Relationship of the degree of goniodysgenesis and other ocular measurements to glaucoma in Great Danes

Abstract

Objectives - To assess the association between goniodysgenesis, ocular measurements, and glaucoma in Great Danes. Animals - 180 Great Danes. Procedure - Eye examination and measurements were obtained from 180 Great Danes; for 30 of these dogs, depth of the anterior chamber, vitreal body length, and total depth of the globe were also measured. These data were merged with electronic pedigree information on 43,371 kennel club registered Great Danes. Relationships among goniodysgenesis, ocular measurements, and glaucoma and the heritability of goniodysgenesis were estimated. Results - The degree of goniodysgenesis was significantly and positively associated with the likelihood of glaucoma. There was a significant association between the degree of goniodysgenesis in offspring and parents. The estimated heritability of the degree of goniodysgenesis was 0.52. The depth of the anterior chamber of the eye was also a good predictor of goniodysgenesis (ie, the dog was almost certain to have glaucoma if the depth was < 3.7 mm). If both parents had goniodysgenesis < 70%, then with 95% confidence, the occurrence of glaucoma in the ensuing offspring would be < 4/1000. This strategy translates to ensuring that the depth of the anterior chamber of the eye is > 3.7 mm for both parents. Conclusions and Clinical Relevance - The strong and significant correlation among goniodysgenesis, other eye measurements, and glaucoma and the significant heritability of goniodysgenesis suggests that glaucoma may be heritable in Great Danes. If so, glaucoma can be controlled by breeding only from sires and dams with a minimum degree of goniodysgenesis.