Sudden enlargement of the eye

Sudden enlargement of the eye

Our question this week was:

My dog's eye suddenly (in a 24 hr span of time) started to tear and blow up. The left globe is very noticeably enlarged. At times appears to turn bluish-white and then seems to return to brown. Prednisone seems to be keeping it in check. My DVM ruled out glaucoma and blunt trauma. We are waiting to see an ophthalmologist. My vet says she has never seen anything like this. Have you? Theories we have are tumor behind eye (although blood work did not show any cancer flags) or she started to form a cataract and her body is attacking it. Once again no elevation in white count and there are no piles of white cells in eye. Holly is a very young, active 11 yr old.

Thank you,



Hi Sandy, thanks for your email. I'm sorry to hear about your dog's eye. It sounds like a difficult situation. It sounds like the eye is displaying several abnormalities including enlarged globe, tearing, and an abnormal color to part of the eye (I'm not sure which part you are referring to but I'm guessing it is the cornea.

If we just look at the enlarged globe of the eye, I worry about a few different conditions. There is a situation where the position of the eye has changed called "exophthalmos" making it often appear bigger or abnormal. When the globe is actually bigger, that condition is referred to as "buphthalmos". They can be difficult to differentiate.

Many of the reasons the globe may be bigger or appear bigger can be the same. Glaucoma is certainly a consideration but it sounds like they ruled that out. There are several reasons for this ranging for an abscess, cancer, auto-immune disease and others. I'll include some information from and article on that indicates some common reasons for a change in globe size. Possible causes include:

  • Cancer of the tissues behind or beneath the eye – Cancer behind the eye is one of the more common causes of exophthalmos in the older dog.
  • Abscess or infection of the soft tissues surrounding the eye (especially behind the eye) – Infection behind the eye is often caused by migration of foreign material from the mouth, or by extension of infection from the roots of the teeth in the upper part of the mouth. Occasionally, infections somewhere else in the body can spread to the tissues behind the eye. Infection behind the eye is a common cause of exophthalmos in the dog.
  • Bleeding or hemorrhage behind the eye – Trauma to the face from blunt objects, automobile or bicycle accidents may result in bleeding behind the eye. Trauma is a common cause of exophthalmos in young dogs that are allowed to roam free. A rare cause of bleeding behind the eye occurs in dogs that are unable to clot their blood properly.
  • Myositis or inflammation of muscle – Myositis may involve the muscles of the eye itself or the muscles of the head responsible for chewing. Both conditions tend to occur in young large breed dogs, and both may result in exophthalmos.
  • Zygomatic salivary gland disease – The zygomatic salivary gland sits on the floor of the orbit, just beneath the eye. If this gland becomes enlarged from infection, cyst formation or tumor growth, then it may push the eye forward. Diseases of the zygomatic salivary gland are uncommon in the dog.
  • Cyst formation – Cysts may arise from the zygomatic salivary gland or the lacrimal gland (which is the major tear gland in the orbit). Cysts that cause exophthalmos are also uncommon in the dog.

    I totally support your seeing a veterinary ophthalmologist. That is exactly what I'd do if she was my dog ¡V and the sooner the better. They can do some additional tests to figure out the underlying cause.

    We have an article on our site on Exophthalmos in Dogs that might be useful to you.

    Let me know what the ophthalmologist says – I'm curious.

    Best of luck!

    Dr. Debra

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