Why Does My Boston Terrier Have One Blue Eye? Health Issues.

Does your Boston Terrier have one blue eye and one brown eye? Have you ever wondered what might cause this and if this is something that you should be concerned about?

This article will review the cause for a blue eye in a Boston Terrier and potential health considerations for Bostons with one blue eye.

Why Does My Boston Terrier Have One Blue Eye? Health Issues.

Why Do Some Boston Terriers Have Only One Blue Eye?

Boston Terriers traditionally have brown eyes. The Boston Terrier Club of America’s breed standard for Boston Terriers states that Bostons should not have blue eyes.

Yet, some Boston Terriers have one or two blue eyes. Blue eyes occur because of a genetic abnormality

Typically, vision will be unaffected, but the genetic abnormality causing the blue eye may also be associated with an increased risk for deafness. If you are concerned about deafness, you should consider speaking with a veterinarian.

Read further to learn more about the health issues related to deafness and blindness due to blue eyes in dogs.

Could your Boston’s short nose put them at risk for brachycephalic syndrome? Check out this article, What Is Brachycephalic Syndrome In Boston Terriers? 

Why Does My Boston Terrier Have One Blue Eye? Health Issues.

Boston Terrier Breed Standard For Eyes

The Boston Terrier Club of America’s official standard of the Boston Terrier states that the eyes should be “wide apart, large and round and dark in color.” It disqualifies Bostons with “eyes blue in color or any trace of blue.”

Genetic Explanation for Blue Eyes in Boston Terriers

Blue eyes in Boston Terriers occur from a specific genetic abnormality in the breed.

Some Boston Terriers have the piebald gene, which shows up as excessive white fur on the head or excessive white patches in the coat. This piebald gene is usually the reason for blue eyes.

The piebald gene leads to a lack of brown pigmentation within the colored part of the eye, the iris. This lack of brown pigment results in the eye appearing bright blue.

Do you know what the common cause of death is for Boston Terriers? Check out this article covering the three common reasons, What Do Most Boston Terriers Die From – 3 Common Reasons.

Why Does My Boston Terrier Have One Blue Eye? Health Issues.

Veterinarian Explains Blue Eyes

Dr. Reinhard Explains Why Some Boston’s Have A One Blue Eye.

In this video, I interview Dr. Addie Reinhard to discuss why some Boston Terriers have blue eyes. We also cover any health concerns these particular Boston Terriers might have.

Are There Any Health Concerns If A Boston Has One Blue Eye And One Brown Eye?

The main health concern for a Boston with one blue eye and one brown eye is deafness. Typically, Bostons with one blue eye have normal vision.

There is an increased risk for deafness for Bostons with one blue eye because the gene that results in the blue eye may also be associated with deafness. 

It has been estimated that around 80% of deaf Boston Terriers have excessive white on the coat or have one or two blue eyes.

Because of the increased risk for deafness, I typically do not recommend breeding Bostons who have one or both eyes that are blue.

By breeding Bostons with blue eyes, there is an increased risk that the puppies will be deaf even if the parents can hear normally.

Are Dogs With Blue Eyes Deaf?

Deafness is a potential concern for dogs with blue eyes, especially when the breed typically does not have blue eyes.

Dogs that have blue eyes are not all deaf. 

Just because a dog has blue eyes does not mean they are automatically deaf. However, certain dog breeds with blue eyes have been shown to be at a higher risk of being deaf.

Congenital deafness is typically more common in dogs with white in their coats. Two genes are commonly associated with congenital deafness in dogs: the merle gene and the piebald gene.

Dog Breeds With Reports Of Congenital Deafness

Many dog breeds are at risk of having congenital deafness. Congenital deafness means that these dogs were born deaf. Some experts estimate that approximately 80 dog breeds have a risk for congenital deafness. 

Congenital deafness seems to be most common among Dalmations.

Are you ensuring your Boston Terrier is not going to develop diabetes? Here are 10 Signs Your Boston Terrier May Have Diabetes.

Why Does My Boston Terrier Have One Blue Eye? Health Issues.

The following are some of the dog breeds that may be at risk for congenital deafness:

  • Australian Cattle Dog
  • Australian Shepherd
  • Boston Terrier
  • Bull Terrier
  • Catahoula Leopard Dog
  • Dalmatian
  • English Cocker Spaniel
  • English Setter
  • Jack Russel Terrier
  • Shetland Sheepdog

Symptoms Of Deafness In Boston Terriers

These are a few symptoms you can watch for if you are concerned your Boston may be deaf:

  • Not Responding To Being Called
  • No Response To Toys That Make Noises
  • Sleeping Soundly Through Loud Noises
  • Being Startled By Touching

How Do You Test For Hearing In Bostons?

There are two ways you can test for deafness in your Boston Terrier. The first example is testing their hearing at home, and the other is a Brainstem Auditory Evoked Response test.

1. The At-Home Test

When your dog is asleep, start calling their name or making a loud clapping noise to see if they wake up. 

If your dog can hear, typically, they will wake up when they hear the loud noise. If your dog is completely deaf, it will usually not wake up when you make loud noises.

The at-home test is pretty nonspecific but can be helpful if you are trying to determine if your dog is completely deaf or not. Also, this test cannot determine if your dog is only deaf in one ear.

For a more specific hearing test, consult with your veterinarian. They may recommend a more advanced test called a BAER test.

Would you like to learn more about health issues related to the Boston Terrier breed? Check out the Boston Terrier Society’s health article section here, Boston Terrier Health Articles.

Why Does My Boston Terrier Have One Blue Eye? Health Issues.

2. Brainstem Auditory Evoked Response Testing

BAER testing, short for Brainstem Auditory Evoked Response, is a test that can be performed by a veterinary specialist to check a dog’s hearing. 

A veterinarian will perform the BAER test by attaching electrodes to the dog’s head, which can often be done without sedating the dog. This test detects electrical activity in the brain to test hearing. 

Typically, the BAER test can be performed in puppies six weeks and older.

BAER testing is the gold-standard test to check hearing in dogs and can determine if your dog is deaf in one ear or both ears.

Are Dogs With One Colored Eye Blind?

The good news is that typically vision is not affected when a dog has one blue eye. The eye typically has a normal function even though it is a different color.

Usually, even with one blue eye, dogs are still able to see well with both eyes.

Did you know Boston Terriers could develop cherry eyes? Learn more about what cherry eye is and what causes it in this article by Dr. Reinhard, Cherry Eye In Boston Terriers: What Is It? And How To Fix It!

How Can I Test My Boston Terrier’s Vision at Home?

One easy way to test if your dog can see out of the colored eye is to perform the menace response test.

To perform this test, you will move your hand quickly toward your dog’s eye without touching the eye or the eyelashes, stopping several inches away from your Boston’s face.

If your Boston blinks when you move your hand toward the face, then the vision is likely normal. This test is only for older puppies and adult dogs and does not work for puppies less than four months of age.

If you are unsure if your dog can see out of the eye, you can also have your Boston’s eye examined by a veterinarian.


If your Boston Terrier has one blue eye, this is typically not cause for concern.

Boston Terriers typically have two brown eyes, so a blue eye suggests a genetic abnormality. The main risk is that this genetic abnormality may also be associated with an increased risk of deafness. Typically, the vision in dogs with one blue eye is unaffected.

Breeding Boston Terriers with one or two blue eyes is strongly discouraged due to the increased risk for deafness in the puppies.

If you are concerned about the eye or the potential for deafness, you should consult with your veterinarian. They may recommend performing special testing to ensure your Boston is healthy.

Why Does My Boston Terrier Have One Blue Eye? Health Issues.


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Addie Reinhard, DVM

Addie Reinhard, DVM- Dr. Addie Reinhard is an experienced small animal veterinarian. She is a Boston Terrier lover and always enjoys caring for her Boston patients at the veterinary clinic. She is passionate about providing helpful educational resources to pet parents regarding animal diseases and preventative care. She lives in Lexington, KY with her husband, greyhound, and four cats.

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