By Dr. Karen Burgess
What is conjunctival tissue?
The conjunctiva is the pink fleshy tissue that covers the eye and tissue surrounding it. In a cat or dog with healthy eyes this conjunctiva should not be easily seen. In cases of conjunctivitis where the conjunctiva is inflamed owners will often notice angry red tissue near the eyelid. The conjunctiva is made up of mucous secreting cells similar to that found in the mouth and nose and serves to help protect and lubricate the eye.
What are symptoms of conjunctivitis?
Mild cases of conjunctivitis may appear as increased tearing that is clear or colored in nature. More severe cases can develop swollen pink or red bulging tissue that appears to almost cover the eyeball. The eye may become increasingly painful causing a pet to hold it shut or paw/rub at eye. In severe cases it may be difficult to see any part of the normal eye.
Why do cats and dogs develop conjunctivitis?
There are numerous reasons for the conjunctiva to become inflamed. Infectious causes include viruses and/or bacteria. In some cases infections will develop secondary to some other underlying cause of conjunctival inflammation. For cats viral conjunctivitis is extremely common and closely related to upper respiratory viral infections they are exposed to at a very young age. In several of these situations the cat may recover from the initial infection but the virus remains dormant in their body reappearing later in life at times of stress or illness. Non-infectious causes of conjunctivitis are typically related to the anatomy (size, shape, and location) of the eyeball itself. Dogs often develop a condition where they stop producing tears which then leads to a “dry eye” and secondary conjunctivitis. Some breeds of cats and dogs are more prone to having flat faces or bulging eyes which can change how the eyelid sits against the eye. In these cases eyelashes or facial fur may rub against the eye and conjunctiva causing inflammation. Allergic disease, foreign material caught in the eye, tumors, and immune disease are all additional causes of conjunctivitis.
How is conjunctivitis diagnosed?
A veterinary examination will typically reveal the presence of conjunctivitis. Additional testing of the cornea and tear production may also be necessary. If systemic disease is suspected bloodwork may be recommended. In complicated cases referral to an ophthalmologist may be recommended.
What are treatment options for conjunctivitis?
Definitive treatment of conjunctivitis involves diagnosing the underlying cause for treatment and controlling secondary bacterial infections. This may involve topical drops or ointment, oral medications, eye lubricants, or surgery. It is important to protect the eye from self-trauma by using a protective collar or Elizabethean collar. Pain medication may also be prescribed to help with associated discomfort.
What is the prognosis with conjunctivitis?
Prognosis is directly related to the ability to treat the underlying condition causing the inflammation.
KCS (Kertaoconjunctivitis Sicca)
By Dr. Karen Burgess
What is a KCS or dry eye?
KCS, otherwise known as keratoconjunctivitis sicca or dry eye, is a condition of decreased tear production. The eye has several associated glands that produce tears. Tears are necessary to remove foreign substances or debris and to keep the eye lubricated. With decrease in tear production, the eye can become dry leading to irritation and increased discharge surrounding the eyes.
Why do dogs develop KCS?
The most common cause of KCS in dogs is an autoimmune related disease. With immune system disease, the body starts inappropriately attacking something that is normal, in this case the tear producing cells. There may be a genetic predisposition to the development of KCS and many breeds are thus predisposed. Other potential causes of dry eye include a reaction to particular medications or hypothyroidism. Sometimes tear production will appear decreased due to inflammation in other parts of the eye; once the underlying disease is addressed the tear production may return to normal in these cases. Lastly there is a neurologic cause that typically causes a very dry nose on the associated side of the face with the diseased eye.
What does a KCS look like?
Owners may first notice increased ocular discharge with KCS. The eyes may be painful demonstrated as squinting, holding the eyes shut, or excessive blinking. Over time, dogs with KCS are more prone to developing corneal ulcers and scarring which often appears as black pigment on the cornea.
How is KCS diagnosed?
A Schirmer Tear Test (STT) is used to diagnose dry eye. This test involves placing a small strip of test paper under the eyelid and quantifying the amount of tears produced over a minute time. Previous application of any eye medication or drop can affect results of the STT. Additional testing may be done to evaluate the cornea for damage (fluorescein staining), to evaluated intraocular pressure (looking for associated glaucoma), and to evaluate the quality of tears being produced.
What are treatment options for KCS?
The first goal of treatment for dry eye is to replace tears artificially allowing protection of the delicate cornea. This is done by administering a topical tear replacer that is often applied every few hours throughout the day (the more the better). The second goal of treatment is to stimulate the body’s natural production of tears. Tacrolimus and cyclosporine are the most commonly used medications for this and are applied topically at least twice daily. These medications are often compounded or specifically made by the pharmacist for a specific pet. General hygiene is also important, gently wiping the face and eye area to help prevent buildup of debris. Ultimately there is surgery available to treat dry eye if topicals are not an option, but this is not without the possibility of complications.
What is the prognosis with KCS?
With the medications currently available dogs with KCS have a good prognosis for returning to a normal comfortable eye. It is important to understand that treatment is life-long and cure is not expected.
By Dr. Karen Burgess
What is nuclear or lenticular sclerosis?
Nuclear or lenticular sclerosis is the normal aging process of the lens. The lens is a transparent structure within the eye that bends light and reflects images to brain’s visual center or retina. Over time the lens stays the same size but becomes harder as more fibers are continually laid down within.
Why do dogs develop nuclear sclerosis?
Nuclear or lenticular sclerosis is a normal aging process of the eyes.
What does a nuclear sclerosis look like?
Most owners will notice a symmetrical gray blue haze to the eyes often easier to see from the side than the front. Sometimes nuclear sclerosis can be confused with cataracts which are more opaque and white in nature. Cataracts represent a more serious condition that affects vision.
Does nuclear sclerosis affect vision?
Typically nuclear sclerosis does not significantly impact vision. Some owners may notice change in depth perception or seeing items close up. Additionally as the normal retina ages, night vision may become more difficult.
What are treatment options for nuclear sclerosis?
There is no treatment for nuclear sclerosis indicated or necessary.
By Dr. Karen Burgess
What is a corneal ulcer?
The cornea is the clear surface of the eye (where a contact lens is placed in humans). This window to the eye contains several very thin layers of cells. A corneal abrasion or erosion occurs when the most superficial layer of cells (epithelial cells) are damaged. Lesions that affect the epithelium and the deeper stroma are called corneal ulcers. If the final and deepest layer of the cornea (Descemet’s membrane) of the cornea is also affected permanent loss of vision and collapse of the eye may occur.
What causes corneal ulcers?
Corneal ulcers are typically caused by external trauma, foreign bodies, chemical irritants such as shampoo, or self-inflicted trauma (example pet scratching or rubbing eye). Some breeds are also predisposed to decreased tear production which can dry out the cornea leading to erosions.
What are symptoms of corneal erosions/ulcers?
Corneal lesions are usually very painful. In an effort to relieve associated itchiness and discomfort, pets will often rub the affected eye against the ground, against furniture, or with their paws. The eye will often be held closed, be more sensitive to light, and appear red. Drainage may also be present.
How do you test for a corneal ulcer?
Your veterinarian will apply a fluorescein stain (eye drop) that will effectively highlight any damage to the cornea. Testing for adequate tear production may also be performed.
What is the treatment for corneal ulcers?
The severity of the corneal lesion will determine treatment. In severe cases referral to an ophthalmologist may be necessary for surgery in an attempt to save vision. In milder cases topical eye medications, lubricants, and pain medicine may be prescribed. Atropine drops may also be used to dilate the eye thus helping with discomfort. If atropine is prescribed the dilation will last for several days beyond treatment and will cause light sensitivity. An Elizabethean collar will also be necessary to help prevent any further self-trauma to the eye. In uncomplicated cases the cornea will tend to heal in just a few days. A recheck of the eye should be performed two to three days after initiation of treatment to ensure improvement. Be aware that pets may taste any medications applied to the eye due to tear ducts which drain into the mouth. This may cause drooling or pawing at the mouth after eye medication application. Topical anesthetics are not recommended to treat ulcers as they can hinder healing. If your pet is more uncomfortable after application of eye meds, contact your veterinarian; in some situations a pet may be sensitive to a particular product.
Conjunctivitis (Cherry Eye)
By Dr. Karen Burgess
What is a “cherry eye” technically?
A cherry eye or “haw” as it is often called occurs when a dog’s third eyelid gland prolapses or pops out. The third eyelid is the pink fleshy tissue seen toward the middle of the lower eyelid. Instead of moving up and down like upper and lower eyelids, the third eyelid moves from side to side, or from nose to ear. The third eyelid serves as an extra layer of protection for the eye. The gland of the third eyelid that is affected by cherry eye produces an important portion of the eye’s protective tear film.
Why do dogs develop cherry eye?
The third eyelid gland is normally firmly attached to the lower portion of the eye. For unknown reasons, in particular in some breeds, there is weakening of this attachment causing it to pop out. Over time, the now malpositioned gland becomes inflamed and swollen, making it more difficult for it to stay in its proper position.
What does a cherry eye look like?
What most owners notice with a cherry eye is a red swollen mass like appearance protruding from on the nose side of the eye. Cherry eye is typically not painful. They can vary in size and in some cases will come and go.
What are treatment options for cherry eye?
Definitive treatment involves surgically tacking the prolapsed third eyelid gland back in place. This surgery involves a high degree of technical skill for best chances of success and should be performed by and ophthalmologist (veterinarian that has received advanced training in ocular disease and surgery). There is another surgical procedure that involves removing or amputating the third eyelid gland. This is not recommended and can lead to lifelong complications with tear production and thus a potentially painful and non-visual eye. In some cases, use of a topical steroid and gentle external massage can pop the proptosed gland back in place. In some milder cases this can be done at home by owners as needed for temporary control.
What is cherry eye’s prognosis?
With surgical treatment performed by an ophthalmologist the prognosis is good. In some cases (up to 20%) additional surgery may be required, thus making it that much more important to have a skilled person doing the surgery from the beginning. Untreated cherry eye can eventually damage the cornea, affect vision, and become painful for the pet.