Pets’ Eyes: The Big Picture
Sight is a very important sense to your pet dog, cat, or rabbit. I want to provide a broad overview of what is normal appearance and anatomy, then discuss the most common ocular diseases, and to finally make you aware of some ocular emergencies.
Like humans, our pet’s eyes have corneas, the clear front outer wall that is made up of several layers of tough connective tissue covered with a thin layer of skin cells. The iris, the colored part you can see through the cornea, regulates the amount of light coming through the lens which can change shape and focuses that light onto the retina. The retina is composed of light-sensing cells that create the impulses which are sent to the brain. There is also a third eyelid which humans don’t have that helps to spread the tear film and can slide up and cover the cornea to help prevent corneal injuries.
A healthy eye is one that is bright and shiny, looks moist, has no red inflammation, and the eyelids are held open. Any deviation from normal should catch your attention and rechecking a couple times that day may reveal a temporary resolving condition or one that is escalating to one of the following conditions.
Red Eye, or Conjunctivitis, is a very common eye disease that can have many causes. Eye infections, allergies, or exposures to irritating substances are common. Cats can have lifelong recurring viral conjunctivitis that is very common. Trauma to the cornea like scratches and ulcers are also common in pets. Sometimes internal eye problems like inflammation, termed uveitis, can also cause external eye redness. The treatments are many and varied and depend on the diagnosis by our veterinarians.
Dry eye in one or both eyes is a common condition of mostly adult and senior dogs, but can be congenital. A decrease in tear production from one of several causes is at fault. Chronic eye irritation and redness with thick yellow-green mucous is often a tip-off to dry eye. Fortunately, today we can usually control dry eye with lifelong medications.
Glaucoma can be suspected when the sclera (white of the eye) is chronically blood shot, has an enlarged pupil continuously in any light, and the eye may even appear larger than the opposite one. Pressure within the eye can be increased many fold leading to significant pain and loss of vision. Diagnosis is confirmed by our Veterinarians checking the eye pressure. We do have medical treatments for the various types of glaucoma, and sometimes surgery by one of our three local veterinary ophthalmologists can be helpful to alleviate this painful condition. Certain breeds like cocker spaniels and others are predisposed.
Sudden Wide Pupil Dilation especially in geriatric cats. High blood pressure may cause a bleed behind the retina causing retinal detachment with temporary or permanent blindness. This is most common in geriatric cats who have chronic kidney disease or hyperthyroidism. We will check blood pressure and initiate therapy to decrease blood pressure. Some cats regain sight.
Cataract of the Lens occurs in many pets as a congenital or acquired condition. The proteins of the normally clear lens undergo changes that lead to a lens that becomes opaque to varying degrees. There is surgery to replace the lens with a plastic one just like for our eyes. However, if one eye is still normal or has partial vision, many pets adapt and seem to do well without surgery.
Eyelid Entropion / Extropion A common condition in many breeds involves the eyelids rolling inward against the eye with lashes and hairs rubbing the cornea until an ulcer develops. This is called entropion and may be a congenital condition or secondary to eyelid trauma. Outward rolling eyelids (Extropion) predisposing to eye irritation also occurs. Both conditions are correctable with surgery performed at our Clinic.
Eyelid Tumors are very common as dogs age. Most of the round nodules or black “cauliflower like” growths right on the black eyelid margin are benign oil gland tumors. They are excised by creating a narrow wedge shaped excision of the lid margin and tumor then closing the wedge with very fine dissolving sutures. So it is preferable to remove them when they are small. Once they become larger than 3-4 mm, extra surgical procedures or even plastic surgery have to be employed to prevent shortening the length of the eyelid leading to entropion of the eyelid (described above).
True Ocular Emergencies Some of the conditions above can require attention soon within a day or two, but there are a few true ocular emergencies.
- 1) One might be a red eye with continuous squinting that never opens even in a darker room. Severe deep ulcers and penetrating injuries can cause this, and they require immediate care.
- 2) Glaucoma with severely elevated eye pressure can rapidly lead to blindness and requires immediate attention.
- 3) In breeds with bulging eyes, like Pekinese and Pugs, the eyeball can actually pop out of the socket which is definitely an acute emergency.
- 4) Sudden onset of cloudiness within the chamber of the eye.
- 5) Sudden onset of blood or pus within the chamber of the eye, especially in an older cat with dilated pupils.
- 6) Sudden onset of wide dilation of one or both pupils.
- 7) Acute onset of blindness from any cause.
Because time can be of the essence with severe eye problems, our office makes every attempt to schedule our clients’ pets with serious acute ocular problems that day, or as soon as possible. On weekends or after hours, care can be received at our local emergency hospitals. For very serious eye problems, the emergency service at the Pittsburgh Veterinary Specialists and Emergency Clinic can transfer pets to their three Veterinary Ophthalmologists the next day for expert care.
SUMMER BOARDING KENNEL & DAYCARE ALERT!
Many kennels and doggie day cares will be requiring Canine Flu vaccines this summer. The two strains of Canine Flu in the US are novel viruses that ALL DOGS WHO CONTACT IT WILL CONTRACT.
Social dogs who frequently go to day care, dog parks, or kennels should be immunized twice the first year, then annually. Many of our local doggie daycares and kennels have imposed a time deadline by which your dog must be immunized. To assist our clients’ compliance, if your pet has had a wellness exam within the past six months and is not obviously ill, a technician visit can be scheduled for the initial immunization and boost 2-4 weeks later.
Call our receptionists to set up a flu vaccine appointment.
Pittsburgh Spay & Vaccination Clinic is a state-of-the-art, full-service suburban veterinary facility serving the Pittsburgh Area since 1980.. We offer diagnostic, medical, surgical, and dental care to dogs, cats, ferrets, rabbits, and pocket pets in the Pittsburgh area.
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