If your dog’s eye suddenly looks red, puffy, and watery, there is a good chance you are dealing with conjunctivitis — inflammation of the conjunctiva, the thin pink membrane that lines the eyelids and covers the front of the eye. It is one of the most common eye problems veterinarians see in dogs, and while it often looks alarming, most cases respond well to treatment when the underlying cause is identified early.
Common Symptoms of Conjunctivitis in Dogs
- Redness of the eye or the tissue around it
- Discharge that may be clear, yellow, or green
- Squinting or excessive blinking
- Pawing at the eye or rubbing the face on the floor and furniture
- Swollen eyelids that may be held partially closed
- A cloudy or “blue” appearance in more serious cases
The type of discharge offers a useful clue about the cause. The table below summarises the three patterns vets most often see.
| Type | What It Looks Like | Typical Cause |
|---|---|---|
| Serous | Watery, clear drainage | Irritants such as dust, wind, or early allergies |
| Purulent | Thick, yellow or green pus | Bacterial infection |
| Allergic / follicular | Persistent itching and tearing | Environmental allergies such as pollen or mould |
When to See a Vet
Eye problems in dogs can deteriorate quickly, so a red eye should never simply be watched and waited on. Contact your veterinarian within a day or two for mild signs, and seek same-day care if you notice any of the following red flags:
- The dog keeps the eye tightly closed or shows obvious pain
- There is heavy discharge, a bad smell, or swelling that worsens
- The surface of the eye looks cloudy, white, or bluish
- You suspect a foreign body such as a grass seed behind the eyelid
- Symptoms affect both eyes or keep coming back
Untreated conjunctivitis can progress to corneal ulcers, deeper infection, or even loss of the eye, so early assessment matters far more than it might seem.
Common Vet-Directed Treatments
Diagnosis starts with a full eye examination. Depending on findings, your vet may run a Schirmer tear test to check tear production, apply a fluorescein stain to reveal scratches or ulcers on the cornea, measure eye pressure to rule out glaucoma, or take a swab for laboratory testing. Treatment is then aimed at the cause:
- Antibiotic drops or ointment for bacterial infections
- Anti-inflammatory or steroid drops to reduce swelling, once ulcers are ruled out
- Artificial tears and lubricants, especially for dry eye (keratoconjunctivitis sicca)
- Antihistamines for allergy-driven cases
- Removal of foreign bodies, sometimes under sedation
- Surgery to correct eyelid problems such as entropion that keep triggering flare-ups
Home Care During Recovery
Your role at home is to keep the eye clean and comfortable. Wipe away discharge with a soft gauze pad moistened with cooled boiled water or sterile saline, always wiping from the inner corner outward, and use a fresh pad for each eye. Give every medication exactly as prescribed and finish the full course even if the eye looks better after a few days. An Elizabethan collar prevents your dog from scratching and undoing the treatment. Never use leftover human eye drops — some contain steroids that can make a corneal ulcer dramatically worse.
Prevention
While not every case can be prevented, you can lower the risk by keeping your dog away from smoke, dust, and strong wind, checking for grass seeds around the eyes after country walks, keeping the face fur of flat-nosed breeds trimmed and clean, and staying current with vaccinations, which protect against viral diseases such as distemper that can inflame the eyes. Dogs with allergies or dry eye benefit from regular vet check-ups so recurring conjunctivitis is caught before it becomes chronic.
This article is for educational content only and is not a substitute for professional veterinary advice. Always consult a licensed veterinarian if you are concerned about your dog’s eyes.