Hi everybody. Welcome to this webinar. My name is Riaholder and I'm a final year ophthalmology resident at the University of Edinburgh, with a background in, in equine, GP practise before I went down the ophthalmology route.

And today we're gonna be talking about the sore eye emergency, that you might get called to. And these are relatively common in, in GP equine practise and hopefully just make you guys a little bit more comfortable, going to these calls and not get that kind of sinking feeling when you see an eye case on your, on your diary. So, plan is, we're initially just going to chat about how you would approach these cases in terms of the examination, and I'll talk about a nerve block that's really easy to perform and will make your life a lot easier as well.

And then we'll go through. Some of the more common causes of a sore eye, in horses and how we can treat them. The main ones we're going to cover are corneal ulcers, uveitis, and eyelid lacerations.

And because of time restraints, obviously, we can't talk about every, cause of a sore eyes, but yeah, we'll, we'll focus on those ones. And as we go, I'll mention when it's probably more appropriate to to refer to an ophthalmologist or at least offer it to the owner. And then we'll finish off by just going over a few tips and tricks that I've picked up along the way that that might help you guys as well.

So just to mention, I'm not going to go over these conditions which can also show as a sore eye, just because we don't have time to go over everything, but just bear in mind that there are obviously other causes that might cause a horse to have a sore eye. So let's imagine you've got that call through. About a sore eye case, how urgent is this case?

How quickly do you have to see it? Well, it's not life-threatening. It's, it's probably urgent, but it's not emergent.

So I would tend to try and see it as soon as feasibly possible. But, you know, if it's a weekend and you've got a colic or a foaling as well, do all those first, you know, and I can wait, a little bit of time before you go and see it. Having said that, A lot of these sore eyes will be because of the cornea and damage to the cornea.

And the cornea is the most densely innervated tissue in the whole body. So if they've got, for example, a corneal ulcer, it can be really, really painful. So I would suggest, if you can't see it, maybe the same day, try and get some analgesia on board if the owner's got some on the, in, on the yard or in the stable, and see it as soon as you can the following day.

So I'd say ideally see it the same day, but if not the next day. And before you head out to it, I think it's really important with eye cases to make sure you've got everything you need. There's nothing worse than getting there and realising you don't have some key piece of equipment that you need.

And there's a few really useful things I would always have in my car when I went out to an eye case, which I'll just run through with you. So fluoresce stain is obviously really important, these little strips are great, but you can also get the teeny little minims, vials actually as a liquid. Either is totally fine.

Always need those if you go into a sore eye. Some form of a light source. I just used to use the same head torch I've used for dentals, really helpful, especially if you're going to look at a sore eye and it's, you know, the evening or, you know, in the middle of the night.

Really important also to have some form of a swab or this is called a cyto brush, where you can sample a lesion if you see it. So if you see something nasty on the cornea. These cyto brushes are really great because they pick up cells really nicely and you can make a really nice cytology slide with them.

And likewise, Some type of swab for a bacterial culture. We like these, these are called E swabs, and they've got this kind of special tip to them that show, well, there's a study out there that shows that they had a higher positive culture result when these were used compared to normal swabs, but any old swab will do really. Microscope slides for cytology, which I'll talk about later on.

Some form of topical local anaesthetic is really important. And again, it's just something that will make your life a little bit easier. Proxymetacaine is great, it's what we tend to use.

It does need to be kept cool though, so if you don't have a little fridge in your car, and you're probably better off going for something like tetraca, which doesn't need to stay cool. Some form of suture material, appropriate for eyelids is also great, and I appreciate not everyone will be able to get something like this, but 50 virall is perfect for eyelid lacerations. It's, it's small enough so that you can do a really unique job and you don't have these massive sutures from like 30 stuff, but it's not so small that you need magnification.

So here, we would usually use 60, but with that, you need, ideally, a pair of loops on your head. So 5 knot is great for ambulatory vets that don't have any magnification. A direct ophthalmoscope for the blue light, so you can fluoresce fluoresce and also look at fundus and things like that is pretty essential.

Atropine also really important, a lot of eye cases will need atropine. And then these little saline irripods are super, super helpful. I would get through loads of these.

They're basically 20 mL little irripods of, of saline. And they're just really great because it saves you having to dip in and out of a fluid bag and you can twist the top off and basically squirt them onto the eye and get a really decent amount of pressure, more than you would from just a syringe. So really good for kind of flushing out foreign bodies and things like that.

And finally, I'd always carry a subpalpibr lavage kit. I don't think this is something that everyone necessarily needs to take with you, but if you get comfortable placing these, they're really helpful in managing eye cases that maybe can't be referred, but are going to need quite ongoing, treatment. So we've got everything we need.

We've got the yard. What are we gonna do? I would always tend to sedate horses with eye pain, because you're going to have to get really close up to their heads, and you've often got some kit in your hand.

You need to look closely. It's just, it's safer for you. It makes it more bearable for the horse, you know, unless it's an absolute saint, I would, I would sedate it.

And if the horse is really painful, you will really struggle to open their eyelids, because their muscle of their eyelids, which is called the ubicularis oculi, is so much stronger than the muscles of our fingers and thumbs, so you just can't fight it if they're really painful. And that's when our nerve blocks come in really, really useful. So the main one that I would try and learn if, if, if you just want to learn one is the arriculop palpibral nerve block, and this is the one that's really gonna help you out.

So the eryculop palpibral nerve, it's a branch of the facial nerve, and it basically supplies motor innervation to that big albicularis oculi muscle that I was just mentioning. So if we desensitise this, we'll basically stop the horse from being able to clamp its eyes shut, which will mean that we'll be able to really easily open the lids and have a proper look without them fighting us. And it's really easy to perform and if you can get comfortable with this, I promise it will change your life.

So how do you find it? So above the eye, laterally, you've got this, you've got the kind of dorsal rim of your zygomatic arch kind of running backwards. Now, the, the neurovascular bundle that we're interested in kind of traverses over there.

And what you want to do is run your finger kind of up and down that dorsal rim of the zygomatic arch, and you'll actually feel the neurovascular bundle kind of flicking under your finger. So the yellow line in this is kind of dictating where that neurovascular bundle traverses across, finger up and down over that when you feel the little flick, that's what we're aiming for. And what you want to do is get a relatively small needle, like a 25 gauge one or, you know, blue or an orange.

Pop that subcutaneously in that area so that you're aiming for the tip of your needle to end where you can feel that little flicky bundle. So where that kind of yellow line is in this picture. And then hopefully when you deposit the local, it will go right over that bundle.

And you can use, you know, whatever anaesthetic you've got in your car and pica's fine, lidocaine's fine, just bear in mind that, you know, the lidocaine will wear off quicker. And you only need, well, technically, if you get it right in the, in the correct spot, 0.5 mil, but, you know, you can work 2 to 5 mL in there quite happily and, give it a rub, and after about 5 minutes, it should, it should work, and you should notice that top eyelids really floppy.

So I would highly recommend trying that. And once you've done a couple, you'll, you'll feel much more comfortable doing those. So once we've got the horse sedated, ideally blocked, use your light source just to assess for any really obvious damage that might potentially affect what you then do going forward.

So, for example, it's gonna be really obvious if the horse has an eyelid laceration or something, great, but what we want to check is the cornea, ideally. So, If the horse has got, for example, a corneal perforation or a really, really deep corneal ulcer, or a corneal foreign body, for example, this is an eye that we, we don't really want to be messing with too much. And actually, it might be that you take one look and you see something you like, OK, this is a referral job.

And I'll show you a couple of photos of ones that would, would fit into that category. So, this was a picture sent in by a referring vet. And as you can see on this side, it's really chemotic, it's thickened conjunctiva.

Pupil is tiny, pupil can't get much smaller than that's that's called meiosis, suggesting that there's some inflammation inside the eye or some uveitis. But importantly, we've got this little kind of yellowy cream coloured protuberance on that lateral aspect of the cornea there. And that's actually clotted aqueous humour, plugging a full thickness corneal perforation.

So, if you saw something like this, an acutely painful eye, marked uveitis and with some kind of protuberant, yellowy, creamy tissue, think corneal perforation. And what you don't want to be doing is poking that little clot, dislodging it, and then you'll get loads of aqueous humour flow out and it won't end well. So if you saw something like this, just stop, think about referral.

All you can do is offer, they might not want to, but at this point, if I saw this, yeah, ideally this needs surgery. Likewise, if you see something like this, it's a bit hard to appreciate from the photo, but this little lesion in the bottom right hand corner there was an obvious big old crater in this eye, and the horse was quite painful. Again, if you notice a really big defect in the eye, Especially with a clear base, think there's metocele.

So really, really deep ulcer. This eye could go pop if you start putting pressure on it. So again, if you see anything like this, just offer a referral, don't mess about.

And this one, that's what these guys did. And yeah, this one needed surgery. So Assuming you've done all of that and you can't see anything horrendously scary, fine, let's move on.

Let's fully assess the eye for what could be going on. I tend to start outside, work your way in. Obviously, your eyelids will be obvious, and then move on to your cornea.

Look if there's any opacities or any, any craters that maybe weren't quite obvious from from the offset, but when you have a good look with your light source, you can see some. And then just work your way in. As I've mentioned before, the pupil can tell you quite a lot.

So if we've got a really small pupil compared to the good pupil, that's called meiosis, and that's highly suggestive of some uveitis going on. And there's various kind of causes of uveitis which we'll come on to. On the other hand, if our pupil is really big or midriatic compared to the other eye, then we need to be thinking about things like, OK, could this horse maybe have glaucoma, or has this horse recently had atropine when my colleague was out to it last week and things like that.

And then you can kind of work your way back if you're worried about vision or blunt trauma or anything like that, get your direct ophthalmoscope out, have a look at the fundus and and the retina if you can. And then right at the end. I would apply your fluorescine stain, make sure you flush it a lot, just because you can get a false positives pooling and little defects and things like that if you don't, so a little bit of fluoresce, loads and loads of flush, and then have a look with the blue light.

And then once we've done all this, you should hopefully have a bit of an idea of what's causing this pain. If not, you'll have hopefully ruled out a lot of things. So you'll have ruled out things like trauma, external damage, causing lacerations, hopefully your foreign bodies have been ruled out, ulcers, uveitis, or is it something weird?

Moving on to those, we're just gonna go through 3 of the main causes of ocular pain and how we treat them. So starting with ulcerative keratiti, so basically corneal ulcers. Now we tend to divide these into the kind of simple or uncomplicated ones and the complicated ones, and your kind of approach and treatment to those will be slightly different.

So our uncomplicated ones, just diagnosed with fluorocene stain, you put your fluorine stain on, you flush it out, use your blue light and you'll see a big green area or a small green area, and that's, that's our ulcer. And the uncomplicated or simple ones are they're they're superficial. So they're only evolving those that top layer of the cornea, so you're not going to see an obvious crater.

They will usually be quite painful. And in horses, they're usually traumatic in origin, just horses sticking their heads in things or getting some shaving stuck in there and then that scrapes the cornea. But the key with these uncomplicated ones is there's very little other stuff going on.

So you'll have your ulcer and there might be a little bit of corneal edoema around it, which looks a bit bluey, cloudy, but you won't have any cellular infiltrate associated with it. So there'll be no yellow tinge to the cornea or kind of creamy tinge to the cornea. And that's really key.

So I'll just show you a few photos of simple corneal ulcers. So, as you can see here, this one, it's superficial. You know, I can't appreciate a crater.

There's a little bit of cloudiness around it, but the bulk of the cornea otherwise looks fine. Now, this one would be a classic one for having a foreign body behind your third eyelid, just because of the location of it. So just bear that in mind.

If you ever see ones quite immediately, always check behind the third eyelid. Another one. Again, pretty big ulcer at the top there, and then it's got a little one down the bottom, but really kind of crisp edges, really shallow.

Rest of the eye looks really unexciting. So that's a really nice case of a simple two ulcers, but they're both very simple and uncomplicated. And another one, big old ulcer in the bottom there, but really crisp and clean, bit of reflex uveitis there, I don't know if you can appreciate the pupils a little bit small, but no kind of yellow or kind of cream cellular infiltrate.

So what are we gonna do? Rule out an underlying cause. Foreign bodies really common in horses.

What I would do if you ever get a corneal ulcer, put a little bit of local anaesthetic on the eye, wash your hands, and actually use your like naked finger to have a feel behind the third eyelid and down in those conjunctival faunas up and above and just see if you can feel anything. It's amazing what you can find. And I say to use just your, your finger without a glove on, because if you have a glove on, you can miss little bits of grit and teeny little foreign bodies.

So yeah, just clean your hands and have a feel around. And the horse is usually really tolerant of it if it's got some local anaesthetic on it. Yeah, and always check behind the third eyelid, especially if that the ulcer is quite medial.

And with these uncomplicated ulcers, it's very common to get a degree of reflex uveitis. So with those ulcers, loads of little nerve endings are exposed and they're just getting stimulated, and then they get this reflex uveitis, which is quite painful and it results in the pupil clamping down. So how are we gonna treat these?

Well, do we need antibiotics for one? Well, technically, these are not infected with ulcers, they're just wounds on the surface of the eye caused by trauma. Now, probably a lot of these would heal without antibiotics, but the consequences of a corneal ulcer getting infected, worst case scenario can lead to the eye being removed.

So we would always start prophylactic antibiotics with any corneal ulcer. Which ones, well, so there was this really nice paper in 2011, which looked at the kind of normal conjunctital and ocular surface flora of healthy horses in the UK and they basically found that the majority of bugs that they found were sensitive to chlorophenacol, gentamicin, and tetracyclines. And if you think about it, the, the bugs that are going to cause the infection are these, you know, opportunistic, commensals.

So these are the ones that we are basically trying to protect these corneal ulcers against. So any of those are, are, are pretty decent choices, but we'll, we'll go on to how you can, if, if you've got an infected ulcer, which one. It is more appropriate.

But in the first instance, any of those, we tend to go with chlorophenacol. And there's a, there's a drop version and there's an ointment version. The eye drops we'd normally just use 4 times a day, whereas the, ointment, you can usually drop down to twice a day because it kind of hangs around on the corneal surface a bit longer.

Pain relief, super duper important. These are gonna be painful. So flinnexin down, whatever's easiest.

There's some relatively OK evidence that flinnexin is slightly better for ocular pain, and we do tend to prefer prefer flinexin. However, it's expensive and but does the job, but Fenixin is great, you know, if the owners are willing to pay for it. And then also some topical atropine.

The atropine will release that spasm inside the eye, and it will actually act as an analgesia as well. So that's, that would be our bog standard treatment for uncomplicated ulcer. So chlorophenacol, systemic NSAIDs, and atropine.

In terms of follow-up, I think it's really important to, to, to recheck these, even though they look straightforward, you just never know what they're going to do. So always go back, restain, and make sure it's healed before stopping all of your medications. Now, when to recheck is kind of dependent really on the size of the ulcer.

We know that that the cornea heals at about 0.6 to 1 millimetre per day in kind of ideal situation and circumstances. So from that, you can kind of guess how long it's going to take your corneal ulcer to heal based on how big it is.

I always find in equine practise, it's really useful as well to take photos of when you go out to these cases, especially if there's a chance that actually it will be your colleague going to recheck it in a week or two rather than you, because I think, you know, one person's 5 millimetre diameter can be another person's 10 millimetre in diameter. So, you know, take some photos after you've flues and stained it, upload them onto the horse's file. And I think, yeah, your colleagues will thank you for it.

And I always just warn owners that the atropine can have quite a long lasting effect, especially if there's not a high degree of inflammation inside the eye. And it's also something to bear in mind yourselves, you know, if you go back and recheck the eye a week later, but the pupil is still absolutely massive compared to the other eye, don't freak out. It's probably a good thing.

It means there's no more Uveitis. And just warn the owner that, you know, it's normal. So let's move on to the more complicated ones.

So these are the ones that might not be superficial, for example, so you've got an obvious crater in the eye. Or they look infiltrated or infected. Or they might be superficial and look similar to those ones before, but it's just not healing as expected, given that we know how quickly it should heal.

So if you've seen a superficial ulcer, you go back a week later and it's exactly the same. That's obviously not, not normal. Something else is going on.

Or you can have a combination of these that make it complicated. So I'll just show you a few photos of what we would class as a complicated ulcer and, and why. So this eye is obviously horrible.

We've got really marked chemosis and thickening of that conjunctiva. Lots of horrible discharge. Obviously, there's some fluoresce in it, but you can probably appreciate it looks a bit porulent and pus-like, in its appearance rather than clear.

And then on the cornea, we've got kind of diffuse corneal edoema, that's that bluey cloudiness, and then this horrible crater in the middle of the eye that has this yellowy cream-tinged fluffy edge around it. Now, that's the cellular infiltrate that I've mentioned a few times. So that's just packed, packed full of inflammatory cells, probably some bacteria as well.

So this is a nasty infected corneal ulcer. Another one, sorry, your photo is a little bit blurry, but you can probably appreciate here that again, we've got diffuse corneal changes. We've got lots of blood vessels growing across the eye, which shouldn't be there if this was a straightforward ulcer.

We've got a really uneven appearance to the surface of the eye as well. And then this is that same horse that I showed you earlier with the Desmatocele, but this is post-fluorocene staining. So you can probably appreciate how the sides of this crater are staining with fluoresce, but the base of it isn't taking up any stain at all.

So if you ever see that pattern of fluorocene staining, start to panic slightly, this eye is down to its last, last layer of cells and, and could perforate at any time. And yeah, this is the one that was referred in to us and this had a little graft placed over the defect and it did really well. And then this is one where, you know, we don't have a massive crater on the surface of the eye.

We don't have loads of cellular infiltrate either, but this also has been here for over 3 weeks and it's not made any progress. And you might be able to appreciate how we've got the outline of the defect, but we've got fluoroce stain that's kind of seeped under, so that's called underrunning. Which suggests that the edges of this ulcer are not kind of nicely adhered to the to the underlying stroma.

The blood in this photo is just because we placed a subalpy of our system, so don't worry about that. So what are we gonna do about these? First thing, if you find an infiltrated ulcer, any kind of yellowy creaminess, take some cytology.

So this is super helpful, it's super quick as well, and it will basically allow us to see if there's an infection there. Now you can do a cytology sample with those little cyto brushes that I showed you earlier, which are perfect for this. Or if you don't have them, because not everyone keeps those in the car, you can just use a sterile swab and rub the infiltrated area gently and then just roll your swab on a microscope slide.

And you can put local anaesthetic in before you do that. If you put loads of local anaesthetic in, it, it can be bactericidal, which obviously we don't want when we're taking a cytology sample, but a little bit of proxymecaine is totally fine, and I would do that because they will feel it. And then if you've got an in-house lab to do a quick cytology on the same day, rather than kind of send it off to wherever and then come back three days later, it will allow you to pick the most appropriate treatment.

So just to guide your kind of empirical choice. And it's, you know, we're not talking about fancy cytology here, it's really basic, but super helpful. So this is a spider brush.

Use it taking a sample from an infiltrated ulcer, and what you do with these is you just spin it over the area of infiltration and then yeah, just like you swab, you roll it on your microscope slide and just do a simple diff quick stain in-house if you've got it. If you don't, fine, send it off. It's just really nice to do this on the same day so that you can pick the appropriate antibiotic.

So this is an example of cytology that we did the other week. Now, this is, you can probably see these cells, there's, there's kind of 3 or 4 cells visible. These are typical corneal epithelial cells.

They look kind of like fried eggs. So if you see them on your slide, that's great. It means you've, you've sampled the right place.

So as you can probably see on this slide, we've got a few epithelial cells and then it's absolutely hooching in these kind of rods shaped bacteria. Now that's really useful and I'll come on to why in a second. If you were actually to see this kind of shaped bacteria, these are kind of cockeye shape, you know, more likely to be gramme positive, whereas your rods are more likely to be gramme negatives.

And then if you're lucky enough to see anything like this, these kind of linear but branching structures, these are fungal hyphae. So that would suggest you've got a fungal keratiti, which is bad news usually. So we've done our cytology.

If you're seeing loads of rods, like I said, that's most likely to be gramme negative, we would usually then go with gentamicin or something like afloxacin, because they have a better gram-negative spectrum. If, however, you were to see cockeye, they're more likely to be gramme positive and chlorophenacol has pretty good sensitivity to gramme positive, so we tend to reach for that if we see cockey. And then the fungal hyphae, if you see them, then you need to pretty much up the ante quite a lot and really start quite intensive treatment with voriconazole topically as many times a day as you possibly can or ideally refer because yeah, fungal keratiti can can go south really quickly.

All of these will have some degree of reflex uveitis, so give them some atropine as well. And you might actually need to give them atropine repeatedly if that pupil starts to come down again. So if you're not referring, you can teach the owner to monitor the size of the pupil by comparing it to the other side, and if it starts to get small, they can give some more atropine.

If the ulcer looks really gelatinous, or what we call malasic, where it looks like the surface of the eye is kind of melting off, serum or EDTA are really good because they help to stop, or at least slow down that melting that melting process. So the serum, obviously, you can just take that from the horse, spin it down, and leave it with the owner. EDTA you can make up just with some blood tubes and just get that in as often as you can and same with the antibiotics if if you've got an infection.

Systemic NSAIDs for pain relief obviously as well. And with these cases, I would warn the owner that it might be a very long arduous few weeks of treatment. Some of them even drag on for months, so they need to be committed if they're going to try and treat this, or obviously offer a referral if they're not keen, just warn them that, you know, this could go on a while until you're heading in the right direction.

And always offer referral if you feel out of your depth. Placing a sub puppy rule of our system, I think it's always a good idea in these complicated ones that you owner's not keen for a referral, you suspect it's going to need, you know, maybe a few weeks of treatment, because what happens is the horses just start getting absolutely fed up. They get head shy.

Compliance in terms of owner applying eye drops, drops, and then, you know, it's kind of a snowball effect from there. So, I would always try and offer placing a subpalpibrallavas system in ulcers that I just know aren't going to take, you know, a week to heal. Yeah, they're a few 100 quid, but if you place them early on in the disease process, it just, you know, they can stay in for weeks, and it means that you know that the meds are getting in and the horse isn't going to get more and more headshy throughout the whole process.

So if you can play one, do. I haven't got time to go into how to do it in this presentation, but there's loads of videos on YouTube, whether to put it in the upper or lower lid. It doesn't really matter.

I think Harry Karslake did a nice kind of metro analysis of it, and found no significant difference in terms of complication rates. I tend to place them in the lower lids, purely because if there is a complication, I find that they're easier to manage in the lower lid because you can see the foot plate when you put it in the lower lid, whereas in the upper lid, you can't, you can just feel it. But yeah, it, it really doesn't matter.

As long as you secure it tightly with sutures, the complication rates are the same. So moving. Past those kind of infected ones, and now moving on to those superficial ones, which, you know, they look OK, they're not too scary, but they're just not healing at that appropriate speed.

So these are usually just superficial, so just the epithelium is missing. They're not infected, so there's no horrible nasty infiltrate. You might see that underrunning of the fluoresce stain, which suggests there's some non-adherent epithelial margins around it.

And there was a nice paper in 2013 that looked at these superficial non-healing corneal ulcers in horses, and they did some histopathology on, on the samples, and they basically found that the majority of these had these epithelial cells next to the ulcer that just weren't stuck down to the basement membrane underneath. And it's interesting because in dogs, so these types of ulcers are really common in dogs, and we call them sked, box ulcers, basically, and they don't heal because they get this abnormal hyaline membrane forming, which basically prevents new cells sticking down to that basement membrane. But interestingly, only about 25% of the equine corneal, non-healing corneals had that abnormal membrane.

So we don't fully understand the pathogenesis of these in horses, but what we do know is we've got these non-adherent, epithelial cells. So how do we treat these? So these are the ones that we need to be thinking about debriding to get rid of those non-adherent epithelial edges and basically strip it all off, start from scratch and hopefully then kickstart the more normal healing process of the cornea.

And there's a couple of ways that you can do this debridement. We tend to use this little thing down the bottom there called the diamond burr. It's just a little handheld kit.

It's about 200 pounds, you can buy it on the internet, and that little metal ball at the end just rotates and you run that all over the ulcer, and that strips back all of those non-adherent edges. You can also just do it with a kind of sterile cotton tip, but you do have to be quite aggressive with your cotton tips and press quite hard and be quite rough. Whereas with the diamond bear, you just kind of gently rub it across and it's a really nice piece of kit.

If you do Do a debridement, make sure you sedate the horse, try and do that ariculop palpebral block that we went over. And just do a quick prep of the surface of the eye, just to make sure it's nice and clean. So I tend to make a 1 in 50 povidone iodine solution and then just slowly kind of trickle that over the eye for 3 minutes, making sure you're getting all down in the, in the lids as well.

After you've prepped it, I tend to place multiple drops of local anaesthetic, so proxymehacaine on over a minute, and that gives you a good amount of desensitisation of the cornea for you to then do your debridement. And what is really important with these is When you've done a debridement, don't be tempted to repeat the debridement too soon. So we know that it actually takes 2 to 3 weeks for that new layer of cells to not just grow across, but then also to Stick down to that layer underneath.

So if you saw this back a week after you, you burned it or, you know, used a cotton tip deridement, if you poke that with a cotton tip, you would disrupt all of the epithelium again and basically undo all of your good work. So, feel free to recheck it before 2 to 3 weeks, but don't attempt to debride it before that point. And there's a really nice paper in 2014 that had a look at the success rates of this, technique and 92% of non-healing corneal ulcers in horses healed following a diamond bird debridement.

So it's really, really successful. So that's our ulcerative keratiti. Let's now move on to uveitis, which is inflammation of the uveal tract, the uveal tract being the iris, the ciliary body, and the choroid.

Now this is usually a really painful disease as well. And they'll present with really marked leprospasm, probably be really photophobic, there might be eyelid swelling, epiphora. Meiosis is really important in this because this is a really easy way to differentiate between, for example, conjunctivitis, which might also present with laphrospasm and photophobia and eyelid swelling, etc.

But you won't have meiosis if you've got conjunctivitis. If it's really bad, you might have loads of crud in the anterior chamber called aqueous humour flare or even some fibrin floating around which looks like a kind of stringy mesh. And the main causes of uveitis in horses are reflex uveitis, which we've already spoken about, and that's usually due to some form of injury to the eye.

So a corneal ulcer would be a classic that can cause, sometimes quite a marked reflex uveitis or trauma, if they bash their head and bash their eye, you can get uveitis as well. However, If you have more than one bout of uveitis in the same horse, and the second or subsequent time, there's no obvious inciting course. So there's no ulcer, there's no history of trauma, then we want to be thinking maybe this could be something called equine recurrent uveitis.

Which is different to reflex uveitis. They might look the same, but the pathogenesis is very different. So an equine recurrent uveitis is actually immune-mediated, and I'll come on to it in a bit more detail later.

So how are we going to treat it? If we've got no corneal ulcer, etc. And it's not recurrent in nature, so this is the first time the horse has had it.

Topical corticosteroids are your go to. So we would normally use something like predforte or Maxadex, which is dexamethasone. 4 times a day, more if it's really bad.

Systemic NSAIDs as well, whatever you want to use clinic and be done on again. Atropine, really important, not just from a pain relief point of view, but you want to keep that pupil nice and big so that you don't get any kind of sticky adhesions in the eye, which you can get secondary to uveitis. Because you're putting atropine in and because the horse has UVIs, it will also be quite photophobic and really shy of the light on the side that that's affected.

Always suggests that the owner puts a face mask on or, you know, they keep the horse stabled until it's resolved. Now, if it is just straightforward uveitis due to, you know, trauma, for example, it should respond really quickly to treatment. So even the following day, after having, you know, one dose of systemic NSAIDs and a few doses of your topical steroids, the owner should notice a really marked improvement in the comfort levels.

And then it's just important to kind of slowly taper these rather than just suddenly stopping because you want to almost test the eye a little bit and see if it's OK to taper it down. If you start tapering and the horse becomes more uncomfortable, just go back up, leave it at that for a few more days and then slowly taper again. Just don't, don't just suddenly stop.

So EU, however, these are horses that have had previous bouts of uveitis, and there's no obvious cause when it's happened. It's the leading cause of blindness in horses. We don't fully understand the pathogenesis, but we do know that there's some form of disruption of the blood ocular barrier, and we get the CD4+ T lymphocytes into the eye where they shouldn't be in there and they stay in there.

And then there's these two processes called molecular mimicry and epitope spreading, where basically the eye gets primed and the horse's immune system basically causes this recurrent inflammation in the eye for no good reason. There's probably some genetic factors and also environmental factors. For example, we know some some breeds, Appaloosas, for example, are more predisposed to this.

But it's really poorly understood. But basically, we get these recurrent flare-ups of uveitis, or persistent low levels of uveitis that eventually lead to horrible permanent damage inside the eye, including cataracts, retinal detachment, and glaucoma. And a lot of these cases will end up needing their eye removed.

So if we're talking about ERU and that's what you think this horse has, we need to be more aggressive with our treatment than just a straightforward non-recurrent UVI test. And the rule of thumb is you want to treat these horses for 4 weeks beyond the resolution of clinical signs. Talk to the owner about this disease, educate them that it.

If it is ERU, the horse has a relatively good chance of losing the eye. Eventually educate them about how to look. Look for signs of uveitis, so pupil size is really, really easy to look at and for owners to monitor and also tell them to act fast.

Any signs of ocular pain, get the vet out. And sometimes the owners actually are aware of things that trigger their horses flare-ups. For example, if the, if it's really windy, or if they've just been wormed or vaccinated, and, you know, talk to them about those triggers and how you can kind of mitigate those effects if possible.

Likewise, if they think it's, if they think their flare-ups happen when it's been really sunny, put them, put a UV mask on them. And any possible ERU case, I would strongly recommend you refer these guys. There are options to be more proactive in terms of delaying this disease process and trying to retain sight for as long as possible.

So this is a a cyclosporin implant that we're placing, and there's things like gentamicin injections and steroid injections that that we can do. And The important thing to remember is this, we can do all these things, but there's no cure for this disease at present. Once a horse has got this, they'll have it for life.

And as I mentioned before, it's amazing how many horses have had a history of recurrent conjunctivitis that we see for uveitis, and their eye is an absolute mess inside. And you just wonder whether all of those conjunctivitis episodes were actually uveitis. And it's really easy to differentiate between the two.

Like I said, conjunctivitis won't have meiosis, so always look at the pupil. Now, there's been a few papers that have shown that a lot of horses when they're referred in for ERU they're basically blind. And too many of these horses are basically being referred to late when the eye looks like this, which is just a mess.

There's nothing we can do for this eye. This is a slightly more acute eye. It's got some chronic changes in there, but you know, we can still see it to the back of the eye a bit.

There's still a reflection, and we can make a bit more than this one. So please refer these early. Finally, moving on to eyelid lacerations, so super, super common, horses are not the smartest.

They often put their heads down and as they're lifting their head up, they catch their eyelid on something. And it's usually the upper lid that they lacerate because it's, you know, it's much more mobile. And actually the upper lid is the more important lid because it's because it's more mobile, it blinks more than the bottom one, and that's really important for spreading the tears over the eye.

So when you do get an eyelid laceration that involves kind of the eyelid margin, it's really important to get a really nice acquisition of the eyelid margin so that when the horse blinks, they can spread that tear fill nicely and we, we don't get kind of long term chronic ocular problems because of a poorly opposed eyelid margin. 5 knots future would be awesome. Try not to use like 2030, it's just so big, especially if it's an eyelid margin defect.

It's, it's just too big. Close it in two layers. If you just do the skin, all of the kind of tissue underneath on the conjunctival side will be separated and it will heal really gnarly.

There's a risk long term that if it's scars and fibrosis, you could get recurrent ocular irritation every time they blink from this really kind of sclerotic, horrible underside of the lid. So close your subcutaneous layers and your skin. Now, there's this really lovely suture called the figure of 8 suture, which is perfect for trying to oppose eyelid margin lacerations, and I've got a photo of it coming up.

If you do have an eyelid margin laceration, do your figure of 8 suture first at the eyelid margin to make sure that's really nicely opposed. Then once you've done that, you can sort out the rest of it. Because it's that eyelid margin that's the most important part.

And obviously don't forget to check the cornea if you've got a really gnarly eyelid laceration, it's really easy to just focus on that. But underneath the eyelid, you may well have, for example, a corneal laceration or an ulcer as well. If you've got quite a complex eyelid defect, for example, if the horse has actually teared a chunk of eyelid out, they require quite advanced surgery, what we call bleph blephroplasty, where for example, we might need to bring in a rotational flap or some extra tissue from somewhere.

I really wouldn't try to attempt to repair that yourself if you've got a big old defect or multiple lacerations offer a referral because that's not an easy job to to sort out yourself on the yard. Likewise, if they've really made a mess of the medial canthus, there's a chance that they might have severed their lacrimal puncture, which is where their tears drain. If they've severed that and you try and stitch it back up, but you actually stitch the punter closed accidentally, then you could end up with these chronic epiphera, or chronic tear overflow, and then chronic infections and things like that.

So if the medial aspect of the kind of lower lid looks pretty gnarly, I would also offer referral at that point. So these are just a couple of photos which aren't actually really involving the eyelid margin, it's more the, the lateral aspect. So these are ones that you probably could have a go at, attempting yourself on the yard.

And yeah, these two came together relatively nicely. This is just a little image of the figure of 8 suture that I was mentioning. There's lots of videos of this online about how to do it, and once you've learned how to do it, it's really nice, because it just brings that eyelid margin together perfectly if you make sure you do your bites all kind of equidistant.

So it's something that, you know, have a practise on, on some kind of a banana or something, and it's, once you can do this, it's really useful. OK, so I think that's us. What I'm going to do now is just go over a few little tips, which I hope will come in handy at some point.

One thing which I found quite useful was when I had a really melty horrible kind of malasic ulcer, I wanted to start some form of anti-alaggenase to, to slow down that malasic process. Our options are, as we said before, plasma or EDTA. Now plasma is great if you can pull it from the horse, get to the lab, spin it down, put it in the tubes, and then give it back to the owner.

However, the problem with plasma is a, that's a bit of a faff, but also, the, the plasma is basically like a broth for bacteria. And I remember going to one owner that I'd given some plasma to, and she, she got her plasma out when I was there. And it turned into basically a disgusting bacterial broth, and she'd been putting this on this eye.

So, If you can give them plasma, great, but just tell them to keep it in the fridge, ideally, and also just keep a little bit in a tube at once and bin it after a week and get a fresh one. What is, what I found easy was to use EDTA. EDA EDTA is not quite as good as plasma, but it's better than nothing.

And what you can do is basically get one of your big blood EDTA tubes and fill that half full. With sterile water, give it a shake, and then you've got an EDTA eye drop. And again, I would tend to leave them, you know, a few little tubes of it so that they can dip into one tube for a few days and then bin it, and get the next.

So it's just something that you can make there and then it's not super messy, and you can start it straight away then. Also, I know we haven't spoken too much about kind of trauma or anything like that, but using your ultrasound scanner on eyes is really helpful and I think quite under underutilised. Even a, you know, a rectal probe will give you a lot of information on the eye.

For example, if you, if you, the eye is so swollen that you can't. See into it, you know, put some local anaesthetic on the eye, loads of gel on your probe, and just scan it and, and see what's going on inside there. You know, you might see that it's got, you know, it's lenses fallen to the back of its eye or it's retina is detached or there's just a whole load of crud in the front of the eye.

And yeah, it's, it's just really useful, to get, get practised in popping your scanner on eyes and seeing, you know, what's normal and what's not. Just a couple of things. So Pred 40 eye drops, which we use a lot, especially for UVI, as we mentioned, always tell the owner that you've got to shake these eye drops, which I know sounds daft, but if you don't tell them that it's, it's basically a suspension, so it completely separates out.

And if you don't shake it before use, they get, they're not probably not getting all of that good prednisolone that you want in there. So always tell them to shake the Pred4 drops. The SPLs, if you are using them on a regular basis, I would always try and carry some 2 gauge catheters in my car, which are obviously way too small for anything else to do with horses, but they're really useful for repairing SPLs.

So when they break at the, at the little injection port, they usually break where the catheter's gone in, so you usually need to tip it off and insert a new catheter in the end. And it's the 20 gauge pink ones that fit into them. So it's always handy to have a few in in your car if you do deal with SPLs.

If the owner is struggling with eye drops and they're not keen to try an SPL. I would tend to change to an ointment because some owners just find ointments much more easy to apply because you can smear a little bit on a glove finger and then gently pull the lower eyelid down and kind of smear the ointment on the conjuntiber inside the lids. And sometimes some owners just find that easier, so worth trying, rather than telling them to just keep battling with the drops, maybe changed to an ointment.

And then if you need advice, there's loads of friendly ophthalmologists out there that are more than happy to give advice. You know, even if you're not thinking of referring, it's totally fine. We get advice requests all the time, and we actually quite enjoy getting them.

But what is really helpful is to have some accompanying photos with, you know, a brief summary of the history and what's going on. And good photos are key in this. So what we really like is a picture of the eye, you know, just the eye, not the whole head, with a light shone on the eye and the eye in focus.

So I know that might sound really obvious, but it's amazing how many we get, which the photos are just completely useless. If you can, if you're struggling to get that, a video can often be easier, you know, if the horse is moving, but try and get quite close to the eye and have a light shone on it and send them over to, to an ophthalmologist, and they'll be able to help you. There's, there's very few that wouldn't be happy to.

And there's this little app, which that is what that logo is for in the bottom right hand corner called Camera Plus, which is a really useful app for takingi photographs because it allows you to fix your flash on, which most iPhones and things don't allow you to do that when you're taking photos. So it means that, you know, you don't have to be asking the owner to shine a light or you're trying to shine a light whilst taking, a photo. So Yeah, recommend the app called Camera Plus.

It's also really good for taking Fundus pictures if you're into that, and then you can send those pictures across to an ophthalmologist and they can hopefully help you. Brilliant. Well, that's me done.

Thank you very much for listening. My email address is on the bottom of there. If ever you guys have any questions or if you have any interesting cases or ones that you're struggling with, please feel free to send across some photos and I'd be more than happy to help.

Thank you very much.