Keratitis and Keratoconjunctivitis in Pigs: Cloudy Eye Causes & Care

Keratitis is inflammation of the cornea, the clear front surface of the eye. Keratoconjunctivitis means the inflammation involves both the cornea and the conjunctiva, the pink tissues lining the eyelids and covering part of the eye. In pigs, either problem can make the eye look cloudy or bluish, and both can be painful.

This is not one single disease with one single cause. Instead, it is a description of what the eye is doing in response to irritation, injury, infection, or surface damage. Some pigs have mild redness and tearing. Others develop a corneal ulcer, thick discharge, marked squinting, or reduced vision.

Because the cornea is delicate, eye surface disease can change quickly. A pig that seemed mildly irritated in the morning may look much worse later the same day if an ulcer deepens or infection takes hold. That is why a cloudy eye should be treated as a prompt veterinary problem, even when your pig is still eating and acting fairly normal.

The good news is that many pigs improve well when the cause is identified early and treatment matches the severity of the eye changes. Your vet can help decide whether conservative care, standard treatment, or more advanced eye support makes the most sense for your pig and your situation.

In pigs, cloudy eye and eye surface inflammation often start with irritation or trauma. Dusty bedding, rough straw ends, hay stems, feed particles, fighting, or rubbing the face on fencing can scratch the cornea. Once the surface is damaged, bacteria can take advantage of that injury and make the problem worse.

Infectious causes also matter. Merck notes that Chlamydia suis infections are endemic in domestic pigs worldwide and can cause conjunctivitis. Chlamydial conjunctivitis can involve the eye and may occasionally be accompanied by upper respiratory signs. Other bacterial infections may occur secondarily, especially when pigs are stressed, housed in poor air quality, or dealing with other illness.

Environmental stress plays a big role. Ammonia buildup, poor ventilation, overcrowding, and dusty housing can all irritate the eyes and make infection more likely. Young pigs and pigs in group housing may be more likely to spread infectious eye disease through close contact and contaminated surfaces.

Less common causes include eyelid abnormalities, foreign material trapped under the eyelid, tear film problems, or deeper eye disease that only looks like a surface problem at first. That is one reason home treatment without an exam can backfire. Different causes can look similar from the outside, but they do not always need the same care.

Your vet will start with a full history and a close eye exam. They will want to know when the cloudiness started, whether one or both eyes are affected, what bedding your pig uses, whether there has been dust, fighting, recent transport, or illness in other pigs, and whether any eye products were already used.

A careful ophthalmic exam usually includes checking the eyelids, conjunctiva, cornea, and the type of discharge present. Fluorescein stain is especially important when an ulcer is possible. This dye sticks to damaged corneal tissue and helps your vet see whether the cornea has been scratched or ulcerated. In many veterinary species, fluorescein staining is a standard first-line test for painful cloudy eyes and corneal ulcers.

If infection is suspected, your vet may collect an eye swab for cytology, culture, or targeted testing. That can be useful in recurrent cases, herd problems, or eyes that are not improving as expected. Diagnostic laboratories in the US commonly offer ocular susceptibility testing, which can help guide antibiotic selection when routine treatment is not enough.

Some pigs need sedation for a safe and complete exam, especially if the eye is very painful or the pig is difficult to restrain. Your vet may also look for herd-level contributors such as ventilation issues, ammonia, dust load, or contagious disease patterns, because treating one eye without addressing the environment can lead to relapse.

Prevention starts with the environment. Keep housing as low-dust as possible, improve airflow, and reduce ammonia buildup from urine and manure. Clean, dry bedding matters. So does avoiding sharp or irritating materials that can poke the eye. If you use straw or hay, check quality and dust level closely.

Group management also helps. Overcrowding increases stress, contact spread, and the chance of rubbing, fighting, or contaminated secretions moving from pig to pig. Watch newly introduced pigs carefully, and isolate animals with active eye discharge until your vet advises otherwise.

Routine observation is one of the best tools a pet parent or caretaker has. Catching mild tearing, redness, or squinting early can prevent a small irritation from becoming a painful ulcer. In herd settings, note whether several pigs are affected, because that pattern may point toward ventilation problems or infectious disease rather than a one-off injury.

Do not use leftover eye medications or human eye drops unless your vet specifically says they are appropriate. Some eye products are unsafe when a corneal ulcer is present. Prompt veterinary guidance, paired with cleaner housing and lower eye irritation, gives pigs the best chance of avoiding repeat problems.