 back at it. So today we're going to start up on our tour of atomic pathology again with cornea. But first we have to go back to Vienna. So this is the palace where the Austria-Hungary empire was centered and where the emperor used to live. Where's your obligatory heroic emperor on a horse? You know I can't imagine emperors usually on horseback meeting armies, but in any event makes for a good heroic soldier. There's the close-up. I can't remember who that was. It was one of the one of the great emperors. This is the pretty much the seat of the old Austria-Hungary government. Now what's interesting is the one time I was there previously, this was the Sissi and basically Franz Josef who was you know the elderly emperor. You know they married him off to a princess from another country. He was probably 40 years younger and Sissi decided she didn't want to hang around with the emperor so she built several palaces all over and that was pretty boring. So then she decided she wanted adventure and kind of went to different countries and you know for adventure. Unfortunately when she was visiting one of these countries an Italian anarchist figured out she was there and assassinated her sadly. But in any event they put together a nice you know a nice exhibit of the things that she gathered when she was the emperor's wife. And so as you're going through you can see you know these aren't exactly you know plastic dinner plates you know and so a lot of a lot of gold. Gold was the theme and so a lot of gold you know it's great being king because you know you can pretty much do what you want and so they had this really elaborate works made up for her and here again just you know some little little bobbles made of gold so we'll kind of go through some of the little bobbles that we had. I just thought it was interesting what you know kings live well. All right so we're going to talk about cornea so since you're in the hot siege you get to go ahead and sort it out. So tell us about the layers of the cornea starting from anterior to from external to internal. All right so bonus bonus question what stain is this third time's the charm. This is actually a PAS stain and the way you can tell it's very subtle but look at the epithelial basement membrane staining there and not Bowman's layer. Look at the dark staining of the decimaceous membrane so again as you stated Bowman's layer is not a basement membrane decimaceous membrane is so there's a difference in how they stain. All right so Chris since you joined us here tell us about the epithelium. Tell me about corneal epithelium. Epithelium is a stratified swim is non-caretonized epithelium. Typically about five to seven layers thick. Tell me a little bit about how corneal abrasions repair themselves. So you've abraded that epithelium how does it repair? Yeah so we have um so we have uh limelostum cells that can help regenerate epithelial cells. The epithelial cells themselves even in the center can regenerate so if you've got a focal area of an abrasion the epithelial cells alongside of it will kind of release from their basement membrane and slide over and then other epithelial cells will grow in their place and so it's a very rapid process. I mean you know if you see patients with a corneal abrasion I mean it'll heal in 24-48 hours so very very rapid process. The only problem is is these will will stop growing by kind of contact inhibition and so if you let these cells get inside the eye so you've got a you know traumatic injury and these epithelial cells gain access to the inside of the eye they'll grow like crazy there's nothing to inhibit them so these grow very very very rapidly and then of course as we've mentioned Bowman's layer is an area of condensed stroma underlying the epithelium and it is there congenitally and so what's important to remember is Bowman's layer does not regenerate. So Bowman's layer is kind of a historical record of what's going on and so if you've had something happen that that causes Bowman's layer to be damaged or to be lost it does not regenerate. Alright and again what kind of stain is this? PAS. PAS so you can see that the basement membrane of the epithelium is this line right here Bowman's layer is not a basement membrane so it does not stain with the PAS stain. Alright so what layer are we looking at now here Brad? This is the stromal layer of the cornea. Alright so we're looking at the stroma here tell me a little bit about the stroma. It's pretty thick it's around 500 cell layers thick it's no about 500 microns. Microns sorry. I think there's 500 cells here. Microns thick. I don't know what would you. So the the cells that are here in the stroma are these little keratocytes and normally they're these little quiescent spindle shaped cells but if stimulated keratocytes can become like fibroblasts. So if you have a traumatic injury to the cornea the keratocytes can become like fibroblasts and they can heal that injury. The problem is is when they heal that injury they have irregular fibers of collagen they can cause scarring and what's interesting is these bands of this connective tissue go all the way limbus to limbus so the cornea is incredibly strong. Once you break that say you're doing the surgical procedure of cornea transplant or there's an injury then even though it heals up it's not nearly as strong and so normally the keratocytes are quiescent they're spindle shaped they're not really doing anything but given enough stimulation they can become like fibroblasts and they can start laying down collagen. All right so what are we looking at here? So decimase membrane and then the endothelial cells. All right so decimase membrane we already mentioned that it is indeed a basement membrane and so when you look at decimase membrane if you were to look at it with electron microscopy there is kind of a congenital element of decimase membrane there's what we call an anterior banded layer banded just as the way the collagen fibers are when you look at them with the M but then the posterior part of decimase membrane gets a little bit thicker throughout life because it's the basement membrane of the endothelial cells so as life goes on decimase membrane gets a little bit little bit thicker okay Shrav I see you hiding back there. Tell me about the endothelial cell layer important layer in the cornea. So the endothelial cells there that these tight junctions between them they look cuboidal and then if you look at like comfortable like off the beat you can see the hexagonal shape they don't regenerate after they're lost. So they're almost hexagonal in shape when you look at them and interestingly enough in three dimensions whenever you have cells that are covering a dome they take on what's called a geodesic dome configuration and that's just nature's way of covering a curved surface and so they're hexagonal and they link together almost like a geodesic dome does there are tight junctions between them and that helps to keep the aqueous fluid from just pouring into the stroma and so there is some active transport going on there there's some nutrients coming from the aqueous into the cornea they're drawing some fluid off from the cornea now they don't regenerate at least in in primates. In non-primates for example rabbits rabbits aren't a good model to look at the effect of something on endothelium because they'll regenerate it I mean you can really damage rabbits you know endothelium really extensively like doing fecal and other things yet they will regenerate more humans they don't although people are now looking at getting ways to get endothelium to regenerate and so it's not a hard and fast rule there may be some ways. Dr. Kinoshita in Japan is actually looking at Rokinase inhibitors to see if they can stimulate endothelial cells to grow and so that that's a potential in the future. All right so any questions on just the normal anatomy of the cornea? All right Catherine what are we looking at right here? What could that be? Right and what do we call this condition? Mancharotopathy. So it's well named because it looks like a band it's within the palpebrofishers you know where the lid covers it for some reason you don't get the deposition of the of the calcium and so it's here within the palpebrofishers it'll start at the limbus and then it'll move centrally from there what causes this? Exactly so it's really a nonspecific sign of inflammation and when we look at the look at this a little bit closer here's a bonus question here's the calcium here what are these little kind of dark spots with these little holes here? Exactly so as the nerves come up they pop through Bowman's layer and then they spread underneath the epithelial layer there and so where they do the calcium doesn't get deposited so it leaves these empty spaces. All right Tina what stain do we use to stain calcium? So you can see it's easy to remember because it stains it red now I put this sideways just because I really wanted to highlight that so here's the epithelium up here and here is the calcium and where does the calcium usually lie when you've got Bancurtopathy? It's like it's just below the epithelium. Even more specific? Sub Bowman's layer. Or even in Bowman's layer. Exactly so you get deposition of calcium along Bowman's layer underneath the epithelium and you get this extensive calcification now here's epithelium what is this stuff in between here? This is dying here okay there you can see it from here to here between epithelium and Bowman's with the calcium is what is this material in here? Scoring or oh okay. There's a different aspect of it so oftentimes you don't see just Bancurtopathy by itself when you've got chronic inflammation what else can you see? Panacea. Panacea is material growing in again from the limbus between the epithelium and Bowman's layer and you can have a fibrous panacea you can have fibroblast cells up here you can have a fibrovascular panacea you can have vessels in it you can even have an inflammatory panacea. Panacea and Bancurtopathy often run together because they're both signs of just chronic inflammation of some kind and so just signs of just chronic inflammation so this is a vascular type of panacea and here we've got a more fibrous type of panacea but again it's got Bancurtopathy with it there's the calcium along Bowman's layer there's the epithelium it runs in between you even get calcification here so Bancurtopathy panacea often run together signs of chronic chronic inflammation okay I'm sorry I don't know you. I'm awesome I'm a third year med student. Hi med students don't get panacea you're lucky. Caleb. So external photograph clears on the limbus and then there's this opacity it's kind of a circular shape. So what do we call that? Denilus. Arcus senilus and what does that signify? What causes that? It's lipid venisonic stroma. Okay so as we look right here we've got you can see here's the stroma here and here's the deposition of lipid now what kind of stain is this? What do we have to do to get that stain? Fresh tissue. So if you want to stain for lipid you've got to have fresh tissue you freeze it and then stain it and this is a oil red O because it stains oil red with these little lobes it's a oil red O. Interestingly enough the deposition we think it's some kind of a diffusion pattern because whenever you see a slight clear zone and then the deposited material it usually means it's diffusing from the limbus somehow and so you can see and it's also kind of shaped like an hourglass in that there is more lipid anterior in the stroma here and more lipid posteriorly and then it thins out in the center so you get that idea that it's kind of an hourglass shape. What does this signify? It doesn't necessarily signify. Exactly so if you look at people like when you guys are at the VA anybody over the age of 70 has an arcus and so we used to be taught that this meant they had diseases with you know lipid problems you know hypercholesterolemia and other problems it turns out it's really not the case although you can get depositioning people with high cholesterol it doesn't necessarily mean that this patient has high cholesterol. All right so I'm sorry again you are Michael and you are okay all right well you can answer this then what do you see in here? This is external sodium fluorescent to stain the cornea. All right so when you see dendritic staining like that what do you think of? Exactly so this is your classic herpes simplex dendrite and so you see that it's got staining a fluorescein in the center what does the fluorescein staining mean? Exactly so it means the epithelium is denuded in that focal area because then the fluorescein stain takes it up so you can see that you've got denuded epithelium here and then you've got these little bulbous outpouchings coming off here and that's very common when you see the herpes and this is usually herpes simplex one but what do I always tell you guys to say could be two okay so if you take anything away from this cornea lecture if any attending shows you any picture of a cornea and they say what's the differential and you're not sure what it is you say well of course herpes is on the differential so you just say that offhandedly well of course herpes and then the attending will go well yeah I guess because herpes does everything and then they say well which one you say well likely one but could be two okay so these are pearls now you gotta remember these now I'm not sure what's going on all right so we look at the the pathology here and what you'll see in these cases is that the epithelium will be denuded in the center and then if you're going to look for the infection if you're going to do a scraping and try to do some you know special stains or cultures for herpes you want to be at the edge of that not in the center because the centers that denuded epithelium here and then you've got a small lymphocytic infiltrate now the problem with herpes is you can also get stromal herpes and we're going to have the you know the cornea people will talk to you about these at length because these are the difficult ones to treat but you can get herpes that'll be involved in the stroma and then you'll get this deeper almost an immune type reaction because you can get with stromal herpes you get an immune type reaction and you'll even get giant cells here posteriorly by decimates membrane and so you can get an immune reaction stromal herpes which is different than just the simple epithelial herpes and this is just showing you a close-up when you get herpes you get these inclusion bodies in the cells I'm sorry this is a scraping that we tried to stain but you get these little inclusion bodies here in the nucleus with herpes so now that we've got you know you can do the stains that we've got now that that you know I'll tell you for sure if it's herpes before we had those you had to scrape them and then look under the microscope and try to figure out if that was herpes or not all right what do we see in here uh so we got an external photograph of I can see a little left left eye with a lot of corneal edema and there's lots of I guess white white thinning of the cornea and then there's a lot of extreme injection of a conge so what would you be worried about here so I'd be worried about like infectious keratitis exactly so this is a corneal ulcer and this patient would you know wearing contact lenses and unfortunately you know if you've seen people all the time I see them driving on foothill where the you'll see this and they just want to just honk and go down but um so you know unfortunately if you don't take care of your contacts or you over wear them you can hepothelium breaks down bacteria start to live on the contacts and then they can get into the eye a bacterial corneal ulcer is one of our true ophthalmic emergencies because remember we talked about the body's immune system so bacterial ulcer stimulates an acute inflammatory reaction PMNs and so you know PMNs have granules that um you know deposit you know release materials to try to kill the bacteria and those materials are great when you want to kill a bacteria but they're not great in the you know stroma of of the cornea so you can get a tremendous amount of damage you can get melting they put out proteases collagenases and so this is a true emergency you want to kill that bacteria as soon as possible before the body's immune system kills off that cornea and so we look at a close-up here and you can see that here is a cornea this indeed perforated which is how I got the pathology but you can see that there's this acute inflammatory cell reaction remember the corneas we looked at were that nice healthy pink color when you look at this now it's white this is a melted cornea that stroma can melt and an aggressive bacteria such as like a pseudomonas bacteria themselves have put out collagenations and things you can melt a cornea and lead to perforation in 48 hours these are truly an ophthalmic emergency and there's a close-up showing you these PMNs here this acute inflammatory cell reaction so again they're good at killing bacteria they're not so good in the cornea so you want to take care of those immediately fortified antibiotics every hour you want to watch them very very carefully make sure that you don't get a perforation all right what do we see in right here yeah so similarly a external color photograph left eye and again a lot of hemorrhagic hemosis and then it looks like there's a central opacity likely another corneal ulcer all right so history on this is this is an old farmer from Idaho and finally his wife makes him come in because and this is true his his history is i've got some well my eyes a little blurry how long's that been going on oh i don't know two weeks three weeks i don't know it's been going on well yeah had any exposure any vegetative material and then he kind of looks at you like well duh i'm a farmer and so evidently he was out you know thrashing crops or something or other what farmers do and got something in his eye about three weeks ago and then finally they dragged him down to to take a look what do you think this could be could be a fungal care all right so when you see a more indolent ulcer you think fungus and so especially if there's a history of vegetative exposure oftentimes you'll see fungus and what stain do we do for fungi uh the gms stain gms which stands for gamori methamine silver silver so it kind of stains the the hyphae here this silvery black stain so fungal keratitis tends to be more indolent vegetative exposure all right we're coming back around the corner here so here we see an external photo um looks like the epithelium is kind of there in the center and it's just very easy so this would also let me think about infectious uh keratitis as well you know this has a few signs that would tell you what infectious keratitis this would be so you've got a chronic kind of non-healing corneal ulcer and you've got this ring infiltrate and eye hurts yeah so this is a classic acanthamoeba so this is a classic then maybe you'll often get a non-healing corneal ulcer the problem is is these will often be um thought of as as a herpes and so they'll be treated for you know a certain period of time before we finally realize what they are so this is a classic appearance of acanthamoeba how do we usually catch these yeah how do you get them oh uh contact lens yeah so contact lens is the most common culprit but you know these things live in the ground they live in warm water hot tubs have been a source of these and so if you're in a hot tub don't put your face in it face out of the hot tub and so these these will grow in hot tubs and all that it could be a contaminated contact lens case again when we had a young guy who was the worst case I'd ever seen and he was a wrestler and so I don't know if you guys remember from high school those are the guys who would take their sweats and hang them up and then the next day they'd just be standing up they'd wash them like once a month you know and so this guy I'd never you know take care of his contacts we looked at his contact lens case and there was like stuff growing out of it and we literally staying for acanthamoebas and so he got it from his contacts the problem is is these can invade into the nerves they can go from the cornea into the scleron these can be very very difficult to treat and what's the special stain we use to stain for this and I hard to remember all they say this is a gridly stain and so the gridly stain will stain the stroma green and here you see the cyst of the acanthamoeba the reason these are so hard to treat is they tend to incest and so medicine can't get in them and so interestingly enough the most common treatment that we use is most successful is actually swimming pool disinfectant because that will kill you know get into these cysts and kill them it takes weeks to get rid of it there's another medication called Broly and propaminine you have I don't know if it's even approved in the U.S. we used to have to order it from England and they send it over you know sometime polymixin can can affect this a little bit but mostly it's the swimming pool disinfectant that kills these off but you want to recognize these early because once they've spread these are very difficult to treat and you know cornea transplants you do and they can recur from the you know cornea scleroside so very very difficult to treat and here's just an e.m. just kind of showing you this triple walled cyst which is why these are really difficult to treat. All right Tricep, what are we seeing here? You can see. I'm sure. Yeah, that's Tricep's laugh. Rachel. Tricep was leaving. Can you see there are some epithelial changes in this cornea? Our regions that have. Almost kind of a pattern here where you've got some you know changes here. What do you think that could be? All right so what we're going to do now is we're going to kind of segue a little bit into some of the corneal dystrophies and there are all kinds of corneal dystrophies but the way I like to do them again I'm kind of a splitter I like to put little mailboxes individual ones and so when we start thinking about anterior we can think of anterior and the most anterior is epithelial epithelial basement membrane dystrophies and so when these occur you see this classic kind of picture it's it's it's like a map it's like a fingerprint and this is kind of to show you what it looks like and so this is the light trying to show you little fingerprint lines and so when you have an epithelial basement membrane dystrophy you get thickening irregularly the epithelial basement membrane it can look like fingerprints it can look like a map it can even look like little dots and so you literally call this map you know dot fingerprint you know and you can even abbreviate it you know map MDF dystrophy and you want to watch for these very carefully because what's the problem with these I mean they really don't give you that much vision effect but what's the problem with them exactly so you get recurrent corneal erosions from these and so the problem is is that that basement membrane doesn't really work like it should and the epithelium doesn't stick down so these people can get recurrent erosions you really want to not miss these before you do cataract surgery because again if you didn't notice it ahead of time and you do cataract surgeon that people are getting recurrent erosions and irregular epithelium you cause that so that's the key thing you got to remember recognize everything ahead of time because if not your surgery caused it in the patient's mind and so same thing with like even epiretinal membranes and things like that look very carefully and someone that you operate on because if you didn't see it pre-op and you see it post-op you caused it it's your fault so here you can see again map dot this is the dot and the map and the fingerprints so corneal epithelial basement membrane dystrophy and here you can see this is again a fellow took this because it's out of focus and again Caleb said mech they go no i didn't but you can see sometimes what will happen is is they'll get a little erosion partial and then it'll heal and then another erosion and then it'll heal and so you'll get this multi-stacked almost looks like stack of pancakes of epithelium with this thick and irregular basement membrane in between so map dot fingerprint dystrophy and this just shows you what happens with one of these when you do like a scraping to try to get it to re-heal look at how thick the basement membrane is this is epithelium this is all basement membrane with what kind of stain Rachel? PAS okay so epithelial remember basement membrane stains PAS easy one remember PAS so you can see that this massively thickened epithelial basement membrane there's a close-up okay now we start to get into the I call these the weird ones and so there are more corneal dystrophies some people will call these bowman's layer dystrophies the sub epithelial dystrophies there are so many of these that you're going to have to memorize them for the boards but I just want to show you a few just classic ones and so if we look at this one Brad what what are we seeing here when you're looking at the slut lamp so it looks like more like cystic types of structures and it looks as though I mean this is a hard picture is that this isn't the corneal stroma it's in the corny it's really anterior it's kind of under the epithelium anterior stroma so it's a little bit more localized cystic structures within the epithelial just start thinking of here like Miesmann's exactly so this is a classic picture of like Miesmann's dystrophy and and what's interesting about Miesmann's is they some pathologist I can't remember who call this stuff peculiar substance and it's stuck so it's literally this stuff is called peculiar substance and some people will say it's an epithelial basement membrane dystrophy some will say it's a bowman's dystrophy and you can see right here you've got some thickened basement membrane you've got these little kind of round structures that are in here so when you see these multiple dots underneath there this is called Miesmann's dystrophy and it's characterized by deposition of peculiar substance so interesting stuff that's a PIS thing it's PIS positive but it's got some other characteristics to it that aren't just normal basement membranes it's really as peculiar stuff all right so what are we looking at here strong yeah i'm kind of showing the broad beam and i'm sorry it's not a great picture but you've got kind of this irregular or whiteish grayish stuff again it's anterior stroma bowman's layer around there but diffuse kind of scallop sometimes so it's more diffuse at probably the macular dystrophy if it's in the stroma okay let's say it's more superficial than that it's not quite in the stroma yet it's really anterior almost you know again bowman's layer subepithelial so there's another dystrophy you guys will have to memorize for boards called called Riesbuchler and so Riesbuchler dystrophy is it's kind of got two different you know ones it's a type one and a type two basically it's again an anterior type of dystrophy and when you look at it you'll see that bowman's layer will be disturbed so it's not so much epithelial basement membrane but it's bowman's layer is disturbed it's absent you'll get some focal irregular scarring in in that area all right so now we want to spend a little bit of time talking about corneal stromal dystrophies and there was a mnemonic put together and I heard this when I was even a pre-residency fellow I don't know who first invented this but it's been passed down through the ages and so you know get out your little pens if you haven't written this down so the mnemonic is Marilyn Monroe really always gets her man la california all right so Catherine m maryland it stands for macular dystrophy and so what does macular dystrophy look like this little collage of some different macular dystrophies more central kind of some clear areas here depositions of mucopoly saccharine okay so you look at the depositions here and the key thing when you look at them the spaces in between are not clear so you'll see there'll be some haziness even in between the area of the deposits so Marilyn macular Monroe mucopoly saccharide really are really is recessive and so easy to remember because this is the only one that's recessive that's why we toss it in the rest of these are dominant so the other two are dominant this is recessive okay always all shin blue and here's the all shin blue stain and so all shin blue stains the mucopoly saccharide here in the stroma blue so it's easy to remember and so here you see so the reason this mnemonic is good is it tells you what it's called what the material is and what the stain is and so that's why it's a really valuable mnemonic these are always on board somewhere because it's just it's mindless memorization which is what boards are made to test so you can see all shin blue and you've got the staining of the mucopoly saccharides here in the stroma all right here's again an all shin blue Tina gets granular now the granular if you'll notice a little bit different than the macular the granular is these individual i call them almost like cookie crumbs but the key is you see that the space in between them is clear and there's a clear zone here out to the limbus so this is granular her a highland highland okay there's a retro illumination man son trichrome so you can see the highland it's here and they're really in the anterior stroma in the mason's trichrome the trichrome stains collagen connective tissue blue it stains the hyaluronic acid it stains it red okay oh you're back sorry i called rachel therese my my apologies i don't know who i've offended more but probably offended both of you guys but okay didn't have to tell okay l lattice all right and so you see lattice is well named it looks like a little lattice work you know kind of the rose bushes growing so you've got these little lattice lines all over the place okay a no so a remember the second one is always the stuff that's in there so what is this stuff it's amyloid so a is for amyloid la and then california the stain right kongal red now i always say it's a misnomer i mean that doesn't look red to me it's kind of burnt orange but in any event kongal red stains amyloid you know red if you will kind of a red stain and so that's the way you remember these now there's something really cool about amyloid and with a kongal red stain and that is exactly so if you put two polarized filters on and cross them the amyloid lights up so this is an actual cornea and we've cross polarized them and taken a picture and all these areas where it's lighting up bright are where the amyloid deposition is and so you can get a lighting up with cross polarization with them so Marilyn Monroe really macular mucopolysaccharide recessive gets granular her highland man mason strachrom l lattice a amyloid california kongal red so that's what you'll always remember the corneal stromal dystrophies okay all right um okay look yeah what are we seeing here this is an unfair picture because i look at that you can't tell what this is this could have been who knows a chemical injuries could have been ganas what but believe it or not here we do a kongal red stain and we cross polarized so it lights up so you can also get amyloidosis affecting the cornea without lattice and so systemic amyloidosis sometimes will you know there's a systemic type of amyloidosis that does not affect the cornea but there's a systemic type of amyloidosis that does affect the cornea very uncommon but you can get deposition of amyloid and again here's kongal red here's all of this amyloid throughout the cornea and there it is lighting up when we do cross polarizations remember even systemic amyloid can affect the the cornea all right what are we looking at here all right so this i was trying to show you is kind of deeper cornea so this is really deep and if you look at the pattern you see all kinds of little irregular people call this a you know a beaten metal look so this is fuchs dystrophy and so you know by beaten metal what i mean is i don't know if you guys you know in the olden days back in less enlightened times in you know junior high boys took shop and girls took homek and i don't make this up you know so in shop you worked with metal and so some of the you know less studious of the students in the metal shop used to love getting the you know the shop teacher really upset because you take a ball peen hammer and you take his smooth metal and just hammer the hell out of it so a ball peen hammer is a rounded hammer and so a beaten metal look if you take a rounded hammer and you ping a thin piece of metal it gives you this little look and so this is what fuchs dystrophy looks like and so it's got that beaten metal appearance to it if you do retro illumination you see these little dots you know coming coming out at you so this now we've worked our way deeper now this is there's a whole bunch of dystrophies of decimates and i'm not going to show you all those because we could do a whole hour on those but this is the most common one and this is a posterior dystrophy this is called an endothelial dystrophy so fuchs dystrophy is an endothelial dystrophy what causes those little dots what's the path equivalent well it is but what are they actually what what are the little missing pieces of endothelium but there's more than just that there's actually little deposits that form that are called gutata and so what you're seeing is you're actually seeing those abnormal endothelial cells start to lay down more decimates membrane if you look at this look at decimates membrane here that's like four times normal thickness so fuchs dystrophy you get a markedly thickened decimates membrane but you get irregular deposits of basement membrane material these are called gutata and then the endothelial cells eventually die off you know it's an inherited dystrophy we're now finding a lot about what the actual enzymatic defect is that causes this but the problem with fuchs dystrophy is you eventually get endothelial cells damaged they get knocked off and then you'll get corneal edema and that's why you eventually need to do surgical now we used to do corneal transplants for these but now you'll do a de-sec or de-mech you just need to replace the endothelium so these are called gutata it's deposition of this abnormal base of membrane material and then you can even get thick decimates membrane now there is a condition called gutata less fuchs where you get thick decimates membrane uh but you really don't get you know deposits that you can recognize and this is interesting because only department chairman corneal attendings can see gutata less fuchs at the same time it's the s1 murmur you don't know if you remember your cardiology attending would have that s1 murmur and you never hear it it doesn't exist but the tending could could hear it and gutata less fuchs only you know chairman corneal attendings can see it mere mortals cannot but there is you know an entity where you just get more of a smooth deposition of decimates membrane rather than lumpy bumpy and so fuchs dystrophy all right what do we see in here it's got a man looking down on both eyes and you can see that the corneas are especially the right one is truting most likely keratoconus okay so what do they call this for bonus points uh one big sign months inside months inside now this is a really crude way of diagnosing keratoconus and so this is a severe cone i mean obviously we have more sophisticated ways we look at corneal topography and you know severe keratoconus like this isn't the difficult thing to diagnose it's the subtle or what they call the form-fruits keratoconus that's hard to to diagnose and you really want to make sure before you do a lasik procedure on somebody who's a myope with some irregular stigmatism make sure they don't have keratoconus because you can actually really cause some ectatic problems in the cornea if you do but this is a severe keratoconus called months inside the patient looks down and you literally see the cone shaped outpouching of the cornea all right so we look at the pathology Mike what's the pathology here of the keratoconus um so it looks like there's a focal break there and uh bowman's layer exactly so you get a little focal break here in bowman's layer so some would argue this is a bowman's dystrophy you know so you can argue back and forth but you get these focal discontinuities your breaks in bowman's layer okay central cornea what do you what is the thickness of the central cornea about 600 microns well i mean in the keratoconus oh it's so it'll be much thinner so it's thin exactly so keratoconus is characterized by progressive thinning of the stroma in the center of the cornea or inferior center also thinning of the epithelium so when you look at the path the epithelium may only be three or four cell layers thick instead of six the stroma will be diffusely thin and then you get these focal discontinuities in bowman's layer and that's classic keratoconus that's the pathology of keratoconus all right so chris we'll give you a hint this person has keratoconus they come in with sudden visual loss so here we see an external photo of the eye looks like there's these kind of regular areas of kind of darkness this makes me kind of interested in beating a regular appearance about uh so areas of thinning so in keratoconus we can see bully formation on those kind of things that make me think what this is what exactly do we call this so patient with keratoconus they're going all i'm fine they wake up one morning and their vision's totally blurry and if you look at the beam that cornea is actually really thick rather than really thin and these are regular kind of foldings here indicative of edema um and there's a specific entity that affects keratoconus that can cause this rachel hydrops exactly what is hydrops well it actually it's not in in bowman's that the breaks are it's actually in decimates and so my simplistic way of thinking about it is is that cone is pushing out it's pushing out the cornea is thinning thinning thinning thinning you know decimates is it's kind of collagenous but it's also elastic and then decimates just breaks and so because it breaks fluid just gushes from the anterior chamber into the cornea itself and you get this acute corneal edema or thickening and if you look at what the pathology looks like this again is a p as stain here is decimates membrane and look there's a break there and so decimates membrane stretches stretches stretches stretches then it breaks and like a rubber band it's got a little elasticity to it the edge is curl and so they'll curl there and then you'll get this acute corneal edema so we'll rush in now you don't necessarily have to do a cornea transplant urgently because eventually what can happen if you can get the patient through this is that those endothelial cells that are here they won't more of them won't form but some of them will start to slide over and eventually they'll fill that gap start making new decimates membrane in the cornea can sometimes detergesse on its own so you don't urgently have to do a cornea transplant in high drops and there's a close-up here's decimates membrane you can see there's endothelial cells still on the inside surface of it as it's curled in so these endothelial cells can eventually slide over and fill that gap and this can go down so that's when you get acute edema in a patient with keratoconus you know acute loss of vision think high drops all right now there's another entity i'm sorry i don't have a picture of it but i just wanted to show you this just so you guys could always remember these and so brad i don't expect you know what this is but what is the stain that we stain for iron prussian prussian blue so it stains iron blue and how do we remember that um something to do with metal and tanks and war exactly so the prussians the prussians were the military that really welded together germany and you know helped us stay one more one and one more two but um so so you know prussians think of of metal and iron and so prussian blue stains for iron and so remember now you can have multiple iron stains of the cornea and so there could be various ones now let's say since we're talking about keratoconus here anyway this is a prussian blue stain of a patient with keratoconus what do we call the iron ring and keratoconus fleischer fleischer fleischer fleischer ring and so kind of like the kaiser fleischer that you see with deposition of copper but anytime you get pooling of tears you can actually get deposition of iron in that area so at the base of a cone you can get what's called the fleischer ring you can even get right where your lids normally sit some little subtle linear iron lines about it you know third of the way up from the limbus on the inferior cornea those are called hudson stahlia lines you can even get iron lines at the head of a teridium you get iron lines with a blab that's that's coming down so you get iron lines from all kinds of things but for keratoconus you get what's called the fleischer ring all right so teresa what are we looking at right here looks like there's some of the denuded epithelium in the centers all right so this is a corneal but it's been cut in half the previous sutures here tell you that this patient is out of previous corneal transplant pkp it's very thick it's white it's opacified and let's say this is what that looked like before we remove the corneal what are we looking at here layer is below right so this is what we call bolus keratopathy and what's important here is here's bowman's layer again pis stand look here's the basement so edema percolates through the stroma now when we process stroma you know during our regular pathological processing it shrinks a little bit so these little spaces here are not signs of edema you don't judge edema by spaces in the stroma because you know that happens just from normal processing but the fluid percolates up here and then you get swelling of the epithelial cells eventually the swelling will make these cells pop and then you'll get a boli a blister with the basement membrane still down on bowman's layer and then this blister here so this is called bolus keratopathy and this can be caused by anything that affects which layer it's the endothelium so remember the endothelium has tight junctions and it's the endothelium that keeps the cornea detritus just keeps from getting in there so anything that affects the endothelium can cause corneal edema which can cause bolus keratopathy so this is what bolus keratopathy looks like so this could be um fuchs distrofee even it could be damage from surgery when you know like mike's in there with me with a 30 000 hertz ultrasound right under the endothelium you know killing off 10 000 cells at a time that could cause this too this is the most common reason why cornea transplants fail just the process of putting that taking the graft off a donor putting it on putting sutures in it you knock off 50 percent of the endothelial cells so eventually those cells can can you know not function still and you'll get corneal edema so bolus keratopathy is kind of an end stage of anything that can affect the corneal endothelium okay so again this is sissy's porcelain that they had made up from china and sent over so next week we're going to do lens okay so read up on on the crystalline lens all the various factors that can affect questions