Exposure Keratitis in Cows

Exposure keratitis is inflammation and injury of the cornea that develops when the eye surface is not protected well enough by the eyelids and tear film. In practical terms, the cornea dries out, becomes irritated, and may then develop edema, scarring, or an ulcer. In cattle, this is usually not a primary disease by itself. It is more often a consequence of another problem that leaves the eye exposed.

The most common setup is lagophthalmos, which means the eyelids cannot close completely. Merck notes that lagophthalmos leaves the cornea vulnerable to drying and trauma, and corneal scarring, pigmentation, and ulceration can follow. In cattle, exposure keratitis may also occur when the globe protrudes forward because of orbital disease, or when facial nerve dysfunction reduces blinking and lid tone.

This condition can look similar to other eye problems, especially infectious bovine keratoconjunctivitis (pinkeye), because both can cause tearing, squinting, corneal cloudiness, and ulceration. That is why a hands-on eye exam by your vet is important. The treatment plan depends on whether the main issue is exposure, infection, trauma, cancer eye, or a combination of these problems.

The direct cause is corneal exposure. The cornea needs a smooth tear film and regular blinking to stay healthy. When the eyelids do not close normally, or the eye protrudes too far forward, the surface dries and becomes vulnerable to irritation, ulceration, and infection. Merck describes lagophthalmos as an inability to fully close the eyelids and protect the cornea from drying and trauma.

In cows, this can happen for several reasons. Facial nerve dysfunction can reduce blinking and lid tone. Trauma around the face or eye can distort the eyelids. Severe swelling, scarring, or eyelid defects can keep the lids from meeting. Orbital disease can also push the globe forward. Merck notes that cattle with orbital infiltration from lymphosarcoma may develop exophthalmos, reduced ocular mobility, exposure keratitis, and corneal ulceration.

Exposure keratitis may also develop alongside other eye conditions rather than alone. Corneal ulcers become more likely when there is an aggravating factor such as lagophthalmos, a foreign body, or infection. In cattle, your vet may also need to sort out whether infectious bovine keratoconjunctivitis, photosensitization, neoplasia, or trauma is contributing to what you are seeing.

Environmental stress can make a bad situation worse. Wind, dust, UV exposure, flies, and rough forage can all increase irritation once the cornea is already exposed. These factors may not be the root cause, but they can speed up ulcer formation and make healing slower.

Diagnosis starts with a careful eye exam and a look at how the eyelids move. Your vet will usually assess blinking, whether the lids close completely, the position of the globe, and whether there is facial asymmetry or nerve dysfunction. They will also look for clues that another disease is driving the exposure, such as trauma, swelling behind the eye, cancer eye, or severe conjunctival inflammation.

A fluorescein stain is commonly used to check for a corneal ulcer. VCA notes that this stain adheres to damaged corneal surface and highlights ulcers clearly. Your vet may also examine the cornea for edema, blood vessel growth, discharge, and depth of any ulcer. If the ulcer is deep, infected, or not healing as expected, additional testing such as cytology or culture may be recommended.

In cattle, diagnosis also means ruling out look-alike conditions. Merck describes infectious bovine keratoconjunctivitis as a common cause of tearing, blepharospasm, corneal opacity, and central corneal ulceration. Photosensitization can also cause epiphora, corneal edema, and blindness in cattle. If the eye is protruding, your vet may investigate orbital disease or neoplasia. The final diagnosis is often a combination of findings: exposure keratitis with or without secondary corneal ulceration, plus the underlying reason the eye is exposed.

Prevention focuses on protecting the cornea and catching eyelid or eye-position problems early. Watch for cows that are not blinking normally, have facial asymmetry, or seem unable to close one eye completely. Early tearing or squinting is worth a prompt call to your vet, because a dry cornea can ulcerate before the problem looks dramatic.

Good environmental management also helps. Reduce dust when possible, manage rough seed heads and irritating forage, and support fly control. Merck recommends controlling face flies as part of cattle eye health programs, and eye patches may help reduce exposure to flies and sunlight in selected cases. Shade access can also reduce light sensitivity and surface irritation while the eye heals.

Preventing the underlying causes matters too. Address trauma around gates, feeders, and trailers. Monitor cattle with periocular masses, severe swelling, or suspected cancer eye before the globe becomes exposed. If your herd has recurring eye disease, ask your vet whether pinkeye prevention, pasture management, fly control, and earlier treatment protocols could reduce secondary corneal damage.

Not every case is preventable, especially when exposure keratitis is caused by nerve injury or orbital disease. Still, fast recognition and early veterinary care usually create the best chance to protect comfort and preserve vision.