Good evening, everybody, and welcome to another Thursday night webinar proudly brought to you by the webinar vet. My name is Bruce Stevenson, and I have the honour and pleasure of chairing tonight's webinar, with a return speaker that we have all listened to before and thoroughly, thoroughly enjoyed. I don't think we've got any new members on tonight, so not much housekeeping.
Same rules apply. Pop your questions into the Q&A box and we will post those to Ron at the end and discuss them. So Ron Offrey was a member of the charter class of the Coret School of Veterinary Medicine, Hebrew University of Jerusalem, Israel.
After graduation, he moved to the University of Florida, where he spent the next 4 years undergoing clinical training in veterinary ophthalmology and obtaining his PhD. During this time, Ron developed an interest in the physiology of vision, focusing on retinal electrophysiology and animal models of retinal diseases. Upon his graduation, Ron returned to Israel and joined the faculty of his alma mater, where he is currently a professor in veterinary ophthalmology and winner of numerous teaching.
A Teacher of the Year awards. He has published widely and he is a diplomat of the European College of Veterinary Ophthalmology, former, European College Executive board member, and in 2002 to 2005, he served as president of the European Society of Veterinary Ophthalmology. Ron, welcome back to the webinar, vet, and it's over to you.
Thank you very much for the warm introduction, it's pleasure to be with, with you. I think it's fair to say that exotic pets are becoming increasingly popular in veterinary practise. We all see increasing numbers of rabbits and guinea pigs and hamsters and chinchillas, and that's just the mammals.
I'm not talking about fish and birds and snakes and iguanas and You know, lions and tigers and bears. Oh my, I mean, owners really expect us to know everything about any species that walks, flies, crawls, trots through the door. And could literally spend hours talking about these exotic pets.
Unfortunately, we don't have hours. We only have 50 or so minutes. So I decided to limit myself to Small mammals and more specifically to rabbits and guinea pigs.
I know all of you are right now looking at the picture and saying that's not exactly a small mammal. Case in point, true, but we can Talk about lots of species in this talk and by popular demand, if you wish, we can be back to talk about other species. Today, as I said, we'll talk only about two of them, starting things off with rabbits, I should say, as always, that they have no financial relationship with any product, but I do want to acknowledge two books that have served as a source for many of the pictures that I'll be showing.
One is a book that I've co-authored with colleagues from UC Davis and University of Madison, Wisconsin, which has a chapter on exotic pet abing ophthalmology and a book by David Williams, devoted to ophthalmology of exotic pets. So as I said, we'll start things off by talking about rabbits and we really talk only about common conditions or peculiar conditions that we see in rabbits and not in other species, and we will maintain an anatomical order in the talk going from the front part of the eye to the back part of the retina, but before starting with the front part of the eye, we start actually with the orbit. And the important thing to keep in mind regarding the orbit of a rabbit is that they have a huge venous plexus behind the eye, and that becomes very important whenever you have to nucleate a rabbit cause if you Damage the plexus as you're nucleating, you have a very fair chance of killing the rabbit.
It will die of massive bleeding that you're unable to control. And therefore, With a nucleating rabbit, we should stay very close to the globe. We should cut the extraocular muscles at their distal end on the globe, leave all the tissue behind, retain all the tissue with the plexus so as not to damage it.
I should say that this is the way we used to do a nucleation, but things may have changed recently. This is a paper that came out literally just two months ago, published by my colleagues from the University of California Davis, that introduces a new technique for hopefully what will be safer nucleation of rabbits. Here you can see the Venus plexus that I mentioned and you can see why it is so scary because literally it is so easily damaged during the nucleation.
And the technique intro introduced in the paper have you beginning nucleation in the usual manner transconjunctival, undermining lifting the globe, and as you lift the globe and you start exposing the retrovolbar tissue, then you use this instrument Ligasure, which is a Bipolar electrosurgical vessel sealing device, you can see here, and that's being used to cut and cauterise the extraocular muscles, the third eyelid, the optic nerve, and you are seeing the vessels as you go along and thereby avoiding this fatal bleeding which otherwise could be very, very fatal as I mentioned. Still with the orbit, rabbits will often present with exophthalmus, and as in any other species, exopthalmus may be bilateral or unilateral. If you're presented with bilateral exophthalmus, very frequently it may be just due to stress.
The rabbit is stressed to be in the clinic and all of a sudden, will present with exothalmus. If you're seeing bilateral exotalmus, the first thing for you to do is to ask the owner whether the rabbit is like that at home or not. If it's not like that at home, then you're probably looking at the case of stress.
If it does have bilateral exopthalmus at home, you probably want to use radiology looking for amiddiacil mass, that would be your leading differential. If presented with a unilateral exopthalmus, then the most common cause of unilateral exopthalmus in rabbit is a retro bulbar abscess, which It is usually bacterial, often the tarella is implicated or it is suspected and we base our diagnosis on some sort of imaging, be it ultrasound, CT or MRI. Now, we all know that in dogs we would drain these abscesses by the oral route, make an incision behind the last smaller tooth and drain the abscess this way.
Unfortunately, due to the presence of the venous plexus that I mentioned earlier, we cannot do that in rabbits because once again, that's a pretty That guarantees that you'll kill the rabbit due to massive haemorrhage. And unfortunately, there means that frequently we don't have a good and effective way of draining those abscesses and the sad news is that often, we are required to nucleate these patients. I mean, we try treating them with long-term antibiotics.
They will not resolve and frequently we are forced to nucleate. And continue with long term antibiotics, be it penicillin or otherwise. Again, antibiotics are problematic in rabbits, as you know, so recurrence of the abscess is not uncommon and sometimes eventually we may have to euthanize the animal or because of the darn abscess that we could not drain because of that venous plexus.
So now to start our anatomical journey from the eyelids going back to the part of the eye, rabbits may suffer from entropion and just like in dogs, it may be secondary or primary. If it's secondary entropion, then it's probably Due to chronic inflammation of the eyelids, the phitis, causing scarring of the eyelid muscle and the secondary entropion, so we're talking about tricial entropion and here you can see it in the upper eyelid causing this corneal ulcer. Entropion as in dogs may also be inherited, especially in the New Zealand white and the French lo breeds and the World Cup, it would be similar to that of the dog.
So you want to put topical anaesthesia to determine the extent of the tropeon and then you would surgically repair it using the modified hot cells technique that you would use in a dog. One strange eyelid disease, that you wanna consider in rabbits is staph blephritis, lephritis caused by Staphylococcal infection, and I say it's an unusual disease cause infection and inflammation are confined only to the skin of the Eids they do not involve the conjunctiva. They do not involve the lacrimal system, so simply a cutaneous infection and inflammation which is very responsive to topical and systemic gentamicin.
So whenever you see severe skin lephritis, but the inner aspect of the eyelid and the conjunctiva look unaffected, please consider stuff and please consider gentamicin as your treatment of choice. Another strange eye disease is the so-called rabbit syphilis or the reponemacuniculi, an infectious organism that is transmitted from infected mothers to their offspring to the neonates and the affected neonates present with crusting and ulceration of the eyelids such as you're seeing here. You can confirm the diagnosis by Taking a scrape of the conjunctiva and actually seeing the organism which thankfully is sensitive to penicillin injections, 3 injections, 1 week apart at this dose, but again, we always want to be careful when administering penicillin to rabbits.
Moving on from eyelids onto the lacrimal system, just like in dogs, we divide lacrimal into the production part and into the drainage part. So looking at tier production here you have the Schirmer tier test values in rabbits. You can see that they are on the low side.
And what you can also see is that there is a huge range of normal values, 0 to 15, a very important point I'll come back to in a minute in the next slide. If you look at rabbits, you may notice that they don't blink much. Maybe once every few minutes, and a couple of reasons have been suggested for that.
Number one is the fact that they have 4 tear glands, so you've got lots of tear glands and therefore a very stable tear film. That's one reason for not blinking. Or as I'll point out in a minute, unlike most mammals, rabbits have only one puncta, only the lower nasolacin puncta draining tears from the ocular surface, and that means that maybe tears remain in contact with the eye for a longer period of time and once again less frequent blinking.
Now, as I said, there is a huge range of normal values of tear production and that means that if you suspect dry eye, then you will have to base your diagnosis not only on Schmer tier test but also on the clinical signs. Or other diagnostic tests. Those of you who attended one of my previous talks about lay in dogs may remember the til breakup test shown here and also corneal ulceration, etc.
Etc. All of the clinical signs associated with it. Unfortunately, cyclosporin is probably not a very effective, remedy in rapid dry eye.
There is only one report on it. It's supposedly safe, but we really don't have much experience. Most people would treat these patients with artificial tears and top antibiotics in cases of ulceration such as you are seeing here.
Moving on from production onto drainage, then as I said, the rabbits have just one puncta to drain the tears, the lower puncta shown here, and here you can actually see the anatomy of the entire system and I am showing it. It starts off. As usual with the lacrimal canilliculi and the lacrimal sac going onto the nasolacrimal duct, but unfortunately, it's got two points where it's susceptible to obstruction, because of severe bending of the nasollamal duct.
One is here marked as PB which is the proximal maxillary band. Here and then IB, which stands for another band of the incisor tooth, and you can see them here. Here is the proximal maxillary band and here is the incisor tooth.
So these are two bands where again the larymal passes next to the molar and the incisor teeth, and that means that due to these bands, the rabbit is predisposed to obstructions and inflammations of the drainage system. And as you can gather, this would be frequently due to dental disease. Again, problems with the roots of the incisor and the molar teeth.
Actually, it can be sometimes regarded as a multifactorial disease cause it combines both a dental disease involving, as I said, the roots of the incisor and molar teeth, but Rabbits frequently will also suffer from low levels of calcium due to nutritional hyperthyrothyroidism, that would lead to changes in the maxillary bone and unfortunately, The tooth may push itself into the weakened maxillary bone, thereby aggravating the nasal lacrimal obstruction. So really two causes combined to cause these acryo cystitis. So when presented with acreocystitis, you should really think about diagnosing and correcting the primary problem, which, as I said, is frequently dental, .
Clinical exam may show it or you may choose radiography both for workup of the dental problem and to highlight the obstruction of the tier drainage system using what we call dryocytoinnography, contrast radiography to show the dilated sac as you can see in this picture here. The rabbits will present with purulent oxidate from the puncta again, just a lower puncta, so you will see purent discharge from this punkta and you can cannulate it as you'll see in the next slide. And flush it.
If you can cannulate the puncta, maybe you can cannulate the system, from the nose, what we call retrograde flushing in cases of severe, inflammation when this puncta is blocked. And here you have a slide showing you a punta with a cannula. You can cannulate it most easily with a 24 gauge intravenous cannula and then flush it maybe with saline.
Or maybe with dilute polydine iodine, maybe with antibiotics, maybe with steroids as the case may be fit. If you flush it and you have inflammatory material coming out of the nose, you may collect. That for culture and sensitivity and we have a wide range of organisms that have been cultured Marcela and Boatella and even Soudomonas and as I said posterella once again is implicated.
We may have to repeat this treatment several times, so we may have to cannulate and flush again and again. You may consider leaving a fine, monofilament nylon in the duct to prevent strictures due to chronic inflammation. You may have to provide long term.
Topical and systemic antibiotics and as I said, your greatest fear here is that you will get scarring of the system, which is why we want to try and avoid it with cannulating using monofilament nylon. Speaking of the nasal lacrimal system, we cannot avoid speaking about cherry eye. Yes, rabbits may get cherry eye just like dogs.
As I said, they do have 4 tear glands, and one of them, the herderian tear gland, may prolapse. You may be tempted to Cut it off and remove it because you tell yourself, well, they've got 3 more, so I'm not running the risk of dry eye that we have in dogs, but again, I remind you of the venous plexus. You cut this and you may very well kill your patient.
So no, we do not cut them, we replace them just like we replace the cherry eye in a dog. Moving on from eyelids and the nasallacrimal system to the conjunctiva, so rabbits, just like any species may get conjunctivitis. And speaking of infectious conjunctivitis, we may have bacterial or viral starting things off with a bacterial conjunctivitis.
It may spread from infection of the eyelids or infection of the cornea or once again, it may be primary infection of the conjunctiva. And again and again and again, I'll say pastorella can't avoid this organism when we're talking about rabbits, but it's considered the most common bacterial pathogen rabbits though once again stuff hours may be more common and I remind you again of the peculiar lephritis that I mentioned earlier with only skin involvement. So when presented with conjunctivitis, just like in, many other species, you may consider cultural insensitivity until you get your results, chlorophenol or ciprofloxetine may be your antibiotics of choice, and if you have recurrence, then you may have to switch gears and treat the patient systemically.
As I mentioned, rabbits may also get viral conjunctivitis and here you want to consider the pox virus or the myxoma virus and you want to consider it because actually it is a fatal disease in unvaccinated animals and And sometimes in these animals actually conjunctivitis may be the only sign noted before death. So it's really, I urge you to take conjunctivitis in rabbits very seriously and inquire about vaccination and . Considered possibility that you are looking at pox virus which, as I said, may be fatal.
However, in the more common subacute form, you will get conjunable hyperemia which will progress to chemosis with lots and lots of discharge, . The discharge may the infection, sorry, may enable secondary infection by once again pastorella. So we do have immunosuppression caused by myxoma enabling secondary infection with pasturella or other organisms.
So this would be the subacute form of the. But it may have the acute form which will cause inflammatory and edematous lesions of the eyelids and the conjunctiva such as you are seeing here. You will get dematous and exive lesions also in the mouth, and the anus and in the genital area.
This is really pathognomonic for the disease, though you could do. Cytology and see the inclusion bodies in causal scrapings and confirm the diagnosis this way. One more very strange disease that we see in rabbits concerning the involving the conjunctiva is conjunctiva.
Overgrowth, it's really a disease that we see only in rabbits. Some of you may be familiar with the name Pyrigium because pyrigium is a disease in humans where sometimes we get conjunctiva growing over our cornea, slowly covering our cornea, very, very irritating disease that you see quite often in human patients. Well, you'll see that this one is called pseudoptery.
Because the conjunctiva grows over the cornea but is actually no adhered to the cornea as evidenced here, you can see the cannula going underneath the conjunctiva but moving freely over the cornea, so that makes it pseudoprigium and also explains the other names. It's a pre-corneal membrane. You have conjunctival centralization.
The conjunctiva grows over the cornea, causing conjunctival strictures, again growing from the limbus. We really don't know what causes it. Maybe some sort of weird collagen dysplasia.
As you can see, it can grow massively. Causing significant visual deficits and here are some more pictures showing what I mean by significant visual deficits. So you may be tempted just to come and remove it surgically, but as it says here, simple excision of this mass will cause recurrence within a few weeks.
Which is why we're all thankful for to my colleague in Berlin, Ingrid Algover who developed or introduced us to this very interesting, surgical correction. What she did is make 6 incisions in the conjunctiva here in the overlying conjunctiva. So again that would be 123456 incisions all around.
And then taking the fine sutures, she actually used the 70 suture in her paper passage from the skin of the eyelid to the inner aspect of the eyelid, grab the conjunctiva, come out again and. Tie your knot. Repeat again and again and again until you have 6 knots all around, removing all the conjunctiva and that's it.
Just leave the knots in place until they fall out. She has follow up for as long as 5 or 6 years with no recurrence, so that is a technique that you may wish to adopt if presented with this cellopped radium. Rabbits may get glaucoma.
Actually, for many years, rabbits were a very popular animal model for glaucoma and I'm talking specifically about the New Zealand white rabbits in which glaucoma is inherited due to a mutation in the B gene. BOU stands for thalmus. Yes, they present with thalamus just like dogs.
It's a semi-lethal gene as you can see, carriers may give birth to small litres of unhealthy pups, and the mutation causes gonutis genesis that you can see here, malevelopment of the iridocorneal angle, see how very little angle has developed. At the beginning, infected rabbits will be born with normal IOP, but, pressure rises very quickly. By 3 months, you may get pressure of over 25 and as high as 48.
Millimetres of mercury, clinical signs that will make you suspect, you have glaucoma, are slow PLRs and slowly progressing corneal edoema that you can see here. Rabbits are responsive to some drugs that we don't use too frequently in, I, I was gonna say large animals, but I mean dogs and cats. We're talking mainly about beta blockers such as immolol, betaxolol, or oral diclophenide.
Those are probably the drugs of choice. It is a self-limiting, Disease fortunately, and I say fortunately because these are not very effective drugs, but over a period of several months pressure will return to normal maybe because the elevated pressure actually destroyed the ciliary body that produces the aqueous humour and thereby reducing pressure. Keep in mind, of course, that you may also get secondary glaucoma in rabbits just like in many other species.
Moving on to the lens and another unique, disease that I we see in rabbits actually, it's not unique because recently it's been described in some cats and in some dogs. I'm talking about infestation in with encephalitozoiculli, which is a microsporiial parasite. What happens is that affected animals shed the spores in the urine and, this, sorry, .
Animals will become infected when eating food contaminated with the urine, as you can see here. It can affect the central nervous system signs and the the central nervous system and the kidney causing non-ocular signs, but We don't care about that. In this talk, what we care about is the vertical transmission from the mother into the pups at embryonic stage and the organism, the parasite, actually makes its way into the lens and it's in the lens before the pups are even born and lives there happily for many, many months or years until one day it wakes up, if you will.
And starts multiplying in the lens, causing spontaneous rupture of the lens capsule, cataract, leakage of lens material into the interior chamber, very severe UVI. You can see here a secondary iris granuloma. Usually unilateral dwarf rabbits may be susceptible and as I said, it's been recently, described in cats.
So, whenever presented with cataracts and severe UVI tests in rabbits, please consider Ericuli as your organism. You may do serology to confirm the diagnosis and, many of them will test positive on IFA. You can do cytology of tear smears and actually people have reported seeing spores consistent with Eculi in tears or if the rabbit went into surgery, then your veterinary ophthalmologist can confirm the diagnosis using it by doing PCR on the lens material.
So yes, these cataracts do need to be removed by surgery. Animals must be treated, aggressively for the UVI with non-steroidal drugs such as diclofenac or flurirofen and albendazole or some other anti-parasitic drug for the organism. Still with the lens, just like any other species, rabbits can get cataracts.
They can get, we spoke about the secondary cataracts due to the, A caniculi infection, but they can also get hereditary cataracts. Here is a study by Bob Munger from Houston, Texas looking at 950 rabbits, New Zealand and New Zealand white with New Zealand reds, and overall incidence of 4.3% cataracts, more common in the New Zealand white, both species probably have an autosomal recessive mode of inheritance.
We do perform cataract surgery on, rabbits. It's done quite often. A bit tricky due to two factors.
Number one, they have a very shallow anterior chamber, so frequently, the iris may come out through the incision. That's one problem, and the surgeon needs to remember to wash out or remove all of the cortex, otherwise, you may get regrowth of cataracts. And finally reaching the retina and the end of anatomical journey in rabbits.
Here is what a rabbit fundus looks like. We call it a meningiotic retina cause ah unlike a dog or a feline retina where you have blood vessels going every which way, you can see that in rabbits you have. Blood vessels going just towards the 3 o'clock and 9 o'clock position, so just two bands of blood vessels, lots of myelinated nerve fibres, and a huge optic cups, so really a very, very beautiful, looking optic disc if you ever get a chance to look at it.
As I said, I have time to talk only about two species, and the second one I've chosen to talk about is guinea pigs. And again, I cited David Williams' book at the beginning. I should also cite his study looking at the survey of 1000 guinea pigs, which certainly increased our knowledge of these species.
Again, some diseases that are frequently presented in guinea pigs. And some that are unique to guinea pigs, starting things off with entropion and I hope everyone can appreciate the entropion in this guinea pig here and you can see the secondary keatitis, the ulceration here, and the blood vessels. Entropion may be Inherited in some guinea pig breeds and as in, as I mentioned in rabbits and as in most other species, it is corrected with a modified hot cellsis.
Please, when you do this surgery, please remember that guinea pigs have very thin skin, so don't be very careful as you cut, make your incision. Make sure you have proper instrumentation and magnification. Guinea pigs may also suffer from tracheosis, facial hair, irritating the cornea, and that's a clinical problem, especially in breeds that have grizzly hair, such as Tael and Rex breeds, so that's A problem in this guy here with the soft hair, but definitely a problem in these guys here.
When they are young, I think lubrication is probably the best choice you can offer the owners. Lead plastic surgery should be avoided or delayed, and again, a few cases of traysis. I think that grooming and lubrication may be the best way to avoid them.
Moving on to the conjunctiva, we can get infectious conjunctivitis in guinea pigs just like in rabbits. And here the organism you want to consider is chlamydia with two species of chlamydiaittaca and cavia are the two most common ones, or some would argue it's because we use guinea pigs to study human chlamyosis and that's why so many, we are So conscious of the disease and tend to isolate them so much. But anyhow, you can take if you are presented with conjunctivitis in a guinea pig, you should consider conjunctival scrape and cytology may show you the intracytoplasmatic in inclusion body that you're seeing here, or you can send samples for PCR .
As in cats, it may be a self-limiting disease or you could consider treatment with tetracycline. Keep in mind that other organisms such as hysteria and the pastorella and stuff that we saw in rabbits can also affect guinea pigs. Conjunctivitis may be not only infectious, it is often caused by habitat, the straw and the hay that is used in the bedding of the animals frequently gets into the eye.
So when presented with conjunctivitis, please look very carefully in the phonics for, foreign bodies and remove them. Note that these foreign bodies may also cause cleratitis because the globe is so prominent, because they have no third eyelid and because of the minimal blinking, I'll just like in the rabbits and I'll bring it up again when we talk about that. However, keep in mind that not every secretion that you see, in the conjunctive area is pathological.
White mucoid secretion such as what you're seeing here is considered normal and may be a grooming problem. And the last cause of conjunctivitis that I want to bring up, which we don't frequently consider in other species, is nutritional conjunctivitis. And conjunctivitis may be an early sign of vitamin C deficiency, just like sailors in the good old days when they didn't get enough vitamin C and they'd have lots of scar.
So animals could present with anything from slight reddening of the conjunctiva all the way to thick, pure and discharge, . You would have, manifestations of lack of vitamin C in the teeth, in the kidneys, and in the respiratory system. So definitely may be fatal.
So be on the alert for conjunctivitis as it may deteriorate, . And become a systemic problem. If you do suspect the nutritional cause, this is the dose that you want to administer to your patient.
At the other end of the scale, we talked about lack of vitamin C. Sometimes we can have diets that are too rich. And basically, we are talking about fat-rich diets that some, breeders or owners, I should say, give for grooming.
So you, this is definitely a fat, guinea pig, . The fat, rich diet may be combined with the metabolic disease, maybe combined with inheritance to combine to cause this presentation and the subconjunctival lipid deposition called a PI. So it's not really conjunctivitis, but you do see this subconjunctive lipid deposition, send blood tests and you can confirm the diagnosis.
Sometimes you'll also see manifestations of hyperlipidemia in the cornea. Here are two pictures very similar to what we see in dogs of lipid deposition in the cornea of a guinea pig and again, you should suspect nutrition problems and hyperlipidemia. Moving on to tiers, we spoke about low tier production values in in rabbits previously, look at the values in guinea pigs, 0, basically.
I don't know if you're all familiar with Shermer1 and Shermer 2. Shermer 1 is what we usually do in our patients. You stick the Schmer tier test, in the patient and measure the amount of wetting per minute.
However, as you know, in dogs and other species that includes the basal production, but also the reflex tearing, the tearing that is produced in Reaction to the foreign body irritation induced by the test strip. So that is countered by putting topical anaesthesia in the eye and then you are measuring only the basal production, we call that Schmerir test 2. As you can see, Shimmert test 1, Schmert test 2 are the same in rabbit, meaning that they probably have no reflex t secretion.
And because these values are so low, really you can't do schmer tier test in a guinea pig, what you want to do is a phenol red, a thread tier test. So same principle as Schumer tear test, but instead of sticking the piece of paper, you stick this thin thread here that you stick it in for 15 seconds only. It changes colour as it absorbs tears, and here you see that the values are.
Much more measurable. As I mentioned earlier, than just like rabbits, guinea pigs, don't think much. 0 to 17/10 minutes, my God.
We are talking about 3 blinks per eye per 10 minutes. Again, showing great stability of the tear film. Nonetheless, they do suffer from dry eye, and I think that even without PRTT or Schmert test, you can see that this is a dry eye.
Thankfully, they are more responsive than rabbits to cyclosporin and that can be used for treatment. Guinea pigs can get cataracts just like the rabbits that we mentioned with the prevalence is high as 40%. Again, we may be talking about the metabolic disease, the grooming, the fat guinea pigs, so it may be diabetic, it may be age-related or senile, or it may be congenital due to treatment of the mother in during pregnancy, it may be inherited.
And it also may be iatrogenic if you chronic grave chronic tryptophan to treat the guinea pigs. . Yes, we should treat the secondary uveitis with nonsteroidals, and frankly, I don't know of anyone who has done cataract surgery on guinea pig.
The eye may be. Just too small and frankly, you know, if it's a guinea pig living in a cage all day long, not sure about the effect that it has on its life quality. One unique disease with which I will end and this is a good way to end the talk cause it may really blow your mind, talking about exotic pets, you may get some very exotic diseases and none is more exotic than this.
See these white lesions in Inside the eye of these two guinea pigs, these are actually bones. This is bone growing inside of the eye. We call it heterotopic bone formation because it's a bone growing in an unusual place and it's actually coming from the ciliary body.
The ciliary body undergoes osseous metaplasia and you have this white formation growing into the interior chamber. And it is probably due to high levels of ascorbate in the ciliary body which triggers bone formation. So when you dig deeper, it is probably secondary to kidney disease and or diet.
There is no other concurrent, ophthalmic disease. Look at the massive bone here and here. And there is no treatment.
We can't remove it. We don't want to remove it cause the tissue may actually be vascularized or hematopoieically. Active.
Sometimes we respect glaucoma or UVITs, but as I said, usually there is no concurrent, ophthalmic disease. Eventually it may fill the entire globe. You just watch it grow.
There is nothing you can do about it. And once again, I conclude with a picture of the guinea pig fundus. Again, a very strange looking fundus.
It has no blood vessels. We call it an angiotic fundus, no blood vessels, no tepium. So if we suspect retinal degeneration in guinea pigs, we really have no Way of confirming it because as you may remember from canine ophthalmology, we diagnosed retinal degeneration based on hyperactivity of tepium and narrowing of blood vessels.
Well, if we got no tepitium and we have no blood vessels, we have no way of confirming the diagnosis, except by using ERG. So that would conclude my talk about rabbits and about guinea pigs. As I said, many strange creatures out there for us to talk about, and I'll be glad to come back again some other time for another talk or right now to take your questions.
Ron, thank you very much. That was really very interesting. And I especially like the pictures of the, of the back of the eye, in the rabbit.
It, it just looks absolutely amazing. Yes, it does. And actually, if you're gonna look for it, it's dorsal.
It's very dorsal. So you have to get down on your knees and lift your head up, and it will be way up there if you are looking for it. Amazing.
Absolutely beautiful pictures that you've got. Thank you, and again, thank David Williams and the book I co-authored, as sources for most of the pictures. Yeah, fabulous.
Ron, it's no wonder you've received so many awards for, being a top, lecturer. Your, your talks are always amazing and tonight was absolutely no different. So thank you so much for your time.
Thank you very much. We have no questions for you. You've answered everything.
Or you've stunned everybody into, into silence with it. So, until the next time, thank you so much for being with us and to everybody who's attended. Thank you for your time tonight and I hope you enjoy it as much as I did.
Thank you very much. And I just say that if you want your questions, mail them to the office. I'll be glad to answer them.
Thank you for attending and have a good night. That's great. Thanks, Ron and thanks to Peter, my controller in the background.
Good folks.
