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Captive fish populations, such as those encompassing aquarium and pet fish, offer significant economic value and are integral to conservation, research, and education. However, these ornamental fish exhibit a reduced ability to protect their ocular surfaces, and our understanding of the ocular diseases that affect them remains limited. Although corneal neoplasms in carp are uncommon, identifying their distinct characteristics is crucial in selecting appropriate therapeutic interventions that aim to preserve vision, prevent the ocular loss, and ultimately ensure the survival of the affected fish. This study provides clinical and histopathological details of various proliferative corneal masses in Cyprininae species, including five koi (Cyprinus carpio) and four goldfish (Carassius auratus). It discusses a spectrum of neoplasms, including soft tissue sarcoma, spindle cell sarcoma, chromatophoroma, and papilloma, in addition to conditions like exuberant granulation tissue and proliferative carp pox. These findings bear significant implications for clinical decision‐making and treatment, offering valuable insights into the incidence and characteristics of corneal tumors in captive fish, which could inform further studies in this area. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to define the antimicrobial peptide (AMP) expression pattern of the equine ocular surface and amniotic membrane using a targeted qPCR approach and 3'Tag‐sequencing. It will serve as a reference for future studies of ocular surface innate immunity and amniotic membrane therapies. Procedures: A targeted qPCR approach was used to investigate the presence of orthologs for three of the most highly expressed beta‐defensins (DEFB1, DEFB4B, and DEFB103A) of the human ocular surface and amniotic membrane in equine corneal epithelium, conjunctiva, and amniotic membrane. 3'Tag‐sequencing was performed on RNA from one sample of corneal epithelium, conjunctiva, and amniotic membrane to further characterize their AMP expression. Results: Equine corneal epithelium, conjunctiva, and amniotic membrane expressed DEFB1, DEFB4B, and DEFB103A. DEFB103A was expressed at the highest amounts in corneal epithelium, while DEFB4B was most highly expressed in conjunctiva and amniotic membrane. 3'Tag‐sequencing from all three tissues confirmed these findings and identified expression of five additional beta‐defensins, 11 alpha‐defensins and two cathelicidins, with the alpha‐defensins showing higher normalized read counts than the beta‐defensins. Conclusions: This study identified AMP expression in the equine cornea and conjunctiva, suggesting that they play a key role in the protection of the equine eye, similar to the human ocular surface. We also determined that equine amniotic membrane expresses a substantial number of AMPs suggesting it could potentiate an antimicrobial effect as a corneal graft material. Future studies will focus on defining the antimicrobial activity of these AMPs and determining their role in microbial keratitis. [ABSTRACT FROM AUTHOR]

Background: The iridocorneal angle (ICA) is the major pathway of aqueous humour outflow from the anterior chamber of the eye. Ultrasound biomicroscopy (UBM) has been utilised to characterise the morphology of this drainage pathway in numerous species. UBM may allow for early recognition of aqueous humour outflow obstructions in horses, allowing for earlier recognition of risk for glaucoma, a vision‐threatening and painful disease. UBM morphology of the normal equine ICA has yet to be described. Objectives: To determine the ultrasonographic morphology of the equine ICA by UBM in standing sedated horses. Study design: In vivo experimental study. Methods: Thirty healthy adult horses underwent UBM of the ICA at four locations (superior, temporal, inferior, nasal) of each eye utilising standing sedation, topical anaesthesia and auriculopalpebral perineural anaesthesia. Anatomic structures were defined on ultrasound images through comparison to published histologic photomicrographs of the equine ICA. Results: Ultrasound imaging of the ICA at all four locations was easily performed in standing, sedated horses. High‐resolution images of the ICA allowed for identification of the pectinate ligament, corneoscleral trabecular meshwork (TM), uveal TM and supraciliary TM. Main limitations: Pupil size was midrange in all eyes, but was not strictly controlled. Lighting conditions not controlled. Various breeds included. Conclusion: In vivo UBM of the equine ICA is feasible and provides high‐resolution images of the structures of the aqueous humour outflow pathway. [ABSTRACT FROM AUTHOR]

Objective: To determine corneal thickness (CT) and axial anterior chamber depth (ACD) using ultrasound biomicroscopy (UBM) in normal adult horses. To compare corneal thickness measurements between UBM and ultrasonic pachymetry. Animals studied: Sixty eyes of 30 healthy adult horses aged 8–24 years. Procedures: Ultrasonic pachymetry (velocity of 1640 m/s) was utilized to obtain measurements of the central, superior, temporal, inferior, and nasal cornea. Triplicate images of the same corneal locations were acquired using UBM (50 MHz). Images of the axial anterior chamber were used to measure ACD. Intraocular pressure (IOP) was estimated using rebound tonometry, and axial globe length was measured using ultrasonographic biometry. Results: CT (mean ± SD µm) measured by UBM was 854 ± 61 (central), 994 ± 58 (superior), 930 ± 57 (temporal), 979 ± 55 (inferior), and 898 ± 48 (nasal). CT measured by UBM was greater than that measured by ultrasonic pachymetry at all locations and was statistically significant at all locations except inferior (p = 0.0006–0.048). No sex nor age effect was detected for CT at any location. The repeatability of ultrasonic pachymetry was superior to that of UBM. Mean ± SD ACD was 5.74 ± 0.41 mm. A weak positive correlation was identified between central CT and IOP and between central CT and axial globe length. Conclusions: Normal data for CT and ACD of the adult horse obtained using UBM are provided. CT determined by UBM was greater relative to pachymetry at all corneal locations. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: To compare the timing and efficiency of the development of Macaca mulatta, a nonhuman primate (NHP), induced pluripotent stem cell (rhiPSC) derived retinal organoids to those derived from human embryonic stem cells (hESCs). Results: Generation of retinal organoids was achieved from both human and several NHP pluripotent stem cell lines. All rhiPSC lines resulted in retinal differentiation with the formation of optic vesicle‐like structures similar to what has been observed in hESC retinal organoids. NHP retinal organoids had laminated structure and were composed of mature retinal cell types including cone and rod photoreceptors. Single‐cell RNA sequencing was conducted at two time points; this allowed identification of cell types and developmental trajectory characterization of the developing organoids. Important differences between rhesus and human cells were measured regarding the timing and efficiency of retinal organoid differentiation. While the culture of NHP‐derived iPSCs is relatively difficult compared to that of human stem cells, the generation of retinal organoids from NHP iPSCs is feasible and may be less time‐consuming due to an intrinsically faster timing of retinal differentiation. Conclusions: Retinal organoids produced from rhesus monkey iPSCs using established protocols differentiate through the stages of organoid development faster than those derived from human stem cells. The production of NHP retinal organoids may be advantageous to reduce experimental time for basic biology studies in retinogenesis as well as for preclinical trials in NHPs studying retinal allograft transplantation. [ABSTRACT FROM AUTHOR]

This report describes the clinical and histological findings, genetic study, and treatment in a 1.3‐year‐old rhesus macaque with bilateral cataracts and unilateral secondary glaucoma. Intravitreal injection of gentamicin decreased the intraocular pressure from 56 to <2 mm Hg. A putative genetic cause of the cataracts was not identified. [ABSTRACT FROM AUTHOR]

Feline infectious peritonitis (FIP) is caused by a mutant biotype of the feline enteric coronavirus. The resulting FIP virus (FIPV) commonly causes central nervous system (CNS) and ocular pathology in cases of noneffusive disease. Over 95% of cats with FIP will succumb to disease in days to months after diagnosis despite a variety of historically used treatments. Recently developed antiviral drugs have shown promise in treatment of nonneurological FIP, but data from neurological FIP cases are limited. Four cases of naturally occurring FIP with CNS involvement were treated with the antiviral nucleoside analogue GS‐441524 (5‐10 mg/kg) for at least 12 weeks. Cats were monitored serially with physical, neurologic, and ophthalmic examinations. One cat had serial magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis (including feline coronavirus [FCoV]) titers and FCoV reverse transcriptase [RT]‐PCR) and serial ocular imaging using Fourier‐domain optical coherence tomography (FD‐OCT) and in vivo confocal microscopy (IVCM). All cats had a positive response to treatment. Three cats are alive off treatment (528, 516, and 354 days after treatment initiation) with normal physical and neurologic examinations. One cat was euthanized 216 days after treatment initiation following relapses after primary and secondary treatment. In 1 case, resolution of disease was defined based on normalization of MRI and CSF findings and resolution of cranial and caudal segment disease with ocular imaging. Treatment with GS‐441524 shows clinical efficacy and may result in clearance and long‐term resolution of neurological FIP. Dosages required for CNS disease may be higher than those used for nonneurological FIP. [ABSTRACT FROM AUTHOR]

Objective: To determine the efficacy of automated imaging software of the Nidek ConfoScan 4 confocal biomicroscope at analyzing canine corneal endothelial cell density and morphology in health and disease, by comparing to a manual analysis method. Animal studied: Nineteen eyes of 10 dogs were evaluated and include three Beagles, three Jack Russell Terriers, and four miscellaneous breeds. Twelve clinically normal and seven eyes affected with corneal endothelial dystrophy (CED) were scanned and analyzed. Procedures: Endothelial cell density (ECD), mean and standard deviation (SD) of cell area, percent polymegathism, mean and SD of the number of cell sides, and percent pleomorphism were calculated using automated and manual methods for each scan. Results: The automated analysis showed significantly greater ECD in comparison with the manual frame method due to misidentification of cell domains in CED‐affected dogs. No significant differences in ECD were observed between normal and CED‐affected dogs in automated analysis, while CED‐affected dogs showed significantly lower ECD in manual frame method and planimetry. Using both automated and manual methods, CED‐affected dogs showed greater variability of cell area or the number of cell sides than normal dogs. Conclusion: The automated imaging software is unable to accurately identify cell borders in CED‐affected dogs resulting in inaccurate estimates of ECD. Thus, manual analysis is recommended for use in clinical trials assessing adverse events associated with novel medical treatments and/or surgical procedures. [ABSTRACT FROM AUTHOR]

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 (PBonferroni < 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. [ABSTRACT FROM AUTHOR]

Objective: (a) To evaluate the epidemiology of equine eosinophilic keratoconjunctivitis (EK) in the western United States, (b) to ascertain the efficacy of keratectomy and diamond burr debridement vs medical management alone, (c) to determine the efficacy of various medical therapies, and (d) to further characterize the histopathologic findings of the disease in horses. Animals studied: Twenty‐nine horses (47 eyes) diagnosed with EK from 1993 to 2017. Procedure: Retrospective medical record review; owner questionnaire. Results: Average age of presentation was 11 ± 4 years. Warmbloods were significantly overrepresented (P = 0.024). Twenty horses were treated with medical therapy alone, five were treated with superficial lamellar keratectomy, and four were treated with diamond burr debridement. Follow‐up data were available for 38 eyes of 23 horses. Median time to resolution for horses treated with either superficial keratectomy or diamond burr debridement (62 days) was not statistically significantly different from those that underwent medical therapy alone (46 days; P = 0.33). Eyes treated with topical steroids had a statistically significant longer median time to resolution (61 days) compared to those that did not receive topical steroid (44 days; P = 0.023). Common histopathologic findings in keratectomy samples included the presence of eosinophils, vascularization, and an eosinophilic membrane spanning areas of ulceration. Conclusion: In this population, time to EK resolution was similar for horses treated with medical and surgical management. The use of topical steroids was associated with a prolonged time to resolution. Keratectomy samples from horses with EK had similar findings to those reported in other species. [ABSTRACT FROM AUTHOR]

Objective: To determine the effect of 5% sodium chloride ophthalmic ointment (5% NaCl) on thickness and morphology of the normal canine cornea using ultrasonic pachymetry (USP), in vivo confocal microscopy (IVCM), and Fourier‐domain optical coherence tomography (FD‐OCT). Methods: Five healthy laboratory Beagles received ophthalmic examinations including USP, IVCM, and FD‐OCT prior to and at fixed intervals following treatment. The right and left eyes were treated with 5% NaCl and artificial tears ophthalmic ointment (AT), respectively, every 2 hours for 4 treatments/d (days 2‐9), and then hourly for 7 treatments/d (day 10). Treatment groups were statistically compared using mixed‐effects linear regression. Results: Treatment with 5% NaCl resulted in a 12 μm decrease in corneal thickness from baseline (P < .001), while there was no significant difference in corneal thickness between values obtained at baseline and following treatment with AT (P = .82). Epithelial cell density significantly increased from baseline (530 ± 52 cells/mm2) to 577 ± 43 and 567 ± 15 cells/mm2 with 5% NaCl and AT, respectively (P = .003 and.005, respectively). However, keratocyte cell density in the anterior and posterior stroma and endothelial cell density did not significantly differ following treatment with 5% NaCl or AT ointment (P > .05). Conclusions: Short‐term topical treatment with 5% NaCl decreased corneal thickness in normal dogs with no observable changes in corneal morphology or signs of ocular toxicity. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The course travelled by corneal epithelial cells from their stem cell niche at the limbus toward the vertex of the cornea is normally not evident due to their transparency, but in certain conditions, the epithelial cells can be rendered visible to the clinician. In such cases, the pathway taken by epithelial cells can manifest as a whorl pattern described using a variety of terms including hurricane keratitis/keratopathy, vortex keratopathy, whorl keratopathy, cornea verticillata, and at times, named after causative agents as exemplified by amiodarone keratopathy. Here, we briefly discuss the terminology used and the spectrum of conditions that can result in keratopathies with whorl patterns in human patients. We review the manifestations of such patterns in veterinary patients and discuss the state of understanding of the underlying forces that create the whorl distribution of epithelial cells on the ocular surface. [ABSTRACT FROM AUTHOR]

Abstract: 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. [ABSTRACT FROM AUTHOR]

Collie eye anomaly (CEA) encompasses a spectrum of different ophthalmic phenotypes from clinically inconsequential choroidal hypoplasia to blindness from coloboma of the optic nerve head (ONH). A previous study found a 7.8-kb deletion in intron 4 of the NHEJ1 gene to be associated with CEA. A genetic test based on this association is recommended for many breeds, including the Nova Scotia Duck Tolling Retriever (NSDTR). Collection of ONH coloboma-affected NSDTR showed lack of concordance of the NHEJ1 intronic deletion with ONH coloboma. Using genomewide single nucleotide polymorphism (SNP) genotyping in 7 ONH coloboma-affected NSDTR cases and 47 unaffected NSDTR controls with no ophthalmic signs, one SNP, located on chromosome 7, demonstrated genomewide significance. However, high genomic inflation may have confounded the results. Therefore, the genomewide association study was repeated using EMMAX to control for population structure in the cohort of 7 cases and 47 controls. However, no regions of the genome were significantly associated with ONH coloboma. These results failed to document significant association with the CEA locus. Due to the complex genetic etiology of ONH coloboma, the NHEJ1 intronic deletion test results should be carefully considered when making breeding decisions. If the goal is to select for visually competent dogs, our data suggest that eye examinations of puppies would be more effective as a guide in selection of breeding pairs than relying solely on currently available genetic tests. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective To obtain normative data for the normal laboratory beagle cornea using high-resolution in vivo confocal microscopy ( IVCM). Animals studied Sixteen eyes of eight healthy young female intact beagles. Procedures The central cornea was imaged using IVCM. Mixed effects linear regression was used for statistical analysis. Results in vivo confocal microscopy allowed detailed visualization and quantification of epithelial cells (superficial epithelial cell diameter: 43.25 ± 6.64 μm, basal cell diameter: 4.43 ± 0.67 μm), and nerve fibers (subepithelial nerve fiber diameter: 2.38 ± 0.69 μm, anterior stromal nerve fiber diameter: 16.93 ± 4.55 μm). Keratocyte density (anterior stroma 993.38 ± 134.24 cells/mm2, posterior stroma 789.38 ± 87.13 cells/mm2) and endothelial cell density (2815.18 ± 212.59 cells/mm2) were also measured. Conclusion High-resolution IVCM provides detailed noninvasive evaluation of the cornea in the normal laboratory beagle. [ABSTRACT FROM AUTHOR]

Objective To obtain normative data for the canine cornea and conjunctiva using high-resolution time- and Fourier-domain optical coherence tomography ( TD- OCT and FD- OCT) and ultrasound pachymetry ( USP). Animals One hundred sixty-eight eyes of 133 healthy young intact laboratory beagles. Procedures The cornea and conjunctiva of 16 eyes of 8 healthy young intact female beagles were imaged using FD- OCT. Corneal thickness was measured with FD- OCT and USP, while corneal epithelial thickness and conjunctival epithelial thickness were measured with FD- OCT. The central corneal thickness ( CCT) was determined in 152 eyes of 125 healthy young adult intact female (35) and male (90) beagles using TD- OCT. Mixed effects linear regression was used for statistical analysis. Results The CCT was (mean ± standard deviation) 497.54 ± 29.76, 555.49 ± 17.19, and 594.81 ± 33.02 μm as measured by FD- OCT, USP, and TD- OCT, respectively. The central, superior paraxial, superior perilimbal corneal epithelial thickness and superior bulbar conjunctival epithelial thickness were 52.38 ± 7.27, 56.96 ± 6.47, 69.06 ± 8.84 and 42.98 ± 6.17 μm, respectively. When comparing techniques used for measuring CCT ( USP vs. FD- OCT and FD- OCT vs. TD- OCT), USP and TD- OCT generated significantly greater values in comparison with FD- OCT (both P < 0.001). For all dogs, CCT increased with increasing age and body weight (both P < 0.001) and was higher in intact males vs. females using TD- OCT ( P = 0.034). Conclusion High-resolution FD- OCT and TD- OCT provide detailed noninvasive evaluation of in vivo canine anterior segment structures. Normative values of the canine cornea and conjunctiva are reported. [ABSTRACT FROM AUTHOR]

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 μ m). 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 μ m 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 μ m), BRL 42359 (1.06 m m), or penciclovir (40 μ m) 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]