Have you ever wondered why your pet’s eyes can appear to glow in photographs or why their night vision seems to be significantly better than yours?
Animals have a clear disc, the cornea, which rests at the front of their eyes. Light passes through the cornea and travels back to the retina, allowing sight to occur. Unlike humans, cats and dogs also have a layer of bluish green tissue called “Tapetum Lucidum”, located behind their retina. It is this colored tissue that causes a pet’s eyes to seemingly glow and allows them to see so well in the dark.Eyelids, eyelashes, sclera (the white part of the eye) and conjunctiva (pink tissue that sits inside the eyelids) are other important parts of an animal’s eye. Interestingly, dogs and cats actually have three eyelids! These eyelids and your pet’s eyelashes help to provide protection from dust, dirt and other irritants. The third eyelid closes in from the side, rather than from top to bottom. It also has a gland that produces some of the tear film.
It’s important to know when your pet may be experiencing trouble with one or both eyes. Any type of eye problems should be treated immediately, as even slightest inflammation can cause intense pain and result in damage to your pet’s vision. Cloudiness and redness in the sclera, overall inflammation around the eyes, and squinting are all reasons to quickly see your veterinarian. Some of the most common types of eye problems for pets are corneal ulcers (scratches or damage to the cornea), conjunctivitis (irritation of the conjunctiva of the eye), dry eye (also called “Keratoconjunctivitis Sicca” or “KCS”), and glaucoma (increased pressure in the eye).
There are many causes of corneal ulcers, including trauma, chemical burns, and herpes viral infections. Your pet may have a corneal ulcer if you notice squinting (which often indicates pain), watery discharge, and redness in the eye. An uncomplicated corneal ulcer will usually heal in about seven days. However, it is crucial to seek immediate medical treatment, as damage progresses rapidly if the ulcer becomes infected. It is also very important not to use any medications without first seeking advice from your vet as some medications cannot be used in an animals’ eye and some can make conditions worse.
Conjunctivitis, the inflammation of the conjunctiva, is often the result of an infection or allergic reaction. However, this bothersome condition can also be caused by irritant particles. In certain animals, simply rubbing the eyelashes or eyelids against the sensitive tissue of the eye can cause this redness. KCS, or dry eye, can also cause conjunctivitis. This immune-mediated condition causes inflammation of the tear ducts, which can lead to thick, goopy eye discharge in one or both eyes, extra pigment on the corneal surface, or redness of the eye.
Glaucoma is a painful and dangerous condition that is more common in dogs than cats. This condition can be hereditary or secondary to inflammation, cataracts, or even cancer within the eye. Glaucoma causes increased pressure in one or both eyes and, if it is not immediately controlled, can result in loss of vision within a matter of hours. Signs of glaucoma can be subtle. Seek immediate medical care for your pet if you notice any type of redness, cloudiness, or an enlarged appearance of the eye.
The key to helping your pet maintain the best possible vision is to catch any eye problems as soon as possible. Contacting a veterinarian immediately and getting the necessary treatment for your pet helps to ensure the best possible outcome. Routine annual exams will also help with this process. When it comes to keeping your pet’s eyes healthy, veterinarians are always happy to “see” you!
Dr. Tom Hemstreet is a veterinarian with LakeCross Veterinary in Huntersville. The vets in the big yellow house have been treating pets like family for 20 years. For more information, call 704-948-6300.