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.

Clinical features and MRI characteristics of retinal detachment in dogs and cats.

The aim of this retrospective observational study was to characterize the MRI appearance of retinal detachment (RD) in a sample of dogs and cats. Study inclusion was based on the following medical record criteria: (a) had a diagnosis of RD in at least one eye by either funduscopic examination or ocular ultrasound and had an MRI evaluation including the eyes, or (b) had a diagnosis of RD documented in an MRI report for at least one eye and also had a clinical eye examination. Eighteen patients (12 dogs, 6 cats) and 35 eyes met the inclusion criteria, although four eyes that were clinically examined could not be visualized funduscopically and did not have ocular ultrasound performed (criterion 2). The MRI and clinical diagnosis (via either funduscopy or ultrasound) of RD/no RD was concordant in 27 of 31 eyes (87%). Qualitatively, RD appeared as a variable intensity curvilinear structure located internal and adjacent to the sclera on all sequences and was best delineated on T2W sequences. RDs inconsistently contrast enhanced and, although there was no statistical difference, subjectively appeared more clearly delineated on dorsal and parasagittal images. In conclusion, findings from the current study support using MRI as an ancillary diagnostic test for confirmation or further characterization of RD in dogs and cats.

A novel surgical technique for enucleation in rabbits to reduce the risk of intra- and post-operative orbital hemorrhage.

A 10-year-old male castrated Holland Lop rabbit (Oryctolagus cuniculus) was presented for severe ulcerative stromal keratitis of the right eye and a luxated hypermature cataract and glaucoma of the left eye. Staged bilateral enucleation was elected. A LigaSure™ electrosurgical bipolar vessel-sealing device was used as a means to minimize intraoperative and post-operative hemorrhage, especially that associated with the orbital venous plexus. The LigaSure™ was used to ligate and transect all extraocular muscles, the optic nerve bundle, and the base of the third eyelid with no complications encountered. Overall, the LigaSure™ was easy to use, resulted in minimal hemorrhage, and reduced surgery time. This is the first report of the use of a LigaSure™ to aid in the enucleation of a rabbit. Although only positive results were achieved as an alternative to conventional methodologies, its use in clinical practice should be that of caution until a larger study evaluating the long-term results is performed.

Retrobulbar vs peribulbar regional anesthesia techniques using bupivacaine in dogs.

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.

Cofactors associated with Sudden Acquired Retinal Degeneration Syndrome: 151 dogs within a reference population.

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.

Multiple ocular developmental defects in four closely related alpacas.

OBJECTIVE: To describe the clinical, gross pathologic, and histopathologic findings for a visually impaired 5.8-year-old female alpaca with multiple ocular abnormalities, as well as the clinical findings for three closely related alpacas. ANIMALS STUDIED: Four alpacas. PROCEDURES: Ophthalmic examination was performed on a 16-month-old female alpaca following observation of visual impairment while hospitalized for an unrelated illness. Following acute systemic decline and death 4.5 years later, the alpaca's brain, optic nerves, and eyes were examined grossly and histologically. Ophthalmic examination of three closely related alpacas was subsequently performed. RESULTS: The 16-month-old female alpaca (Alpaca 1) had ophthalmoscopic findings suggestive of a coloboma or hypoplasia of the retinal pigment epithelium (RPE) and choroid, and suspected optic nerve hypoplasia OU. Histopathology performed 4.5 years later revealed moderate to severe choroidal, RPE, and retinal hypoplasia with multifocal retinal detachments OU. However, the optic nerves were normal in size and histologic appearance when compared to an age-matched control. Clinical evaluation of the 2-year-old son of Alpaca 1 revealed iris colobomata OU and choroidal dysplasia/hypoplasia OD in addition to nonpathologic variations in melanin density including heterochromia iridis and a subalbinotic fundus OU. Clinical evaluation of the 13-year-old mother of Alpaca 1 revealed heterochromia iridis, cataracts, and a subalbinotic fundus OU. A 2-year-old half-brother of Alpaca 1 had an RPE and choroidal coloboma OS. CONCLUSION: The developmental ocular abnormalities diagnosed in these closely related alpacas are likely hereditary.

Gross, histologic, and computed tomographic characterization of nonpathological intrascleral cartilage and bone in the domestic goat (Capra aegagrus hircus).

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.

Comparison of corneal degeneration and calcific band keratopathy from 2000 to 2013 in 69 horses.

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.

Novel retinopathy in related Gordon setters: a clinical, behavioral, electrophysiological, and genetic investigation.

PURPOSE: To conduct ophthalmic, behavioral, electrophysiological, and genetic testing on two related Gordon setters presented for day blindness and compare findings with those of nine related and unrelated Gordon setters. METHODS: All dogs underwent comprehensive ophthalmic examination. Maze testing was conducted under different light intensities. Rod and cone function was assessed electroretinographically. DNA samples were screened for five canine retinal disease gene mutations. RESULTS: Ophthalmic examination was unremarkable in all dogs. There was no notable difference between day blind dogs and the reference population in scotopic and mesopic maze tests. Day blind dogs performed worse in the photopic maze with slower course completion time and more obstacle collisions. Electroretinography revealed extinguished cone function in day blind dogs and depressed rod responses in all but two reference dogs. One reference population dog presented with day blindness 1 year after initial examination. Mutations that cause achromatopsia (in CNGB3) and cone-rod dystrophies (in ADAM9 and IQCB1) were not detected in any dog tested, although five reference dogs were carriers of the mutation in C2orf71 that causes rod-cone degeneration 4 (rcd4) in Gordon setters and in polski owczarek nizinny dogs. CONCLUSIONS: This report describes a novel retinopathy in related Gordon setters that has clinical signs and vision testing results consistent with achromatopsia but electroretinographic results suggestive of cone-rod dystrophy. The majority of Gordon setters in this study had low rod responses on electroretinography but it is unclear whether this was indicative of rod dysfunction or normal for the breed. Longer-term observation of affected individuals is warranted.

The effect of needle gauge, needle type, and needle orientation on the volume of a drop.

OBJECTIVE: The purpose of this study was to determine impact of needle gauge, type, and orientation on average volume of drop dispensed. PROCEDURE: Five needle gauges (22G, 23G, 25G, 27G, and 30G) were examined. For each gauge, volume of drop delivered was determined for standard sharp beveled tip, blunt tip, and after breaking off of the sharp needle from the hub. Vertical and horizontal orientation of the needle was tested for effect on drop volume for 22-G and 30-G sharp beveled needles. RESULTS: Mean drop volume was affected by needle gauge, needle orientation, and whether the needle had been broken off from its hub. Mean drop volume scaled directly with needle diameter with drop volumes of 25.0 µL (±20.2) and 83.9 µL (±16.5) being found for 30-gauge and 22-gauge needles, respectively. Intermediate gauges (27, 25, 23G) yielded intermediate drop volumes. Blunt needles tended to produce larger drop volumes compared to sharp beveled needles, but these differences did not reach statistical significance. Breaking off of the needle from the hub produced substantially larger drop volumes with little difference being found between needle gauges. Average volumes of 1 drop from a 22-G vertical, 22-G horizontal, 30-G vertical, and 30-G horizontal sharp beveled needle were 20.2, 9.1, 10.1, and 3.3 µL, respectively. CONCLUSIONS: These findings have relevance for controlled delivery of topical ophthalmic medications to patients.

Gross anatomy and morphometric evaluation of the canine lacrimal and third eyelid glands.

OBJECTIVE: The lacrimal gland (LG) and the third eyelid gland (TELG) are two intraorbital glands that, in dogs, secrete the aqueous component of the tear film. Despite the central importance of these structures for maintaining ocular surface health, the gross anatomy of the glands remains understudied. We investigated the macroscopic morphometric characteristics of the LG and TELG in three different dog breeds. PROCEDURES: Twenty-six dog heads were dissected to expose the LG and TELG; the length, width, thickness, and weight of each were measured. During the dissections, the relationships between the glands and adjacent ocular structures and the blood and nerve supplies to the LG were photo-documented. RESULTS: The LG had a flat and irregular shape with morphological variations among dogs. The LG was located on the dorsolateral aspect of the globe underneath the orbital ligament. The average length, width, and thickness (SEM) of the LG (mm) were 16.5 ± 0.7, 12.5 ± 0.4, and 2.7 ± 0.1 and of the TELG 10.5 ± 0.6, 11.0 ± 0.3, and 3.3 ± 0.1, respectively. The mean weights (SD) of the LG and TELG (mg) were 315.7 ± 21.1 and 263.3 ± 13.2, respectively. Beagles were observed to have significantly smaller LGs compared to pit bull terriers and pointer mixed-breed dogs. CONCLUSIONS: The present study provides detailed normative anatomical and morphometric data for the LG and TELG. These data will aid researchers investigating alterations induced by disease states and should inform strategies for the local delivery of pharmacologic and cellular therapeutics.

Detection of equine herpesvirus in horses with idiopathic keratoconjunctivitis and comparison of three sampling techniques.

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.

Genome-wide association and linkage analyses localize a progressive retinal atrophy locus in Persian cats.

Hereditary eye diseases of animals serve as excellent models of human ocular disorders and assist in the development of gene and drug therapies for inherited forms of blindness. Several primary hereditary eye conditions affecting various ocular tissues and having different rates of progression have been documented in domestic cats. Gene therapy for canine retinopathies has been successful, thus the cat could be a gene therapy candidate for other forms of retinal degenerations. The current study investigates a hereditary, autosomal recessive, retinal degeneration specific to Persian cats. A multi-generational pedigree segregating for this progressive retinal atrophy was genotyped using a 63 K SNP array and analyzed via genome-wide linkage and association methods. A multi-point parametric linkage analysis localized the blindness phenotype to a ~1.75 Mb region with significant LOD scores (Z ≈ 14, θ = 0.00) on cat chromosome E1. Genome-wide TDT, sib-TDT, and case-control analyses also consistently supported significant association within the same region on chromosome E1, which is homologous to human chromosome 17. Using haplotype analysis, a ~1.3 Mb region was identified as highly associated for progressive retinal atrophy in Persian cats. Several candidate genes within the region are reasonable candidates as a potential causative gene and should be considered for molecular analyses.

Unilateral intraocular mastocytosis and anterior uveitis in a dog with subcutaneous mast cell tumors.

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.

Topical netarsudil for the treatment of primary corneal endothelial degeneration in dogs.

This study evaluated the tolerability and efficacy of the topical rho-kinase inhibitor netarsudil for canine primary corneal endothelial degeneration (PCED). Twenty-six eyes of 21 client-owned dogs with PCED were enrolled in a prospective, randomized, vehicle control clinical trial and received topical netarsudil 0.02% (Rhopressa®) or vehicle control twice daily (BID) for the first 4 months. Then, all patients received netarsudil for the next 4 or 8 months. Complete ophthalmic examination, ultrasonic pachymetry, Fourier-domain optical coherence tomography, and in vivo confocal microscopy were performed at baseline and 1, 2, 4, 6, 8 and 12 months. Effect of netarsudil on central corneal thickness (CCT), percentage of cornea with edema, and endothelial cell density (ECD) were evaluated by repeated measures ANOVA. Kaplan-Meier curves and log-rank test were used to compare corneal edema and clinical progression of eyes in netarsudil versus vehicle control groups. All dogs developed conjunctival hyperemia in at least one eye while receiving netarsudil. Unilateral transient reticulated intraepithelial bullae and stromal hemorrhage were observed respectively in 2 dogs in the netarsudil group. Two dogs showed persistently decreased tear production while receiving netarsudil, requiring topical immunomodulatory treatment. No significant differences in CCT, ECD, corneal edema or clinical progression were observed between netarsudil or vehicle treated eyes. When comparing efficacy of topical netarsudil BID and topical ripasudil 0.4% administered four times daily from our previous study, dogs receiving ripasudil had significantly less progression than those receiving netarsudil.

Breed predispositions to congenital and juvenile cataracts in horses at two academic institutions.

BACKGROUND: Determination of horse breeds predisposed to congenital and juvenile cataracts will enable investigations into potential genetic mechanisms for cataracts in horses. OBJECTIVE: To investigate horse breed predispositions to congenital and juvenile cataracts in two academic referral populations. STUDY DESIGN: Retrospective case series. METHODS: Medical record identification of horses diagnosed with congenital or juvenile cataracts at the Cornell University Equine Hospital (2000-2022) and the University of California-Davis (UCD) Large Animal Clinic (1990-2021). Signalment, examination findings and treatments were recorded. Descriptive statistics were performed, and breed over-representations were determined using Chi-squared or Fisher's exact tests. RESULTS: Thirty-one (Cornell) and 70 (UCD) horses with congenital or juvenile cataracts were identified, for a total of 101 affected horses. Seventy-eight horses were affected bilaterally and 23 were affected unilaterally, for a total of 179 affected eyes. Standardbreds were significantly over-represented at both institutions, comprising 32.5% of congenital/juvenile cataract cases and 10% of the equine hospital population at Cornell (p < 0.001) and 4.3% of cataract cases and 1.3% of the equine hospital population at UCD (p = 0.03). Thoroughbreds were under-represented for congenital and juvenile cataracts at both institutions (p = 0.03 Cornell, p = 0.01 UCD). MAIN LIMITATIONS: Retrospective study, potential for selection bias. CONCLUSIONS: The over-representation of the Standardbred breed for congenital and juvenile cataracts at two institutions suggests an underlying genetic basis in the breed. Future genetic and genomic studies are warranted to investigate heritable cataracts in Standardbred horses.

Symblepharon in kittens: a retrospective study of 40 kittens and 54 eyes (2002-2022).

OBJECTIVES: The aim of this study was to retrospectively evaluate the signalment, treatment, surgical technique and outcomes for feline symblepharon. METHODS: A retrospective medical record review and standardized grading of clinical descriptions and photographs was undertaken. RESULTS: Forty kittens (54 eyes) aged 3-46 weeks had symblepharon of five types in various combinations: eyelid deformation (24 kittens; 32 eyes); ankyloblepharon (four kittens; four eyes); conjunctiva-to-conjunctiva (11 kittens; 12 eyes); third eyelid-to-conjunctiva (24 kittens; 29 eyes); and corneoconjunctival adhesions (14 kittens; 16 eyes). At initial presentation, 23 (43%) eyes were affected by one type of symblepharon, 25 (46%) eyes by two types and six (11%) eyes by three types; 11 (20%) corneas were ulcerated. Twenty-four (44%) eyes of 18 (45%) kittens were managed medically. Surgery was performed under general anesthesia/sedation (30 occasions) or topical anesthesia (21 occasions) on 30 (56%) eyes of 22 kittens; 12 eyes (40%) underwent multiple surgeries. Four techniques were commonly employed: separation of conjunctival-to-conjunctival adhesions ± eyelid margins (14 eyes); resection of third eyelid adhesions ± temporary tacking of the third eyelid (modified Arlt's pterygium technique; 18 eyes); en bloc resection of the third eyelid (two eyes); and separation of corneoconjunctival adhesions (14 eyes). Median duration of follow-up was 55 days (range 1-1051). Median symblepharon grade in kittens treated surgically improved for all types except corneoconjunctival symblepharon. Median symblepharon grade in kittens receiving medical management remained the same or improved. Corneoconjunctival symblepharon opacity decreased for eyes treated surgically but increased for eyes treated medically. Three eyes were enucleated due to complications of corneoconjunctival symblepharon. At final presentation, symblepharon persisted in 46 (85%) eyes; however, menace response was evident in 13/16 eyes and dazzle reflex in 23/23 eyes. CONCLUSIONS AND RELEVANCE: Symblepharon is a heterogeneous group of conditions with diverse anatomic involvement, clinical appearance and impact, optimal treatment and prognosis for vision.

Ocular morphologic traits in the American Cocker Spaniel may confer primary angle closure glaucoma susceptibility.

Acute primary angle closure glaucoma is a potentially blinding ophthalmic emergency requiring prompt treatment to lower the elevated intraocular pressure in humans and dogs. The PACG in most of canine breeds is epidemiologically similar to humans with older and female patients overrepresented with the condition. The American Cocker Spaniel (ACS) is among the most common breeds observed with PACG development in dogs. This study initially sought to identify genetic risk factors to explain the high prevalence of PACG in ACSs by using a case-control breed-matched genome-wide association study. However, the GWAS failed to identify candidate loci associated with PACG in this breed. This study then assessed intrinsic ocular morphologic traits that may relate to PACG susceptibility in this breed. Normal ACSs without glaucoma have a crowded anterior ocular segment and narrow iridocorneal angle and ciliary cleft, which is consistent with anatomical risk factors identified in humans. The ACSs showed unique features consisting of posterior bowing of iris and longer iridolenticular contact, which mirrors reverse pupillary block and pigment dispersion syndrome in humans. The ACS could hold potential to serve as an animal model of naturally occurring PACG in humans.

Topical Ripasudil for the Treatment of Primary Corneal Endothelial Degeneration in Dogs.

Purpose: The purpose of this study was to evaluate the tolerability and efficacy of topical rho-kinase inhibitor ripasudil in the treatment of primary corneal endothelial degeneration (PCED) in dogs. Methods: Twenty-one eyes of 12 client-owned, PCED-affected dogs received topical ripasudil 4 times daily. Ophthalmic examination, ultrasonic pachymetry (USP), Fourier-domain optical coherence tomography (FD-OCT), and in vivo confocal microscopy were performed at baseline and 1, 3, 6, and 12 months. Effects of treatment on corneal thickness, corneal edema extent, and endothelial cell density (ECD) were evaluated by repeated-measures ANOVA or Friedman test. Individual eyes were classified as improved, progressed, or stable at 12 months using clinical response criteria. Kaplan-Meier curves and log-rank test were used to compare ripasudil-treated eyes to age-, breed/size-, and disease stage-matched historical controls. Results: During treatment, 12 dogs developed conjunctival hyperemia, 4 demonstrated reticular bullous epithelial edema, and 2 developed corneal stromal hemorrhage. No adverse event necessitated permanent cessation of ripasudil. Central corneal thickness measured by USP significantly progressed from baseline to 12 months. Corneal thickness by FD-OCT, ECD, and edema extent did not differ over time. Considered individually, 5 eyes improved, 8 remained stable, and 8 progressed. The log-rank test found less edema progression in ripasudil-treated eyes compared to historical controls. Conclusions: Ripasudil was well-tolerated in PCED-affected dogs. Response to therapy varied; 62% of eyes showed improved or stable disease whereas 38% progressed. Ripasudil-treated eyes progressed more slowly than historical controls. Translational Relevance: Topical ripasudil offered a therapeutic benefit in a subset of patients using a canine model of endothelial degeneration, which may guide future trials in humans.

Effect of Withdrawing Chronic Topical Immune Modulating Treatment on Schirmer Tear Test Values in Dogs with Dry Eye Disease: Relevance to Dry Eye Studies.

Purpose: To determine the effect of discontinuing chronic topical immune modulating (IM) treatment on Schirmer tear test (STT) values in dogs with dry eye disease (DED). Methods: Serial measurements of STTs from 14 dogs (16 eyes) previously diagnosed with DED were obtained before and after discontinuation of topical IM agents. Dogs with moderate to severe DED that had been well controlled with a topical IM treatment were included. After initial assessment topical IM treatment was discontinued, but topical lubricant was continued, and STT values were obtained sequentially. A mixed-effects regression model was used to evaluate the effects of age, gender, breed, clinical score, frequency of treatment, baseline STT value, and drug type on final STT values after IM withdrawal. P < 0.05 was considered statistically significant. Results: During the follow-up period after the IM treatment had been discontinued (136 ± 29 days), 50% of the eyes (n = 8) exhibited STT values that never decreased to <10 mm/min. In the other 50% (n = 8), STT values decreased from 15.9 ± 4.7 mm/min to 6.1 ± 0.9 mm/min. In this group, the time it took to decrease the STT to <10 mm/min was 21.1 ± 9.5 days. Severe clinical signs of DED and low baseline STT pre-IM treatment significantly affected STT post-IM treatment withdrawal (P < 0.05). Conclusions: The duration that a residual effect of topical IM treatment persists needs to be taken into consideration when studies are designed utilizing dogs with previous IM treatment for DED.