Veterinarian column: Red eyes! ? conjunctivitis? [What causes red eyes? ]

by Alice's Dog & Catスタッフ

Alice's Dog & Cat Veterinarian Column Your dog's eyes are red! ? Canine conjunctivitis? What causes red eyes?

Many patients come to veterinary hospitals with the chief complaint of red eyes in their dogs and cats.

Red eyes can be caused by a variety of reasons, including infection, allergies, corneal disease, intraocular inflammation, and glaucoma. This time we will explain in detail the causes of red eyes.

◎ Infection

Infection causes redness in the conjunctiva. Yellow or green eye discharge appears.

・Infectious conjunctivitis

Treatment: Antibiotic eye drops

If necessary, drug sensitivity testing will be performed.

◎ Allergies

・Allergic conjunctivitis. It is accompanied by itching.

Treatment: anti-allergy eye drops

◎ Corneal disease

The pain is caused by a scar on the cornea. The owner notices that the dog's eyes are shaky due to pain.

・Corneal ulcer

Treatment: Corneal protection treatment (hyaluronic acid eye drops, contact lens wearing, etc.)

Secondary infection prevention (antibiotic eye drops)

Anti-collagenase effect (acetylcysteine ​​eye drops, autologous serum eye drops)

◎ Inflammation within the eye

Inflammation of the iris and ciliary body within the eye occurs due to infection, trauma, or systemic disease, causing the eyes to turn red.

・Anterior uveitis

Causes of uveitis:

Systemic diseases (infectious diseases, immune-mediated diseases)

Cataract (lenticular uveitis)



lens dislocation

corneal ulcer




retinal detachment

optic neuritis etc.

Treatment: Treatment of the cause (identify and treat the cause of uveitis)

Treatment/steroid eye drops

・Non-steroidal anti-inflammatory eye drops

・Immunosuppressants, etc.

◎ High intraocular pressure

High intraocular pressure causes the episcleral blood vessels to become congested, causing the eye to become red.


Glaucoma is a disease that can lead to blindness. Early detection and early treatment are necessary.

Causes of glaucoma:

primary glaucoma (often hereditary)

Secondary glaucoma (lenticular disease, uveitis, intraocular tumor, retinal detachment)

Treatment: if secondary, treatment of cause

Treatment to lower intraocular pressure (eye drops, drips, oral medications)

surgical treatment

Alice's Dog & Cat Veterinarian Column Your dog's eyes are red! ? Canine conjunctivitis? What causes red eyes?

Red eyes can be caused not only by conjunctivitis, but also by serious diseases such as glaucoma, which can lead to blindness. If inflammation that occurs in the eye is left untreated, it can lead to complications from corneal ulcer to uveitis, and from uveitis to glaucoma.

If you notice red eyes in your pet, don't wait and see a veterinarian as soon as you notice them to diagnose and treat the cause.


Dog and Cat Treatment Guide

Practical Veterinary Ophthalmology Clinical