Eosinophilic Keratitis: An Uncommon Cat Eye Condition

Just like in humans, cats can develop rare and odd conditions that you don’t commonly hear about. I shouldn’t have been surprised when the most dramatic cat in my pride, Dolly, developed a weird eye condition. Let’s take a look at eosinophilic keratitis – pronounced e-oh-sin-oh-feel-ick care-ah-tight-iss.

Eye Spy: Cloudy Spot

While petting my cat Dolly, and noticed a cloudy spot on her iris, right where the white starts. My #1 concern with eyes is always corneal ulcers because they are painful and require treatment. They present as a tiny raised dot. I was relieved I didn’t see a dot on Dolly’s eye, so I decided to give it a day and see if the cloudy spot went away. The following day, it was actually worse, and I saw red blood vessels (corneal vascularization) around the cloudy spot. Having only seen blood vessel on the cornea with corneal ulcers, I was very concerned she had one that I couldn’t see. I took her to the vet.

They grabbed a few cells from the eye and checked it under a microscope, which showed eosinophils (type of white blood cell). The diagnosis was eosinophilic keratitis aka an inflamed cornea, a condition only found in cats and horses. Since she recently had a feline herpes flare up (kitty cold), her amazing vet, Dr. Morgan Shafer, said it was likely from that.

What Causes Eosinophilic Keratitis?

In all honesty, the condition isn’t fully understood, and there can be a handful of different causes. Let’s discuss what they think happened with Dolly because her circumstances are the most common.

Felines produce more eosinophils when they’re sick – it’s part of the the body’s immune system response. Dolly had a kitty cold a few weeks before the spot appeared.We treated her with antivirals and her cold cleared.

Some cats like Dolly have eosinophils that decide to throw a party in the white part of the eye (called the sclera). As word spreads and more eosinophils show up, the drinks flow fast. Next the party moves to the cornea (clear front part of eye), where they set up beer pong tournaments. Having such a good time, they invite more friends, causing a fluid build up that results in a cloudy spot.

The location of party spot can vary. Although Dolly’s seemed concentrated on the cornea, some cats also get it on the membrane coating of the eye (conjunctiva). An inflammation of the cornea AND the conjunctiva is called eosinophilic keratoconjunctivitis.

Although eosinophilic keratitis can lead to visual impairment, we caught it very early. The treatment was simple: two different eye drops for two weeks. The first drop was an antibiotic to prevent a secondary bacterial infection (erythromycin). The second drop was a steroid to take down the inflammation (tobramycin). Within a day, the cops showed up and started kicking eosinophils out, and within a few days, they had all left the building.

Keep an Eye Out – Pun Intended

As I mentioned, this isn’t a common condition, but I think it’s worth knowing it exists. Because the feline herpes virus is always in your cat’s system, kitty colds can break through at any time. Even after your cat is feeling better, remain observant for a few weeks to make sure their immune system doesn’t throw a party in one of their eyes. Also, there are other diseases that can cause cloudiness – eosinophilic keratitis is just one. If you notice anything off with your kitty’s eyes, make an appointment with your vet.

Speaking of parties, you know the opposite of a party? Feline dental disease. Learn about different conditions affecting your kitty’s mouth in my post Foster Diary: The Curious Case of Sir Buttons’ Teeth.