Gonioscopy in the dog: inter-examiner variability and the search for a grading scheme.

OBJECTIVES: To investigate inter-examiner variability in gonioscopic evaluation of pectinate ligament abnormality in dogs and to assess level of inter-examiner agreement for four different gonioscopy grading schemes. MATERIALS AND METHODS: Two examiners performed gonioscopy in 98 eyes of 49 Welsh springer spaniel dogs and estimated the percentage circumference of iridocorneal angle affected by pectinate ligament abnormality to the nearest 5%. Percentage scores assigned to each eye by the two examiners were compared. Inter-examiner agreement was assessed following assignment of the percentage scores to each of four grading schemes by Cohen's kappa statistic. RESULTS: There was a strong positive correlation between the results of the two examiners (R=0·91). In general, Examiner 1 scored individual eyes higher than Examiner 2, especially for eyes in which both examiners diagnosed pectinate ligament abnormality. A "good" level of agreement could only be achieved with a gonioscopy grading scheme of no more than three categories and with a relatively large intermediate bandwidth (κ=0·68). CLINICAL SIGNIFICANCE: A three-tiered grading scheme might represent an improvement on hereditary eye disease schemes which simply classify dogs to be either "affected" or "unaffected" for pectinate ligament abnormality. However, the large intermediate bandwidth of this scheme would only allow for the additional detection of those dogs with marked progression of pectinate ligament abnormality which would be considered most at risk of primary closed-angle glaucoma.

Prevalence and progression of pectinate ligament dysplasia in the Welsh springer spaniel.

OBJECTIVES: To determine the prevalence of pectinate ligament dysplasia in a large group of Welsh springer spaniels; to investigate associations between pectinate ligament dysplasia and age, sex and intraocular pressure and between intraocular pressure and age and sex; and to investigate progression of pectinate ligament dysplasia in individual dogs. METHODS: In a prospective study, gonioscopy was performed in both eyes of 227 Welsh springer spaniels and intraocular pressure measured by rebound tonometry. Eyes were classified as "unaffected" if 0% of the iridocorneal angle was affected with pectinate ligament dysplasia (grade 0), "mildly affected" if <20% was affected (grade 1), "moderately affected" if 20 to 90% was affected (grade 2) and "severely affected" if >90% was affected (grade 3). In a retrospective study, progression of pectinate ligament dysplasia over time was investigated for 65 dogs. RESULTS: One hundred and thirty-nine of 227 dogs (61·2%) were affected by pectinate ligament dysplasia (grades 1 to 3) and 82/227 (36·2%) were moderately or severely affected. There was a significant association between pectinate ligament dysplasia and age. There were no associations between pectinate ligament dysplasia and intraocular pressure or pectinate ligament dysplasia and sex. Thirty-five of 65 dogs (53·8%) demonstrated progression of pectinate ligament dysplasia. CLINICAL SIGNIFICANCE: Prevalence of pectinate ligament dysplasia was high despite widespread screening and selection against the condition. Our data indicate that gonioscopic features of pectinate ligament dysplasia can progress in the Welsh springer spaniel. Dogs deemed unaffected at an early age may subsequently be diagnosed with pectinate ligament dysplasia.

Survey of ophthalmic abnormalities in the labradoodle in the UK.

One-hundred and seventy-five labradoodles underwent slit-lamp biomicroscopy and direct and indirect ophthalmoscopy between January 2008 and December 2009. These examinations were performed at shows by the first author. In addition, labradoodle eye certificates from the 2008 and 2009 British Veterinary Association/Kennel Club/International Sheep Dog Society (BVA/KC/ISDS) Eye Scheme were analysed (n=260). The results of the examinations were reviewed, and all ophthalmic abnormalities were recorded. The prevalence of any abnormality was compared with that reported by the Eye Scheme and the KC during 2009 for the labrador retriever, miniature, toy and standard poodles. Multifocal retinal dysplasia (MRD) was identified in 20 labradoodles (4.6 per cent), and cataracts were identified in 16 labradoodles (3.7 per cent). The prevalence of MRD in labradoodles was significantly greater than in labrador retrievers (P<0.0001). There was no difference in the prevalence of cataract between labradoodles and labrador retrievers (P=0.4866). The results of this study suggest that MRD is a relatively common finding in the labradoodle population in the UK. Given such an apparent high prevalence of MRD, routine screening for hereditary eye disease before breeding is advised for this increasingly popular new crossbreed.