, and frequency and severity of complications associated with a subpalpebral lavage system placed in the medial aspect of the equine inferior eyelid. The inferomedial subpalpebral lavage (ISPL) tube is positioned deep in the medial aspect of the inferior conjunctival fornix so that the footplate lies flat between the lower eyelid and the anterior surface of the nictitans. Retrospective data from the placement of 92 ISPL systems placed in 86 horses during a 31-month period were examined. Tube placement was performed using sedation and regional anesthesia only in 59% of horses. The median duration of tube placement was 19 days (range: 1-61 days). Seventy-one horses were treated for up to 55 days following discharge from hospital with an ISPL tube in place. No complications were reported with 59% of ISPL systems. Non-ocular complications were found in 38% of ISPL systems and included tube displacement from the conjunctival fornix (18%), suture loss requiring resuturing of the system to the horse's head (14%), and damage necessitating replacement of the injection port (6%). Ocular complications were recorded in 3% of horses and were limited to inferior eyelid swelling. Vision was retained in 88% of horses. The ISPL system is easily and safely placed, and well tolerated for extended periods. It appears to be associated with infrequent and minor complications when compared with placement of subpalpebral lavage tubes in the superior eyelid.