title: Survey of the incidence of pectinate ligament dysplasia and glaucoma in the UK Leonberger population.
abstract: OBJECTIVE
  To determine the prevalence of pectinate ligament dysplasia (PLD) in UK Leonbergers and identify cases affected by glaucoma. Also, to define the spectrum of pectinate ligament (PL) appearance in this breed and determine whether gonioscopic monitoring should be recommended.
  
  
  METHODS
  Data were compiled from 78 prospective gonioscopy examinations performed by one author (GF) and retrospective analysis of 233 UK eye scheme certificates (2009-2014). Clinical cases of glaucoma in Leonbergers diagnosed by UK veterinary ophthalmologists, where gonioscopy of the fellow eyes or histology of affected eyes had been performed, were also reviewed.
  
  
  METHODS
  In the prospective study, intraocular pressure was recorded prior to gonioscopy using a rebound tonometer. Gonioscopy was performed using a slit-lamp biomicroscope with a Koeppe goniolens. PLD was categorized according to the percentage of the iridocorneal drainage angle affected (grade 0 = <25% affected; grade 1 = 25-50% affected; grade 2 = 51-75% affected; and grade 3 = >75% affected), and the degree of narrowing of the angle was noted.
  
  
  RESULTS
  Of 78 dogs examined prospectively, 64/78 (82%) were grade 0, 7/78 (9%) were grade 1, 3/78 (4%) were grade 2, and 4/78 (5%) were grade 3. A large phenotypic variation was observed. Spearman's rank correlation showed a positive correlation between age and severity of PLD (P < 0.0055). 52 (22%) of Leonbergers examined under the UK eye scheme 2009-2014 were affected by PLD. Five clinical cases of glaucoma were reviewed where gonioscopy had been performed and one where histology was performed. All individuals had grade 3 PLD with gonioscopy of the contralateral eye or severe goniodysgenesis with histological sections of the affected eye.
  
  
  CONCLUSIONS
  This survey suggests the prevalence of PLD is sufficient to justify ongoing screening of Leonbergers.
authors.affiliation: Davies Veterinary Specialists, Manor Farm Business Park, Higham Road, Higham Gobion, Hertfordshire, SG5 3HR, UK. Georgina.Fricker@vetspecialists.co.uk.
authors.forename: Georgina V
authors.initials: GV
authors.lastname: Fricker
authors.affiliation: Davies Veterinary Specialists, Manor Farm Business Park, Higham Road, Higham Gobion, Hertfordshire, SG5 3HR, UK.
authors.forename: Kerry
authors.initials: K
authors.lastname: Smith
authors.affiliation: Davies Veterinary Specialists, Manor Farm Business Park, Higham Road, Higham Gobion, Hertfordshire, SG5 3HR, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Gould
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000453:epidemiology*; D004285:Dogs; D005901:Glaucoma / Q000453:epidemiology / Q000662:veterinary*; D006068:Gonioscopy / Q000706:statistics & numerical data / Q000662:veterinary; D015994:Incidence; D007429:Intraocular Pressure; D008022:Ligaments; D009135:Muscular Diseases / Q000453:epidemiology / Q000662:veterinary*; D011446:Prospective Studies; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D006113:United Kingdom / Q000453:epidemiology
keywords: Leonberger; goniodysgenesis; gonioscopy; iridocorneal angle; pectinate ligament dysplasia; primary glaucoma