Cat Keratitis Treatment: are steroid eye drops best? (CTV #36)

Make no mistake, if your dog or cat has a problem with their eye then it can go from being a minor inconvenience or irritation to something really serious within a day or two. It could even result in permanent blindness or loss of the eye.

You definitely want to make sure that they are being given the right treatment for keratitis or any other form of eye disease!

 
treating keratitis in cats - are steroids the right thing for a cat with a cloudy eye?
 
My cat was given steroid eye drops for keratitis. Was this appropriate?
— Marcy
  • Keratitis is an inflammation of the surface of the eye - the cornea. There are 2 main categories: ulcerative and non-ulcerative

  • Keratitis in cats is most often caused by infection with herpesvirus, but can also be due to other causes including trauma, irritation, immune system dysfunction, increased intraocular pressure (glaucoma), and dry eye

  • The surface of the eye becomes pink/white/chalky with raised lesions, you may also notice new blood vessels growing over the eye

  • So long as no ulceration of cornea then steroid drops are the most common treatment of keratitis in cats, although this will depend on your cat’s history and the suspected underlying keratitis cause.

    • If a corneal ulcer is present - something your vet will check using fluorescein stain - then antibiotics will be given first to allow the eye ulcer to heal

    • Additional treatment may be needed alongside the steroid eye drop. These can include oral or injectible steroids and antiviral medication

  • Treatment may be needed lifelong. Once a cat has herpesvirus then it is often with them for life and may cause a permanent or intermittent keratitis (as well as other problems)

  • If your cat is receiving steroid eye drops and any discharge is geting worse or their eye becoming painful then stop the medication and get your cat’s eye checked over straight away. If an ulcer is present and steroid eye drops are continues then it is possible for a deep ulcer to form that can then burst

+ Full Transcript

Let's jump into today's question, which was asked by Marcy who wrote in to say my cat was given steroid eye drops for keratitis. Was this appropriate?

So to answer that question, we've got to think of what keratitis is. So it's actually inflammation of the surface of the eye or the cornea, which is the clear bit that you're looking through, or light is passing through if you like.

And keratitis can be caused by a number of different things. So in cats, very often there is an underlying herpes virus infection. And what happens here is that keratitis is actually due to an immune reaction to this virus rather than an infection as such. And that causes that cloudiness and the discoloration that you'll see in the normally clear surface of the eye.

But there are other causes as well as herpes virus for keratitis. And that can be things like trauma, so knocked to the eye. It can be irritation. So just something's got into the eye, it's kind of scratched or it's a chemical and is irritated. An immune system dysfunction can cause keratitis. So a little bit like the keratitis with herpes virus is due to the immune system kind of depositing complexes, that are opaque rather than clear.

Similarly, the immune system can dysfunction. Now that's more of a thing in dogs. I'm thinking German shepherds in particular, but certainly can be something that we see in cats. And then other causes can be an increase in the pressure within the eyes, so we call that the intraocular pressure and that results in something called a glaucoma, which is an increase in that intraocular pressure.

Dry eye is also another potential cause, again, that's more of a dog problem, but that's where the tear production isn't quite as much as it needs to be. So the eye becomes dry, that becomes irritating and scratchy. If you wear contact lenses for example, and your eye gets dry, then you'll know what that feels like and that can cause this inflammation within the cornea that then results in this keratitis.

So what you're going to see if your cat does have keratitis. So there's two forms than I guess the form that I suspect that Marcy's cat has is something called a non-ulcerative keratitis. And what you'll see in these cases that the surface of the eye, it's going to become kind of pink and white. You might get chalky, kind of raised lesions.

You may also notice new blood vessels growing over that opaque cornea. And that's the body's attempt to heal, to kind of bring all of the good inflammatory cells and good, all the healing chemicals that are needed to try and sort out that problem. So those blood vessels are actually a sign that the body is responding, but in keratitis that can, they can overgrow and they can become part of the problem as well.

So are steroid drops appropriate for this?

Well, the bottom line is yes, it depends on the underlying cause. But so long as there's no ulceration of the cornea, then steroid drops are absolutely appropriate and they are the most common treatment given.

So you'll have noticed that when I was talking about the causes that a lot of it is due to the immune system kind of overreacting or a dysfunction of the immune system. And what steroids do, amongst other things, they have anti-inflammatory properties and they especially could at dampening down and reducing an excessive immune response.

So an example of that would be allergies as well or allergic skin disease where steroid medication was, used to be the kind of the number one treatment that we use. There are different drugs that we use for that now, but it did a great job and it still does a great job.

So yeah, depending on the underlying cause is whether the steroid eye drops are going to be used alone or whether there's going to be other treatment needed, and that other treatment might be oral or injectable steroids.

If the topical treatment, the eye drops aren't having as good enough effect as we would like. It could be antiviral medication for example. If we think that there's a herpes virus and again the steroid eye drops aren't doing the job or they might be other medication that's needed. Tear replacers, a whole load of different things depending on the underlying cause.

So like I say, that is as long as there is no ulcer present and the way to determine that, the way your vet is going to determine that is they going to put some stain in there. So it looks orange when it's applied to, that's a fluorescing stain. But when it's actually in the eye, it looks like a bright fluorescent green stain.

And what happens there is if there's a disruption to the surface of the eye to the surface of that cornea. So if there's an ulcer, then that stain actually sticks to it and shows it up really well.

You might think that an ulcer in the eye would be really easy to see just with your bare eyes. But actually they can be very subtle and really impossible to see without that staining.

So that staining is really important. Without that, I wouldn't be giving steroid eye drops because there is the potential that if an eye has an ulcer and steroids are given, then that also can get worse. It won't heal. The ulcer will become deeper and ultimately the eyeball can rupture.

So that is clearly something that's really serious. So if there is any hint of an ulcer then steroid eye drops aren't going to be used or certainly they're not going to be used initially when that ulcer is being supported in its healing. Some antibiotic, eye drops are going to be used instead. There might be another form of anti-inflammatory use. So a non-steroidal anti-inflammatory eye drop might be used and that's then going to be monitored to make sure it's improving really well.

And then it might be that once everything's healed up nicely, steroid eye drops might then be used depending on what the eyes looking like. So it's really important that we get the diagnosis right. The first step is to know whether there is an ulcer there or not. And then the second step is thinking what the underlying cause is.

Now, very often, if it's the first time that it's happened or it's happening really infrequently, we're actually just going to trial treat. So we'll start the steroid eye drops. If it's improving, fantastic. We don't need to do anything else.

If it's not improving, then you know, that's when we can maybe do other diagnostic tests or we can try different treatments. Times when that might not be appropriate is if things are really, really bad. And we're really keen to get that diagnosis first because it might make a huge difference.

Now if your cat or your dog is on steroid eye drops, then it's really important that you keep a close eye on their progress. So if the discharge is getting worse, if they're developing a thick discharge, if it's getting worse and it's consistency is becoming kind of thicker and pussy looking or if the eyes becoming painful itself.

So if the eye was open, but your dog or your cat has started to squint, they start to rub their eye, and it's becoming pretty uncomfortable, then you definitely want to stop those eye drops and get it checked out straight away because obviously the last thing we want to do is to keep going.

If there's an ulcer present, which could then get worse and could ultimately result in a rupture of that eyeball and a loss of that loss of sight and a loss of the eye, which is something that we clearly want to avoid.

Now, if that does happen, and occasionally that will happen with a really severe ulcer. If it's picked up too late, if it comes on really quickly or maybe say your cat goes missing for a few days when they come back. And that can happen really quickly.

So one thing with any kind of eye problem is that they can go from looking pretty mild, not too much of a problem to really severe over a day or two.

So it's very important that we get them checked out quickly. It's very important that we have regular checks to make sure that healing is progressing as we would like. And it's very important if there is any change, especially any detrimental change to your pet's eye that you get that checked rather than just waiting till maybe your next revisit appointment, which had been scheduled in a week's time. So definitely keep in touch with your vet.

And then if your cat does have keratitis that is caused by herpes virus, and herpes virus is something that's part of the cat flu complex, but it's also the same family of viruses that cause cold sores in us. And if you do suffer from cold sores then you know that once you've had a cold sore, then that herpes viruses with you for life and it will flare up at times of stress. And so that's the same thing with cats.

Once they've got a herpes virus, then very often they're going to have that for life. And that may mean that they're going to need ongoing management either permanently eye drops all the time or just at times of stress. You might need to start up that treatment again. While everything settles down


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