 So, good morning everybody, I'm really glad to see so many people here, and we have a special treat today. I get to introduce Dr. and Professor Clara Landau, who's a professor and chair at the University of Missouri. I was fortunate enough to get to be in her department for six months teaching residents and working in neuro-ophthalmology. And Professor Landau actually grew up in Czech Republic, Czechoslovakia, moved to Switzerland, and went to undergraduate school and graduate school and medical school at the University of Zurich. Then she did internship and residency partly at Zurich, but partly also in Israel. And then came back to the University of Zurich, and in 2002 she became the first woman chair of a clinical department and has been the chair of ophthalmology since that time and has built a fantastic department of wonderful gifted clinicians. She's been the president of the Swiss Ophthalmology Society. She's the president-elect of the European Neuroophthalmology Society. She is also the vice chair of the Gender Equality Office, or Gender Initiative with the Gender Equality Office, and that was the program that I was a part of. And so I can't tell you how excited I am to have her here. We set up a lectureship in neuro-ophthalmology, and Clara is the first lecturer to present for our division. So Clara, we're thrilled to have you here, and she's going to be giving us a lecture on trochlear nerve palsy tricks and tips, the TTT lecture. So Clara, I'm going to turn it over to you. Well, thank you very much, Kathleen. This is really a wonderful occasion for me to see where you come from, and I'm overwhelmed just these past 10 minutes. I have seen this building, and we are now thinking of how to increase our department, and there is no space, and I love this feeling of big, big space you have here, and it's a wonderful, as I said, a wonderful experience for me. And that all is based on what you just heard that Kathleen was with us for half a year, and it was the most wonderful year and exciting year we had in our department with her, and you will see a few pictures of it. Now, Kathleen asked me that before I talk on the trochlear nerve palsy, people may be interested in a little bit of history or a few facts about our department in Zurich. So I've done a very short presentation here, and you may be familiar with a few of these names. Well, first of all, this is Zurich, so we do have mountains as well up here, not quite as high, but not every day can you see them from Zurich, but this is our town, and the University of Zurich is a little bit up the hill, so on nice days we have this view. Here is the Department of Ophthalmology, but not only ophthalmology, we have three floors here, but there is also the ENT department and maxillofacial surgery, but this is our, it's actually the newest building in this university hospital. Here is the first chair of Department of Ophthalmology, you may know his name, Friedrich Horner, and I find this kind of nice that a pupil expert came to our place where the most famous, well, let's say most famous publication of Friedrich Horner has to do with the pupil. Anyway, so he started, he was the first professor of ophthalmology, before that ophthalmology was part of general surgery, and it was actually Bilrod, whom you may have heard about as well as surgeon in the 19th century, who realized that this eye surgery is just a little bit too special to have it within general surgery, so he was the strong man at the faculty and he decided that Horner could be the first professor of ophthalmology. So he did that for quite a number of years, over 23 years, and built up the department. Now, the next one, well, that's just the official letter of appointment of Friedrich Horner, which as you know, Kathleen is hanging in our department on the wall, and he got 1,000 francs a year, so that was his salary. So things changed since then, luckily. Anyway, he was really very famous, he became very famous, and people started to be interested in this specialty. So the next, his next was Otto Harp, and you may be familiar with Harp's strier, in congenital glaucoma, so he's the one who described them. Besides that, he invented a huge magnet to take out metallic foreign bodies out of the eyes, so this was bigger than a person, a huge magnet, so people, all patients were brought to Zurich to have their metallic foreign bodies taken out of their eyes. The next was quite a short period of time, so he didn't really make a big impact. He passed away soon after he was appointed as Zidler. But then the next one was Alfred Fockt, another name you may be familiar with, Fockt-Quirnagiharada, for instance. That's the Fockt, it's not Fockt, it's Fockt. And he wrote a fantastic book of Slitlamp, an atlas actually, of Slitlamp biomicroscopy, which is really quite amazing. I mean, they didn't have photography, they had wonderful, you know, at least as much merit goes to the person who illustrated this book as to Professor Fockt. So I can't go into details here, but again, a famous name, Mark Amseller, who took over from Fockt. And may I just show you, you know, this was a tough guy. He wasn't very pleasant. There is a story that the residents had to open the, you know, in ground floor, they had to open the elevator door for him. Then he would go in and then they had to run up to third floor to be there in time to open the door again. So that's the story, I don't know whether it's true or not, but it's a good one. And Mark Amseller was just the total opposite, very nice and still, you know, very productive. And of course he invented the Amseller net, which until today is called after him for exploring metamorphopsia or visual field defect in the central field. Okay, Rudolf Wittmer was the next. He may not be that famous. He was a fantastic, he was interested mostly in uveitis and he was a very, very good corneal surgeon. So people came from all over the world to have his double suture corneal transplant done by him. Then came Balda Glor, who is still alive. So all the others passed away, but Balda Glor is now over 80 and he was a glaucoma specialist who also did some of his training in the US and whom I knew very well, of course, because I worked with him and for two years his, the next chair was Theo Zeiler who is a corneal and refractive surgeon and who after two years in a way had to leave because it didn't work out very well, not for him and not for the department definitely. So then I came, but this is our department today, you know, with some of the key people here but of course I can't tell you more than that. And as I said, all these people greet you. They had so much good time with you. Kathleen was fantastic in teaching. She had just a little bit more time than we did and she really took this upon her to teach the residents. She distributed the journal club. So we had a half a year of neuroctomology journals, you know, really one after the other and people are now really on top of it. And here she is teaching. This is actually the neurology. She did that also in neurology. This is the neurology department with these very old-fashioned, you know, but that reminded you of what Boston is a dome. Okay, it's not, but it's a little smaller probably. Okay, good. She participated in some of the teaching activities, you know, bigger events. Like of course with Michael Warner, her husband on neurology and of tomology complications in pregnancy. That was a big event. On April 24, we have some regular such events in the ophthalmology department. So she talked on photophobia. And then we had a very fun course which takes place every two years in a castle actually next to Zurich on the Zurich Lake. And that's the neuro-automology course with some guests from abroad. And Kathleen was one of them. And this is just the wrong, that's the one for two years before. So, you know, I put in the wrong one. But anyway, it looked very nicely and very similar next year. Thank you. Okay, so, so far for a short introduction about our department and about the time we had together. And now, what about trochanography? Well, this lecture is simple. It's not anything complicated. I just know that vertical strabismus is quite often a challenge when these patients come into your office, you're alone, you may not have too many people to rely on at the moment and you want to do the best out of it. So, let's go and take a trip on this. So, as you all know, the three-step test developed by Parks is a very neat way to start. So, now all you have to do is look at this scheme and kind of cover your left eye and look at it with your right eye, right eye in the center. And then you have to know your functional anatomy as far as this. You have to know that looking up and right is mostly the job of your superior rectus muscle. And here the inferior rectus muscle and the obliques are just the other way around. So, that's easy, right? But that you have to know. And then you have to give it a thought. The first step is which eye is the higher one? So, if you find a patient in whom, on alternate cover testing, you have a right over left, what is wrong with the right eye? Is it the elevators that are peretic or is it the depressors? Well, of course, it's the depressors. Otherwise, that's why the eye is higher than the other one, right? So, all you have to do, it's the depressors and you just make your line here, okay? Then you compare, is it worse on right gaze or on left gaze? Does this vertical deviation increase on right gaze or on left gaze? In this case, it increased on left gaze. So, all you have to do is put your mark, put your line on the left side. And the third step, as you know, is comparing the amplitude of this vertical deviation on right head tilt and left head tilt. And in this example, it was larger on right head tilt. And now you have your scheme and you have one box in which all three lines interact and that's the answer. So, the peretic muscle is the right superior bleak. And so far, so good. You can have another situation in which, you know, it's this way round. So, you have one box which is free. No line goes through it and that's the left superior bleak, okay? So, now we are set for doing this unless if you have a result which doesn't make much sense. Well, it does. It could be that the left inferior bleak is peretic. That's what your three-step test tells you. But that's not a muscle which is inner rated by only one cranial nerve. So, it may be the case. It may not be the case. And then it's your general judgment, of course, you know, and all the other aspects. It could be even just restriction. It could be anything. So, there is actually a nice article by Bert Kushner who cautions this and who says that there may be some errors in the three-step test in the diagnosis of vertical strabismus. And he starts this article by saying, the three-step test is wonderful for every and each patient who comes into your office and says, better, could you please tell me which one of my eight cyclovertical muscles is peretic? All these patients, you can treat with this and you get your answer. Okay. So, let's go into some. Yeah, and you have seen that some, this is actually very old and it's from my time when I was a resident and I just have it in my pocket and I kind of can do it quickly. And that's what I wanted to show you. There are other ways to do it, I know. But again, let's go to the anatomy. So, what are some special features of the trochanal nerve? As you all know, it's very long and very thin. As we said, it only has to supply one small, but important muscle, extraocular muscle. It's also the only cranial nerve that exits dorsally from the brainstem. All the others come out on the ventricle side. And it's also the only one that crosses and that it does so in the midbrain at the level of the inferior colic line. Both these very short fascicles, as I said, they cross at the bottom of the fourth ventricle and thus they actually the... the nucleus of the fourth nerve on the right side finally supplies the left supere oblique and vice versa. And this is all taken from... you probably also teach with... or do you use the Bahandas Klein and Bahandas book for teaching the residents? Yes. This is, of course, very schematic, but it's nicely put so you see where the nucleus is and how this long nerve has to cross dorsally to the other side, go around the whole brainstem and then here between the posterior cerebral artery and the superior cerebral artery goes between here to the clivus here and into the cavernous sinus and then finally through the superior orbital fissure into the orbit. So that's just another view to see how the nerve is. Of course, here you will rarely have an isolated fourth nerve palsy within the cavernous sinus. It could be the case, but it would be unusual. One more picture here of the potential lesion sites. It can be, of course, within the brainstem. It's much more rare, but it does exist. Trauma actually happens probably here mostly and then cavernous sinus and the orbit. So what are some special functional features of the trochanal nerve? Well, this is really a puzzling entity, the congenital palsy, people who, and we will talk more about that, who actually, in whom, is it the nerve or is it the muscle? That's a huge discussion and it's probably both and it's very heterogeneous, but another special feature is that being this such a thin and vulnerable nerve, even a minor trauma can cause a palsy. Then there is this entity of superior oblique biochemia which I'm not going into, but these patients who have been to so many ophthalmologists before and everybody thinks they are crazy, but actually they are not and if you look at them and if you can provoke the symptom, then you see that this eye, with your sleep-lamp examination, has a very, very quick rotatory nystagmus in this one eye and people really say there is something wrong with my eye and many times they don't get diagnosed, especially if it's intermittent, of course, and it's benign. And then trochlear nerve schwannomas, well, that's a rare entity, but it's so rare actually that a big, big group of neuro-ophthalmologists had to pull together a few cases that was published a couple of years ago. Okay, and it's, of course, benign, but not really treatable other than by performing some extraocular muscle surgery. Okay, so let's go to congenital trochanal nerve palsy. You know, when I actually did my fellowship in San Francisco and, you know, in Israel, my teacher was Moshe Oliver, who was a pupil of Marshall Parks, so I came to Switzerland with the American view on many things, especially strabismus, and I was struck how different strabismus is being looked at in Europe. I don't know, some of you may know the name of Josef Lange, who was a very famous strabologist in Europe, and he had a big fight with Parks. You know, so Parks talked about the monofixation syndrome, and Lange talked about microstrabismus and whatever, it was the same entity, but they called it differently. Anyway, they were both great giants of strabismus, but somehow Europe and America didn't get along too well, so there is another name to it in German or Latin, strabismus surso adductorius, which means that the eye goes up on adduction, the eye goes up. Okay, so it's very, very frequent, and you know this saying, fat scan instead of cat scan family album tomography is much cheaper than computer-assisted tomography, no side effects. It's a great way to diagnose this, and so if you have somebody, you know, since first grade, always looking into the camera in group photos, that's the best group photos. They always look like this, then they have, what, right, so their vertical fusional ability is just amazing. I mean, they come to you with a little head tilt, and then you start your checking, and then the eyes go like this. They confuse 30, even 40 prison doctors of vertical deviation. Now, you try that, that's really tough. You can't do it. So that's a very good sign of something very, very old, and thus not very dangerous. Motility, what I mean here is the overaction of the antagonist of the inferior bleak is so pronounced in these cases that, you know, when they look to the side of the palsy, when I have a right trochanter of palsy, I look to the left, my right eye goes up, and it's even, you know, the deviation is even larger when I look left and up than when I look left and down. So the kind of the overaction of the inferior bleak is more pronounced than the underaction of the superior bleak. Here, just a few examples. So this girl had a congenital nerve palsy, and this young chap had actually acquired trochanter of palsy. Anyway, the nine directions of gaze in this acquired case are not very abnormal. I mean, this is the primary gaze, and, you know, you don't see much, and this is what happens in acquired palsy. You check the motility, and it's actually normal, and the patient still, bitter complaints of double vision. There is some overaction here of the inferior bleak. Okay. The third step of the third three-step test is also called, at least again in Switzerland, we don't speak that much of the three-step test. We have the Bielszowskie head tilt test, and Bielszowskie is another famous name you may know. Okay. So this girl, when being forced to have a left tilt, her left eye goes up a lot, so she avoids that, and this is a left congenital in her case. Congenital nerve, forced nerve palsy. This was a patient who really didn't want to get operated for a long time, but then, finally, he agreed. So this was before the surgery, and that's after surgery, just this left gaze, and his right eye now stays nicely in place. And this was his nine directions of gaze before surgery with this huge overaction of the inferior bleak on the right side, and now much better. So you can do that. You can have the patients suffer a little longer and give them sometimes prisms, which may help for a while. You know, when they drive, they just do this instead of looking to the side because otherwise they will definitely not find the right spot. But then that's my opinion. It's nice to really have them at a stage when they want you to operate because, of course, that's not only for strabismus. Then they will be much happier when things get better. And so this is, I don't know how much you use this type of HES screen. You don't? Okay. Well, HES, Brutalf HES, was actually a Nobel Prize winner who was an ophthalmologist at some time and then switched to physiology It's a true story. When he had enough money after having been an ophthalmologist for a few years, he went to do what he really loved to do, which is physiology, and he won the Nobel Prize. So this is the HES screen test with the left eye here, you know, instead of being... Well, you see that there is a right over left with an overaction of the inferior bleak. Then it became worse. That's the same patient. So now he decided, okay, let's do it. He was a lawyer, you know, so I wasn't too eager to operate on him either. Okay. And this is the way it was before the operation and after the operation, kind of a nice improvement, and he was quite happy. So how do you treat it? And this again is something I've seen, you know, there are books, and of course, they are wonderful, but after a while, for at least in strabismus surgery, you really develop your own ways based on mistakes, usually. Try and error. So what I really could say after all these years, I almost never performed more than a weakening of the inferior bleak in these cases, not a second muscle at the same time. So you could do it in extreme cases, but in the literature it says, you know, from 15 or 20 prism diopters on, you should do two muscles. Don't, okay? If you take my advice, because these patients, even though they confuse 30 or 40 prism diopters before the operation of, let's say, right over left, they can't do even two or three prism diopters left over right. That's just not what their brain is being trained for. So they will not be happy. And so what we do is an anterior position of the inferior bleak, which corresponds to the 10-millimeter recess described by Parks, and it's quite an easy operation. So we just put together our cases of 45 patients in the, you know, this is the H, and they have been operated between 2000 and 2010. And we see all patients, of course, before surgery, and then we have them back three months after surgery and a year, which is very helpful to, you know, to make your own quality control and studies. So this would be the result of this group of patients. It's always the status before surgery, then three months after, and one year after, and that's, you know, the vertical deviation here, just the vertical deviation. So of course, hopefully it went down. And in every position of gaze, we did this, and it's interesting, actually something I did not expect necessarily, that it even further improves, you know, between three months and one year, which is good, because eventually, actually, these patients may come back after a few years more. We just had this one-year follow-up. Okay, so of course the vertical, that was what you saw was the vertical deviation before three months and after one year, that goes down, but also the horizontal, which is usually not very large, diminishes and the torsional as well. So this is in the clinician, that's Bledtov for Augen Heil Kunde. I'm sure that everybody reads this journal. Well, you're laughing now, but you know, this was actually founded by Albrecht von Greife. This is a very old journal, and you can publish in English in there, and it's connected to the Swiss Ophthalmological Society, so that's why we have to publish there. Okay, so this antroposition of the inferior bleak muscle is a really interesting surgery because what we found out and what I kind of felt, but here it was evident in the study, the larger the deviation, the bigger the effect of surgery. Well, isn't that wonderful? I mean, where have you, you know, this no other muscle will do this for you. You know, this is just fantastic. Whatever it takes, it will be done. You know, it's just fantastic. The inferior bleak, as you see. Okay. Any questions so far? Any comments? Well, on time? Okay. So let's go to the acquired trochanal nerve palsy and a few rules. This is again from Bajangas and Klein. This 10-2030-40 rule, 10% etiology is compression, so not much, but it's possible, of course. 20% ischemia. You know, the microvascular ischemic nerve palsy can hit any cranial nerve. Some, you know, they had to have some 30 here, so that's diverse or unknown, and lots of trauma, and that's actually the message. So many, many have a trauma background, and that's, of course, usually easy to find out. So, of course, as always, what you have to do is make a very good neurological exam and find out whether this is truly isolated or not, and if it's not, then, of course, the other sides will lead you to make the correct diagnosis. And as I said before, motility can really appear to be almost normal, so the usual scenario is of a patient, you know, having had a concussion and then waking up in the emergency room with a surgeon and then complaining of double vision, and after all, they do the motility exam, but it's normal, so they say, oh, come on, you know, that's nothing. And at some point, they get to us, and usually they come like this, right, because they usually have a bilateral trochlear nerve palsy, and you need your superior bleaks leased when you look up, so they come like this, and everything like this, and everything is crossed, and it's just terrible. But on motility exam, it looks normal, and even on cover testing, it may look quite normal, because the main problem is the torsion, and that you, of course, can't find out with cover testing. So this would be an example. This was put together, you know, using the harm's tangent screen. Kathleen, you have seen it. It's huge. It's, you know, a huge thing on our wall in the Strobismus department, and people have a headset on their head, and it's being done by an autoptist. Do you have a autoptist here? I hope so. We have a school of autoptics, and that's really fantastic. That's such a big help. So they do these exams usually, and it's, of course, you have to dissociate between the two eyes, and the patient has to show where both eyes have, you know, where the image of each eye is located, and there is also a line where they can adjust the torsion. So it's not just the point which you have in the head screen test, but in this harm's tangent screen, you can also get a subjective measurement of all three directions, vertical, horizontal, and torsional deviation. So this, as you see, the largest vertical deviation is on down gaze, and the largest x-cycle torsion is on down gaze. And you can also do the same in an objective manner. So you put a surge coil on the patient's eye, and we have that set up as well. This is a magnetic field in which the patient, again, looks in all nine positions of gaze, and you get from the same patient similar, well, not similar, actually, somewhat different, more pronounced deviations. That's probably because the patient was already fusing some of it, but here there is no fusion involved here. It also gives you the x-cycle torsion, but not in the absolute value. It's just relative to the primary. The primary is defined as zero, and then there is an in-cycle torsion in up gaze and an x-cycle torsion in down gaze. So this is a nice way, but it's not very practical. It's very cumbersome, and you can put it in a nicer picture. And we actually compared this. This is quite a couple of years ago, 2006, we did this study to compare the subjective and the objective way of measuring all three deviations in trochlear nerve palsy, and now we are now, of course, the next step is videography. That's the best, and we are working on some special goggles with Cony Weber, you know, that there is a research project going on to make it a little bit easier than this huge magnetic field and search coil, which, for instance, you can't do in children, and it's quite cumbersome. Anyway, so again, so what do you do when you have a patient with a forced nerve palsy, which is acquired usually post-traumatic? Well, first of all, be sure that it's not bilateral. It may be asymmetrical, but then you operate on one eye and the other palsy kind of comes out of the bush, and then you have another... I would still probably do the one side first, but tell the patient before that there may be a bilateral problem. If you see from the very beginning that there is a bilateral palsy, then of course you treat both in the same procedure in your same surgery. So how do you look for these sides of possibly bilateral palsy? Well, the x-cycle torsion will be really huge because that adds up, you know, each superior bleak muscle is palsy. That means that all of your in-cycle torsional capacity is gone, and that means that your x-cycle torsion will be very large. On the contrary, your vertical deviation may be zero because if the amount of the palsy is the same on the right side and on the left side, that kind of neutralizes itself. So you can really have a patient with no vertical deviation at all or very, very small. And you will have a very pronounced V pattern because your superior bleaks, as you know, are bleaks. The B in the obliques tells you that the inferior obliques and the superior obliques have a little bit of an AB-duction effect. Okay, so there will be a pronounced V pattern because of that, because you need your obliques more than superior obliques when you look down, which gives you an isotropial shift downwards. And of course, if you have even that, if you have a switch on right over left here and left over right here, then things are very clear. Good. So now, in these cases, it's not primarily the inferior bleak, the antagonist, it's the palsy muscle which you have to strengthen, which usually was a tuck. And then you may do it with or without the inferior bleak as well. And there are tables for that and patients are usually very happy. So here I am. My general remarks would be that all roads lead to Rome, as you know, and this is really something quite special about strabismus, I think. You develop your own methods and that's the ones that actually have a success. So why not? And the future dream would be to have a model and I think many people are working on this, many groups, where you just put in your pre-operative measurements and it comes up with a precise operative plan and it works. That's the other thing that should be nice to have, but on the other hand, then we strabologists will not be needed anymore, so maybe it's not that good. So I think I'm at the end of my talk. This is a very nice detail of a picture which is in the art gallery in Zurich. It's by Amadeo Modigliani. It's actually his almost wife. He almost married her, but then he got to her closest and he died and she actually was pregnant, eight months pregnant and jumped out of the window a day after he died. So, you know, a very tragic story. I don't know whether she did have a person of policy or not, but it's a beautiful picture and it's just to tell you that there's lots to see in Zurich and please come and visit. Well, if there is a clear history of trauma, that would be enough. You know, if you can document this force nerve policy with your whatever you use, the tangent screen, the S screen, then you have a set of data and then you wait I usually wait a year before operating because really it's amazing how well they can actually improve within a year. It's usually more in the first half of the year than in the second half here. But if you think whether to do more exams like an MRI or anything, if it's very clear I probably wouldn't. But you know, then again the medical ecosystem is different here, but there is lots of discussion of incident alomas, you know, do you want to do an MRI and find something you don't want to know about which is not related to what you're looking for and these things. So, I think if the situation and if the double vision was there from the beginning, if it's half a year after the trauma but it's newly symptomatic, then of course it may not be related at all. Is that a good answer? Thank you. That and thyroid it's always thyroid, you know, not always, but that's really so common and then much less. Anything else is really that's true. And they somehow always usually, you know, it's sometimes tough for the patient to find the person who gives them the clear answer and I've just seen a patient who came all the way from Slovenia and who had lots of MRIs and still vertical and just looking at the MRIs which he already had showed a thick inferior rectus muscle in that one orbit. I mean it fitted so well but, you know, when the neuroradiologist tells you normal scan, then and if you don't look at it yourself I mean, you know this. Yeah. Look at the scans yourself or talk to the neuroradiologist. You always said the neurolofimologist is reinterpreted of normal MRI scans. And they are either normal because the disease doesn't show that's like myostinia or something like that or they are normal because neuroradiologists just missed it or they are normal because they are not imaging the right place. That's the three reasons. And if you do get a chance to go into a really disappointed by the city it's lovely and the university is a very old and famous to think that this... Well, if you want to hear more, you know there is foked, as I said was not the nicest guy on Earth. I didn't meet him, of course but he had a big fight with Hans Goldman. Does that ring a bell? Hans Goldman? Good. So Hans Goldman was a chair before he was chair. He was in Bern. So he is the famous guy in Bern and they had a fight over what causes the cataract of people who work with glass. What's the name? Yes, yes. Is it the heat or is it something else? And of course Goldman was right. But folk didn't never forgive me for being right. Anyway, so, you know, what else? In Geneva there was a famous chair by the name of Francescetti. Does that ring a bell? Genetics? And maybe the name you must know is Lausanne. We have five universities in Zurich. Zurich... Sorry, Switzerland. Zurich, Bern, Basel, Lausanne and Geneva. One had, the I department is called Gona, Jules Gona hospital because Gona was the one who was a retinal surgeon and who actually first discovered that you should that the hole in the retina is not the consequence of the detachment but the cause of the detachment. So you have to close the hole and then the retina will so that's quite an amazing discovery. And he had to fight a lot before this was accepted. I would like to thank Clara from coming from Switzerland to give us this lecture and we're going to be heading over to neurology now to talk about perimeter so to hear about perimeter it's going to be the PPP lecture. Thank you very much for having me. Thank you. Thank you.