What this means
An enlarged eye is usually first noticed by the owner looking at the dog's face from the front. One eye may look bigger, sit further out of the socket, or show more of the white than the other side. Sometimes the eye is also red, the clear front surface looks cloudy, the pupil is wider, or the dog blinks and does not like to be touched around the head. A photo taken from the front that shows both eyes is a great help for comparison.
A change in the size of an eye can have very different causes: pressure inside the eye, inflammation, bleeding, an injury or a growth behind the eye. Only a vet who examines the eye can tell these apart, so there is no need to guess at home. What matters is that some of these conditions are painful and can quickly damage sight, so it is not worth waiting to see whether it passes by itself.
Note down when you first saw the change, whether it came on suddenly or grew slowly, whether the eye is red or watering, and whether your dog rubs it, squints or avoids light. Notice whether your dog has knocked its head or been in a fight with another dog. Do not put any drops in the eye and do not use home remedies, because they may do harm while the cause is not known.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
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Raised pressure inside the eye
When the fluid in the eye does not drain as it should, the pressure builds and the eye can begin to enlarge. Redness, a cloudy front surface and pain often go with it.
About the condition: Glaucoma -
Inflammation inside the eye
Inflammation can make the eye swell, redden and become sensitive to light. The eye may look cloudy or have changed colour.
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Injury or bleeding
A blow, a bite or another injury can cause bleeding or swelling. The dog may keep the eye half closed and avoid being touched.
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A growth or swelling behind the eye
When something grows or swells behind the eye, the eye can be pushed forward. The change usually grows slowly and the dog may find it hard to open its mouth.
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The eye pushed out of its socket
After a blow or a fight the eye can be pushed forward, especially in flat-faced dogs with shallow sockets. This is urgent, because the risk of losing the eye is high.
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Swelling of the eye surface or eyelids
An allergic reaction or inflammation can swell the eyelids or the lining of the eye so that it looks bigger. Only a vet's examination can tell the real size of the eye.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- When and how you noticed the change: suddenly or gradually
- Whether the eye is red, cloudy or has changed colour
- Whether the pupil is wider than in the other eye
- Whether your dog blinks, squints, waters or rubs the eye
- Whether your dog avoids light or does not want its head touched
- Whether your dog seems dull, is not eating or is vomiting
When to book a routine visit
An enlarged or bulging eye is always a reason to see a vet the same day. Say when you noticed the change and whether it came on suddenly.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
Body systems: Eyes