‘Aye, aye, aye!’ The Case of Red Eyes in Pets

May 01, 2019

A sudden eye issue in your pet can be worrisome and frustrating. Often, pet owners wonder, “Is this serious enough to need a veterinary visit?” or “Can this wait until a more convenient time?”

Causes of eye issues can be as simple as allergies or as complicated and urgent as glaucoma. The problem is that many eye conditions, whether mild or serious, just appear to be ‘red eyes’ to the untrained (or even sometimes to the trained) eye without further testing.

Conjunctivitis, or ‘pink eye,’ is a general term that means redness or pinkness of the eyes. Despite common misconception, ‘conjunctivitis’ is an observation more than a diagnosis. The term does not always indicate an infectious or contagious cause, and in fact does not tell us the cause at all. To find the cause (and therefore best plan of treatment), we need to do a thorough ocular exam and usually other testing.

The most common eye problems that we see when an owner reports ‘red eyes’ include foreign material in the eye; corneal ulcers; glaucoma; allergic conjunctivitis; ‘dry eye;’ bacterial or viral infection; upper respiratory infection; and others. Unfortunately, these, and many other eye conditions, all have almost exactly the same symptoms: red eyes, +/- clear to yellow/green discharge, +/- squinting or rubbing eyes, +/- swelling of the soft tissues of the eye, +/- cloudiness of the surface of the eye, etc.

Most of the time, we need 4 things to help us rule in or rule out conditions once we establish that a pet has conjunctivitis:

1. An ocular exam with an ophthalmoscope – this allows us to visualize the internal structures of the eye, including the lens, retina, and iris. We can also see signs of inflammation within the eye with this instrument, but the cause is not always known just by seeing the presence of inflammation or other abnormality within the eye. Sometimes, a specialist’s (a veterinary ophthalmologist’s) equipment is needed to visualize these structures in greater detail when we see an abnormality.

2. Tear test – this allows us to diagnose abnormalities with tear production in the eyes. Some conditions are associated with increased tear production, whereas others are associated with decreased tear production. This can help us make a diagnosis in favor of one condition over another.

3. Eye stain - there are scratches or abrasions (termed ‘ulcers’) on the cornea, this stain highlights them a neon green color. Knowing if there is a defect in the cornea is vitally important, as using some medications within the eye can be detrimental or even lead to loss of the eye if the cornea is damaged.

4. Eye pressure test – this painless test allows us to know what the pressure is inside the eyes. This is especially important to help rule out conditions such as glaucoma (elevated pressure within the eye), but other conditions are associated with elevated or decreased eye pressure as well.

It is difficult and sometimes impossible to diagnose a condition just by looking, without an exam with an ophthalmoscope or further testing. If foreign bodies, corneal ulcers, bacterial or viral infections, glaucoma, or ‘dry eye,’ etc. are left untreated or are treated too late, serious complications or even loss of vision or loss of the eye itself can occur.

In general, a good rule of thumb is to never wait when the eyes are involved. The reason is simple: nearly all these conditions look the same, and it is too risky to wait if it does happen to be a more serious problem.

Never use human eye medications or medications given in the past (even if given for the same pet) without consulting your veterinarian first. Using inappropriate medications can make eye conditions worse very quickly. Always call us and/or schedule an appointment if you notice an issue with your pet’s eyes. If you can’t find time in your schedule to bring your pet in right away, we can help figure out the best way to proceed until you are able to bring him or her in. Your veterinarian can let you know if she feels it is an urgent situation or if you can ‘keep an eye on it’ (pun intended) for now.

Dr. Tashina Elswick