Bulging Eyes in Dogs

What Are Bulging Eyes in Dogs?

Normally, a dog’s eyes do not bulge outside of the eyelid, and the eyelids should be able to close completely over the eyes.  

Bulging eyes can be caused by a change in the position and/or the size of the eye. As the eyes start to bulge, this can cause swelling and pressure changes. Even slight changes in pressure can cause pain, corneal damage, impaired vision, and a risk of blindness very quickly.

Bulging eyes are considered a medical emergency. If you notice your dog’s eyes have changed position or are swelling or bulging, contact your veterinarian or urgent care vet immediately.

Here are the three main reasons that eyes can bulge in dogs:

• Proptosis—when the eye is suddenly loosened out of the eye socket

• Exophthalmos—when the eye bulges forward but is still in the eye socket

• Buphthalmos—when the eye itself is enlarged

Symptoms of Bulging Eyes in Dogs

Not every symptom will be present in every case of bulging eyes in dogs, but signs may include one or more of the following depending on the underlying reason.

Signs of proptosis in dogs may include:

• Whining, pawing at the eye, restlessness, trying to bite

• Severely red eye

• Dry cornea

• Ruptured eye muscles (eye hanging to the side)

• Ruptured optic nerve (eye dangling by frayed whitish fiber)

• Blood inside the eye

• Ruptured eye (has a hole, looks deflated, is leaking)

Signs of exophthalmos in dogs may include:

• Unable to completely close eyelid

• Corneal ulcer

• Pain opening the mouth

• Swelling of the tissues around the eye

• Swelling and redness of the conjunctiva (membrane on inner eyelid and whites of eye)

Signs of buphthalmos in dogs may include:

• Red eye

• Cloudy cornea, possibly small blood vessels on the cornea

• Dilated pupil

• Luxated lens (lens out of place)

• Blindness

Causes of Bulging Eyes in Dogs

Each of the ways that a dog could suffer from bulging eyes has its own underlying causes.

Proptosis in Dogs

• Head trauma is the most common cause, such as a dog fight or being hit by a car.

• Excessive pressure around the neck from choke collars or scruffing (grabbing a dog by the scruff of the neck).

• Short-nosed (brachycephalic) dogs are at higher risk

Exophthalmos in Dogs 

• Orbital cellulitis: Orbital cellulitis is an infection of the tissues behind the eye due to bacterial or fungal infection. It can be the result of trauma to the eye socket, tooth root abscess, or a foreign body (e.g. piece of stick or foxtail) stuck behind the eye.

• Retrobulbar abscess: A retrobulbar abscess is a pocket of pus behind the eye due to an infection from one of the causes listed above.

• Hemorrhage: This is bleeding behind the eye, which can be due to trauma to the eye, rat/mouse poison, low platelets, or a coagulation disorder.

• Tumor: While tumors in the tissue behind the eye are uncommon, a nose tumor or brain tumor may cause the eye to bulge forward.

• Masticatory myositis: This is an autoimmune swelling of the muscles of the head and the muscles behind the eyes. The typical signs are pain opening the jaw, with difficulty eating and drinking. Swelling of the muscles behind the eyes causes them to bulge forward and may lead to blindness. It is common in Labrador Retrievers, Golden Retrievers, German Shepherds, and Weimaraners.

• Extraocular myositis: This is an autoimmune swelling of the muscles that attach the eyes to the socket. It is a rare disorder, but it is more likely to occur in Golden Retrievers than in other breeds.

• Craniomandibular osteopathy: In this disease, puppies develop excess bone on their skull starting at about 5–8 months of age. They are in a lot of pain and can have difficulty eating and drinking. Puppies can develop bulging eyes and glaucoma because of added bone in their eye sockets.

• Temporomandibular joint (jaw) dislocation: If the jaw joint becomes dislocated, the eyes will bulge forward. This is more common in Basset Hounds, which can have dysplasia of the jaw joint.

• Zygomatics salivary gland mucocele: Severe swelling or blockage of the salivary gland below the eye can cause the eye to bulge forward.

• Breed-related: Brachycephalic dogs with short noses such as the Pug or French Bulldog tend to have eyes that bulge forward normally. This causes no discomfort on a day-to-day basis. However, these dogs are more prone to corneal ulcers and proptosis with even a slight head injury.

Buphthalmos in Dogs

• Glaucoma: In glaucoma, fluid cannot drain normally from the eye, enlarging it. Glaucoma can be inherited in the Miniature Poodle, Boston Terrier, Shar-Pei, Chow Chow, American Cocker Spaniel, Basset Hound, Great Dane, and Welsh Springer Spaniel.

• Tumor inside the eye: Tumors that occur inside the eye include melanoma, ciliary body tumors, and metastatic tumors that have spread to the eye from elsewhere in the body.

• Hemorrhage, bacterial, or fungal infection inside the eye: The causes for each are the same as above but occur inside the eye, causing the eye itself to become enlarged.

How Veterinarians Diagnose Bulging Eyes in Dogs

To diagnose bulging eyes, the veterinarian will do a complete history and physical examination plus an eye examination. All eye examinations will include an intraocular pressure check for glaucoma and a fluorescein test to check for corneal ulcers.

Other possible tests may be a Schirmer tear test to measure tear production, blood tests, X-rays, eye ultrasound, fine-needle aspirate, or biopsy to figure out the cause.

Treatment of Bulging Eyes in Dogs

Treatment will depend on the underlying reason causing the eye bulging and how much damage has occurred to the eye.

Proptosis 

If there has been minimal trauma, the veterinarian may recommend surgery to reposition the eye with sutures to hold it back in place. If the eye has sustained serious damage and long-term pain and blindness are expected, the veterinarian may recommend removal of the eye.

Exophthalmos 

Orbital Cellulitis and Retrobulbar Abscess

Infection without a foreign object or abscess may be treated with antibiotics or antifungal medication. Sometimes surgery is needed in cases of infection of the nearby eye socket to remove infected bone.

If a dental tooth root abscess was the primary cause, dental surgery is needed to remove the affected tooth along with antibiotic therapy.

Hemorrhage

Treatment for bleeding depends on the primary cause, such as vitamin K1 for rat/mouse poison, treatment for low platelets, or the primary cause of a coagulation disorder.

Tumor Behind the Eye

Treatment options depend on the diagnosis and typically also on advanced imaging such as a CT scan or MRI.

Masticatory Myositis and Extraocular Myositis

These autoimmune disorders typically respond well to prednisone (a steroid), which should be tapered very slowly under the direction of your veterinarian.

Craniomandibular Osteopathy

There is no cure for this disorder. The excess bone will start to completely or partially break down when the puppies are about a year old. Treatment is focused on giving puppies the nutritional support and pain relief they need, as well as glaucoma medications if their eyes are affected.

Temporomandibular Joint (Jaw) Dislocation

Treatment for jaw dislocation is surgery to repair any fractures, dysplasia of the jaw, or dental issues. Dogs may need a feeding tube or liquid diet during the recovery period.

Zygomatic Salivary Gland Mucocele

Treatment for a salivary gland mucocele is surgery to remove the salivary gland. This is a small gland, and its removal does not affect long-term saliva production.

Buphthalmos

Glaucoma

Eye enlargement due to glaucoma is an emergency and is treated with eye drops and potentially with intravenous (IV) mannitol or oral medications. Your veterinarian may recommend referral to a veterinary ophthalmologist or emergency clinic for your pet’s treatment.

Tumor Inside the Eye

Tumors within the eye itself are rare but may need referral to a veterinary ophthalmologist and/or veterinary oncologist for treatment. Treatment options include surgery, radiation, chemotherapy, cryotherapy, or possibly removing the eye.

Hemorrhage, Bacterial, or Fungal Infection Inside the Eye

Treatment is the same as above, except that management of disorders within the eye rather than outside it is much more delicate. Your veterinarian may recommend referral to a veterinary ophthalmologist.

Recovery and Management of Bulging Eyed in Dogs

Since the causes of bulging eyes vary, recovery depends on both the disease and the treatment the dog receives. In general, an issue that can be treated with surgery will resolve more quickly than other diseases or infections. Some bacterial or tick-borne infections may require long courses of antibiotics.

Glaucoma is typically a chronic, lifelong disease unless the dog develops it secondary to another disorder that can be corrected, such as an infection or lens luxation.

Prevention of Bulging Eyes in Dogs

Prevention is key when it comes to limiting bulging eyes in dogs. Outside of underlying causes that can trigger the issue, there are ways to prevent trauma or injury to your pup’s eyes:

• Use harnesses instead of collars on short-nosed (brachycephalic) dogs.

• Don’t let your dog play or run in areas where there are long, dry grasses with potential foxtails.

• Don’t breed dogs that have had known inherited medical issues.

• Get your dog to the vet as soon as you see any squinting, redness, or discharge from your dog’s eye(s). Your vet would rather see a dog before the eye is bulging, when it is easier and less expensive to treat.