Choroidal Hypoplasia in Dogs: Understanding the Inherited Eye Disorder

Choroidal Hypoplasia is a relatively uncommon yet important inherited eye disorder found in dogs. This condition affects the choroid, a crucial layer of tissue in the eye that plays a vital role in maintaining vision. Understanding Choroidal Hypoplasia is essential for dog owners and breeders alike, as early detection and proper management can significantly impact a dog’s quality of life.

What is Choroidal Hypoplasia?

Choroidal Hypoplasia, also known as Choroidal Hypoplasia Syndrome (CHS) or Collie Eye Anomaly (CEA), is a congenital eye disorder primarily seen in certain dog breeds, including Collies, Shetland Sheepdogs, Border Collies, and Australian Shepherds. The condition is characterized by an underdeveloped choroid, leading to vision impairment in affected dogs.

Causes of Choroidal Hypoplasia

Choroidal Hypoplasia is inherited as an autosomal recessive trait, meaning both parents must carry the faulty gene for their offspring to be affected. Dogs that inherit two copies of the defective gene will develop the disorder.

The specific gene responsible for Choroidal Hypoplasia in dogs is called the NHEJ1 gene, which is responsible for repairing DNA damage in the choroid. Mutations in this gene prevent proper choroidal development, resulting in the disorder.

Symptoms and Clinical Signs

Choroidal Hypoplasia can vary in its severity, and the symptoms may differ from one dog to another. Common clinical signs of the condition include:

  1. Vision Impairment: Dogs with Choroidal Hypoplasia may have reduced vision or blindness, depending on the extent of choroidal underdevelopment.
  2. Ocular Abnormalities: Affected dogs may display other eye abnormalities such as coloboma (a gap or cleft in the structures of the eye) and retinal detachment.
  3. Pupil Abnormalities: Changes in the shape and size of the pupils may be observed in dogs with Choroidal Hypoplasia.
  4. Photophobia: Dogs with this condition may be sensitive to light and may squint or avoid well-lit areas.


A thorough ophthalmic examination by a veterinary ophthalmologist is necessary for diagnosing Choroidal Hypoplasia in dogs. The examination may involve indirect ophthalmoscopy, electroretinography (ERG), and ocular ultrasound to assess the extent of choroidal underdevelopment and associated abnormalities.

Treatment and Management

Unfortunately, there is no cure for Choroidal Hypoplasia in dogs. Since it is an inherited disorder, prevention through responsible breeding practices is essential. Dogs diagnosed with Choroidal Hypoplasia should not be used for breeding to avoid passing on the faulty gene to future generations.

Management of the condition focuses on providing supportive care to enhance the affected dog’s quality of life. This may include:

  1. Regular Veterinary Checkups: Frequent visits to a veterinary ophthalmologist are necessary to monitor the dog’s eye health and address any complications promptly.
  2. Eye Protection: Protecting the eyes from injury or trauma is vital to prevent further complications.
  3. Environmental Adaptations: Creating a safe and familiar environment for the dog by avoiding rearranging furniture and keeping potential hazards out of their way.
  4. Dietary Supplements: Some nutritional supplements may be recommended to support eye health, although their effectiveness in treating Choroidal Hypoplasia is limited.


Choroidal Hypoplasia in dogs is a genetically inherited eye disorder that can significantly impact a dog’s vision and overall well-being. Understanding the causes, symptoms, and management options for this condition is crucial for dog owners and breeders to ensure responsible breeding practices and provide the best care possible for affected dogs. While there is no cure, early diagnosis and appropriate management can improve the affected dog’s quality of life and prevent further complications. If you suspect your dog may have Choroidal Hypoplasia, consult a veterinary ophthalmologist promptly for a comprehensive evaluation and personalized care plan.