Collie eye anomaly is an eye disease that not only affects collies but several other dog breeds too. Since this disease often leads to blindness it is important for owners of at risk breeds to understand this condition and know the signs associated with it.
What Is Collie Eye Anomaly in Dogs?
Collie eye anomaly (CEA) is also known as collie eye defect and is a disease of the eye that affects how the eye develops. It is a genetic, inherited disease that dogs are born with. Collie eye anomaly usually causes the blood vessels inside an eye that provide blood flow to the retina to be underdeveloped. This disease can lead to blindness if it is severe enough since the retina does not receive proper blood flow or becomes detached.
There are actually several different eye abnormalities that can be classified as a part of collie eye anomaly and because of this the disease is often described as a syndrome.
- Choroidal Hypoplasia or Chorioretinal Changes: These are the most commonly seen abnormalities in collie eye anomaly and they affect the blood flow to a vascular layer underneath the retina called the choroid. These choroidal issues are considered to be the least dangerous of CEA abnormalities so dogs do not usually lose their vision.
- Retinal Folds: As the name describes, this abnormality occurs when the retina folds in on itself. This condition usually improves with age so dogs do not usually lose their sight.
- Staphyloma, Coloboma or Ectasia: These issues all involve a bulging inside the eye, usually around the optic disc. They can lead to retinal detachment and blindness depending on the severity of them.
- Vascular Disease or Tortuous Blood Vessels: These issues are problems with the blood supply in the eye where the vessels are small, underdeveloped, or even non existent.
Signs of Collie Eye Anomaly in Dogs
- Abnormally small eyeballs
- Sunken in eyeballs
- Bumping into things
Collie eye anomaly is not a disease that is obviously seen by pet owners but occasionally more obvious eye abnormalities are seen alongside CEA. Microphthalmia is a condition where a dog has smaller than normal eyeballs and enophthalmia is a condition where the eyeballs are sunken into the dog's head. Either of these conditions can be seen in a dog with collie eye anomaly and are the only real visible changes to the eyes that can be seen without special equipment.
Causes of Collie Eye Anomaly in Dogs
Collie eye anomaly is due to a recessive gene that is passed on to offspring. It is inherited so a dog will be born with this genetic change even if the signs or symptoms of CEA are not immediately noticed. CEA is not a contagious disease.
Diagnosing Collie Eye Anomaly in Dogs
A veterinary ophthamologist will dilate your collie's eyes and use an ophthalmoscope to look for changes in the eyes or signs of collie eye anomaly. In order to definitively diagnose a dog with collie eye anomaly though a genetic test must be performed.
Treatment of Collie Eye Anomaly in Dogs
In some instances, surgery is available to prevent retinal detachment if that is a concern for your dog's specific symptoms of CEA. In general though, collie eye anomaly is not considered to be treatable. Some dogs may not fully lose their vision while others do but it is important to remember that dogs adjust well to losing their vision and can still lead very happy lives.
How to Prevent Collie Eye Anomaly in Dogs
Genetic testing and selective breeding are currently the only ways to decrease the incidence of collie eye anomaly. Tests are available to screen dogs before they are used for breeding and can tell breeders if a dog is simply a carrier or has a form of collie eye anomaly. This test uses a cheek swab or blood sample to look for genetic markers but an eye examination should also be performed by a veterinary ophthamologist.
Some breeds are more commonly affected than others so these breeds should be considered at-risk and tested for collie eye anomaly prior to breeding.