A dog’s eyesight is very important, especially for herding dogs like Collies. Collies have great peripheral vision because of the position of their eyes, and they are also equipped to see well in low light and observe subtle movements from far distances.
Unfortunately, however, some Collies can have problems with their eyesight if they are born with an inherited developmental condition known as Collie eye anomaly (CEA). This condition has been seen in every type of Collie, as well as the Shetland Sheepdog, Australian Shepherd, and other herding dogs. Read on to learn the causes, symptoms, and treatments of Collie eye anomaly.
Causes of Collie Eye Anomaly
Collie eye anomaly occurs when there is an abnormal development of the eye due to a chromosome mutation. This can result in defects in different parts of the eye, and in some cases severe consequences like retinal detachment and blindness.
This is an inherited, congenital disease, one that is present at birth. The recessive gene that causes the abnormal development must be inherited from both parents in order for the pup to show symptoms. The pup can also inherit one bad copy of the gene and one good copy and still be a carrier of the disease, but not show symptoms. Breeding these dogs should be done with caution and an awareness of the potential mate’s recessive gene status.
Types of Collie Eye Anomaly
The most common and mildest form of CEA is choroidal hypoplasia, which is a lack of development of the choroid. The choroid is the layer of blood vessels and connective tissue between the retina and the white of the eye (the sclera). Choroidal hypoplasia typically does not cause vision impairment, but it is an indication that the dog is a carrier of the CEA gene (or genes).
A more serious form of CEA is colobomas, which is characterized by depressions in the sclera, often near the optic disk. These depressions, or holes, may be small or large, and can cause vision impairment or retinal detachment when fluid accumulates behind the retina.
Symptoms of Collie Eye Anomaly
The symptoms of CEA can vary from dog to dog. Sometimes, there will be no clinical signs until vision impairment begins to set in. Depending on the severity of your dog’s condition, the vision impairment may be mild or your dog may become completely blind.
In some cases, CEA can be detected early. Your veterinarian should be able to see a thin or defective choroid in puppies as young as 5 weeks old, so be sure to take your pup for an examination as soon as they arrive home.
Treatment for Collie Eye Anomaly
Unfortunately, there is no cure for Collie eye anomaly. In milder cases, the disease is not likely to progress, and the only takeaway will be the knowledge that your dog is a carrier of a CEA gene.
In more severe forms, as in the case of colobomas, surgery may be performed to minimize the effects of the condition. Surgical options typically include laser surgery, retinal reattachment surgery, and cryosurgery, which destroys cells or tissues by freezing them with liquid nitrogen. This can sometimes prevent retinal detachment.
Your veterinarian will determine what treatment -- if any -- is appropriate for your dog.
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This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.