Dogs with one blue eye are often referred to as “wall eyes” or “odd-eyed dogs.” This eye coloration is the result of a genetic condition called heterochromia, where an animal has two different colored eyes. While heterochromia can occur in many animal species, it is relatively common in certain dog breeds. Some of the most well-known dog breeds that exhibit heterochromia and may have one blue eye include Siberian Huskies, Australian Shepherds, Border Collies, Weimaraners, Welsh Corgis, and Australian Cattle Dogs among others.
What causes heterochromia in dogs?
Heterochromia in dogs occurs due to a disruption in melanin (pigment) distribution during development in the womb. Melanin is the substance that gives color to a dog’s skin, coat, and eyes. For dogs with one blue eye, the eye lacking pigment will appear blue due to how light scatters in the absence of melanin. Meanwhile, the other eye contains normal melanin levels and has a brown, amber, or hazel coloration.
While it is not completely clear why some dogs end up with two different colored eyes, research suggests genetics play a major role. The traits for coat color and eye color are closely linked in dogs. Variations in the genes responsible for coat color distribution can also lead to irregular distribution of eye pigment. Certain dog breeds likely have a genetic predisposition for heterochromia.
Common Dog Breeds with One Blue Eye
Siberian Husky
One of the breeds most associated with heterochromia is the Siberian Husky. Their thick, fluffy coats and piercing blue eyes make Huskies instantly recognizable. Particularly among working lines, heterochromia is an extremely common trait. Estimates suggest around 15% of the Husky population has blue eyes or odd-colored eyes.
In Huskies, blue eyes and odd-eyed coloration is linked to a reduced amount of pigment, which is also what causes their coats to be white. Merle coat patterning along with piebald spotting contributes to irregular pigment distribution that results in blue eyes. The genetics behind eye color in Huskies is complex, but breeding studies have identified it is polygenic – meaning multiple genes are involved.
Australian Shepherd
Australian Shepherds are another breed prone to having one blue eye due to the merle coat genes they carry. Merle refers to a genetic modification that produces a marbled coat pattern of darker pigment patches against a lighter background. It also dilutes pigment in the eyes, so dogs with merle coats may have pale blue eyes or odd-eyes.
Around 5% of Aussies are born with heterochromia. The merle genes produce higher amounts of white in the coat as well as reducing pigment in the iris. If an Aussie inherits merle genes from both parents, the coat is even lighter and they have a higher chance of being odd-eyed or blind and deaf. Responsibly bred Aussies will avoid merle-to-merle pairings to prevent this.
Border Collie
Intelligent working dogs like the Border Collie may also exhibit one blue eye. As with Aussies, border collies carry the merle gene. Blue eyes or odd-colored eyes will occur more often in dogs showing more extensive merle coat markings. However, bud eyes are not linked to hearing loss in border collies like they are in Aussies.
Outside of merle, some non-merle border collies may have white spotting genes that produce too little pigment around one eye. The eye lacking pigment will be blue while the other is brown, amber, or hazel. This type of heterochromia is rarer than that associated with the merle pattern.
Weimaraner
Weimaraners are best known for their distinctive “ghostly” gray coats. As puppies, Weimaraner eyes are blue-gray, then change to shades of light amber or gray as adults. While unusual, some Weimaraners keep blue-gray eyes their entire lives. Selective breeding for light-colored eyes may be behind this breed’s propensity for azure eyes and heterochromia.
Their dilution genes give Weimaraners pale coats and sometimes also affects eye color. Inheritance of heterochromia in Weimaraners is not thoroughly understood. But it likely results from complex interactions between genetics for coat color dilution, eye color, and white spotting.
Welsh Corgi
Both the Pembroke Welsh Corgi and Cardigan Welsh Corgi may have mismatched eyes. Heterochromia is fairly uncommon in Corgis though. When it does occur, it can result from the merle genes or piebald spotting genes Corgis carry.
The merle pattern in Corgis produces a dappled coat with patches of diluted pigment and sometimes one or two blue eyes. Piebald spotting leads to random depigmentation of the coat and occasionally the eyes. A Piebald Corgi with one blue eye will have white fur on the same side as the blue eye.
Australian Cattle Dog
The Australian Cattle Dog is born with blue eyes that change to brown over the first few weeks of life. In some cases, one or both eyes retain a blue color into adulthood. Australian Cattle Dogs do not have merle patterning. The blue eyes are caused by a simple recessive gene that prevents the eyes from producing pigment.
When only one eye lacks pigment and stays blue, it results in heterochromia. Deafness is not linked to blue-eyed Cattle Dogs like it is in other breeds. Selective breeding by some breeders has produced Cattle Dog lines where blue eyes are a relatively common trait.
Other Dog Breeds with Heterochromia
In addition to the breeds above, heterochromia also pops up less frequently in other breeds where merle or white spotting genes are present, such as:
- Cardigan Welsh Corgi
- Great Dane
- Dachshund
- Chihuahua
- Catahoula Leopard Dog
- Alaskan Malamute
- Pug
- Pomeranian
- Shetland Sheepdog
- German Shepherd Dog
Certain rare coat colors increase the chance of heterochromia in dogs. For example, piebald Dobermans, harlequin Great Danes, spotted Dalmatians, and parti-colored Poodles may have one blue eye due to lack of pigment around one iris.
Is there any health concern with dogs having one blue eye?
For most dog breeds, having one blue eye is purely a cosmetic difference and causes no health issues. However, in some cases dogs with blue eyes or odd-colored eyes are more likely to be deaf. Connection between blue eyes and deafness mainly applies to dogs with the merle pattern, like Aussies and border collies. Among these breeds, dogs with two blue eyes have a higher risk of being deaf in both ears.
Why merle and blue eyes increase deafness risk is not fully proven, but is thought to stem from having less pigment inside the ear. Lack of pigment likely damages the development of the inner ear. However, one blue eye alone in dogs like Huskies or Cattle Dogs does not elevate deafness risk.
Additionally, some eye conditions like glaucoma or cataracts may be more visible if a dog has one darkened and one blue eye. But heterochromia itself does not cause or worsen eye disease in dogs.
Are dogs with blue eyes more sensitive to sunlight?
Dogs with one blue eye do not have increased light sensitivity. Melanin in dogs’ irises does not play a role in regulating how much light enters the eye. The iris pigment only impacts eye color and does not affect vision or light sensitivity.
In rare cases, dogs with very light blue eyes from extreme merle genes, albinism, or other conditions may squint in sun. But in general, dogs with one blue eye due to heterochromia have no changes in light sensitivity compared to brown-eyed dogs.
Do dogs with blue eyes have vision problems?
There is no evidence that having one blue eye or two blue eyes results in visual deficits in dogs. The only influence of blue iris pigment is on eye color. Melanin does not impact eyesight or visual acuity.
Some may think dogs with lighter colored eyes are visually impaired. In reality, most vision problems associated with blue eyes in dogs are tied to the merle genes. Merle causes retinal defects and blindness in dogs homozygous for the genes. But the vision issues are not caused by having a blue eye itself.
Any breed can develop various eye disorders leading to vision loss. But when it comes to congenital vision issues in breeds like Aussies, the merle genetics are to blame, not the simple fact the dog has one or two blue eyes.
Do puppies change eye color as they mature?
Puppies are often born with blue eyes that become darker as they grow up. Eye color changes as melanin pigment develops in the iris over the first few months of life. Most puppies complete the eye color transition by 8-12 weeks of age.
For breeds with merle genes like Aussies and border collies, puppies with one or two blue eyes may retain some blue color into adulthood. Their eye color at maturity depends on the distribution of merle pigment. Solid merles often keep bluish eyes while those with small merle patches end up with darker eyes.
In huskies, malamutes, and other Nordic breed dogs, blue eye color persists from birth into adulthood. Eye color in these breeds ranges from amber to brown to blue, but does not change dramatically as the dog matures.
So in summary, puppies may start out blue-eyed at birth, then have their mature eye color set anywhere from 2 to 3 months of age depending on the breed. Some blue-eyed puppies stay blue-eyed for life based on their genetics.
Are dogs with blue eyes more expensive?
Some breeders charge premium prices for dogs with rare blue eyes or odd-colored eyes. Eye-catching blue eyes are considered desirable by many husky, border collie, and Australian shepherd enthusiasts. Breeders may advertise these dogs as “show quality” and increase their price.
On average, breeders often charge $500-1500 more for dogs with blue or mismatched eyes compared to regular brown-eyed puppies. However, blue eyes that stem from excessive white spotting or the double merle gene combination may still be avoided due to potential for deafness.
For crossbreed designer dogs like Labradoodles or Maltipoos, one blue eye is very uncommon and many buyers find it attractive. A mix-breed puppy with one blue eye can fetch $1000 or more due to novelty appeal.
However, not all breeders choose to charge more for blue-eyed puppies. What matters most is producing healthy, well-socialized puppies with good temperaments. Some breeders charge the same price regardless of whether a puppy has blue eyes or not.
Conclusion
One blue eye in dogs is a striking trait that results from decreased melanin pigment around one iris. Heterochromia is relatively common in certain breeds such as Huskies, Border Collies, and Australian Shepherds. While the odd-colored eyes may look unusual, in most cases it causes no vision or health problems for dogs. One blue eye is simply an intriguing genetic quirk of nature that provides some dogs with a distinctive and captivating appearance.