My Dog Has Discharge From Their Eye: What It Means

A small amount of clear or slightly coloured discharge at the inner corner of a dog's eye after sleep is generally normal. The colour, quantity, consistency, and whether it is accompanied by other symptoms tells you a great deal about whether the cause is benign or needs veterinary attention.

Is This an Emergency?

Go to a vet immediately if your dog:

• Has a closed, half-closed, or visibly painful eye
• Has a cloudy or bluish appearance to the eye (possible corneal ulcer or glaucoma)
• Is pawing at the eye with apparent distress
• Has sudden swelling around the eye
• Has a discharge that developed after a known eye injury or a foreign object in the eye

Call your vet the same day if:

• Discharge is green or yellow and persistent
• The eye is red or the surrounding tissue is swollen
• Discharge appeared after a walk in long grass or a run through undergrowth (possible grass seed)

Wait and monitor if:

• A small amount of clear discharge appears after sleep and clears quickly
• Your dog has always had a slight discharge and is otherwise well

What Causes Eye Discharge in Dogs?

Normal sleep discharge

Clear or slightly rust-coloured discharge at the inner corner of the eye, sometimes referred to as sleep crust, is a normal result of tear evaporation during sleep and requires no treatment.

Conjunctivitis

Inflammation of the conjunctiva (the pink tissue surrounding the eyeball) can be caused by infection, allergy, or a foreign body. It produces red eyes, swelling of the conjunctiva, and a discharge that may be clear, yellow, or green. Treatment depends on the underlying cause.

Dry eye (keratoconjunctivitis sicca, KCS)

Insufficient tear production leads to a thick, sticky, often yellow-green discharge alongside a dull or cloudy appearance to the eye. Dry eye requires lifelong treatment with artificial tear drops or medication to stimulate tear production.

Corneal ulcer

A scratch or abrasion on the cornea causes acute pain, squinting, excessive tearing, and sometimes a visible cloudy area on the eye surface. Always a veterinary emergency, as untreated corneal ulcers can perforate.

Grass seed

A grass seed entering the eye, particularly during summer walks through long grass, causes intense pain, squinting, and a sudden watery discharge. Requires prompt removal under sedation by a vet.

Epiphora (tear overflow)

Some breeds have anatomical features that cause tears to overflow onto the face rather than draining properly, leaving rust-coloured staining beneath the eyes. This is a structural issue rather than a sign of infection.

Which Breeds Are More Prone to Eye Discharge?

• Cocker Spaniel, West Highland White Terrier, Bulldog: High incidence of dry eye (KCS)
• Bichon Frise, Maltese, Poodle: Epiphora (excessive tearing and staining) due to facial structure
• French Bulldog, Pug, Shih Tzu: Shallow eye sockets increase the risk of corneal exposure and injury
• Shar-Pei: Higher incidence of entropion (inward rolling of the eyelid), which causes chronic irritation

What Will the Vet Do?

Your vet will examine both eyes with an ophthalmoscope and may use a fluorescent dye to check for corneal ulcers. They may recommend:

• A Schirmer tear test to measure tear production and diagnose dry eye
• Swabs for bacterial culture if infection is suspected
• Antibiotic eye drops or ointment if infection is confirmed
• A referral to a veterinary ophthalmologist for complex cases

How to Help Your Dog at Home

• Gently wipe away normal sleep discharge with a soft, damp cloth, always wiping away from the eye
• Use a separate cloth for each eye to avoid cross-contamination
• Never use human eye drops without veterinary advice
• After walks in long grass, check both eyes for signs of irritation
• Keep the fur around the eyes trimmed if it is making contact with the eye surface