Herding dogs like Standard Collies and Border Collies are legendary for their ability to spot and follow livestock, thanks in no small part to their sharp vision. This genetic advantage is part of a double-sided coin, however: these breeds are also susceptible to a syndrome called CEA, or Collie Eye Anomaly (sometimes simply referred to as ‘collie eye’). Because their natural breed behaviors and tendencies rely heavily on clear vision, Collie Eye Anomaly can be a pet parent’s worst fear, even if sheep and cows aren’t milling about in the backyard. How, then, can a concerned Collie owner avoid this affliction in their own pup? Understanding this unique set of Collie eye ailments and their symptoms is a great place to start.

What is Collie Eye Anomaly?

CEA is a term that encompasses a variety of vision disorders in various canine herding breeds – unsurprisingly, the majority of affected dogs are Collie breeds and Collie mixes. There are varying levels of severity with the syndrome, so one dog with CEA might have a little trouble clearly seeing his owners across the yard, while another dog with CEA might be suffering from canine blindness. 

Some important things to note when researching this breed-targeting issue:

• Collie eye anomaly is present from birth: Some owners are completely unaware that their dog is affected by this group of disorders until they start to notice warning signs, which may include bumping into walls or objects that are clearly in their path or confusion when navigating a room. It can also be spotted by a certified canine ophthalmologist by dilating a puppy’s eyes within a few weeks of birth for an examination. Certain mild cases can become visually undetectable after a few months of age. A DNA is the only reliable indicator of genetic propensity. 
• It affects the majority of Collies: CEA is not an occasional affliction: some estimates put the percentage of Collies either carrying or presenting with the gene as high as 95% in the United States. This poses a particular challenge for breeders, which naturally want to avoid creating puppies with the gene whenever possible. In light of the overwhelming majority of the breed having some form of the CEA gene, breeders often fall to selecting silent carriers or mild cases in the hopes of producing as many issue-free Collie puppies as possible. This is also the reason that the genes stay active in such a wide swath of the canine population – much like cancer propensity in Golden Retrievers, breeding out the genes would potentially change many iconic or favorable aspects of the breed in the process.
  
• It’s a very important factor in breeding: Because it’s so prevalent in collies and collie mixed breeds, DNA tests are the only sure way of protecting puppies from the bad genes that cause CEA. Ethical breeders will have both the dam and sire of a breeding pair thoroughly tested for the genes before making a match. If they skip this step or misrepresent the resulting puppies as non-carriers, they risk spreading those CEA genes onto the next generation of Collies through misinformed owners. Thankfully, canine DNA tests are extremely accessible, and require nothing more than a non-invasive cheek swab to test for the genes. 
• It usually doesn’t cause any pain for the dog: It’s not to say that a Collie affected by the syndrome doesn’t have to endure any unpleasantness: reduced or blinded vision in a visually-oriented herding breed can hit him hard. However, because the syndrome tends to be gradual, he can usually navigate his environment more adeptly than, say, a puppy born blind. He’ll live a full, healthy life, even if he loses his sight, with a compassionate and patient owner and proper routine vet care.
• There is no cure: Once a dog receives the CEA genes from his parents and manifests the syndrome, he’ll have it for life. He may have a mild manifestation case, such as choroidal hypoplasia. This mild version of the syndrome won’t cause blindness, and in some cases can’t be visually detected after approximately 3 months of age. Other dogs, however, aren’t as lucky: CEA can cause issues with the vascular systems of the eyeball, or cause retinal detachment and subsequent vision loss or blindness.
• Some symptoms, however, can be treated: Because Collie Eye Anomaly affects various eye-related systems, the result of those issues can sometimes be staved off with timely canine eye surgery. Retinal reattachment surgeries, for example, may save his sight or give him more years with useful sight before going fully blind. Whether these therapies can help an afflicted dog largely depends on the type and severity of his syndrome, overall symptoms, and age.
• It is a hereditary trait, and non-contagious: Collie Eye Anomaly comes from two dogs with CEA genes: either dominant or recessive breeding. It cannot be passed from dog to dog like a cold, which means that it’s safe to let a collie with the syndrome play with other dogs, even other Collies – it can’t be passed on physically.

How Do I Tell if My Dog Has Collie Eye Anomaly?

Knowing there’s such a high chance of their beloved pet having a health issue as serious as CEA, some pet parents nervously search for clues. They might watch their dog extra-closely, and judge “red flags” too quickly: is he just excited, or did he bump into that wall because he didn’t see it? With the invention of medical testing, however, a Collie’s health no longer needs to be a mystery only unraveled through observation. Today, potential pet owners no longer have to take the breeder’s word for their dog’s health if they want to research his genetics.

• Ask a dog’s breeder, and get their answer in writing: While a devoted pet parent will undoubtedly still love their pup with or without eyesight trouble, they deserve to know if he has looming medical issues. Like with any health problem, the sooner the cause is discovered, the more robust the monitoring and symptom management will be. An ethical breeder should have no problem signing off on a puppy’s CEA-clear status, and ideally should have parental testing results available on request.
• If he’s still a puppy, get him examined ASAP: If a puppy is under three months of age, there’s an excellent chance a canine ophthalmologist can spot evidence of CEA in his eyes during a routine eye exam. If he’s older than three months, that evidence may still be visible, but it may also become compromised by shifts in natural eye pigmentation that tend to hide the telltale signs. If the Collie in question is older than three months or is an adult dog, a DNA test will likely be necessary.
• A DNA test will always reveal the truth: With fast results and a reasonably affordable cost, getting a DNA test for a Collie or herding-breed dog prone to CEA is a smart choice. Generally, these types of tests can be completed in minutes, and require a quick cheek swab to collect DNA on the dog. His DNA is then sent to a lab through the mail, and results are usually available in a few weeks or less. If a DNA test is necessary, pet parents should double-check that the test in question covers Collie Eye Anomaly – some tests only offer insights into breed makeup, and not necessarily health issues.

If a Collie seems suddenly clumsy or uncertain in familiar rooms or areas, a vet visit is definitely prudent for him. While these breeds are generally hardy outside of the propensity for eye issues, it’s important to rule out immediate environmental or diet concerns to avoid preventable health problems. Symptoms of other eye issues, such as night vision problems, can also mimic the issues associated with CEA, and testing is the only way to rule them out.

Will My Dog’s Puppies Have Collie Eye Anomaly?

Pet owners hoping to breed their Collies have long worried about this particular question. While it can be troublesome or disappointing to discover that a beloved pet with amazing traits has the canine eye anomaly gene, it’s important to avoid passing it on. Ideally, that means refraining from breeding altogether, but realistically, more collies carry the gene than not. Selecting a breeding pair with either low-level CEA cases or recessive genes can help lower the chances of puppies carrying it on, but this approach isn’t foolproof. 

Getting a dog tested for the gene as early as possible ensures that both owner and bloodline go into the collie breeding process with eyes wide open, and hopefully reduce the risk of genetic carriers along the way. Without both a sire and dam DNA test indicating a lack of the gene present, the answer to whether or not their puppies will have CEA is a statistical wildcard.

Collie Eye Anomaly is ingrained genetically into most of the collie population here in the United States. That’s why owners should educate themselves to recognize the signs and symptoms in their own dog or dogs, as this will help them get a diagnosis and symptom treatment quickly and easily when it’s needed most.

Sources Cited:

1)      “Collie.” American Kennel Club (AKC.org), (no publish date), https://www.akc.org/dog-breeds/collie/. Accessed May 26, 2020.

2)      Allen, Meredith. “What Is A Collie Eye Anomaly?” PetCareRx, February 6, 2020, https://www.petcarerx.com/article/what-is-a-collie-eye-anomaly/1656. Accessed May 26, 2020.

3)      Kruzer, Adrienne; RVT, LVT. “Collie Eye Anomaly in Dogs.” The Spruce Pets, January 6, 2020, https://www.thesprucepets.com/treating-collie-eye-in-dogs-4779855. Accessed May 26, 2020.

4)      Downing, Robin; DVM, DAPPM, DAVCSMR, CVPP, CRPP. “Collie Eye Anomaly.” VCA  Hospitals.com, (no publish date), https://vcahospitals.com/know-your-pet/collie-eye-anomaly. Accessed May 26, 2020.