What Is Collie Eye Anomaly?

Collie Eye Anomaly — sometimes abbreviated as CEA and also referred to as Choroidal Hypoplasia (CH) — is a hereditary ocular disorder in which the eye fails to develop normally during the embryonic stage. The condition originates in the choroid, a layer of blood vessels and tissue situated beneath the retina that supplies oxygen and nutrients to the eye. When a dog inherits the genetic mutation linked to CEA, this choroidal layer remains underdeveloped, disrupting the normal architecture of the eye.

What makes CEA particularly challenging is the wide range of outcomes it can produce. Some dogs with the mutation show no visible signs of impairment whatsoever, while others develop serious secondary complications including bleeding inside the eye, detachment of the retina, and in the most severe cases, permanent blindness. Crucially, even dogs with mild or no outward symptoms can carry and transmit the faulty gene to their puppies.

The disorder is rooted in a 7.8 kb deletion within intron 4 of the NHEJ1 gene, which disrupts the proper formation of the inner eye structures during foetal development. The condition presents at birth and can typically be detected in puppies as young as 4 to 8 weeks of age.

Possible Clinical Signs of CEA

While mild cases may go unnoticed, more severely affected dogs can display:

Abnormally small eyeballs (microphthalmia)
Eyes that appear sunken within the socket (enophthalmia)
Cloudiness or mineralisation of the cornea
Coloboma — a defect in the structure of the optic nerve or eye tissues
Intraocular haemorrhage (bleeding within the eye)
Partial or total retinal detachment
Reduced or absent vision, including complete blindness

Because symptom severity can differ significantly even between dogs from the same litter, a DNA test is the only reliable way to determine a dog’s true genetic status.

Why Should You Test Your Dog for CEA?

There is currently no cure or treatment that can reverse the structural damage caused by Collie Eye Anomaly. This makes prevention through responsible breeding the most effective tool available to dog owners and breeders alike.

Knowing your dog’s genetic status for CEA allows you to:

Protect future litters by avoiding pairings that risk producing affected puppies
Understand your dog’s health risks before symptoms ever appear
Make evidence-based breeding decisions backed by scientific results
Give peace of mind if your dog tests clear of the mutation

Even if your dog appears visually healthy, it may be a carrier — meaning it carries one copy of the mutation and can pass it on to offspring without showing any signs of the disease itself. Without testing, carrier animals can unknowingly spread CEA through a breeding line across multiple generations.

Which Breeds Are at Risk of Collie Eye Anomaly?

Despite its name, CEA is not exclusive to Collies. The mutation has been identified across a wide range of herding breeds and their relatives. Research suggests that between 70 and 97% of Rough and Smooth Collies in the UK and US carry at least one copy of the CEA-associated mutation, making it the most prevalent inherited eye disease within these breeds worldwide.

Breeds known to be susceptible to CEA include:

Rough Collie
Smooth Collie
Border Collie
Shetland Sheepdog (Sheltie)
Australian Shepherd
Miniature American Shepherd
Bearded Collie
Lancashire Heeler
English Shepherd
Boykin Spaniel
Nova Scotia Duck Tolling Retriever
Long-Haired Whippet
Old English Sheepdog

If your dog belongs to any of the breeds above — or is a crossbreed with significant herding ancestry — genetic testing for CEA is strongly recommended, particularly before breeding.

How Does the EasyDNA CEA Test Work?

The EasyDNA Collie Eye Anomaly test is straightforward, non-invasive, and can be completed entirely from home. There is no need for a veterinary appointment or blood draw.

Step 1 — Order your test
Place your order online and we will dispatch a sample collection kit directly to your door.

Step 2 — Collect the DNA sample
The kit includes everything you need to collect a simple cheek swab from your dog. Detailed instructions are provided to make the process as easy as possible — it takes just a few minutes and causes no discomfort to your pet.

Step 3 — Return your samples
Place the swabs back in the return envelope included in your kit and send them to our accredited laboratory for analysis.

Step 4 — Receive your results
Once our laboratory has received and processed your samples, you will receive your results by email within 7 working days.

Understanding Your Test Results

Your CEA test result will fall into one of three categories:

CLEAR — Your dog has not inherited the CEA mutation. It has two normal copies of the NHEJ1 gene and is free from the disorder. A clear dog will not develop CEA and will not pass the mutation to its offspring.
CARRIER — Your dog has inherited one normal copy of the gene and one copy carrying the CEA mutation. Carriers are typically unaffected but will pass the mutated copy to approximately 50% of their puppies. Breeding two carriers together creates a 1 in 4 chance of producing an affected puppy.
AFFECTED — Your dog has inherited two copies of the mutated gene. It is highly likely to show signs of CEA, ranging from mild choroidal underdevelopment to more serious complications, and will pass the mutation to all of its offspring.

Understanding your dog’s result enables you to take appropriate steps — whether that means tailored veterinary monitoring, adjusting your breeding strategy, or simply knowing that your companion is in the clear.

Cost of the EasyDNA Collie Eye Anomaly DNA Test

The CEA DNA test is priced at £55 per dog. Additional samples can be ordered at an extra cost, making it a practical option for breeders testing multiple animals.

Other Dog Inherited Disease Tests from EasyDNA

At EasyDNA, we offer a full range of genetic screening tests to help you stay ahead of hereditary health conditions. Alongside the Collie Eye Anomaly test, our inherited disease screening includes:

Dog Degenerative Myelopathy Test
Dog Multidrug Resistance 1 (MDR1) Test
Exercise Induced Collapse (EIC) Test
Hyperuricosuria (Uric Acid) DNA Test
PRA-prcd (Progressive Retinal Atrophy) Test
von Willebrand Disease DNA Test

For the most comprehensive genetic health picture, our DogCheck 4.0 Genetic Disease Test screens for 175+ diseases and traits in a single test — an excellent option for breeders seeking thorough pre-breeding health assessments.

Other Dog DNA Tests from EasyDNA

Looking beyond health screening? We also offer a wide range of other dog DNA tests, including our 430+ Breed Identification Test, Dog Allergy Test, Dog Age Test, and KnowYourDog Genetic & Breed Test.

Give your dog the best possible start — order your CEA DNA test today and breed with confidence.

For questions about this test or any of our services, please contact our Customer Service team or call us on 01227 502962.