Common Eye Diseases in Dogs and Cats: Conjunctivitis, Keratitis and More

1 Abnormal Eyelash Growth and Cherry Eye

Eyelashes protect the eye, growing forward along the lid edge. When their direction or position changes, it is abnormal growth. Cats have no eyelashes, so this is mostly dogs — distichia, ectopic cilia and the like.

Symptoms: can be congenital (St. Bernard, Golden Retriever, Cocker, Shih Tzu); Cocker often has double rows. Acquired forms come from trauma, entropion, spasm or scars. Signs: tearing, red conjunctiva, spasm, light sensitivity, even keratitis, corneal haze and ulcers. If the dog rubs its eye and is restless, check it.

Treatment: if no harm is done, none is needed. For chronic keratitis or ulcers, surgery removes the abnormal lashes. Afterward, neomycin sulfate eye drops fight bacteria and aid healing of ulcers, inflammation, pus and itch.

Cherry eye (third-eyelid gland prolapse) comes from an enlarged gland popping over the lid edge; mostly dogs (Cocker, Beagle, Bulldog, Shih Tzu). From over-secretion or inflammation of nearby tissue. The red swollen mass can cause conjunctivitis or keratitis and vision loss if untreated. Usually surgery; if from inflammation, antibiotic drops often cure it.

2 Entropion and Ectropion

Entropion: the lid rolls inward toward the eye, one or both lids, one or both eyes; lashes irritate the conjunctiva and cornea, causing tearing, conjunctivitis and ulcers. Common in Shar-Pei and Chow. Causes include congenital small eyes, secondary spasm from a foreign body, conjunctivitis, corneal scratch or trichiasis, or a sunken eye from lost fat. Chronic conjunctivitis or post-surgery scarring also cause it.

Symptoms and treatment: the inward lid constantly irritates the eye and can lead to corneal blood-vessel growth and ulcers. See a vet promptly for the cause and corneal surgery; after surgery use an Elizabethan collar and remove stitches in 10 to 14 days.

Ectropion: the lid turns outward, mostly the lower lid; St. Bernard, Cocker and Newfoundland are prone. The exposed cornea reddens, swells and tears, and pigmentary conjunctivitis or keratitis and vision loss can follow. If medication fails or keratitis/conjunctivitis appears, surgery is needed.

3 Blepharitis and Styes

Blepharitis is inflamed lid tissue, often with conjunctivitis and meibomian inflammation, from mechanical or chemical irritation that triggers over-secretion and bacterial or fungal infection.

Symptoms: acute bacterial forms show a red swollen lid margin with yellow crust; after the crust falls, small pustules appear at the lash roots. If it spreads, the conjunctiva congests and swells with gray-yellow pus points and discharge. Chronic forms bring lid-margin erosion or ulcers, lost lashes, a thickened deformed lid, misdirected lashes and tearing.

Treatment: remove the source and treat locally. Wash the lid margin with saline 2 to 3 times daily and give antibiotics. A vet-formulated compound amoxicillin powder (broad-spectrum, pet-specific) quickly inhibits bacteria; once daily for 5 days or as directed.

A stye (chalazion) is usually staph entering lash follicles or glands — a pus-forming inflammation. The lid is red and swollen with a hard lump; an external stye has a painful pustule on the outer lid, an internal one is smaller with a white pustule at the meibomian base and more pain. In 4 to 7 days the abscess matures with a yellow-white head and may drain; severe cases cause orbital cellulitis. Early: warm compress and antibiotic eye medicine; severe needs surgery. Never squeeze it before it forms — that risks orbital cellulitis or sepsis.

4 Conjunctivitis and Keratitis

Conjunctivitis is inflammation of the conjunctiva from irritation or infection. Symptoms: light sensitivity, tearing, red swollen conjunctiva, pain and more discharge. Causes: mechanical, infectious, nearby disease, allergy. Early is catarrhal (serous or mucous); purulent has much pus and stuck lids, then corneal haze and eyelid eczema.

Treatment: fight infection and keep the animal in dim light. Early use neomycin sulfate antibiotic drops to kill bacteria such as E. coli and Proteus. Allergic conjunctivitis: cortisone acetate drops (a corticosteroid) ease inflammation, allergy, pain and itch. Chlorpheniramine maleate tablets treat allergic conjunctivitis and keratitis, quickly relieving itch and swelling.

Keratitis: the cornea inflamed by virus, trauma or chemicals; signs include light sensitivity, tearing, pain, lid closure, haze, ulcers and even perforation. Types: traumatic, superficial, chronic superficial, interstitial, ulcerative. Treatment removes the cause; keratitis from parasites such as schistosomes or eyeworms can be treated with praziquantel tablets, a broad-spectrum dewormer.

These diseases hurt the eyes and vision, so do daily eye care, avoid trauma, and use a suitable eye wash for routine cleaning. Consult an online vet if you have other questions.