Gonioscopy--Although we don't have recent basset-specific data, there's evidence in other breeds (Flat Coats, Great Danes) that goniodysgenesis is significantly associated in affected dogs with the development of glaucoma, goniodysgenesis is heritable, and that breeding dogs with no or minimal goniodysgenesis decreases the incidence of glaucoma within a breed.
The study below (Great Danes) indicates that if both parents have no more than minimal goniodysgenesis, then glaucoma would affect their offspring at a rate of < 4/1000.
Am J Vet Res 2001 Sep;62(9):1493-9
Relationship of the degree of goniodysgenesis and other ocular measurements to glaucoma in Great Danes.
Wood JL, Lakhani KH, Mason IK, Barnett KC.
Epidemiology Unit, Animal Health Trust, Newmarket, Suffolk, UK.
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.
PMID: 11560283 [PubMed - indexed for MEDLINE]
Discussion of the significance of goniodysgenesis in Flat Coats can be found here.
The following is an exerpt from this webpage.
Detailed studies have been carried out of the disease in the UK population of flatcoats, involving diplomate clinicians, as well as epidemiologists and statisticians. These studies have now been published in the scientific journal Veterinary Ophthalmology (Vol 1, pp85-90, 91-99). These studies have enabled several important facts about the disease in flatcoats to be properly established.
The data demonstrated a close relationship between the degree of goniodysgenesis (or PLD) and the likelihood of an animal developing glaucoma. Animals that are only very slightly affected (or are clear) are unlikely to get glaucoma and as the proportion of the eye that is affected increases, then so does the risk.
Overall, there was no indication of a substantial worsening of the condition with age and so an animal, which is screened clear at a young age, is unlikely to develop the disease later in life. Thus, animals can be screened as young adults and the likelihood of them developing glaucoma can be accurately assessed (as well as their suitability for breeding, see below).
The degree of goniodysgenesis (or PLD) was highly heritable (h2>0.7), indicating that if one bred from animals with no, or only very limited goniodysgenesis, then the offspring would be most unlikely to suffer from glaucoma. Although glaucoma itself was not shown to be inherited, the close association between the predisposing condition (goniodysgenesis) and the disease and the high heritability of goniodysgenesis can be taken to indicate that glaucoma is inherited. This is the first time that the heritability of this disease has been demonstrated scientifically in dogs.
[ September 18, 2003, 09:45 PM: Message edited by: Betsy Iole ]