Breed and conformational predispositions for prolapsed nictitating membrane gland (PNMG) in dogs in the UK: A VetCompass study.

BACKGROUND: Prolapsed nictitating membrane gland (PNMG) is the most common disorder of the third eyelid in dogs. However, the epidemiology of PNMG in the wider dog population remains understudied. METHODS: Using de-identified clinical data from the VetCompass Programme, this cohort study aimed to report the prevalence, demographic and breed-related risk factors of PNMG in dogs attending UK primary care veterinary practices in 2016. RESULTS: There were 1,802 PNMG cases identified from 905,543 dogs, yielding an annual prevalence of 0.20% (95% confidence interval (CI) 0.19-0.21). The median age at first diagnosis was 0.63 years (IQR 0.33-1.98, range 0.11-18.00). Dogs aged under 1 year had 10.82 times the odds (95% CI 9.17-12.76) compared with dogs aged from 2 to under 4 years. Neutered animals had higher odds than entire animals within both sexes. Breeds with the highest odds of PNMG compared with crossbred dogs included Neapolitan Mastiff (odds ratio (OR) 34.26, 95%CI 15.92-73.75), English Bulldog (OR 24.08, 95% CI 20.62-28.13), Cane Corso (OR 14.66, 95% CI 8.18-26.28), Lhasa Apso (OR 12.37, 95% CI 10.26-14.92) and American Cocker Spaniel (OR 11.57, 95% CI 5.59-23.96). Purebred dogs had 1.43 times the odds (95% CI 1.26-1.63) of PNMG compared with crossbreed dogs. Breeds with brachycephalic skull conformation had 6.71 times the odds (95%CI 5.89-7.64) compared with breeds with mesocephalic skull conformation. Insured dogs had 1.89 times the odds (95% CI 1.65-2.16) compared with uninsured dogs. CONCLUSIONS: This study reports the largest cohort of primary-care PNMG cases assembled to date. The results showing young age at diagnosis along with the breed, purebred and brachycephalic skull conformation predispositions suggest a hereditary involvement in PNMG development. These results may help to guide breeding strategies to reduce the prevalence of PNMG and improve welfare in predisposed individuals.

Neurogenic keratoconjunctivitis sicca in 34 dogs: A case series.

OBJECTIVE: To describe the clinical findings, imaging features, underlying conditions, treatment, and progression of dogs presented between 2010 and 2019 with neurogenic keratoconjunctivitis sicca (NKCS). METHODS: Dogs diagnosed with NKCS were searched in the clinical database. Inclusion criteria were STT-1 readings <15 mm/min, clinical signs of KCS with concurrent ipsilateral xeromycteria. RESULTS: Thirty-four cases were identified. Mean age at presentation was 8.2 years, median 8.9 years (0.3-14.7). Twenty dogs were male, and 14 dogs were female. Concurrent neurological deficits included facial neuropathy (n = 13, 38%), peripheral vestibular syndrome (n = 10, 29%), and Horner's syndrome (n = 5, 15%). Advanced imaging was acquired in 53% of cases (n = 18). Etiologies included idiopathic (n = 18, 53%), endocrinopathy (n = 6, 18%), otitis interna (n = 4, 12%), head trauma (n = 3, 9%), iatrogenic (post-TECA-LBO, n = 1, 3%), brainstem mass (n = 1, 3%), and an area of inflammation in the pterygopalatine fossa (n = 1, 3%). Treatment for NKCS was initiated in most cases (n = 30, 88%) including: oral pilocarpine 2% and lacrimostimulant (n = 19), oral pilocarpine 2% only (n = 3), or lacrimostimulant only (n = 8). A mean time follow-up of 3.7 months, median 3 months (1-14) was available in 23 cases (68%). Eleven cases with follow-up were responsive (48%) with resolution of the clinical signs in a median time 4 months (1-10), and all of them were treated with oral pilocarpine (±lacrimostimulant). CONCLUSIONS: Most cases presented as idiopathic NKCS; in others, an underlying cause of facial neuropathy was identified. All responsive cases were treated with oral pilocarpine 2%.

Incidence and risk factors for surgical glove perforation in small animal ophthalmic surgery.

OBJECTIVE: To determine the incidence of perforation of surgical gloves and identify associated risk factors that contribute to glove perforation in small animal ophthalmic surgery. STUDY DESIGN: Observational cohort study. SAMPLE POPULATION: Surgical gloves (n = 2000) collected following 765 small animal ophthalmic procedures. METHODS: All the gloves were tested for perforation at the end of the procedure using a water leak test. The potential risk factors for glove perforation were recorded, and associations between these risk factors and perforation were explored using univariable (Fisher's exact test) and mixed effect logistic regression analysis. Results were considered significant if P < .05. RESULTS: Glove perforation was detected in 6% of procedures. Glove perforation was 1.97 (95% CI: 0.98-4.22) times more likely in extraocular than in intraocular surgeries (7.3% vs 3.9%; P = .0462). The incidence of perforations was not statistically different between main and assistant surgeon (P = .86). No significant association was found between the risk of glove perforation and duration of the procedure (P = .13). Perforation of the nondominant hand was 2.6 (95% CI: 1.38-4.98) times more likely than the dominant hand (74% vs 26%; P = .0028). Only 22% of the perforations were detected intraoperatively. Multivariable analysis identified only extraocular surgery as a risk factor for perforations. CONCLUSIONS: There is a low incidence of glove perforation in small animal ophthalmic surgery, but extra care of the nondominant hand is required, especially during extraocular procedures.

Clinical, histopathological and genetic characterisation of oculoskeletal dysplasia in the Northern Inuit Dog.

Seven Northern Inuit Dogs (NID) were diagnosed by pedigree analysis with an autosomal recessive inherited oculoskeletal dysplasia (OSD). Short-limbed dwarfism, angular limb deformities and a variable combination of macroglobus, cataracts, lens coloboma, microphakia and vitreopathy were present in all seven dogs, while retinal detachment was diagnosed in five dogs. Autosomal recessive OSD caused by COL9A3 and COL9A2 mutations have previously been identified in the Labrador Retriever (dwarfism with retinal dysplasia 1-drd1) and Samoyed dog (dwarfism with retinal dysplasia 2-drd2) respectively; both of those mutations were excluded in all affected NID. Nine candidate genes were screened in whole genome sequence data; only one variant was identified that was homozygous in two affected NID but absent in controls. This variant was a nonsense single nucleotide polymorphism in COL9A3 predicted to result in a premature termination codon and a truncated protein product. This variant was genotyped in a total of 1,232 dogs. All seven affected NID were homozygous for the variant allele (T/T), while 31/116 OSD-unaffected NID were heterozygous for the variant (C/T) and 85/116 were homozygous for the wildtype allele (C/C); indicating a significant association with OSD (p = 1.41x10-11). A subset of 56 NID unrelated at the parent level were analysed to determine an allele frequency of 0.08, estimating carrier and affected rates to be 15% and 0.6% respectively in NID. All 1,109 non-NID were C/C, suggesting the variant is rare or absent in other breeds. Expression of retinal mRNA was similar between an OSD-affected NID and OSD-unaffected non-NID. In conclusion, a nonsense variant in COL9A3 is strongly associated with OSD in NID, and appears to be widespread in this breed.

Rhomboid blepharoplasty and cryotherapy for the treatment of a squamous cell carcinoma on the lower eyelid in a horse.

A rhomboid blepharoplasty can be used to achieve functional and cosmetic eyelid reconstruction at the medial canthus in the horse. Combination of a rhomboid blepharoplasty with cryotherapy is a treatment option for eyelid ocular squamous cell carcinomas.

CLINICAL AND MAGNETIC RESONANCE IMAGING FEATURES OF IDIOPATHIC OCULOMOTOR NEUROPATHY IN 14 DOGS.

Ophthalmoplegia/ophthalmoparesis (internal, external, or both) has been reported in dogs secondary to neoplasia affecting the oculomotor nerve and is usually given a poor prognosis. The purpose of this retrospective study was to describe the clinical findings, magnetic resonance imaging (MRI) findings, management, outcome, and follow-up in a group of canine cases with idiopathic oculomotor neuropathy. Inclusion criteria included cases with ophthalmoplegia/ophthalmoparesis (internal, external or both) as sole neuroophthalmologic signs, complete ophthalmic and neurologic examination, head MRI, and a minimum follow-up period of 1 year. Dogs with progressive neurological signs not related to oculomotor neuropathy were excluded. Fourteen cases met the inclusion criteria. All cases were unilaterally affected. Magnetic resonance imaging showed equivocal enlargement of the oculomotor nerve in three cases, mild enlargement in five, and marked enlargement in six. Contrast enhancement was present in 12 cases, being marked in six. When present, the contrast enhancement was focal in eight cases and diffuse in four. The median follow-up time was 25 months. External ophthalmoparesis improved in seven cases, five cases under no treatment and two under systemic corticosteroid therapy. The clinical signs in the other seven cases remained unchanged. Idiopathic oculomotor neuropathy should be included as a differential diagnosis in dogs presenting with unilateral ophthalmoplegia/ophthalmoparesis (internal, external, or both) with the absence of other neurologic and ophthalmic signs, and with the MRI findings restricted to the oculomotor nerve. Idiopathic oculomotor neuropathy has a good prognosis as the clinical signs do not deteriorate and they can improve without treatment.

Uveal cysts in domestic cats: a retrospective evaluation of thirty-six cases.

OBJECTIVE: The aim of this retrospective study was to investigate uveal cysts in domestic cats by identifying prevalence, predispositions, location, presumed etiologies, and sequelae. ANIMALS STUDIED: The clinical databases of two referral hospitals (The Animal Health Trust in the UK and Animal Eye Care in Australia) were searched to identify cats that had been diagnosed with uveal cysts, either as an incidental finding or as the reason for referral. Thirty-six cases were found. PROCEDURES: The signalment of the patients was recorded, along with any relevant previous clinical history, treatment, follow-up, and sequela. The data were compared with the unaffected feline populations examined by ophthalmologists in the two hospitals over the same 10-year time period. RESULTS: Thirty-six cats were affected, from a total examined population of 5017 (prevalence 0.72%). Twenty-one of the 36 cats were Burmese. The two centers examined 516 Burmese cats in the same time period, giving an incidence in Burmese cats of 4.1%. The mean age of affected cats at presentation was 10.25 years (SD = 4.12 years), and female cats accounted for 23 of 36 of the cases. Only 2 of 36 cats had concurrent intraocular disease. CONCLUSIONS: Uveal cysts in domestic cats are rare ophthalmic findings, and in most cases, they do not cause any clinical problems The Burmese breed is overrepresented in the data, with a relatively high prevalence of uveal cysts.

A Carbohydrate Sulfotransferase-6 (CHST6) gene mutation is associated with Macular Corneal Dystrophy in Labrador Retrievers.

PURPOSE: To locate and identify variants associated with macular corneal dystrophy (MCD) in Labrador Retriever (LR) dogs, in the candidate gene carbohydrate sulfotransferase-6 (CHST6). METHODS: The single coding exon of canine CHST6 was sequenced in one affected LR with MCD and one control LR clinically clear of ocular disease. A further 71 control LR with unknown clinical status were sequenced for the putative causal variant in CHST6. A TaqMan SNP genotyping assay was developed and used to screen an additional 84 dogs (five affected LR and 79 clinically clear LR). Finally, the variant was screened in a third cohort of 89 unrelated LR with unknown clinical status to estimate its allele frequency in the population of LR in the United Kingdom. RESULTS: A single nucleotide polymorphism (SNP) was identified within the coding exon of CHST6, resulting in a missense mutation (c.814C>A, p.R272S). All six LR affected with MCD were homozygous for the mutant allele, while 140/151 control LR were homozygous for the wild-type allele and 11/151 were heterozygous for the mutation, indicating an association with MCD (P < 10-5 ). The mutant allele was present in the unrelated LR cohort at a frequency of 0.017, suggesting carrier and affection rates of 3.3% and 0.028%, respectively. CONCLUSIONS: A missense mutation in the CHST6 gene is strongly associated with autosomal recessive MCD in the LR.

Corneal and anterior segment foreign body trauma in dogs: a review of 218 cases.

OBJECTIVES: To review clinical data on dogs that suffered a corneal and anterior segment foreign body (CASFB) trauma and to determine the risk factors for foreign body (FB) trauma and subsequent enucleation. ANIMALS STUDIED: Dogs with CASFB presented to the Animal Health Trust (AHT) from January 2000 to December 2012. PROCEDURES: Clinical data for CASFB cases were compared to those available for the remaining AHT ophthalmic population over the same period. The depth of the FB trauma was divided into five categories. The type of FB and method of removal were described for each category. The degree of secondary uveitis and lens involvement was graded and correlated with subsequent enucleation. RESULTS: The mean age (standard deviation) of 218 identified CASFB cases was 3.96 (2.95) years. Risk factors for CASFB trauma were dogs younger than 5 years, English Springer Spaniels, Labrador Retrievers, and working dogs. Most dogs required general anesthesia for FB removal, and hypodermic needles were the most commonly used instrument. The lens was involved in some cases with a full-thickness CASFB trauma (n = 49, 45%), but most suffered a minor lens trauma (n = 37, 76%). The lens trauma and phacoclastic uveitis were managed medically in most dogs (n = 37, 76%), and phacoemulsification was only elected as initial treatment in some dogs (n = 10, 20%). Enucleation was required overall in 6% of dogs. Statistically significant associations were found between enucleation and depth of FB trauma, degree of uveitis, and severity of lens trauma (P < 0.001). CONCLUSIONS: Young dogs, English Springer Spaniels, Labrador Retrievers, and working dogs had an increased risk of CASFB trauma. Risk factors for enucleation were full-thickness FB penetration, severe lens trauma, and severe uveitis.