Sunken eyes in dogs

If your dog’s eyes appear to be sunken from their normal appearance, sitting deeper within the skull than usual, this is understandably cause for concern. There are a whole host of potential reasons behind why a dog’s eyes may appear unusually sunken in, some of which are serious and others more minor. The veterinary term for sunken in eyes is “enopthalmia,” which means “eyeballs receded within the orbit.”

The normal position of the eyes

The eyes of the dog are of course housed in the sockets, which are concave cavities in the skull designed to hold the eyes. While most breeds of dog have what is known as a normal eye position, some breed’s natural state is prominent, bulging eyes, called “exophthalmos,” with the Pug, French bulldog and Pekingese being typical examples of this.

Regardless of the breed of dog that you own, you will soon get used to what is the normal eye position for them, and notice if the position of the eyes, and how far they protrude, changes noticeably.

What mechanism causes eyes to appear sunken?

The exact action that leads to eyes appearing sunken in can vary, and some of the most common reasons are as follows:

• The underneath of the dog’s eyes are supported by fat pads, which cushion the eyes and keep them in their normal position. When these atrophy, the eyes can appear sunken.
• Dogs have a retractor muscle under the eyes that can cause the eyes to sink if it spasms, which can happen due to various veterinary conditions.
• Nerve damage to groups of nerves around the sympathetic trunk can occur on one side of the body only.
• A mass or tumour in the front of the eye can push the eyeball inwards, leading to a sunken appearance.

Whether one or both eyes appear to be sunken on any particular dog can go a long way towards reaching a firm diagnosis of the problem.

Unilateral sunken eyes

Unilateral sunken eyes is the term used to describe one eye sunk, while the other appears normal. Some of the potential causes for this are as follows:

Damage to the eye

If the eye is physically injured or damaged, this can cause the eye to lose fluid, which in turn leads to the eye sinking in. This often causes pain too, and you will almost certainly know if your dog has hurt their eye in this way.

Some conditions such as conjunctivitis or ulcers can also lead to the muscles of the eye retracting back into the socket in self-protection, and so if one of your dog’s eyes suddenly appears sunken, you should see your vet asap, in order to give them the best chance of recovery.

Tumours and masses

Tumours and other masses and lumps in the front portion of the eye can cause the eye to sink, and these usually progress slowly, and will not cause a sunken appearance overnight.

Horner’s syndrome

Horner’s syndrome is the name given to the neurological cause for sunken eyes, although often, the exact root of the condition cannot be found. Injuries to the neck of the dog, or disease of the intervertebral discs can cause nerve damage in the spinal cord, which has nerve branches serving the eyes.

Horner’s syndrome can also be caused by infections of the inner or middle ear, or even the use of choke collars that place pressure on the nerves of the neck and spine.

Horner’s syndrome usually comes accompanied with other symptoms, including constricted pupils, drooping eyelids, and the third eyelid showing as well.

Bilateral sunken eyes

Bilateral sunken eyes are eyes that both appear sunken in at once. Some of the potential causes for this are as follows:

Dehydration

Dehydration is one of the most common causes of suddenly sunken eyes in the dog when this affects both eyes at once. Dehydration causes the fat pads around the eyes to lose water and shrink, and the eyeball itself will lose water too, all of which cause the eyes to sink and appear gaunt and deeply set.

This only occurs in severe cases of dehydration, and your dog will almost certainly be displaying other signs of dehydration too.

Emaciation

Dogs that are seriously underweight, or that lose a lot of weight within a very short period of time, may also appear to have sunken eyes as their bodies begin to consume their own fat stores, including those that provide the padding for the eyes.

Systemic conditions

A systemic condition is one that affects the whole of the body, rather than just one localised site. A range of systemic conditions can cause sunken eyes, including tetanus, neurological problems and infections such as Parvovirus.

How much of a problem is it?

While the various causes of both unilateral and bilateral sunken eyes in dogs can be very varied, all of them merit veterinary attention, as they all indicate that something is wrong with your dog. Take your dog to the vet as soon as you notice that something is amiss, in order to get to the root of the problem and find out what can be done to resolve it.