Keratoconjunctivitis sicca (KCS), or dry eye, is common in dogs and can also affect cats. KCS is caused by a problem with the quantity or quality of the tear film. The condition is uncomfortable and can cause blindness. For most patients, KCS is managed with lifelong eye medication.
 
Causes
Tears are produced by glands in the eyelids and third eyelid. The tear film contains water, mucus, and oil. Deficiencies in any of the components of the tear film compromise its functions: lubricating the cornea (the clear structure at the front of the eye), removing debris, and providing nutrition to the cornea.
 
Anything that affects the tear-producing glands can cause KCS. Brachycephalic (flat-faced) animals with protruding eyes that aren’t completely covered by the eyelids also develop KCS symptoms because of excessive water evaporation from the surface of the cornea. These are some of the causes of KCS:

• Immune-mediated inflammation of the tear glands: the most common cause in dogs
• Infection
• Congenital problems with tear gland structure
• Problems with the nerve supply to the eye
• Trauma to the eye
• Endocrine disorders like diabetes and hypothyroidism
• Drug toxicity
• Genetics: dog breeds at higher risk include Cavalier King Charles spaniels, cocker spaniels, English bulldogs, Lhasa apsos, shih tzus, and West Highland white terriers

 
Signs
Animals with KCS typically have thick, sticky eye discharge. The discharge is thick because the watery part of the tear film is decreased or absent, so the tear film that remains is made mostly of mucus and oil. Either 1 or both eyes are affected, depending on the cause of the KCS.
 
Tear film deficiencies increase the risk for corneal ulcers, long-term damage to the cornea, and impaired healing of the cornea. These are signs of KCS and the resulting corneal damage:

• Thick white or yellow eye discharge
• Red eye
• Squinting
• Dark discoloration of the cornea
• Blindness (from corneal damage)

 
Diagnosis
The tear film quantity is measured with the Schirmer tear test, in which a sterile paper strip with measurement markings is placed inside the lower eyelid for 1 minute. The distance that the tear film is absorbed along the strip shows whether the animal has low tear production. Veterinary ophthalmologists use other tests to find out whether a patient has a problem with tear film quality.
 
Treatment
Animals with KCS are treated with a combination of eye medications, most of which need to be applied 2 or 3 times a day. Medications include tear stimulants that reduce immune-mediated inflammation, tear replacements to lubricate the eye, and other medications to treat corneal damage. KCS can be managed but not cured, so medical treatment needs to continue for the rest of the animal’s life.
 
For animals whose KCS doesn’t respond to eye medication, a few surgical options are available. The most common of these is parotid duct transposition, which involves rerouting a salivary duct from the mouth to the inside of the lower eyelid so the animal basically drools onto the eye. This procedure is performed by a veterinary ophthalmologist.
 
Image source: Jennifer Shishmanian on Unsplash

Dogs and cats need regular dental care, including thorough oral exams and dental cleanings. These procedures are best done under general anesthesia, but some pets don’t receive the dental care they need because their owners are worried about the safety of anesthesia. Most animals handle anesthesia well, though, and the risk is greatly reduced with preanesthetic testing, safe anesthetic drugs, and monitoring during the procedure.
 
Reasons for Dental Anesthesia
General anesthesia during a dental procedure allows for better medical care, reduces an animal’s stress and pain, and makes the procedure safer for everyone.

• Visible tartar isn’t the only reason to perform a dental cleaning. The most serious dental problems happen under the gums. The only way to know if a pet has a problem like a root abscess or periodontal disease is to examine all surfaces of all teeth, probe the pockets around the tooth roots, and ideally obtain dental radiographs—none of which is possible in an awake animal.
• A thorough dental cleaning requires scraping underneath the gums with either a hand scaler (a sharp metal object) or an ultrasonic scaler (a powered instrument that sprays water and makes a whining noise). A high-speed polisher, which also makes a noise, smoothes out tiny grooves that the scaling instrument leaves in the tooth enamel. A pet under anesthesia sleeps comfortably through all of this.
• An animal’s head needs to stay still during a dental cleaning. No awake animal can hold their head still when a scaler touches a painful area of gingivitis.
• During anesthesia, the endotracheal tube (tube placed into the trachea to deliver anesthetic gas and oxygen) prevents water and debris from getting into the lungs.

 
Anesthesia Safety
Before an animal undergoes anesthesia, the benefits of the procedure are weighed against the possible risks. Although general anesthesia is safe overall, its risks range from minor drug effects that can be anticipated and managed to potentially fatal complications, which are rare.
 
Animals receive a thorough physical exam before anesthesia and might also have preanesthetic laboratory tests. Preanesthetic tests are especially important for senior animals—the age group most often having dental procedures—because liver, kidney, and heart function all affect anesthesia risk.
 
During the procedure, vital signs like heart rate, respiratory rate, blood oxygen saturation, and blood pressure are monitored. The patient’s level of anesthesia is also monitored and can be adjusted as needed.
 
If your pet will be having anesthesia, tell the veterinarian all of the medications and supplements your pet is getting at home. Your veterinarian will also need to know if your pet has ever had problems with anesthesia in the past. If your pet has been to more than one clinic, be sure the anesthetizing veterinarian has your pet’s complete medical records and knows of any history of breathing trouble, heart conditions, seizures, or other medical problems.
 
Problems With Anesthesia-Free Dental Scaling
Some places offer dental scaling without anesthesia, but this procedure isn’t in an animal’s best interest.

• Dogs and cats can’t keep still during an oral examination and don’t understand why someone is poking their gums with a metal instrument.
• The degree of restraint needed to keep an awake animal’s head still (while using a pointy object in the mouth) can be stressful and frightening for the animal.
• Tooth scaling can hurt, especially for an animal with gingivitis.
• Scraping visible tartar from the teeth is cosmetic only and doesn’t treat disease under the gums.
• Without anesthesia, periodontal disease and other painful dental problems go undiagnosed and untreated.
• Scaling leaves grooves in the enamel that collect bacteria and plaque. A powered dental polisher is needed to smooth out the grooves; brushing with a toothbrush isn’t enough.

 
Photo by mahyar mirghasemi on Unsplash