Dry Eye (Keratoconjunctivitis Sicca) in Cats

Key Takeaways

Keratoconjunctivitis sicca (KCS) is commonly called ‘dry eye’ because it’s caused by a lack of water in the tears. Without watery tears, the surface of the eye dries out and irritants cannot be flushed away. 

• KCS may lead to ocular scarring, and can result in blindness

• The cause of KCS is not always known, although feline herpesvirus (FHV) is a common cause

• Subtle symptoms sometimes mimic other ocular conditions, making an early ophthalmic exam important in order to properly identify the condition

• Treatment targets the underlying condition responsible for KCS along with eye drops, antibiotics, and other medications as needed

• KCS is often lifelong, although cases associated with FHV may resolve

• The prognosis is usually positive because cat eyes are more tolerant of drying out and are less likely to develop pigment and scarring compared to other species

A Closer Look: What is Dry Eye in Cats?

KCS is a rare condition in cats, and symptoms overlap with other, more common ocular conditions, such as conjunctivitis, eye injuries, or a foreign body. Prompt veterinary attention is needed for all signs of eye disease to ensure proper diagnosis before ulcers, permanent scarring, or vision loss occurs.

Since KCS is commonly caused by FHV infection, additional symptoms include nasal discharge, sneezing, lethargy, and appetite loss.

Risk Factors

Severe cases where KCS has resulted in extensive scarring may present with impaired vision or blindness. This can manifest by way of the cat bumping into things, or having difficulty navigating different heights (such as stairs).

Complications may occur, especially if the cat is difficult to medicate. KSC can result in loss of vision, chronic pain, and in severe cases loss of the eye.

Possible Causes

The cause of KCS is often unknown. Numerous factors can temporarily reduce tear production, such as side effects of medication or sedatives, systemic illnesses, or stress, which complicates diagnosis. The most common identifiable cause for cats is herpesvirus infection (FHV). 

Other causes of feline KCS include

• Thermal or chemical burns

• Bacterial infections

• Surgeries or injuries where the lacrimal gland is removed or damaged 

• Congenital abnormalities

• Neurogenic dysfunction

• Radiation therapy

Main Symptoms

In most cases the condition remains mild and asymptomatic.

Otherwise, symptoms include

• Mucus production from the eyes

• Conjunctival (tissue lining surface of eye and inner eyelid) inflammation

Excessive blinking and squinting (blepharospasm)

Elevation of the third eyelid  

• Scarring or cloudiness of the cornea 

• Dull, dry appearance to the eyes (instead of shiny and wet)

Testing and Diagnosis

A Schirmer tear test measures tear production and confirms the diagnosis. Affected cats typically undergo a complete physical and ophthalmologic exam as well as blood work to identify any underlying causes.

Steps to Recovery

The goal of treatment for KCS is to stimulate tear production and replace the lost tear film. If the underlying condition which triggered it can be identified, treatment for that may be all that is needed for symptoms to resolve. 

Topical antibiotics are commonly used, as are moisturizing eye drops. Artificial tear ointments help moisten the eye, although they are not an appropriate substitute for normal tear production. Surgical intervention may be required.

The prognosis and duration of KCS primarily depends on the underlying condition which triggered it. Some cases of FHV-associated KCS resolve when appropriate anti-herpesvirus therapy is initiated. 

The condition may last a lifetime, with treatment focused on symptomatic management. 

Return visits to the vet with multiple follow-ups may be required in the weeks and months following treatment, to monitor recovery.


Regular wellness exams for early identification and treatment of conditions that lead to KCS are the most reliable way to avoid serious cases and prevent complications which lead to more severe damage. KCS is not contagious.

Is Dry Eye Common in Cats?

KCS is rare in cats.

Typical Treatment

• Treatment for the underlying condition

• Topical cyclosporine (immune suppressing eye drops)

• Topical antibiotics 

• Artificial tear ointments 

• Surgery

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