Collie Eye Anomaly


What is it?

  • Collie eye anomaly is a inherited congenital eye disease found in Collies, Shetland Sheep dogs and Border Collies along with Australian Shepherds.
  • Non progressive
  • Condition is bilateral (in both eyes) but often one eye is more severe than the other.
  • Caused by improper development of the eye, more specifically the choroid, which is a collection of blood vessels within a layer of tissue that is located right behind the retina.
  • There is no treatment for CEA


CEA is more prevalent in Collies in the United States but is found much higher is the United Kingdom in other breeds. It is also found in high numbers in Switzerland.

In the United States:

  • up to 97% of Rough Collies are affected but only 2-4% have vision impairment or blindness.

In the United Kingdom:

  • Shetland Sheepdog is the breed with the highest incidence of CEA and Rough Collies are much lower than the united states.

Problems with CEA

Dogs with CEA have bilateral choroidal hypoplasia (CH)
  • This is the thinning of the vascular tissue in the back of the eye which doesn't significantly impure vision in the dog.

Some dogs will also have optic nerve coloboma.

  • This is where the nerve tissue doesn't fully develop around the area of the eye where the optic nerve enters.
  • This can cause the dog to have a hole in their eye, small holes can cause no vision impairment but large hole can lead to complete blindness.
  • This can also cause retinal detachment in severe cases.

Diagnosis and Testing

  • Puppies usually appear normal because few have actual vision impairment.
  • Veterinarians or DNA tests are the only way to diagnosis.
  • Puppies need to routinely be check, especially between 6-8 weeks of age because this is when it will be easiest to find and has the least chance of miss diagnosis.
  • Pigmentation (pale spot) will appear lateral to the optic disk due to the underdevelopment of the choroid in the eye.


  • DNA testing is available to see if your dog is affected, is a carrier of CEA or is clear of the mutation.
  • Companies use a panel of 6 DNA markers called a haplotype to test for the DNA mutation.
  • Testing is available for Rough and Smooth Collies, Australian Shepherds, Border Collies, Lancashire Heelers and Shetland Sheepdogs

Genetic Transmission

Recessive gene mutation

Not sex linked

Caused by mutation on the canine chromosome 37

  1. Affected dogs: have 2 copies of the mutant gene and is homozygous for CEA. Will pass the CEA mutated gene to offspring.
  2. Carrier dogs: have 1 normal gene and 1 mutated gene. Can pass defective gene to offspring (50% chance).
  3. Clear dog: negative for mutated CEA gene and can't pass mutation on to offspring.


When breeding a homozygous dominant collie (clear of the CEA mutated gene) with a heterozygous dominant collie (carrier of CEA):

  • 50% clear of the CEA mutation
  • 50% carriers of the CEA mutation

If you breed two heterozygous dominant collies:

  • 25% clear of the CEA mutation
  • 50% carriers of the CEA mutation
  • 25% affected with CEA

Eradication Methods

When breeding Collies or other breeds that have a high risk of CEA, its best to get a DNA test prior to breeding to know for sure if you will pass the gene on or have a high chance of passing the gene on.

The only way to eradicate or lower CEA is to stop breeding Collies with the mutation or ones that are even carriers to the mutation.

  • The chart below shows the percentages when breeding dogs with or without the CEA mutation.

This is hard to do because some dogs are misdiagnosed by veternarians so breeders don't believe they can pass it on when they can.

Big image


I think that in order to breed Collies or dog breeds with a high incidence of CEA, you should be required to get the DNA test done. And if your Collie is affected you can't breed. This is the only way to eradicate the problem. In order to just lower the occurrence you should only be able to breed Collies that are clear of the mutated gene with others clear of the gene or with a Collie who is just a carrier. This won't completely get rid of the problem but it could lower the number of Collies with CEA. Owners of Collies need to be responsible and have their puppies eyes checked by a veterinarian in the 6-8 week period and several times after that to make sure the disease is caught and if wanting to breed them they need to get the DNA test even if you were cleared by a veterinarian. Also, owners need to be educated on this issue before buying or breeding Collies.


"Collie Eye Defect in Dogs." Dog Collie Eye Disorder. Web. 27 Apr. 2015. <>

"Collie Eye Anomaly." Australian Shepherd Health Genetics Institute. Australian Shepherd Health Genetics Institute, 1 Mar. 2013. Web. 27 Apr. 2015. <>.

Barnett, K. "Collie Eye Anomaly (CEA)." Journal of Small Animal Practice 20.9 (2008): 537-42. Print.

Oliver, James, and Dennis Brooks. "Collie Eye Anomaly." Vetstream. Web. 27 Apr. 2015. <>.

"Collie Eye Anomaly (CEA)." Collie Eye Anomaly (CEA). Animal Genetics Inc. Web. 27 Apr. 2015. <>.

"Collie Eye Anomaly (CEA)." Pet Health Network. 29 Aug. 2012. Web. 27 Apr. 2015. <>.

Picture References

Expected Results of Breeding Strategies for Inherited Recessive Diseases. Digital image. Https:// 7 July 2014. Web.

Collie Eye Anomaly. Digital image. Dogtime. Web.

Collie Eye Anomaly (CEA). Digital image. Pet Health Network. 29 Aug. 2012. Web.

Collie Eye Anomaly. Digital image. Australian Shepherd Heath and Genetic Institute. 1 Mar. 2013. Web.