Collie Eye Anomaly
What is collie eye anomaly?
Collie eye anomaly (CEA), also called “collie eye defect,” is an inherited, developmental disease in dogs. Predisposed breeds include:
- Collies (smooth and rough)
- Shetland sheepdogs
- Australian shepherds
- Border collies
- Lancashire heelers
- Nova Scotia duck tolling retrievers
With CEA, there is a mutation of the gene that determines the development of the eye. This mutation results in defects of many layers of the back of the eye.
What are the clinical signs of CEA?
The most common sign of CEA is blindness. The degree of vision loss can vary, depending on the severity of the developmental defects. Many dogs have normal vision, but vision loss or blindness can occur, especially if the dog’s retinas have detached. CEA may also be associated with more obvious abnormalities in the eye:
- Microphthalmia describes eyeballs that are smaller than normal
- Enophthalmia describes eyeballs that are sunken deep into the eye socket
How is CEA diagnosed?
Many dog breeders screen for this anomaly, with examinations performed by a veterinary ophthalmologist between 6 and 8 weeks of age. Unfortunately, in some cases, CEA is not diagnosed until the dog’s vision is affected. Your veterinarian may diagnose CEA by evaluating the dog’s retina (located at the back of the eye) while the pupil is dilated. Your veterinarian may recommend referral to a veterinary ophthalmologist for a complete eye examination.
There may be areas of thinning (choroidal hypoplasia) or an actual hole, called a coloboma, in some of the structures of the eye. CEA may also be associated with a detached retina, which can occur as a complication of a coloboma.
Is there any treatment for CEA?
Unfortunately, CEA cannot be reversed. In the case of coloboma-induced, partial retinal detachment, laser surgery may be attempted to re-attach the retina if the condition is detected early. Coloboma may not always lead to retinal detachment, particularly if the coloboma remains stable during the dog’s first year of life.
Can you prevent CEA?
CEA is a genetically based, developmental disease, so it can only be prevented by not breeding dogs who carry the abnormal gene. There are now several genetic tests for CEA. Consult your veterinarian if you are planning to breed your dog to determine which pre-breeding tests are recommended.
© Copyright 2025 LifeLearn Inc. Used and/or modified with permission under license. This content written by LifeLearn Animal Health (LifeLearn Inc.) is licensed to this practice for the personal use of our clients. Any copying, printing or further distribution is prohibited without the express written consent of LifeLearn. This content does not contain all available information for any referenced medications and has not been reviewed by the FDA Center for Veterinary Medicine, or Health Canada Veterinary Drugs Directorate. This content may help answer commonly asked questions, but is not a substitute for medical advice, or a proper consultation and/or clinical examination of your pet by a veterinarian. Please contact your veterinarian if you have any questions or concerns about your pet’s health. Last updated on Jun 20, 2025.
