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This is health information for owners, not a diagnosis and not veterinary advice. A veterinarian, usually a veterinary ophthalmologist, is who looks at the eye and says what is there. A DNA result does not replace that exam.
I keep Rough Collies in Jacksonville, so collie eye anomaly is a phrase that shows up on health clearances and puppy paperwork. It is an inherited developmental condition in the back of the eye. You cannot tell by looking at a dog across the yard.
On this page: what it is · which dogs · what an exam finds · symptoms · go normal · the DNA test · pet dog or breeding dog · when to call a vet
What collie eye anomaly is
Collie eye anomaly (CEA) is also called choroidal hypoplasia. The choroid is the carpet of blood vessels behind the retina. In CEA, that layer does not develop fully, and some dogs also have changes in the retina or around the optic nerve. Dogs are born with it. The Collie Health Foundation says the physical changes are present before birth, and that CEA is autosomal recessive: a dog needs two copies of the mutation to be affected.
The mutation the labs test for is a deletion in the NHEJ1 gene. A 2007 study tied a 7.8 kb deletion to CEA in several breeds, and the Orthopedic Foundation for Animals, the UC Davis Veterinary Genetics Laboratory, and the Collie Health Foundation all describe the condition in those terms. OFA adds a point that matters if you breed: the same mutation can look mild in one dog and severe in another, and a dog with mild signs can produce a puppy with severe CEA. Why severity varies is not understood.
Rough Collies, Border Collies, and the other breeds
CEA is best known in Rough and Smooth Collies. The Merck Veterinary Manual also lists Shetland Sheepdogs, Border Collies, Australian Shepherds, Lancashire Heelers, longhaired Whippets, Boykin Spaniels, and Nova Scotia Duck Tolling Retrievers. UC Davis’s current test page adds breeds it considers appropriate for the test, including the Bearded Collie, Australian Cattle Dog, English Shepherd, Miniature American Shepherd, and Old-time Scotch Collie. OFA’s list is longer. If you have a herding breed or a Collie mix, check the lab’s current list instead of assuming the test does or does not apply.
New to the Rough Collie itself? What Is a Rough Collie? covers the breed. Bearded Collies are a different dog, and UC Davis includes them on its CEA list. What Is a Bearded Collie? is the explainer here.
What an eye exam finds
Breeders usually have a veterinary ophthalmologist examine puppies at about 6 to 8 weeks, with the pupils dilated, so the back of the eye can be seen. OFA, the Collie Health Foundation, and VCA Animal Hospitals all describe that timing. The Foundation also asks that dogs be checked again after 6 months of age.
The exam records named findings. It is not a score you can assign from a photo.
- Choroidal hypoplasia. An area of the choroid that did not develop fully. Merck’s professional chapter describes a pale pink area beside the optic disc. The Collie Health Foundation calls this the most common and least severe finding, and says most dogs with only this change function normally.
- Coloboma. A gap or cupped area, often in the optic nerve or beside it. The Foundation says a large coloboma can lead to a retinal detachment. Merck says the more severely affected dogs, about 10 to 20 percent, can have a coloboma of the optic disc or the area around it.
- Retinal detachment and bleeding. The retina can lift off the back of the eye, and a vessel can bleed inside the eye. Merck puts occasional retinal detachments at about 2 to 5 percent, and says vision is not appreciably affected unless a detachment develops. The Collie Health Foundation says a complete detachment blinds that eye.
- Other findings an ophthalmologist may write down. Small eyeballs (microphthalmia), mineral on the cornea, and odd or tortuous blood vessels. OFA and UC Davis list several of these. They are exam findings, not something to measure at home.
The Collie Health Foundation says a mild, moderate, or severe grade used to be written on forms, and that today the abnormal findings themselves are what get recorded. For a research project, the Foundation has also asked ophthalmologists to note the severity of choroidal hypoplasia and of coloboma separately, as normal, mild, moderate, or severe, in the comments on the eye form. That is a request to the examiner. It is not a scale for owners.
Collie eye anomaly symptoms
What you see at home and what the ophthalmologist sees are different. Many dogs with CEA show nothing an owner would notice.
OFA describes the range this way: some affected dogs have no apparent vision problem, some are completely blind, and in moderate cases a dog may hesitate on stairs, bump into objects, or have trouble when the furniture moves or the route is unfamiliar. VCA says the most common sign of CEA is blindness. That does not match Merck, OFA, or the Collie Health Foundation. Those sources say many mildly affected dogs see adequately, and that vision loss is the worry when the retina detaches or the changes are severe. Blindness is part of the range. It is not the typical picture those other sources describe.
Why a puppy can “go normal”
A clear exam later in life is not the same thing as a genetically clear dog. The Collie Health Foundation explains that puppies with a small patch of choroidal hypoplasia can look normal on a later exam because pigment fills in over the thin spot. Breeders called those puppies “go normal.” The Foundation’s current wording is that the area may be “masked,” and that the dog is still genetically affected.
Wisdom Panel makes the same point. It says the lesions should be diagnosed before about 10 weeks of age, because retinal pigment can hide choroidal hypoplasia as the puppy grows. The Collie Health Foundation also says blue merles are harder to judge: pigment in the eye is diluted along with the coat, and a merle can be called choroidal hypoplasia when the pale area is the color pattern, not a lesion.
Merle coat color and CEA are easy to mix up, and they are not the same problem. The Foundation’s health statement says breeding a merle Collie to another merle Collie should be avoided, because those litters have a high risk of abnormally small eyes, blindness, and deafness. That is a double-merle risk. It is separate from the NHEJ1 test.
“Go normal” versus affected is not a second disease. It is an affected dog whose later eye exam started to look clear. The Foundation says the only way to tell a genetically normal Collie from a masked one is a DNA test. The exam still matters, because it is what shows a coloboma, a detachment, or bleeding. UC Davis notes that the NHEJ1 deletion does not explain every coloboma. Some dogs with a coloboma do not have that deletion. DNA status and the eye chart answer different questions.
The collie eye anomaly test
The collie eye anomaly test is a cheek swab sent to a lab that looks for the NHEJ1 deletion. It reports genetic status. It does not look inside the eye, and the Collie Health Foundation says it does not replace an exam by a veterinary ophthalmologist, typically at 6 to 8 weeks.
UC Davis reports three results:
- Normal (N/N). No copies of the CEA allele. The dog will not have this inherited form of the disorder and cannot pass the allele on.
- Carrier (N/CEA). One copy. UC Davis says these dogs are not affected by this form of the disorder. They can pass the allele to about half their puppies. A mating between two carriers is predicted to produce about 25 percent affected puppies.
- Affected (CEA/CEA). Two copies. The dog may develop the disorder and will pass the allele to every puppy. The same lab’s result key also says a two-copy dog “will likely develop the disease,” while the phenotype section of that page says some dogs have no obvious signs and normal vision for life. Read “affected” as genetic status. The eye exam is what shows what that dog’s eyes actually did.
One wording conflict is worth catching before you panic over a report. OFA’s key for a carrier says the dog “is at risk for developing the disease.” That does not match UC Davis or the Collie Health Foundation, which both say one copy does not make the dog affected. If a single-copy result is labeled “at risk,” check which lab wrote the key.
These are labs whose own pages, as of October 2026, offer a CEA result:
- OFA takes the order, sends a cheek swab, and has the sample processed at the University of Missouri. The result can be registered in the OFA database.
- UC Davis Veterinary Genetics Laboratory offers CEA as its own test, including for Rough and Smooth Collies, Border Collies, and Bearded Collies.
- Embark publishes a CEA condition page, and its Breed & Health kit screens a large health panel that includes this condition.
- Wisdom Panel describes the same deletion, and its Premium test links to that CEA page.
A consumer kit is a convenient way to learn clear, carrier, or affected status. It will not tell you whether a coloboma is present.
Embark Breed & Health cheek swab. Embark's CEA page is part of the health panel this kit screens. A DNA result does not replace an eye exam.
A health panel may flag other inherited traits at the same time. MDR1 drug sensitivity is a separate issue from CEA. The Collie Health Foundation lists both on its recommended breeding screens. If MDR1 is the result you are trying to sort out, parasite protection for dogs with the MDR1 gene is the piece on this site.
A pet dog versus a breeding dog
For a pet, the practical question is vision and comfort, not a breeding plan. Nothing repairs the genetic change. OFA says there is no treatment for CEA. Wisdom Panel says there is no cure. VCA says the defect cannot be reversed. Many mildly affected dogs live normal lives. Merck says vision is not noticeably affected unless the retina detaches, and the Collie Health Foundation says most dogs with only choroidal hypoplasia have no obvious vision deficit, and that CEA generally does not cause vision defects unless the dog is severely affected. A severely affected dog can lose vision. That is a range. It is not a percentage anyone can put on one dog without an exam.
If a retina is detaching, that complication belongs to a veterinary ophthalmologist. VCA notes that when a partial detachment related to a coloboma is found early, laser surgery is sometimes attempted to reattach the retina. Whether to do that is the specialist’s decision. It is not a home treatment, and this post does not describe how it is done.
For breeding, DNA status is how people avoid producing affected puppies by accident, and it still does not replace the puppy eye exam. UC Davis says breeders can use the result when they choose mating pairs. The arithmetic on that page is the part worth remembering: two carriers are predicted to produce some affected puppies, and a clear dog does not pass the allele. OFA’s recommendation is narrower. It says a carrier should be bred only to a dog that tested normal, to limit affected offspring. Wisdom Panel says a carrier, or a dog with two copies, can be bred to a clear dog without producing affected puppies, and that carrier-to-carrier matings are not advised. Those are the labs’ statements, not a pairing chart. The Collie Health Foundation adds an exam rule of its own: among CEA findings, choroidal hypoplasia is the only grade it says collie breeders are allowed to use for breeding. Because mild and severe disease can come from the same mutation, a good eye exam on the parents is not a promise about a puppy’s eyes.
When to call a vet
- You have a puppy, especially from parents with no DNA result and no early eye exam. The useful window for seeing mild choroidal hypoplasia is about 6 to 8 weeks, before pigment can mask it. Ask for a veterinary ophthalmologist, not a guess based on whether the puppy navigates the living room.
- Vision changes. Hesitating on stairs the dog knew yesterday, bumping into things, a pupil that stays wide, or blood in the eye can go with a retinal detachment. Merck lists prolonged or unequal pupils, vision trouble, and bleeding inside the eye among the signs of a detachment. That is a same-day veterinary visit.
- A known coloboma. The Collie Health Foundation says a large coloboma can lead to a detachment, and Wisdom Panel recommends ongoing eye exams for dogs that are at risk or already affected. The ophthalmologist sets how often.
Eye exams and specialist visits are part of life with some Collies, so pet insurance is worth looking into before a health issue comes up. You can get a quote from Lemonade Pet Insurance.
FAQ
Can a dog with collie eye anomaly see?
Often, yes. Merck says vision is not noticeably affected unless the retina detaches. OFA says some affected dogs have no apparent impairment and others are blind. The Collie Health Foundation says most mildly affected dogs have adequate vision for life. An exam is how you know which description fits a particular dog.
Does CEA get worse with age?
The Collie Health Foundation says the disorder generally does not worsen over time, and Wisdom Panel describes the choroidal hypoplasia of CEA as non-progressive on its own. A dog born with a severe coloboma or a serious vessel problem can still lose vision later if the retina detaches or a bad bleed happens. That is a complication, not the mild choroidal change spreading.
Is collie eye anomaly the same as progressive retinal atrophy?
No. The Collie Health Foundation says progressive retinal atrophy is unrelated to CEA. The Collie form, PRA-rcd2, is a degeneration of the retina. The Foundation describes it as typically showing signs by about 6 weeks and causing blindness by about 6 to 8 months. CEA is a developmental problem present at birth. A clear result on one test says nothing about the other. Puppies still need the eye exam.
Does a normal eye exam mean the dog is genetically clear?
No. That is the “go normal” problem. Pigment can mask mild choroidal hypoplasia, so a later exam can look clean in a dog that still has two copies of the mutation. DNA testing is what identifies clear, carrier, and affected status. The exam is what identifies a coloboma, a detachment, or bleeding.
Sources
- OFA, Collie Eye Anomaly. Autosomal recessive NHEJ1 disorder, variable vision, choroidal hypoplasia and other findings, diagnosis from 6 to 8 weeks, no treatment, and the lab’s result key.
- UC Davis Veterinary Genetics Laboratory, CEA test. Phenotype, breed list, N/N, N/CEA, and CEA/CEA results, and the note that the deletion does not explain every coloboma.
- Collie Health Foundation, Choroidal Hypoplasia/Coloboma. Exam timing, masked or “go normal” eyes, named findings, and the breeding note on choroidal hypoplasia.
- Collie Health Foundation health statement, approved January 9, 2024. CEA versus PRA-rcd2, the eye exam alongside the DNA test, and merle-to-merle breedings.
- Merck Veterinary Manual, owner page, Collie eye anomaly section. Breed list, detachment, and the genetic test for carriers.
- Merck Veterinary Manual, professional chapter, updated July 2026. The 10 to 20 percent and 2 to 5 percent figures for more severe lesions and retinal detachment.
- VCA Animal Hospitals, Collie Eye Anomaly. Exam timing, the claim that blindness is the most common sign, and the note that the defect cannot be reversed.
- Embark, Collie Eye Anomaly condition page. Same mutation for mild and severe disease, and no treatment that fixes CEA itself.
- Wisdom Panel, Collie Eye Anomaly. “Go normal,” non-progressive choroidal hypoplasia, no cure, and breeding notes for clear, carrier, and two-copy dogs.
- Parker, Kukekova, Akey, and colleagues, Genome Research, 2007. The 7.8 kb deletion paper cited by OFA, UC Davis, and the Collie Health Foundation.
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