What is Collie Eye Defect?
Collie eye defect has no cure, but it can be prevented by having your dog tested before breeding and only buying your puppies from a reputable source. Unfortunately, it is estimated that up to 95% of Collies in the United States are either carriers or have the defect. However, it does not always cause vision loss or other eye issues. In fact, some dogs are not affected at all, even if they have the defect. Luckily, this is not a deteriorating condition, so whatever vision your dog has at 10-12 weeks old is the same throughout life.
The Collie eye defect most commonly affects collie breeds, but it is also known to affect other similar breeds as well. This is a defect that your dog has from birth and can be recognized by a veterinary ophthalmologist when your pet is about two months old. The defect may cause an underdeveloped choroid (the blood vessels in the tissue under the retina), defect in the optic nerve, thinning of the sclera, and retinal detachment. This is an autosomal recessive defect (gene comes from each parent) and not all dogs will be affected in the same way. The defect is described by grades 1-5, depending on the severity, from barely noticeable to complete blindness.
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Symptoms of Collie Eye Defect in Dogs
You may not notice any signs even if your dog has this defect, which is why it is important to get your puppy’s eyes checked by a veterinarian and a certified veterinary ophthalmologist at about eight weeks old. There are some signs that you may be able to see, such as:
- Pale spots on the eye
- Bumping into things
- Afraid to go outside or to new places
- Not blinking when you wave fingers close to the eye
- Grade 1 - Eye has twisted vessels in the retina and minor areas of choroidal lesions
- Grade 2 - Eye has twisted vessels in the retina and major areas of choroidal lesions
- Grade 3 - Eye has twisted vessels in the retina and major areas of choroidal lesions with holes or pits in the eye
- Grade 4 - Eye has twisted vessels in the retina, major areas of choroidal lesions, holes or pits in the eye, and retinal detachment
- Grade 5 - Eye has twisted vessels in the retina, major areas of choroidal lesions, holes or pits in the eye, retinal detachment, and retinal hemorrhage
Causes of Collie Eye Defect in Dogs
Collie eye defect in dogs is inherited through a recessive gene, previously believed to only be seen in collies, but can affect other breeds as well. The breeds most often affected are:
- Australian Shepherds
- Border Collies
- Boykin Spaniels
- Lancashire Heelers
- Long-haired Whippets
- Nova Scotia Duck Tolling Retrievers
- Rough Collies
- Shetland Sheepdogs
- Smooth Collies
Diagnosis of Collie Eye Defect in Dogs
The veterinarian will give your dog a complete physical examination and run some tests before sending you to a veterinary ophthalmologist. The physical includes body temperature, weight, reflexes, blood pressure, breath sounds, abdominal palpation, overall coat and skin condition, pulse, and respiratory rate.
The laboratory tests will include a chemistry profile to check the function of the pancreas, liver, and kidneys; a complete blood count (CBC) to check levels of white and red blood cells, platelets, hemoglobin, and hematocrit; electrolyte test, and a urinalysis. In addition, the veterinarian will take some x-rays (radiographs) of the abdomen for signs of abnormalities. Your veterinarian will then send you to a veterinary ophthalmologist for testing.
The CEA-CH DNA test determines if your dog is normal, a carrier, or actually affected by Collie eye defect. This test can be done by a cheek swab or blood sample, but it cannot tell you the extent of the vision damage in your dog. That can only be done by a veterinary ophthalmologist with an eye examination. First, the ophthalmologist will put drops in your dog’s eyes to dilate the eyes so the inside of the eye can be seen with the ophthalmoscope.
Treatment of Collie Eye Defect in Dogs
Even if you find out your dog has this defect, there may be no reason to treat because the effects may be minimal. If there are side effects from Collie eye defect, there is no cure, so treatment is limited. As a matter of fact, the treatment for Collie eye defect is supportive. Some of the suggestions for treating the effects are:
- Laser surgery may be able to reduce the effects
- Cryosurgery uses extremely cold temperatures to destroy the damaged cell tissue
- Reattaching the retina is also possible with surgery
The most important aspect of treatment is preventing reoccurrence by not breeding your dog and only buying puppies from respected and accredited breeders.
Recovery of Collie Eye Defect in Dogs
If your dog has a serious case of Collie eye defect and has a major loss of vision, you should train your dog to manage without sight just as you would with a human. In fact, since your dog will probably have had this since birth, chances are pretty good that your pet will not need much training. However, if your pet has been having trouble getting around, you can ask the veterinarian to recommend a training program.