Should I Be Worried About My Dog’s Eye Discharge?

Eye discharge is common in dogs, and often simple to treat. However, some eye problems can be more serious, especially in brachycephalic (flat-faced) dog breeds. In these cases, there is a risk that the eye may become damaged and need to be removed. 

Severity:

Usually mild, occasionally moderate or severe. 

Key points

Common in

Dogs of all ages and breeds, but especially brachycephalic (flat-faced) dogs. 

Introduction

A sticky discharge from one or both eyes is a common reason for a trip to the veterinarian. Most causes of sticky eyes are straightforward to treat, but some can be more serious, and require surgery or other specialized treatments. In severe cases, the eye can become damaged or even rupture, which needs to be removed.

Symptoms & types

Eye discharge in dogs is usually easy to spot. It often starts to be noticeable at the inner corner of the eye, then spreads to the lower eyelid, and finally to the upper eyelid if it is severe enough. Your dog’s eyes may also appear red and swollen, and they may rub their eyes with their paws, or on furniture or carpets. 

Several different types of discharge can be seen in dogs’ eyes. Your vet will need to examine your dog to work out what kind of discharge they have, as different kinds have different causes.  

Crusty eyes

Many dogs will have a little crusty discharge at the corner of their eyes each day – this is often most noticeable first thing in the morning. This can be quite normal, and usually does not need to be treated. If needed, you can clean your dog’s eyes using some cotton wool soaked in warm water. 

If you think that the amount of crusty discharge has increased recently, then you should speak to your veterinarian. 

Runny eye discharge

Thin, liquid discharge from the eyes – sometimes called “serous discharge” –  is also common in dogs. You may notice that your dog’s eye looks wetter than normal, and they may have increased amounts of crusting at the corners of their eye. 

Serous discharge can be caused by many different issues, including viral infections, allergies, and damage to the surface of the eye. 

Sticky eye discharge

Thick, sticky discharge from the eye is called “mucoid discharged”, and can come in several different colors, including cream, yellow, green, or brown. You may see this discharge at the corners of your dog’s eye, on their eyelids, or even straked over the surface of their eyes. 

This kind of discharge usually means that a bacterial infection is present in the eye. However, there are many different reasons why dogs can develop an infection, and sometimes there is an underlying condition that will also need treatment. 

Bloody eye discharge

Occasionally, dogs can get discharge from the eyes that is pink or red from blood. This is normally caused by trauma to the eye and is seen soon after the eye is damaged. Dogs with bloody discharge from the eye need to be examined by a veterinarian as soon as possible. 

Many dogs will have a little crusty discharge at the corner of their eyes each day – this is often most noticeable first thing in the morning.

Understanding the diagnostics

Many dogs with eye discharge can be quickly examined and treated in an appointment with a veterinarian. However, in some cases, extra tests are needed to work out the exact cause of the discharge. 

Examination

Your veterinarian will examine your dog’s eyes to see what kind of discharge they have. They will also look for signs of any redness or swelling around the eye, and any signs of damage to the surface. 

Sometimes they may be able to see any foreign bodies (objects in the eye that should not be there, such as a thorn or grass awn), but some of these can only be seen when the dog is sedated, and the vet can lift their third eyelid. 

Ophthalmoscope

Often, veterinarians will use a specialized tool called an ophthalmoscope is used to look at a dog’s eye. This can be used to examine the structures inside the dog’s eye (the iris, lens, and retina) in more detail, and to look for any issues there that might cause inflammation and discharge from your dog’s eye. 

Fluorescein

Your veterinarian may use a special dye called fluorescein to check for any damage to the surface of your dog’s eye. This is an orange liquid that turns green when it is placed in the eye. 

Fluorescein is taken up by any cells on the surface of your dog’s eye that are damaged, causing green streaks or spots to appear. Your vet can use this to find smaller cuts or scrapes and to monitor any issues with your dog’s eye as it heals. 

Schirmer Tear Tests 

Some breeds of dogs are prone to developing dry eyes. Schirmer Tear Tests are small pieces of paper that are placed into the corners of dogs’ eyes to measure how much tear liquid their eyes produce in a minute. If your vet suspects that your dog may have dry eyes, they can use one of these tests to measure their tear production, and they may be able to diagnose them with dry eyes as a result. 

Blood tests

In rare cases, the underlying cause of eye discharge can be an illness that affects the whole body. Your vet may recommend running blood tests to look for signs of any other illness that could be causing your dog’s eye discharge. 

Scans

If your vet suspects that there may be an issue with the back of your dog’s eye (the retina) or the tissues around the eye, then they may suggest doing a scan of the eye. This might be an ultrasound, CT, or MRI scan, depending on what your vet thinks the problem is.

Your veterinarian will examine your dog’s eyes to see what kind of discharge they have.

Learning About The Causes

Viral Infections

Some viruses may cause dogs to develop watery eyes, usually alongside other symptoms such as coughing or sneezing. These viruses usually do not need treatment, but your vet can prescribe medication to help your dog stay comfortable whilst they recover. 

Viral infections usually cause a thin, runny discharge from the eye. 

Bacterial Infections

These kinds of infections are common in dogs. They usually happen when dogs accidentally poke their eye on something like a plant or toy, and bacteria enter accidentally and cause an infection. You can get infections that are passed between dogs, but this is much rarer. 

Bacterial infections will usually cause a thick, sticky discharge from the surface of the eye. 

Allergies

Just like humans, dogs can get a form of hay fever that causes sneezing, coughing, and runny eye discharge. This usually only happens at certain times of year (when the pollen levels are high) but occasionally dogs can be allergic to dust mites or other indoor allergens, which can cause year-round issues. 

Foreign Bodies

A “foreign body” is any object that becomes accidentally trapped in the eye. Common examples include grass awns, thorns, or other pieces of plant material. These will also cause an infection and may cause damage to the surface of the eye (the cornea). 

Corneal Abrasions

There are several different ways that dogs can damage the surface of their eye (the “cornea”). They might poke themselves in the eye accidentally, be scratched by another dog or cat, or even damage it themselves from pawing or rubbing at their face. Dry eyes (see later) can also lead to abrasions as the surface of the eye dries out. 

A shallow scratch to the cornea is called an “abrasion” and can cause runny or sticky discharge from the eye. They will usually heal with treatment, but can occasionally develop into a more serious “corneal ulcer”.

Corneal Ulcers

Corneal ulcers are deeper damage to the surface of the eye. They can happen when an abrasion becomes infected, or when there is a more serious injury to the surface of the eye. They are more common in dogs who have protruding eyes, which includes brachycephalic breeds like bulldogs, pugs, or boxers. 

These ulcers are very painful, and also quite serious, as if they become too deep then the eye can rupture and need to be removed.

Tear Duct Blockage

Dogs’ tears drain out from the eye through a small channel at the corner of the eye closest to the nose, which is called the “nasolacrimal duct”. If this duct becomes blocked, then tears may start to build up and then overflow from the eye, causing the fur around the eye to become damp. 

Entropion

Some dogs are born with eyelids that are rolled inwards slightly more than they should be. This can cause fur from the eyelid to start rubbing on the surface of the eye, which is very painful and irritating. It can also damage the surface of the eye, leading to corneal abrasions or even ulcers.

Entropion can cause either runny or sticky discharge from the eye, depending on how serious it is and on whether there is also an infection present. 

Dry Eye (Keratoconjunctivitis Sicca)

Certain breeds of dogs are prone to develop this condition, where the immune system becomes confused and starts to attack the tear gland. Over time, this reduces the volume of tears that the eye produces, and the surface of the eye can start to become dry. 

Tears are important to lubricate the eye and protect it from infection, so dry eyes can quickly become damaged and infected. This damage can quickly turn into a corneal ulcer if not treated.

Some viruses may cause dogs to develop watery eyes, usually alongside other symptoms such as coughing or sneezing.

Best Treatment Options

Medicated Eye Drops

Many conditions that cause eye discharge are treated with drops. This includes antibiotic drops for infections, antihistamine or steroid drops for allergies, immune-suppressing drops for dry eye, and lubricating drops both for dry eye and corneal ulcers.

Eye drops are usually better than tablets for treating eye conditions, as they get a high concentration of the medication into the right place and avoid the side effects that can happen from drops going to other parts of the body. 

Serum Drops

Dogs who have corneal ulcers may benefit from treatment with eye drops made from serum, as this has been shown to help speed up the healing process. These drops are made by drawing some blood (usually from the dog who needs to be treated) and then spinning it in a centrifuge to remove the cells from the blood. This leaves behind “serum”, which can then be put into a dropper bottle and used to treat the eyes. 

Surgery

Some of these causes of eye discharge may need surgery to treat. For example, entropion will need surgery to correct the shape of the eyelid, so that fur can no longer rub against the surface of the eye. Some more serious corneal ulcers will also need surgery or other procedures to help them heal – there are a wide of options available, and your veterinarian may refer you to a specialist to discuss them.

Many conditions that cause eye discharge are treated with drops.

Conclusion

Eye discharge can be caused by a wide range of different problems. Dogs with eye discharge should always see a veterinarian to get a diagnosis, but treatment is usually straightforward. Occasionally, there can be more complex problems in the eye, which may need more specialised tests and treatment, including surgery. 

Serious conditions can cause dogs to lose their eye, so do not delay seeing a veterinarian if one or both of your dog’s eyes develop a discharge.