Brachycephalic Ocular Syndrome: bulging eyes in dogs

What is Brachycephalic Ocular Syndrome?

Brachycephalic ocular syndrome (BOS) is a congenital disorder characterized by an abnormally large head size, which results in a disproportionately wide skull base and short snout. BOS affects both humans and animals. Dogs are most commonly affected, but other species include cats, horses, goats and rabbits. Most cases occur only in males; however females with BOS have been reported too. The exact cause of BOS is unknown. Some researchers believe it may result from genetic abnormalities or environmental factors such as stress during fetal development. Other research suggests that BOS may be caused by abnormal growth patterns in the developing embryo, which causes the skull bones to grow at an excessive rate.

The condition can affect any age group, but is most common in puppies under 6 months old and usually resolves within one year after birth. However, some cases persist into adulthood.

Symptoms of BOS include:

Larger than average heads and skulls

Wide skulls and long snouts

Large ears and small noses (pupils) due to the increased amount of bone growth in the front part of the face, resulting in an oversized nose bridge.

The eyes can bulge and be misaligned. This is known as ectopia lentis.

The lens may also be displaced, causing the eyes to bulge outwards.

Brachycephalic animals have difficulty breathing due to a narrowed windpipe (trachea) and elongated soft palate (the soft flesh at the back of the throat). These abnormalities cause a worsening of the symptoms listed above.

Brachycephalic Ocular Syndrome Treatment

Brachycephalic Ocular Syndrome: bulging eyes in dogs - at DogPuppySite

The only way to prevent BOS is to not breed dogs that have a close family history of the condition, or to deselect newborns with the disorder. If you own a brachycephalic dog with symptoms of the condition, natural home remedies can help alleviate symptoms.

Consult your veterinarian for professional advice and treatment options.

Some vets perform surgery to correct some of the more severe symptoms of BOS. Other surgical procedures include:

Nasal dermoplasty – widening of the nostrils using a scalpel

Nasal stent placement – this is used to keep enlarged nostrils open and prevent them from collapsing

Outer eye reduction (OER) – surgery to reduce protruding eyes by removing parts of the eyelids, tucking the eyelashes inward, and trimming the edges of the eyelids.

Orbital osteotomy (skeletal surgery) – the goal is to reduce bulging eyes and rearrange the eyeballs into a normal position. Afterwards, eye drops or ointment may be applied to soothe irritated eyes.

Surgery to trim or remove the elongated soft palate (recurrent laryngeal neurectomy).

Home Remedies for BOS

Oral treatment options for the symptoms of an enlarged head and bulging eyes in dogs may include:

Gently rubbing your dog’s nose and inside of their cheeks with a cotton ball that has been soaked in lavender or chamomile tea.

Brachycephalic Ocular Syndrome: bulging eyes in dogs -

Steaming the face and head with a cloth dampened with warm water that has a few drops of lavender essential oil added to it.

Applying a few drops of lavender essential oil to your dog’s skin (for example, on the inner wrist) may help to relax them.

Orally administered drugs such as sedatives and anti-anxiety medication (for example, acepromazine) can reduce some of the more severe symptoms of BOS, but should only be given under the guidance of a veterinarian.

Long-term medication and special food to control allergies may help stop the itching and scratching that causes skin irritations.


Choose brachycephalic breeds wisely and only breed dogs with a history of normal nasal passages and breathing if you want to get into breeding. As always, research any prospective parents of a litter to make sure they are healthy and do not have a history of respiratory issues or other inheritable diseases.

Sources & references used in this article:

Canine Brachycephaly: Anatomy, Pathology, Genetics and Welfare by KJ Ekenstedt, KR Crosse, M Risselada – Journal of Comparative Pathology, 2020 – Elsevier

Brachycephalic dogs—time for action by C Gyles – The Canadian Veterinary Journal, 2017 –

Brachycephalic syndrome in dogs by DA Koch, S Arnold, M Hubler… – … EDUCATION FOR THE …, 2003 –

Bulging eyes and dry corneas: managing common ophthalmology conditions in brachycephalic dogs by C Hartley – BSAVA Congress Proceedings 2018, 2018 –

Great expectations, inconvenient truths, and the paradoxes of the dog-owner relationship for owners of brachycephalic dogs by RMA Packer, DG O’Neill, F Fletcher, MJ Farnworth – PloS one, 2019 –

Keratoconjunctivitis sicca in dogs by S Woodham-Davies – The Veterinary Nurse, 2020 –