Tag archives: eye malformation

Collie Eye Anomaly: The Confusion About “Going Normal”

Collie Eye Anomaly: The Confusion About “Going Normal”

In 1953, a prevalent inherited eye condition of collies was first described by W.G. Magrane in a journal article entitled, “Congenital anomaly of the optic nerve in collies”1. Later termed choroidal hypoplasia by scientists, the disease now known to the general public as collie eye anomaly (CEA) has significantly troubled collie breeders for over 50 years. In 2007, a paper describing a specific genetic mutation of the NHEJ1 gene associated with CEA was published. Identification of this mutation, has made it possible for scientists to develop tests that predictably identify the mutation and subsequently help breeders avoid producing puppies with CEA. Despite its breed specific name, testing has since identified the same CEA associated mutation in several other dog breeds including the Australian shepherd and the Shetland sheepdog.

Though there is significant variability in terms of ocular defects seen in affected dogs, the fundamental characteristics of CEA stem from the malformation of an important structure of the eye known as the choroid. The choroid is a thin layer of tissue containing the blood vessels responsible for supplying blood and nutrients to the retina and other structures of the eye. While mildly affected dogs may maintain normal vision with ...