Glaucoma is an optic neuropathy with characteristic damage of the optic nerve resulting in blindness. Primary glaucomas in dogs are usually accompanied by an increased intraocular pressure (IOP), and often occur in animals affected by pectinate ligament dysplasia (PLD) causing impairment of aqueous humor drainage. PLD is also known as goniodysgenesis from gonio = angle (the space between the iris and cornea through which the aqueous fluid drains from the eye) and dysgenesis = abnormal development. In PLD, the normally fine strands of pectinate tissue consolidate to broadened bands or ligaments, and can be accompanied by a narrowed or closed irido corneal angle (ICA). The constantly elevated IOP causes destruction of intraocular structure and function, resulting in blindness.
This hereditary disorder was previously described in several dog breeds with only a few autosomal recessive mostly breed-specific genetic mutations identified. The Leonberger has been recognized as a breed that is at risk for high prevalence of PLD. Many dogs presenting clinically with primary glaucoma have a high-grade PLD. Identification of the underlying genetics of glaucoma in Leonbergers and subsequent development of a genetic test will help to avoid the breeding of affected dogs and enable earlier diagnosis and potentially more effective therapy.
The Institute of Genetics of the University of Bern, with the collaboration of the Ophthalmology Sections of Vetsuisse Faculty of the Universities Zürich and Bern, the Swiss Association of Veterinary Ophthalmologists (SAVO), and the Swiss Leonberger Club, would like to investigate the genetic origin of glaucoma in Leonbergers and to evaluate the prevalence of PLD and reduced ICA width as well as age distribution of these changes. For that, we are looking for Leonbergers affected by primary glaucoma as well as healthy dogs, which will undergo quick, painless and non-invasive gonioscopy examination.
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