Collie Eye Anomaly

Collie Eye Anomaly The (German Collie eye anomaly, abbreviated CEA) is a hereditary disease of different dog breeds from the family of Collies and related breeds with them. The disease affects the back of the eye and leads to a congenital impairment of vision and even blindness.

Pathophysiology

Collie Eye Anomaly The is based on a genetic malformation and hypoplasia of the choroid and retina during embryonic development. This leads to defects in the development of blood vessels, which may lead to bleeding in the eye. Also coloboma of the choroid and retina may occur. Also, a retinal detachment is possible. Depending on the severity of the changes, the vision may not be affected; severe cases can, however, show a decreased vision to total blindness.

Clinic

Signalment

The disease occurs with long hair and short hair Collies and Shelties and related breeds such as Border Collie, Australian Shepherd and also Lancashire Heeler. Severe cases are usually diagnosed as puppies; milder cases can be determined at any time of life as a random diagnosis.

Symptoms

Affected puppies show from the beginning decreased vision and even blindness. Normally, the disease does not progress; can possibly heavier colobomata later lead to retinal detachment. Minor cases are clinically normal and can only be diagnosed by ophthalmoscopy.

Diagnosis

The diagnosis is made by ophthalmoscopy, by means of which the characteristic changes in the fundus of the eye can be determined. In affected dogs usually affects both eyes; However, the severity of the disease between the two eyes can be different.

Treatment and prognosis

A cure is not possible. Retinal detachments can be treated by laser surgery in some cases. A progression of the disease is not to be expected in dogs with mild CEA. Supportive measures are limited to adapt to the environment of the dog to its reduced eyesight and thereby allow him a good quality of life. The life expectancy is not reduced compared to healthy dogs.

Genetics and breeding hygiene

Collie Eye Anomaly The seems to be controlled by several loci ( polygenic inheritance ). 80 to 90 percent of Collies have changes in the fundus, without their vision is limited. Also Collies without changes of the fundus can be carriers of the disease. It is recommended that all puppies endangered breeds ophthalmoscopy to screen and use the data thus obtained by means of a central database for the estimation of breeding values ​​. Means of screening and breeding restrictions, the number of affected animals are significantly reduced. Many breeds have affected dogs on a 7.8 kb deletion in the NHEJ1 gene. A genetic test is now available.

History

The disease was first described in 1953 by WG Magrane in the United States. Seven years later, the CEA was first examined histopathologically. The mode of inheritance was elucidated in 1968 by Yakely and employees.