Hyphema in Dogs

What Is Hyphema in Dogs?

Hyphema refers to blood collecting in the front of a dog's eye. More specifically, blood gathers in the anterior chamber, which is the space between the iris (colorful part of the eye) and the cornea (clear tissue on the front of the eye). Hyphema is not a disease but rather a symptom of another underlying health condition. Sometimes the underlying cause of hyphema is localized to the eye, such as a tumor, but other times it is due to a systemic disease, such as hypertension.

Most commonly, hyphema appears as bright red blood spread through the front of the eye. It may also look like small blood clots scattered throughout the eye or lines of blood accumulation.

One or both eyes can be affected depending on the underlying cause. For example, high blood pressure, blood clotting abnormalities, and infectious diseases will affect both eyes, while trauma, cancer, or retinal detachment typically affect only one eye.

Hyphema is relatively common in dogs and is considered a medical emergency. If you notice blood present in your dog’s eye, it is important to bring them to a veterinarian right away for proper treatment. Blood in the eye can lead to blindness without prompt veterinary care.

Symptoms of Hyphema in Dogs

Symptoms of hyphema in dogs typically include:

• Bright red blood covering the entire front of the eye

• Localized blood clots scattered throughout the front of the eye

• Layering of blood in the eye, ranging from purple to red

• Pawing at the eye

• Squinting

• Blindness

Your dog may experience more symptoms related to the underlying cause of hyphema. These vary widely among dogs. If you notice your dog experiencing any abnormal behaviors, it is important to bring this to the attention of your dog’s veterinarian.

Causes of Hyphema in Dogs

There are several possible reasons your dog may develop hyphema, which include the following:

• Direct trauma to the eye or head

• Rat bait poisoning

• Cancer of the eye

• High blood pressure

• Blood clotting abnormalities

• Retinal detachment

• Uveitis (swelling of the eye)

• Glaucoma

• Infectious diseases (such as brucellosis, leptospirosis)

• Tick-borne diseases (such as Rocky Mountain spotted fever, ehrlichiosis)

Sometimes congenital eye abnormalities (those present at or dating from birth) can predispose dogs to developing hyphema. At-risk dog breeds include Labrador Retrievers, Bedlington Terriers, Springer Spaniels, Border Collies, and Sealyham Terriers.

How Veterinarians Diagnose Hyphema in Dogs

The veterinarian will complete a physical exam to find any abnormalities that may be contributing to your dog’s symptoms. Your veterinarian will want to know when you noticed blood in your dog’s eye, if any other unusual symptoms are present, and if your pet is taking any medications. Sharing a complete history can help your veterinarian pinpoint the underlying issue.  

Testing to figure out the underlying cause of hyphema may include the following:

• Complete ophthalmic exam—A veterinarian will use special tools to look at the different parts of the eye as well as to test reflexes. Other parts of a complete eye exam include:

  • Tonometry—This is a test used to check eye pressure. A drop of numbing agent is placed on the eye, and a special device is used to gently tap the cornea. This test can show if uveitis or glaucoma is present.

  • Schirmer’s tear test—A small strip of paper is put between the affected eyeball and eyelid to measure tear production. An abnormal result could be contributing to your dog’s symptoms. 

  • Fluorescein stain—A drop of green dye is applied to the affected eye to show scratches or ulcers in the cornea.

• Imaging—If trauma or injury to the eye or head is found, X-rays may be performed to figure out the extent of injury and decide on the right treatment plan. Also, X-rays of the chest and abdomen can be useful to find evidence of cancer or infectious diseases. Ultrasound may be helpful for more detailed views of the soft tissues, such as the abdominal organs.

• Blood work—A small sample of blood will be taken from your dog to check for abnormalities in red blood cells, white blood cells, and platelets that may point to underlying disease. Changes in clotting factors, internal organ function, and electrolytes are also checked.

• Urinalysis—Urine is collected to check for signs of protein that may be due to high blood pressure. Urine may also be sent to a special laboratory if an infectious disease is suspected.

• Blood pressure—Checking blood pressure in a dog is important to rule out hypertension. This is a quick, non-invasive test that is done by placing a cuff on the dog’s limb, similar to what is done for people.

A dog typically does not need all these tests to figure out the underlying cause of hyphema. However, if an obvious cause of hyphema is not seen, a veterinarian will recommend the right diagnostics in the proper order to figure out the cause.

Treatment of Hyphema in Dogs

Hyphema is curable in some dogs with mild disease if prompt and proper treatment is started. However, in dogs with severe disease or with significant damage to the eye, the condition is often not curable, and prognosis is poor. If left untreated, damage to the eye is likely to be permanent.

Specific treatment for hyphema focuses on the underlying cause, which can vary widely among dogs. Your veterinarian will prescribe any necessary medications that are right for your dog’s unique condition. Possible treatment options may include the following:

• Topical or systemic corticosteroids, such as dexamethasone or prednisone

• Topical mydriatic (dilating) medications, such as atropine

• Oral antibiotics for underlying infection, such as doxycycline

In cases that are not healing, a referral to a veterinary ophthalmologist may be needed. In traumatic injuries, surgery may be required. In severe cases, removal of the eye may be necessary.

Recovery and Management of Hyphema in Dogs

Some dogs, particularly those with mild disease, will make a full recovery from hyphema. The condition may clear with treatment in one to two weeks. However, if there is extensive eye damage or the dog’s overall health condition is poor, recovery may not be possible.

Dogs who are recovering from hyphema should wear a cone to prevent pawing or scratching at their eye while it heals. They should be encouraged to stay calm and avoid exercise. Some particularly energetic dogs may need to take a calming medication, such as a mild sedative like Trazodone, during recovery. These medications can be prescribed by your veterinarian, if needed.

Prevention of Hyphema in Dogs

When an underlying disease (such as cancer, or a congenital abnormality) is present, hyphema may develop.

In these instances, management of the underlying health condition may slow the development of hyphema but may not entirely prevent it. However, prompt treatment of any inflammation (swelling) within the eye can prevent damage and development of hyphema if caught early enough.

Keeping up on regular preventative care and giving parasite prevention every month can prevent infectious diseases that may develop into hyphema. Regular veterinary visits also give the veterinarian an opportunity to diagnose health issues early to prevent secondary complications, including hyphema.

In many cases, keeping your dog away from hazardous objects that may cause injury to the head or eye and keeping rat bait out of reach of pets can greatly reduce the risk of hyphema.