Eye problems are common in pets and can range greatly in severity. One common issue pet owners often see in cats and dogs is eye redness, which may occur as the only problem or be accompanied by other ocular issues, such as drainage or swelling. Our Sonoran Sky Pet Hospital team shares 10 reasons why your pet’s eye may be red, and how to protect your furry pal’s eyesight and ocular health.

#1: Allergies in pets

Like people, pets can experience allergic reactions to various allergens such as pollen, dust, mold, or a multitude of other irritating substances. While allergies most commonly cause skin issues in pets, they can also lead to red, itchy eyes. 

#2: Conjunctivitis in pets

Conjunctivitis, or pink eye, develops when the thin membrane covering the eye and the eyelid’s inner surface (i.e., conjunctiva) becomes inflamed. Various bacteria, viruses, allergens, or foreign objects can cause conjunctivitis, which often appears as a secondary sign of an underlying condition. 

#3: Corneal ulcers in pets

Corneal ulcers are scratches or abrasions on the transparent outer membrane of the eye (i.e., cornea), often caused by trauma, foreign objects, or underlying eye conditions. Your pet can also cause a corneal ulcer by rubbing or scratching their face. Most commonly, corneal ulcers develop as a result of an altercation between housemates in which one pet scratches another pet’s eye.

#4: Dry eye in pets

Dry eye, or keratoconjunctivitis sicca (KCS), occurs when the eyes don’t produce enough tears to maintain proper lubrication, leading to irritation and redness. KCS is more common in dogs than in cats and tends to be more prevalent in brachycephalic, flat-faced, breeds. Any factor that interferes with the eye’s tear production can cause KCS and may include immune system disorders, genetics, certain medications, endocrine conditions, infectious diseases, medical procedures, and neurologic problems.

#5: Cataracts in pets

Cataracts occur when the lens becomes cloudy, leading to blurry vision and eventual blindness. They can be congenital or develop because of aging, trauma, uveitis, nutritional deficiencies, or exposure to ultraviolet light, radiation, or toxic substances. Diabetic dogs almost always develop cataracts, especially if their condition remains unregulated. 

#6: Glaucoma in pets

Glaucoma is characterized by increased pressure within the eye. This condition can damage the optic nerve and lead to redness, pain, and vision loss. In some cases, cataracts can lead to glaucoma if they interfere with the eye’s filtration system.

#7: Uveitis in pets

Uveitis occurs when the eye’s middle layer (i.e., uvea) is inflamed. This ocular condition can be caused by infections, trauma, autoimmune diseases, metabolic conditions, hypertension, toxin exposure, or lens damage. Complications secondary to uveitis can also occur, such as glaucoma, retinal detachment, lens luxation, or synechia—the development of attachments between the iris and the cornea or the lens.

#8: Ocular trauma or irritants in pets

Traumatic injuries, such as being struck by a vehicle, in a fight with another pet, or accidentally choked by a collar or leash, can result in eye redness, swelling, or bleeding. Particles such as dust, pollen, or chemicals can irritate your pet’s eyes, leading to redness, while a foreign object lodged in the eye can also cause pain and inflammation.

#9: Upper respiratory infections in cats

Feline upper respiratory infections (URIs) are commonly caused by viruses such as feline herpesvirus (FHV-1) or feline calicivirus (FCV). One of these infections can affect the eyes, causing redness, discharge, and inflammation, and may reappear as a chronic condition throughout your cat’s life.

#10: Eyelid conditions in pets

Eyelid conditions can have various causes, including genetic predisposition, trauma, or underlying health issues. Some of the most common eyelid conditions seen in pets include:

  • Entropion — Entropion occurs when the eyelid margin rolls inward, causing the eyelashes to rub against the cornea, leading to irritation and redness. The condition can be congenital or caused by scarring.
  • Ectropion — Ectropion occurs when the eyelid margin rolls outward, exposing the eyelid’s inner surface and causing eye dryness, irritation, and inflammation. The condition can be congenital or develop as a result of aging, facial paralysis, or scarring.
  • Eyelid tumors — Eyelid tumors can be benign or malignant growths that develop on the eyelids, causing redness, swelling, and eyelid structure changes. An eyelid tumor’s exact cause is often unknown, but factors such as sun exposure, genetic predisposition, and chronic inflammation may play a role.

Red eyes in pets can indicate a range of underlying issues, from minor irritations to serious conditions. If you notice redness or other concerning problems with your pet’s eyes, consult our Sonoran Sky Pet Hospital team for proper diagnosis and treatment.