Biology Reference
In-Depth Information
THE EYES SEE YOU
The eye can be compared to a computerized camera. The pupil is the
camera's aperture, or opening, and can change from wide open to bare-
ly open. The iris works as the shutter, regulating the amount of light
entering the eye.The lens is the focusing mechanism.The retina is the
film; it is where photoreceptors convert the image into electrochemical
signals. Nerves to the brain are the computer lines that transmit the sig-
nal. The brain is where the finished photo is assembled. There are
193,000 optic nerve fibers that transmit information to the cat's visual
cortex in the brain.
Diseases such as cataracts, dry eye, eyelid deformities and glauco-
ma are not frequently found in cats. Most veterinarians can treat com-
mon diseases of the eyes, but will refer you to a specialist if needed.
Board-certified veterinary ophthalmologists have specialized equip-
ment and can perform advanced diagnostic and surgical procedures
on the eyes.
A Scratch on the Eye
A common cause of a squinting and red eye in a cat is a corneal ulcer.
Corneal ulcers are irregularities on the surface of the eye. They are
detected by placing a drop of a fluorescent dye on the eye surface and
then rinsing it off. A normal cornea is smooth, and the dye will flush
off. If any abrasion, scratch or other lesion is present that has affected
the integrity of the cornea, the dye will stick to it.
Ulcerated corneas are quite uncomfortable to an animal, so you
may see a decreased activity level in a cat with an ulcer.
In the springtime when plants and weeds are growing, it is common
for cats to accidentally get foxtails in their eyes. Foxtails are pointy grass
awns that are quite sharp and can get stuck under the eyelids when a
cat goes outdoors. If you live in an area where these annoying plant
seeds are present, be on the lookout for them. They can also get stuck
between toes and in ear canals, and be found throughout a cat's coat.
They can penetrate into the skin and cause more serious problems,
as well.
An antibiotic drop or ointment is usually prescribed to treat a
corneal ulcer. A protective Elizabethan collar may be recommended as
well.An Elizabethan collar is the protective “lampshade” animals wear to
prevent them from rubbing their eyes or faces or to stop licking an area.
