Chloe, a 2 year old pug, came to my animal hospital for a routine checkup. During her exam, I noted black pigment on her corneas - she had about 20% of her field of vision blocked by black pigment over the part of her eye which should be transparent. Chloe’s partial blindness was not evident to her owners because she was able to see well enough to get around, and she had very dark eyes with black pigmentation on her eyelids. Unfortunately, her condition could lead to complete loss of vison if left untreated.
Eye tests performed in the office revealed Chloe had KCS (keratoconjunctivitis sicca), or “dry eye”. Though Chloe could produce plenty of mucous discharge from her eyes, which her owners wiped a few times each day, she was not producing the lubricating and nourishing portion of tears which protect the cornea.
This condition is being treated with medications to increase tear production. Early diagnosis, treatment, and monitoring will protect Chloe from developing further pigmentation and allow her to maintain her vision.
Your pet’s routine, twice a year physical exams should include an ophthalmic exam of the cornea, lids, conjunctiva, sclera (the whites of the eyes), iris, lens, anterior and posterior eye chambers, and the optic nerve and fundus (the back of the eye, which includes the retina and blood vessels). A veterinarian will perform this examination with an instrument called an ophthalmoscope. All veterinarians are trained to perform basic eye exams and to know the common disorders and congenital or hereditary ocular diseases found in common pet breeds.
Some breeds of dogs have an increased tendency to develop ocular disorders. Examples include increased risk of eye trauma in breeds with prominent eyes like Shih Tzus, glaucoma in Cocker Spaniels, lens luxations (displacements) in Welsh Terriers, and PRA (progressive retinal atrophy) in Poodles. Cats suffer from fewer congenital and inherited eye disorders than dogs, but they present with more frequent infections and disorders of the conjunctiva and cornea as a result of a variety of feline viral illnesses.
When abnormalities are found on visual inspection, or when pets show signs of ocular disorders, your veterinarian may perform additional tests including Schirmer’s tear tests, fluorescein stains, and tonometry. In some cases, a referral is recommended for further testing, such as an ERG evaluation of the retina, gonioscopy, and slit lamp evaluation of drainage angles of portions of the eye which are harder to examine.
Pets can’t tell us when something is amiss with their eye health, so knowing the signs of ocular problems will help you determine when your pet needs a checkup. When it comes to ocular health, waiting to schedule your pet’s exam can lead to blindness as a result of lack of quick intervention with the appropriate medication or procedures. Many ophthalmic problems can be effectively evaluated and treated by your local veterinarian, but some conditions may require a referral to a veterinarian with a specialty or board certification in ophthalmology.
Symptoms and behaviors that would necessitate immediate veterinary evaluation include avoidance of light, shying away from touch, bumping into objects, sudden fear or avoidance of going down steps or outdoors, excessive rubbing of the eye on carpets and furniture.
Conditions like perforation of the cornea, glaucoma, proptosis of the eye (complete displacement of eye outside of lids), lens displacement, and loss of blink reflex can be treated in a timely fashion so that visual loss is minimized.
You should call your vet if you see any of the following in your pet, as soon as they are noticed:
- Trauma to the eye or eyelids
- Red lids or membranes
- Squinting or closing of one or both eyes
- A film over the eye
- Bulging or recessed eye
- Blood in or around the eye
- A droopy lid, lack of blink, or unequal eye appearance
- Excessive tearing, or increased staining around the lids
- Increased mucous discharge (yellow or green)
- A gooey or mushy material on the eye
In many cases your pet will have drops prescribed. Apply all medications as directed by the vet, and if you are unable to get the medication into the eye, be certain to notify the office right away. The veterinarian or a vet technician can often see your pet as an outpatient to apply drops, and will be glad to demonstrate some tricks to make medicating easier. Keep your pet’s follow up appointment, even if the eye looks healed, as medication changes are often necessary for optimal healing.