Surgical correction of entropion is commonly recommended in private clinical practice. This surgery may be necessary to permanently alter the shape of the eyelids. In certain breeds such as the Shar Pei, a procedure called an “eye tack” is performed. This procedure literally “tacks” the eyelid up and out of the way of the cornea. This procedure may be done without anesthesia in three week old or slightly older on Shar Pei puppies.
A suture (Vicryl or PDS) is passed through the tissue close to the eyelid margin. Then the same suture is used to take another “bite” dorsal to the first one higher on the eyelid. The suture is then tightened to “gather” the eyelid and rotate the free margin of the eyelid away from the cornea. There may be two or three sutures placed for each upper and lower eyelid. The sutures are not usually removed. As the puppy grows the sutures will form fibrous tracts which can permanently fix the eyelids in a normal position.
This procedure may also be employed in animals that have temporary entropion secondary to a corneal ulcer. This blepharospastic entropion is also treated with the “eye-tuck” procedure until the corneal ulcer is cured. Other breeds may also use this technique until the animal has reached adult size. Too early surgical correction of entropion may result in need to perform the surgery again later in life. The surgical procedure of removing an elliptical or moon-shaped wedge of tissue close to they eyelid margin as shown in the accompanying illustration is commonly done. The wedge of skin that is removed may vary in shape and location depending on the degree of correction needed. More recently, laser has been used to contract the collagen of the eyelid, thereby “rolling” the eyelid outward without surgical removal of tissue.
A sty in the eye is the presence of an infected or impacted gland of the eyelid. This causes a painful swelling on the margin of the eyelid. Medical therapy is usually effective in lessening the signs in most animals and curing some animals. In pets which the sty persists despite medical therapy, surgical lancing is performed. Manual expression is also commonly done but has a risk of internal expulsion of the glandular material into the tissues of the eyelid, worsening the inflammation.
The conjunctiva is the pink glistening tissue that surrounds the eye and lines the eyelids. Conjunctivitis is the term we use for inflammation of the conjunctiva. Conjunctivitis may be caused by infections with virus or bacteria or by irritants such as sprays, shampoo, or smoke. Conjunctivitis may also occur when the rest of the eye is ill such as with a corneal ulcer or glaucoma. The most common form of conjunctivitis in cats is caused by a virus infection – Feline Viral Rhinotracheitis (herpes virus). Feline Viral Rhinotracheitis is very common in cats causing excessive tearing and discharge as well as blepharospasm ( holding the eye shut because of pain). In dogs, common causes of conjunctivitis include, ectropion, exposure to irritants while hunting or running, and bacterial infections. Conjunctivitis is usually treated with antibiotic/steriod combinations assuming a corneal ulcer is not present.
Dry eye is a very common – special form of conjunctivitis caused by lack of tear production. This condition is very common in dogs.
As mentioned earlier, the cornea is “fed” by tears. If there is inadequate tear production, the eyes and the surrounding membranes become inflamed. This condition has two common predisposing causes. One is “cherry eye” surgery. Cherry eye is a common condition affecting the third eyelid of young dogs which is described below. Improper surgical removal of the gland of the third eyelid in order to correct “cherry eye” is a relative common cause of keratoconjunctivitis sicca (KCS). Another predisposing cause is exophthalmus. “Buggy eye” dogs such as Boston terriers, Lhasa apso and shi tzu seem to develop poor tear production late in life. This may be due to the shape and exposure of the eye which require excessive tear production (above that which is possible) or through exposure and subsequent immune system destruction of the tear glands. Regardless of the cause KCS is a common disease that requires early diagnosis and aggressive therapy to prevent blindness. Without tears the cornea will develop a black pigment that will prevent vision. The irritated conjunctiva will produce a thick yellow pasty discharge that almost appears as excessive tears. This discharge however is mostly pus in response to the severe inflammation of the eye. Diagnosis of KCS is usually done with a Schirmer Tear Test. This test uses a filter paper which is placed in the eye to soak up tears. The amount of tears soaked up in one minute is measured on the filter paper test strip. Normal dogs will have a value of 15 to 20 on this test whereas abnormal dogs will have a value of less that 10. This illness is usually caused by an immune reaction to the tear glands which can be treated by the administration of cyclosporine. Cyclosporine is a drug which turns lymphocytes off and was first used in transplant patients to prevent rejection. It is now the mainstay of KCS therapy. Other more traditional therapies can be helpful. Artificial tears provide soothing lubrication to the dry eye. Antibiotic opthalmic solutions are indicated as initial therapy to help control infections. Mucomyst is used in some solutions to break down the thick secretions produced by these inflamed eyes. Pilocarpine is a substance that will cause tearing in normal dogs and has been used in opthalmic preparation as well as given in the food to increase tear production. Most clinics develop their own “KCS” solution which is usually a combination of the above and use this along with cyclosporine to treat these pets. About 75% can be well managed with diligent care by the owner but some will not respond or cannot be easily medicated. These pets are candidates for surgical salivary duct transposition. The parotid salivary duct opens into the mouth at the level of the upper fourth pre-molar tooth. This duct is moved into the conjunctiva of the lower eyelid. The saliva now becomes the tears.