I couldn’t resist the title! Dr. Freihaut, our other full time veterinarian down here at Briarcliff College Park, and I have seen an unusually high amount of eye diseases over the past couple of weeks, so I thought it would be good to do a quick review of eye diseases and what to watch for at home.
The following statements are worth keeping in mind when considering eye disease:
- Eyes are unique in that they are very closed off from the rest of the body.
- They keep themselves inflated by a continuous balance of production and drainage of protein rich fluid, all within the eye.
- The cornea (clear part) of the eye is waterproof from within and without, is about as thick as the edge of a dime, and has connective tissue fibers aligned to allow light to easily pass through it.
- The conjunctiva is the “pink” of the eye, like when you pull your eyelid down. The sclera is the white part of the eye. Both have a lot of blood vessels.
I could go on and on about eye anatomy, since everything in the eye is so small, yet has such a definite function, but I digress…
With these facts in mind, we can quickly see (Ha!) four of the most common eye problems: corneal ulcers, glaucoma, dry eye, and allergic conjunctivitis.
Corneal ulcers happen when something (usually a stick or any other sharp object, but it could even be a hair from the eyelashes) scratches the cornea. The cornea loses the top layer of a modified skin and becomes very painful. The cornea can heal on its own, but can quickly get infected and sometimes be deeper than a superficial scratch. What you will see: The sclera and conjunctiva will appear bright red, the cornea will look a little whiter, and your painful pet will have a lot of squinting and tearing. Yellow or green = infection.
Glaucoma is an increased pressure within the eye. For whatever reason (and there are several), the production in the eye is greater than the drainage out. This creates a increase in the pressure inside the eye (or intraocular pressure). What you will see: The sclera and conjunctiva may appear red, the cornea may appear whitish, and the eye may be squinty with discharge (sound familiar?). The eye may even appear larger than the other eye in severe and chronic cases.
Also called keratoconjunctivitis sicca, this occurs when the lacrimal gland does not produce enough tears for the eye to be healthy. This can irritate the eye, and also result in a corneal ulcer since the eye depends on tear production to stay healthy. What to watch for: The conjunctiva and sclera will appear red, and the eye will have thick, ropey discharge.
This is typically a disease involving both eyes, and as you would imagine looks and feels similar to human allergies. What you will see: Red sclera and conjunctiva and eye discharge, typically out of both eyes.
Since the eye is so closed off, most medications we use need to go right on the eye – either in the form of drops or ointment. Antibiotics for infection, atropine for pain, medications for dry eye and glaucoma, and topical steroids if another condition, called uveitis, exists.
Obviously the concern with the eye is that the conditions listed above look the same. So we test to determine the underlying cause, not only to have an answer, but also because some meds may actually be harmful if given for the wrong condition. Often, quick treatment is required to prevent permanent damage or loss of the eye entirely. I am not writing this blog to make you freak out about your dog or cat’s eyes. Rather, I think that eyes are fascinating, and are very easy to understand because much of their anatomy is visible. Now I can share my amazement with how perfectly eyes are designed, and you can appreciate eyes for what they are – hopefully without seeing what can happen when they don’t work right.
I will try to get into testing for eye problems sometime soon!
– Doc Cleland