Spring may feel fresh and bright, but the dry air and surges of pollen often trigger allergies that leave our animals’ eyes irritated, itchy and uncomfortably dry. Add to that drought-like conditions, wildfires and poor air quality throughout much of the country, and you have the perfect storm for unfavorable ocular health. On this episode of Animal Airwaves Live, Dr. Caryn Plummer, professor, associate chair and board-certified veterinary ophthalmologist at UF, will talk all things Ocular Surface Disease, including parts of the eye that can be affected, why ocular surface disease occurs, as well as signs, symptoms and treatment options, to ensure better blinks are ahead for large and small animals, alike.
Transcript:
DANA HILL: From WUFT-FM, this is Animal Airwaves Live, our weekly hour long show devoted to the discussion of the health and welfare of animals. I’m Dana Hill. So glad you could tune in here on this Friday, the 22nd of May, 2026. And so happy to welcome back to the program today from the University of Florida College of Veterinary Medicine, Dr. Caryn Plummer. And we’re talking today about ocular surface disease. We’re going to learn about what it is, how it perhaps can be prevented and how it might be treated. So let me begin by welcoming you back to the program, Dr. Plummer. I’m really glad that you could be with me today.
DR. CARYN PLUMMER: Thanks, Dana. It’s always a pleasure to talk to you.
DH: If we think about problems with the eye, whether it is our eyes or our pet’s eyes, I think one thing that many of us can certainly understand is that almost any eye problem is going to be very unpleasant to experience for us, for our pets. It’s almost something that if you have a problem with your eye, it can make you really uncomfortable. You kind of can’t even stop thinking about it. Is that the case with what we’re talking about today, ocular surface disease?
CP: Absolutely. So, if anyone who’s gotten an eyelash or a piece of dust or a piece of dirt or something in their eye knows how really uncomfortable that can be. And if you’ve developed what’s called an ulcer, which is kind of like a scratch where some of the outer cell layers on your cornea, which is the windshield, the clear part of the cornea, if that happens, you get that sort of wound, it’s excruciatingly painful because the cornea has more little sensory nerve endings pretty much than anywhere else in your body. So it has this richly developed sensory nerve system that acts as a kind of an alarm system that tells your body something’s wrong and it creates this feedback loop that initiates healing. So it’s very important that if you get a scratch on your cornea, that that is not a persistent problem. It can cause a lot of problems, not only for your comfort, but also for the integrity of your eye.
DH: All right, so when we talk about the eye, I think that it’s useful perhaps, as we often do when you and I are discussing the eye, to maybe have some background information, just some kind of a little anatomy lesson when we talk about our eye and the different parts of the eye. Could you walk us through it?
CP: Sure, Absolutely. So the eyeball has – there are kind of two parts to the eye. There is the globe itself, the round structure that is our eyeball. And then there is what we call the adnexa, which is all the supportive tissue that protects the eye. So our eyelids are lac glands that produce the tears that moisten and protect the surface, the conjunctiva, which is that kind of mucous membrane that lines the inside of your eyelids and covers the white part of your eye. So these all work kind of in concert to make sure that our eyeballs are as healthy and protected as possible. Now, the front part of eyeball is the cornea. That’s the clear part that light passes through.
CP: And then that light will kind of pass through some lenses and get to the back of the eye and stimulate an electrical response that essentially turns into the image that we perceive as vision, what we’re seeing. But the front part of the eye, it’s really important because not only does it kind of focus the light into the eye, but it also provides that barrier that protects all of those very sensitive, delicate structures on the inside of the eye. So your windshield, if you will, serves a bunch of purposes. And when we talk about ocular surface disease, what we’re talking about is any sort of injury, insult, inflammation, disease that affects that front windshield and all of the structures that protect it.
DH: Okay, so any kind of problem with the ocular surface, any problem kind of with the cornea, can be classified then as ocular surface disease. Even like something caused by an injury?
CP: Sure, sure. Anything that affects the front of the eye, the cornea, can be considered ocular surface. Other things as well, like dry eye – so conjunctivitis — anything that’s going to affect how the cornea, that clear part, is surviving in its host environment.
DH: Yeah. Okay, so this gives us a lot to talk about then. So maybe let’s start by, with perhaps the leading causes of ocular surface disease. What do you see most in a clinical setting? And would actually, would you at the University of Florida, in a large veterinary sort of teaching hospital, see most of these cases or are they handled at, you know, the neighborhood veterinarian?
CP: Kind of both. We see a lot of surface disease in our practice. But, you know, the primary veterinarians, the family vets, serve as kind of the first line. So if a dog or a cat is having an eye problem, they generally will go to their primary veterinarian first, and they have kind of the opportunity to kind of be the first ones to recognize when there’s a problem. And that might be a transient little conjunctivitis from, you know, poor air quality or, you know, smoke from wildfires. It might be a chronic inflammatory condition like dry eye or what we call keratoconjunctivitis sicca. I tend to see the ones that are worse that didn’t respond to kind of the traditional or the first line therapies. But, you know, those cases are shared between, you know, general practices and our specialty practices.
DH: Yeah, right on. Okay, so let’s just kind of start then with a topic of recent interest here in North Central Florida. Now, if you’re listening to this episode, and it isn’t May 22, 2026, know that at the time that we were recording this program, we had been experiencing significant wildfires throughout North Central Florida. And, you know, you and I can try to do our best to stay indoors. Many people have jobs that keep them outside, and many of our pets need to go outside in order to get some recreation or do their pet business and so forth. So what kind of exposure does this create an opportunity for maybe ocular surface disease, having this exposure to wildfire smoke?
CP: Well, you know, wildfires are a major problem not just for air quality and, you know, the cardiovascular and respiratory things that I think everybody is kind of already aware of, but the smoke and the particulates that are present in that smoke can be really irritating to the ocular surface. So it can disrupt the tear film, it can cause the ocular immune system to kind of get lit on fire. And if you will forgive the pun, it activates this cascade of inflammatory events that can lead to not only irritation and discomfort, but also it affects the tear quality, it affects the health and the oxygenation of the ocular surface. So there’s a lot of things that can impact not only comfort, but also the health of your ocular surface. And we as humans can, like you say, get away from it. And it’s a little bit harder for our pets, either our companion animals, or even livestock that need to be outside.
DH: I’m so glad that you mentioned tears. I think tears are a kind of underappreciated part of our body. Yeah, right. Without tears, we would be doomed. Talk about how important tears are, how they’re made, and how we can really find our health compromised if we don’t have adequate quality tears.
CP: Yeah, dry eye is a huge problem, not just for our veterinary patients. You know, I see it the number one cause of conjunctivitis in dogs. Number one, it’s a huge problem, and it’s under recognized and under diagnosed and subsequently undertreated, but it is also a huge problem in human medicine. So in the United States alone, about 20% of all of the eye drops that are sold and bought are for dry eye disease, which is a lot, because if you think about all the different eye diseases that we get, we get scratches, we get cataracts, we get inflammation, we get glaucoma. There’s a lot of different types of diseases. But there’s, you know, the one huge market which is dry eye. And in the States alone, the direct medical cost of managing human patients with dry eye exceeds like, I think the last time I looked, it was like between five and six billion dollars a year, which is huge. So if it’s that big a deal, really, with a prevalence of.
CP: And globally in humans, between 10 and 20% of the population has some form of a tear dysfunction. You know, that’s a lot of. And if we, even if dogs even have a fraction of that, you know, generally prevalence reports suggest that dogs have, you know, anywhere from 4 to 10% of dogs will have some form of dry eye. That’s a lot of dogs. So keeping the ocular surface healthy and keeping our tear film healthy is really important. And the tears, they’re really kind of interesting.
CP: They, you know, we think about it as just this water that comes out of our tear ducts and kind of flushes the surface. And then we as humans have the capacity for psychogenic tearing, which is not common in most of our other species. But that fluid.
DH: You mean crying specifically?
CP: Yeah.
DH: Right.
CP: But the pure fluid is – there’s a lot of good stuff in it; provides oxygen to the ocular surface. It provides glucose, which is the energy required for the cells on the ocular surface to do their job and multiply and stay healthy. There are antibodies in the tear film that help prevent from microbial attack. There’s lipids in our tear film that keep that fluid, that thin film of fluid on our ocular surface at all times. There’s mucins, the tear film, that kind of keep that tear film stuck where it’s supposed to be. So it’s really actually quite complicated and quite elegant.
CP: So when we think about tears, we just think about that fluid that comes out and that is produced by a couple of different glands. In dogs and cats, they have a third eyelid, that membrane that sits in the corner of the eye on the inside. That’s…we don’t have that. It’s a structure that kind of went away during development and further evolution. But most domestic species and most exotic species have a third eyelid, and most animals that do have that third eyelid also have a gland or two associated with it that produces that liquid fraction of it here. So an orbital lacrimal gland, one that sits up essentially up above or behind the eye and the gland of the third eyelid, but on top of that, the conjunctiva, which is that thin vascular membrane that lines the surfaces of our lids and over the white part, the square of our eye, that produces mucin. Our eyelids themselves have little glands in them that produce a lipid.
CP: There’s a lot of things that go into the ocular surface that are not just the eyeball itself and the lacrimal glands themselves. It’s this whole sort of system that works together to produce this really important tear film.
DH: So when you say lipid, you mean like a kind of fat sort of that, right?
CP: Exactly.
DH: That is in this tear liquid that we have and our pets have. And this helps kind of what, spread the tears over the surface of the eye and help keep them coated along with kind of the blinking, which is just a natural sort of response that we have. And we do it without even thinking about it. And animals do, too, I imagine. So all of this is designed to ultimately, one, keep the eyes moist, but also to clear away any foreign bodies, that kind of thing. I mean, is that a big function of what tears and blinking do?
CP: Right? Absolutely. That lipid fraction helps prevent premature evaporation of our tears. So it kind of keeps them stuck there and prevents it from going away too quickly because there’s this constant turnover. We’re constantly producing a little bit of tears all the time, and then it drains down our nasolacrimal ducts into the nose or the oropharynx. So there’s this constant production of new fluid. And in an air environment that interface between our corneal tissues and the air in the environment, that fluid is going to evaporate. So that lipid helps keep it where it’s supposed to be.
DH: Now, animals live in just about every kind of natural environment there is, from moist and damp jungles to dry deserts. But let me ask, are certain species better adapted to producing tears in dry environments versus other animals? And the reason I asked this is because, you know, in Florida, we have quite an interesting sort of climate in the wintertime and up, you know, through relatively recently, we experienced a lot of, you know, really sort of dry days where the humidity is quite low. And I wonder whether or not that has any effect on the way that we experience dry eye. Just the dry air making it easier for tears and so forth to evaporate quickly.
CP: It does absolutely. So in more drier climes than where we live, that, that is a bigger problem. So it certainly, certainly does have that, that effect. Additionally, there are, you know, every different species has, you know, developed creative ways to kind of keep themselves happy and to best take care; take advantage of their environmental niches. So all animals have tears. Even snakes that don’t have eyelids per se, they still have tears underneath their spectacle. Marine mammals still have tears.
DH: What? That’s amazing. That’s absolutely amazing.
CP: Yeah, yeah. Their tear film composition is different. So every species is a little bit different in terms of the fraction of lipids and mucin and you know, what exactly goes into the tears that make them adapted to their environment. Yeah, marine mammals have, they have a lot of mucin. It’s quite sticky and viscous. It’s kind of interesting.
DH: Yeah. Okay, so what are some of the factors that can compromise animals’ ability to produce quality tears?
CP: Yeah, lots of things can. But the most common cause in dogs that get dry eye is an immune-mediated condition. So an autoimmune condition where the body essentially attacks the lacrimal glands. So that results in what we call a quantitative dry eye. So essentially we have means of measuring the amount of tears that an animal will produce. And the most common form that we see in dogs is where they essentially don’t produce enough of their liquid tears.
DH: Okay, and with something like that, is that a problem that can be readily diagnosed?
CP: It is. Actually there are a couple of things. Most of the time if you just take your dog to the vet and they are not exhibiting any signs of ocular irritation, their eyes aren’t red, they don’t have any mucus discharge, they don’t have, you know, what some people say is that green sleep that accumulates in the corner of their eyes. You know, it’s not part of the regular routine exam. If you’re going for your annual and you’re getting vaccines. And the eyes are seemingly from, you know, the minimal part of the ophthalmic exam that goes into an annual physical. They’re not going to reach for all the diagnostic testing. But if an animal presents with clinical signs, the eyes are red, the character of the eye discharge has changed, or if the animal is squinting, then that is a pretty straightforward and common diagnostic test to do.
CP: It’s what we call a Schirmer Tear Test. We have these little filter papers that we stick essentially underneath the eyelid and we measure the amount of tears that wick down that little filter paper in a set period of time, which is about a minute. They do the same test in people, it just takes generally a few minutes longer to get the same results.
DH: And if there is a problem that you can diagnose, what kinds of treatment options are available besides eye drops, which, you know, nobody wants to spend a whole day or many days putting eye drops in an animal’s eyes. They’re not going to like it.
CP: Well, you know, sometimes they come to appreciate it. Yes. For dry eye of the immune mediated form, we essentially put them on topical drops. They do get eye drops. And our goals are twofold. We use drugs, drugs like cyclosporine or tacrolimus that essentially decrease the inflammation in the glands, essentially modulating that immune response to allow those glands to produce more of their own good tears. So we call those lacrimal stimulants. And then on top of that, we also recommend supplementing with artificial tears.
CP: So artificial tears are really important to kind of get us over the hump until the eye starts producing more of its own good tears. And unfortunately, when quantitative dry eye is diagnosed, that is generally a lifelong problem. It is not something that you can treat them with for a couple of weeks and then all is well again. It is something that needs to be treated throughout that animal’s life.
DH: I mean, left untreated, it seems like there could be a lot of dire consequences up to. Including blindness, I imagine.
CP: Yeah, absolutely. I mean, in people doesn’t usually get that far. But in dogs, you know, they’re better people than we are. They don’t complain quite to the same extent that we would. But yes, with chronic irritation that leads to blood vessels growing into the cornea. It leads to scar tissue growing into the cornea. In some animals it will lead to actually pigmentation of the cornea where you get this brown pigment that grows over the surface. So all of those changes are going to affect the clarity of the cornea.
CP: So that will affect how that animal sees and how light gets into the inside of the eye to allow that pretty picture to form in our brains.
DH: Yeah.
CP: This, it also makes, makes the eye a greater risk for the development of ulcers or scratches, which can be really painful.
DH: And I imagine that ulcers and scratches are another type of ocular surface disease, Correct?
CP: Correct. Yeah. That’s when you get a physical disruption of the layers.
DH: Yeah. And that gives us a good place to maybe take our first break. I want to remind listeners that this is Animal Airwaves Live here on WUFT-FM, our weekly hour long show devoted to the discussion of the health and welfare of animals. I’m Dana Hill. My guest today from the University of Florida College of Veterinary Medicine is Dr. Caryn Plummer. And we’re talking today about ocular surface disease. We’ll be back with more right after this. Stay tuned.
DH: Welcome back to Animal Airwaves Live here on WUFT-FM. This is a weekly hour long show devoted to the discussion of the health and welfare of animals. I’m Dana Hill and my guest today from the University of Florida College of Veterinary Medicine is Dr. Caryn Plummer. We’re talking about ocular surface disease. These problems with our pet’s eyes that can be a stage extremely vexing. And when we left off, we had talked quite a bit about tears and how important tears are to protecting the surface of the eye and helping to prevent irritation. And you mentioned, Dr. Plummer, before we left off for the break, that ulcers are something that the eye can experience. And I imagine that these could be quite painful in addition to just maybe disrupting vision itself.
CP: Absolutely. Like I mentioned, there’s lots of nerve endings in the cornea and they can be really, really painful. So not only from the surface nerves, but there’s also a secondary reflex that happens when you get a scratch on your eye that causes some inflammation inside the eye. So you kind of have pain coming from two different mechanisms.
DH: Yeah. Okay, so what are some of the primary causes of ulcers? Maybe untreated problems with the tear glands might be one.
CP: Right? Absolutely. So dry eye can predispose both quantitative and qualitative. So you can have dry eye that, where you don’t produce enough liquid tears, but you can also have forms of dry eye that result from dysfunction of the other glands that produce the mucin or the lipids. So meibomian glands, those are the glands that line the eyelids, those produce that lipid. And that can be a real problem. Even if you’re making adequate amounts of liquid tears, if you don’t have that layer and that fraction that prevents it from evaporating, you can essentially have a functional dry eye. And we call that a qualitative dry eye.
CP: Dry eye can cause ulcers, physical trauma. So like a traumatic insult or a wound or kind of going into the bushes and scratching the eye on, you know, a foreign object, foreign bodies, all sorts of things like that can result in ulcers. But generally, we think, at least most of the time in dogs, it’s related to some sort of external irritant or trauma.
DH: Okay, so here’s where I want to point out one real big reason I would never want to trade places with one of our pets, although I will tell you that my cat’s got a pretty good life. If I get something in my eye, I have the ability to try to get it out my pet. And any pet really doesn’t have any kind of ability to try to remove some foreign body that’s gotten in the eye. Now, the eye has maybe some natural kind of means of attempting to remove foreign bodies, but with our pets and their lack of hands, they’re extremely limited in this regard. Does this create real potential for big problems and discomfort and pain for our pets?
CP: Absolutely, it certainly does. And you know, one of the ways the body kind of deals with those sorts of things is when there is a foreign body, it will actually upregulate the amount of tears that are produced. You know, that’s why when we have ocular pain, you know, you start to tear and you have seepage and that sort of thing. And that’s one of the natural mechanisms to try and flush things off the surface. But a lot of times, you know, the foreign bodies that we get on our, on our eyes, they’re so small that even we with opposable thumbs have, have problems getting them out. And you know, a dog or a cat, they experience that discomfort and they’ll self traumatize as a way to feel better. So they’ll rub, they’ll rub with their paws, they’ll rub on their forelimbs. But unfortunately they don’t have, you know, the capacity to dislodge those things as easily as we might.
CP: And I see a of ton, particularly certain times of year when there are certain little seed pods that are out and about. We see a lot of foreign bodies that have been present. They lodged themselves in the cornea and they’ve been there for days or weeks before anyone notices it. And I can tell that based on my exam, I can see there’s blood vessels growing in there and it’s been there for quite some time.
DH: Yeah. Well, look, one big problem here is that our pets, dogs and cats included, they sometimes kind of lead their way through the world with face first. Right. And you know, dogs and cats that are out kind of in the environment, sometimes just walking face first into tall grass, into shrubs, into, you name it. Not only that, but they’re closer to sand and dirt that’s kind of blown up by the wind or whatever. And this creates, I imagine, all kinds of opportunities for foreign bodies to make their way. Whether it’s just dust or dirt or little seed pods, as you say, thorns.
CP: Oh my gosh.
DH: Right.
CP: Yep.
DH: Right.
CP: The spray from insects. We see chemical abrasions from like stick bugs and things on a fairly regular, regular basis. So, yeah, you’re right. They absolutely lead face first and it can cause some problems.
DH: What can we do to identify when our pets are feeling uncomfortable in their eyes?
CP: Well, they’re going to tell you. So, the majority of the time, you know, ocular surface pain is different than like if you had glaucoma pain. So we’ve talked about glaucoma in the past and that kind of manifest. At least people report that manifestation as kind of like a headache type migraine sensation. Ocular surface pain is different. It’s very sharp and oftentimes it’s very acute in onset. So an animal will squint, they will tear. If they have the capacity to produce tears, they will sometimes have an increase in redness or color to their conjunctiva.
CP: Sometimes their eyelids will swell. So, generally, they will behave as if they are experiencing some discomfort. And you could sort of anthropomorphize there and say, oh, I can appreciate how that feels based on how my animal is essentially looking in the face, squinting, tearing, redness, furrowed brow, that sort of thing.
DH: Yeah, yeah, right. Okay. So we might not understand when we see our pets displaying some of these symptoms, what specifically led to the problem. But this is where it’s important to get in touch with a veterinarian. I imagine that eye problems are something that warrant, if not an emergency trip to the veterinarian. Certainly like one without much delay.
CP: Absolutely. Especially if, you know, the signs have come on acutely. Acute onset generally means that’s a same day emergency trip to the vet. And the problem is a lot of the sort of evidence of discomfort and the clinical signs of eye pain, they’re very similar for a whole bunch of different diseases. So for the layperson or even sometimes for the general veterinarian to be able to differentiate between what specifically is causing that pain, that can be quite challenging. And some of them are absolute emergencies that need treatment right now, and some of them don’t. They can wait a little bit longer. But knowing which one is which is really quite a challenge sometimes.
DH: Can we talk about some of the other kinds of traumas that the eye can experience? I mean, anything that you know of a severe injury we might notice. I mean, do the eyes be bleed the same way that other tissues might bleed?
CP: They do most of the time if you have an intraocular hemorrhage. So a bleed inside the eye that is the result of typically either a blunt trauma, some sort of impact like that. Think about getting hit by a baseball or something like that. Or if the eye develops a penetrating wound, so an ulcer that’s ruptured, or some sort of stick to the eye that’s gone all the way through the outer barriers and into the eye that will cause bleeding.
DH: Have you ever seen a dog scratched by a cat, for instance?
CP: Oh, my gosh. So often, yes. And it’s pretty typical, actually, when people get a new puppy and bring it home to the house that has an established older cat who is not having any of it.
DH: That’s right. That’s right. And so with something like that, I mean, are you worried both about the injury and then the potential for infection?
CP: Absolutely. Especially with the catclaw, because there are some interesting buggies that live in their claws, so absolutely, we worry about that. We worry about the damage that can be done to, not just to the cornea, but to the structures inside the eye, the iris, the lens, and for the possibility of implantation of some sort of bacterial agent.
DH: Ooh, yeah. I mean, in that sort of situation, what is your go to? Is that an antibiotics kind of situation?
CP: Yes. So if the globe is penetrated, is ruptured, many times we recommend surgery to kind of fix the wound. If it’s sealed, then we treat with antibiotics, generally, both topically and systemically, to try and minimize the impact and the proliferation of that bacteria within the eye, because that is very, very challenging to treat once it’s established itself. And, you know, sometimes what will happen is you will get them through that initial wound, but there’s a bacteria in the eye and that shows up even a few weeks later as a kind of an increase in clinical signs, an increase in pain and an increase in inflammation.
DH: Yeah, let’s talk a little bit about inflammation and bacteria. I mean, can this affect all parts of the eye, including the eyelids and the areas around the eye and the ducts and so forth?
CP: Yep. The eye has this interesting immune system. It’s called privilege. So the body does everything it can to prevent pathogens, bacteria, viruses, all those sorts of things, from impacting the inside of the eye. But, you know, our eyeballs are out in the world. They are constantly presented with whatever is in our environment. So our corneal surface, our conjunctiva, our eyelids, if there is something that has caused a scratch or a damaged wound that could allow a bug to set up housekeeping, or if there’s some sort of, you know, immunocompromised state that allows a bacteria to kind of proliferate we can see what we call blepharitis, which is inflammation of the eyelids, conjunctivitis, inflammation of the conjunctiva, and keratitis, which is inflammation of the cornea.
DH: Yeah. Okay. Well, Dr. Plumer, this is where we’re going to take our last break of the program. I want to remind listeners that this is Animal Airwaves Live here on WUFT-FM. I’m Dana Hill. My guest from the UF College of Veterinary Medicine is Dr. Caryn Plummer, and we’ll be back with more right after this. Stay tuned.
DH: Welcome back to Animal Airwaves, live here on WUFT-FM. I’m Dana Hill, and my guest from the UF College of Veterinary Medicine is Dr. Caryn Plummer. And we’re talking today about ocular surface disease. And Dr. Plummer, you see a lot of animal patients who come in and are experiencing one of the many different causes of ocular surface disease. And I want to ask, when you see these pets, you’re taking an exam, right. Tell me what your eye exam kind of looks like, so to speak.
CP: Well, I have a kind of systematic approach to it. I want to make sure that I’m looking at all of the different structures and that I’m not missing something. So I, as a general rule, will look from the outside and then go in. So I will look at the animal before I’ve even laid hands on them. I will appreciate the symmetry between the two eyes, whether or not there’s any discharge, whether or not the animal is kind of squinting in one eye or the other or both. And then we move forward and kind of do our greetings. We pet them, we say hello, and essentially then look at the lids, the lid margins. We look at the glands, openings in the lids to see do they look healthy or not.
CP: Then we look at the ocular surface proper, so the conjunctiva and the cornea, and look for foreign material, look for blood vessels, look for defects, look for pigment, look for anything that looks off what we would consider normal or the spectrum of variations of normal. And then we move in and look at the interior structures, the front chamber, the iris, the lens, the retina and the optic nerve. And essentially you are comparing when you’re doing an exam what you’re seeing in real life in the patient that’s in front of you with what you have banked in your brain as what is normal.
DH: Right, right. Okay. So you probably don’t have too much trouble diagnosing some of these, like, larger problems, but are there ever problems related to ocular surface disease that are a bit more challenging to see, to ascertain, to diagnose.
CP: Yeah, sometimes, you know, especially if it’s a kind of early in the course or if it’s the clinical signs are subtle, you know, then that’s when we rely on some additional diagnostic tools. So we will do, like I mentioned, that tier test that measures quantity of tears. There are some other means of doing quantitative measurement in tears, especially in little, tiny animals. We do, you know, have altered means of doing it and really, really tiny eyes. But we also have, you know, some ocular stains that we use to evaluate the quality of the tear film and whether or not the cornea is intact. So there’s…you’ve probably seen that green stain that will get placed on the eye. That’s a stain called fluorescein. And it’s very useful.
CP: It has a lot of different utilities, but its main use is to determine if there’s a defect in the cornea. So the outer layer of cells, that essentially is the barrier cells, the epithelium, if that tissue has been removed, then that stain will essentially be retained by the deeper layers of the cornea. So you’ll have an area that kind of is highlighted green that tells you that is where the wound is. So that stain is very useful in helping us with defects. It also can help us to evaluate the quality of the tear film. So when you put the green stain on the ocular surface, even when there’s not an ulcer, it will diffuse through the tear film. And you can actually kind of time it to see how quickly it takes for it to dissipate. And that is a measurement of quality of tears.
CP: We also have a bunch of other stains that we can use that tell us whether or not the tear film is in good health. So essentially, qualitative measurements or assessments.
DH: Tears, are there, are there problems related to ocular surface disease that are much more difficult to treat or are treatments fairly available for many of the common eye problems?
CP: Well, a lot of the common eye problems, you know, conjunctivitis, which is a nonspecific thing, just means you have surface inflammation. And keratitis, nonspecific, just means that you have corneal inflammation. Those generally respond quite well to symptomatic therapy with anti-inflammatories, so topical steroids, topical antihistamines, those sorts of things. But a lot of times you’re treating the symptom and not the underlying cause. So especially if you have a situation where an animal has some conjunctivitis and you go to the vet and you get a short course of steroids, and it makes everything better. But as soon as you stop treating with the steroids, the signs come back. That typically means that there’s something else that hasn’t been identified and directly treated. So in dogs, most commonly that is that we’re not producing enough tears.
CP: So the treatment for that would be to try and stimulate them to produce their own good tears. In cats, a lot of times it’s because they have an infection, so they have herpes virus or chlamydia or some sort of an infectious ocular surface problem. So identifying that underlying cause is really helpful in kind of not only just finding a more directed treatment course, but also being able to better guide the owner, the pet parent, on what to expect moving forward. So a dog that has environmental allergies, you know, we’re not fixing that, we’re not curing that. We’re managing that with the, you know, the exception of if it’s possible to, you know, exclude whatever that allergen is from that patient’s environment.
DH: Something like a physical trauma, like a twig lashed across the eye or some foreign object that’s gotten in there, like some sand that has scraped up the surface. Do these heal themselves? For the most part.
CP: For the most part, they do, yes. You know, if it’s a foreign material, that certainly needs a little bit of help. But the eye has a great capacity to heal. So if you remove whatever the offending object was, if it’s still there, then the eye is going to heal up. A corneal ulcer. The most part, it’s going, you know, the patient’s going to heal on its own. My job as a veterinarian when I’m treating these is to kind of not get in the way of that normal healing process, but also to make sure that I am kind of augmenting the body’s own reaction. So if I’m concerned about an infection or the possibility of infection, that’s one of the worst things that can happen for a corneal ulcer, because it can make it deeper, it can make it more serious, it can make it more likely to rupture, to perforate.
CP: So we use antibiotics not to heal the eye. The body does itself, just to prevent any secondary complications that you get from a pathogen that was present. We also use anti-inflammatories or things like atropine to dilate the pupil and stop some of the muscle spasms that occur. So we’re treating the pain associated with that. Sometimes we’ll use drops like autologous serum, which is essentially a blood product or other types of what we call anticholinergics to kind of minimize the enzyme activity that takes place in a corneal ulcer that can make it worse. But for the most part, if the foreign object is removed, the body’s going to heal itself. It has a tremendous capacity. We just kind of support it as it’s doing so on its own.
CP: And one of the most important ways to do that is preventing self-trauma. So if your veterinarian puts your pet in an Elizabethan collar, one of those lampshades, it’s not to be a pain or to be obstructionist to your lifestyle. And it’s really important to prevent that self-trauma because our pets don’t, you know, they feel pain. What are they going to do? They rub or they’ll rub their eye against the couch or the carpet. And, you know, it feels really good in the moment, but it’s not helping that healing process. Oftentimes it’s setting them back. So those, especially the rigid cones, they’re really important to prevent that patient from doing damage to cells.
DH: Yeah. Well, Dr. Plummer, that’s really, really great advice. And, you know, when we started out the program, we were talking about, you know, the way that eye problems can be some of the most vexing because it’s hard to think about anything else when something is irritating your eye. And fundamentally, I think what would be most important for listeners to take away is that, you know, veterinarians are there to help you diagnose these ailments and get treatment for your pets so that they feel better.
CP: Absolutely. That’s what we’re here for.
DH: All right, well, Dr. Caryn Plummer is a veterinarian at the University of Florida College of Veterinary Medicine. Thank you so much for joining me today.
CP: My pleasure. Thank you, Dana.
DH: And I want to thank you all for listening to the program today. I hope you’ll join me next time for another episode of Animal Airwaves Live. Bye.
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