Healthy dog eyes are clear, shiny, and have a curious and expectant expression. When a dog frequently squints its eyes or has eye discharge, these are indications of an eye disorder. Eye diseases in dogs can be hereditary, immune-related, or result from infections, foreign bodies, drafts, or injuries. Common eye conditions in dogs, which will be discussed further below, include conjunctivitis, corneal injuries, and glaucoma. For more information on various health topics, refer to our dog guide.

How to Recognize Eye Diseases in Dogs?

When a dog suffers from an eye disease, it often exhibits similar symptoms to humans. There may be increased blinking, squinting, and the presence of eye discharge. If the eye discharge is not directly observed, glued eyelid margins or dried secretions around the eyes may indicate its presence.

Some dogs may also rub their eyes with their paws if they itch or hurt. It is important to observe whether the symptoms occur unilaterally or bilaterally. In some cases, foreign bodies such as dirt particles or awns that have entered the eye and become lodged under the third eyelid are responsible for the symptoms.

Typical signs of inflammation include redness, swelling, or warmth. If the eye discharge is no longer clear but purulent, this is also a clear sign of an inflammatory reaction. Symptoms of eye diseases in dogs summarized:

Causes of Eye Diseases in Dogs

Dogs experience both acute and chronic eye conditions, affecting the eyeballs and surrounding structures. While acute eye diseases are often caused by injuries, foreign bodies, or infections, chronic eye conditions are frequently genetically determined, triggered by immune reactions, or a consequence of systemic diseases.

Examples of congenital eye diseases in dogs include anomalies of the eyeball or eyelids. Microphthalmia, where one or both eyes are undersized, can occur in dogs. Ectropion is a deformity of the eyelids where they are turned outward, preventing complete lid closure. This condition makes the eye less protected against foreign bodies or pathogens.

Trichiasis refers to the growth of inward-directed eyelashes that rub against the cornea with each blink.

The retina of a dog’s eye can also be affected by genetically inherited eye diseases. Two examples are Collie Eye Anomaly (CEA) and Progressive Retinal Atrophy (PRA). CEA can remain clinically inconspicuous or lead to blindness through retinal detachment or bleeding. Early eye examination in puppyhood or a genetic test can identify affected dogs.

PRA results in a gradual loss of retinal function: visual impairment occurs, and the dogs eventually go blind. Eye cloudiness may also occur. The disease is diagnosed through an eye examination or a genetic test.

A common immune-related eye condition in dogs is Keratoconjunctivitis Sicca (“dry eye”). In this condition, little or no tear fluid is produced. If left untreated, the disease leads to inflammatory damage to the cornea with corneal opacity and a restriction of vision. On the other hand, lens opacity (also known as cataract or cloudy eye) is often a concomitant symptom of metabolic disorders. Dogs with diabetes mellitus, for example, may exhibit lens opacity. Cataracts are treated with surgery.

Common eye diseases in dogs and their treatment

In addition to the mentioned conditions, there are numerous other eye diseases in dogs. However, dogs most commonly present to the veterinarian with the following eye problems:

Conjunctivitis in dogs

Conjunctivitis or conjunctivitis in dogs can have infectious causes such as bacteria, viruses, fungi, or parasites. Adenoviruses or herpesviruses are considered common triggers, and among bacterial agents, Staphylococci or Chlamydia are prevalent. Eye irritations caused by dust, drafts, allergens, or foreign bodies can also lead to inflammation of the conjunctiva.

Typical signs include reddened conjunctiva, eye discharge, or swelling around the eye area. A visit to the veterinarian is advisable to determine the exact cause. For example, if a foreign body is present in the eye, it must be removed. The treatment for conjunctivitis in dogs involves using eye ointments or eye drops, administered three to five times daily to the affected eye.

For bacterial agents, an antibiotic eye ointment is used. For irritations, ointments with nourishing and regenerating agents are usually sufficient. With therapy and the elimination of the cause (e.g., avoiding allergens, drafts, or irritating gases, or removing foreign particles), conjunctivitis should subside within two weeks. If this is not the case, the veterinarian will conduct tests for chronic causes.

Corneal defects

The cornea is the outer layer of the dog’s eye. Injuries can occur, for example, during rough play with other dogs, from cat claws, or while romping in the undergrowth. However, corneal defects can also occur as a result of other eye diseases. Especially small defects are not always immediately apparent.

Corneal injuries are painful, and dogs may squint or attempt to rub the eye with their paw. If a corneal defect is suspected, the dog should be presented to the veterinarian. The doctor uses a special dye, fluorescein, to highlight the defects. Corneal defects should always be treated to expedite wound healing and prevent infections.

Corneal defects are divided into perforating and non-perforating injuries. In perforating injuries, the entire cornea is pierced, while in non-perforating defects, only the top layer is affected. The latter can be treated with an antibiotic ointment and eye healing ointments. However, if the cornea is severed, it is an emergency, and treatment involves surgery by an ophthalmologist.

Glaucoma (Green Star)

Glaucoma refers to an increase in internal eye pressure. Aqueous humor is constantly produced in the eye. If it cannot drain properly, the pressure in the eye rises. The consequences are damage to the retina and optic nerve, which can lead to blindness. Without treatment, the eyeball also enlarges over time.

A drainage disorder of the aqueous humor can be hereditary or occur due to pre-existing eye conditions. If glaucoma is suspected, the internal eye pressure is determined with a special device, taking only a few seconds. If deviations from normal values are observed, therapy is initiated because increased intraocular pressure causes pain, and pressure on the retina must be reduced as quickly as possible.

Glaucoma can be treated with medication or surgery. If glaucoma is detected early enough, and the cause can be addressed, the prognosis is good. However, with a significant increase in pressure, acute blindness within a day is possible. In addition to green star, cataracts, also known as cloudy eye, can occur in dogs.