Eye problems in dogs are common. Symptoms vary and may include eye redness, swelling, change in color, discharge changing from yellow to green or white, and a change in consistency of eye discharge. Eyes may appear painful with light sensitivity and reluctance to open. The eyelids may have crust and discharge, and in severe cases be stuck together. Protrusion of the third eyelid from the corner of the eye may also occur. Changes in pupil size from constriction to dilation may occur in many inner eye diseases. Cloudiness may also accompany many cornea and inner eye diseases. If any of these eye symptoms develop in your dog, it is important to have a thorough ophthalmologic exam as soon as possible, because undiagnosed and untreated eye diseases can lead to vision impairment or blindness.

Dry eye (KCS in dogs)
Dry eye (KCS in dogs) is a disorder of the eye glands that produce the liquid part of tears. Dogs with KCS don't produce enough tear film to keep their eyes adequately lubricated. This causes a dog's cornea and conjunctiva to become dry, thickened, red, irritated and inflamed. If not diagnosed and managed, KCS can lead to painful corneal ulceration, eye infection, impaired vision, and even blindness. In most cases, the cause of KCS in dogs is unknown, but an autoimmune condition is believed to take place. KCS may also occur secondary to general anesthesia, trauma, and prior surgical removal of the third eyelid gland. The use of antibiotics and many diseases like hypothyroidism, canine distemper, Cushing's Disease, Addison's Disease, and diabetes may also play a role in KCS. Signs of KCS include excessive squinting or blinking, light sensitivity, eye redness, swollen inflamed eyelids, protrusion of the third eyelid, dull dry cornea, or thick yellow or green discharge. Definitive diagnosis requires a veterinary exam. While various over-the-counter products can be used to lubricate the eyes, including LiquiTears and Puralube Vet Ointment, a medication that requires a prescription from a veterinarian such as Optimmune is best for treating this condition.

Conjunctivitis (pink eye)
The conjunctiva is the delicate membrane that lines the inner surface of the eyelids and covers the outer layer of the eye. When it becomes inflamed or infected, it often leads to what is commonly known as pink eye. Conjunctivitis is the most common eye problem in dogs, and it usually heals without complication if properly treated. If left untreated, it may spread to deeper areas of the eye. Symptoms include red, inflamed eyelids stuck together, and/or thick yellow discharge from the affected eye. Conjunctivitis can have many causes from irritants/allergies (grass, trees, dander, ragweed, mold, pollens) to fungal, viral, and bacterial infections. Canine Distemper is another common cause of secondary conjunctivitis in dogs. While it is difficult to prevent conjunctivitis, in most cases, topical antibiotics will provide a cure. Allergy medication, low allergy diets (when given long term), and fatty acids may also help.

Glaucoma
Glaucoma results when fluid in the eye is produced faster than it can be removed, or there is a blockage to drainage of the fluid. This can lead to optic nerve and retinal damage, and subsequent vision loss. Primary glaucoma is a genetic dog disease that may affect certain breeds such as Beagles and Cocker Spaniels more frequently. Usually the second eye becomes affected within two years of diagnosis of the first eye. Secondary glaucoma is often the result of another eye disease, including uveitis (inflammation of the inner eye), dislocation of the lens, and trauma.
Glaucoma may be acute or chronic. Acute glaucoma results in a sudden painful, tearing and squinting eye, which may appear harder than the normal eye and have a fixed, dilated pupil. This is considered a medical emergency, and immediate diagnosis and therapy is needed to decrease eye pressure and save your dog's vision. This is also one of the main reasons why any dog with a painful, red eye should always have a veterinary exam as soon as possible. For acute glaucoma, Mannitol is typically recommended, available only in the veterinary setting. Other treatments include Timolol, Dorzolamide HCl, Pilocarpine Solution and Methazolamide.
In chronic glaucoma, enlargement and protrusion of the eyeball may occur, which is often harder and more tender than the other eye. Eyes with chronic glaucoma often have no vision, so surgical removal is often needed. Diagnosis of glaucoma is only possible through an ophthalmologic exam, and regular eye exams are the only way to prevent glaucoma. These exams are especially important for the breeds with a predisposition to glaucoma.

Corneal ulceration
A common eye disease in dogs, corneal ulceration is defined as a scratch or break in the cornea. This may occur secondary to trauma, infections, and less commonly as a result of an inner eye disease. Corneal ulceration is seen more in dog breeds with protruding eyes, such as the Pekinese and Shih Tzu breeds. Symptoms include holding the eye closed, light sensitivity, redness, eye discharge, and sometimes clouding of the cornea. Diagnosis is typically made by a physical exam, but definitive diagnosis requires veterinary application of fluoroscein dye. Topical antibiotics are used to treat corneal ulceration. In serious cases, or those that are non-responsive to topical antibiotics, surgery may be needed.