Strabismus in adults has achieved major emphasis. This lecture describes a system for prioritizing and addressing the expectations from surgery of adults with strabismus, and both the opportunities to fulfill their goals and the obstacles that require compromises. As the circumstances involved in prior operations in the remote past often cannot be ascertained, novel and creative solutions are sometimes required. A checklist of parameters to consider, and why, are presented, as well as tie-breakers when there is more than one option. Useful general rules are included.

Lecturer: Dr. Edward Raab, Mount Sinai Hospital, New York, USA.


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DR RAAB: Good morning, everybody. Welcome to this Cybersight offering. My name is Edward Raab. We’re doing this from New York, where my home base is. I’m at the Mount Sinai Medical Center here. And I’ve had a very nice personal experience with Orbis for a long time, and this is my opportunity to give something back for that. So I hope this will prove to be useful for you. You’re very welcome to be present. Well, today’s offering is how to plan for what I call complex and reoperated strabismus cases. Now, reoperated cases are complex, usually. They require more planning than the usual ones that we do. They more typically involve adults. They more typically involve limited rotations. And I use the term “limited rotations” advisedly. We will discuss that in a while. So these are some of the typical scenarios that we have with complexity. Thyroid ophthalmopathy, orbital fractures with limitations, scarring after glaucoma drainage procedures, reoperations of any kind, and also longstanding strabismus that has never been dealt with. So the key to all of this for me and the take-home message for you, which we’ll repeat later, is: When it comes to complex cases, understand that not everything can be resolved. We’re taught as doctors to take all the facts of the case, all the information we gather, and try to tie it up in one bundle. You can’t do that here. Another profession — lawyers. They take facts all the time. But they concentrate on the big ones. And the marginal ones they tend to not try to put into one big package. And that approach is really what we have to do, when we’re dealing with complex cases. Especially reoperated ones. So my message to you is: find the patient’s big problem. Not your big problem. The patient’s big problem. And be prepared to be creative and to change gears in the middle of a surgical operation. And we’re going to examine some of those propositions. So what is the information that I use when I’m planning for a complex case? Well, I certainly want to know about the vision, because if one eye is a very good seeing eye, and the other one is a poorly seeing eye, that can’t be remedied — I’m not talking about amblyopia. I’m talking about macular scars, optic atrophy, developmental defects. We try wherever possible to avoid operating on the one good eye. There are times when you can’t avoid that. One of them, for instance, is in congenital motor nystagmus. Where the head position is such that the better eye is in adduction. And the head turns toward the side of the better eye. Well, if you don’t operate on the good eye there, to bring it to a more central position, you’re not gonna do anything for the no-zone head position, which will still be present. So there’s an exception to that rule. Particularly with rectus muscles, you want to know how many of them might have been operated beforehand. Now, how to know that we will get to. But that’s a piece of information you want. You want to carefully examine rotations, to see if there are any limited rotations. When we describe overactions, particularly, let’s say, of the oblique muscles, the likelihood is that that’s not the primary problem. The primary problem is some underaction of the yoke muscle on the other eye. In any event, we still conventionally think of excess rotations as overactions. You also want to know where the scars are. Because sometimes muscles you want to rework on you can’t. Or you can’t and get the effect you want, because of all the scarring that’s present, and the new scars that you will bring up. Palpebral fissure width is important. If the previous surgery or the previous injury has left the vertical palpebral fissure opening wider on one side, if you have choices, you want to pick an operation that will tend to neutralize that. And I’ll show you a prominent example of that parameter later. And if the fissures are equal before you start, you don’t want to create an inequality. We’ve all been taught that the lower field is more important than the upper field. So you give preference to primary position, and what will work best for the lower field. Remember that when we look down, when we read, we typically direct our eyes at least partially down, in addition to our head. When we’re trying to look way up, that’s typically a head movement, so that you’re really moving primary position directed upward. So the upper field is somewhat less important than the lower, assuming we can’t take care of all positions of gaze. Now, the potential for diplopia is important. Especially in children beyond the age where the binocular system is flexible. So the potential for diplopia is really not a planning parameter. I have it in there mostly to remind you that it should be part of an informed consent. For many adults, what they want to get rid of is diplopia in the usual fields of gaze. That is to say, straight ahead, and a few degrees up and down and left and right. What goes on in the far periphery of those directions is much less important. They want to be free of diplopia, with or without modest amounts of prism power, in order to accomplish it. So, again, that’s not a planning parameter. But it’s very definitely something that should be discussed. All right. Now, I mentioned — how do we get this information? Okay. Well, here’s the first question posed to the audience. What are our best sources of prior information? You have exploration, the history, office records, or operative reports. So let’s take a quick poll, before we go any further. All right. Has everybody voted? Yeah, okay. The votes are… A predominance for operative reports. And for history. And exploration and office records are down the list. Okay. Well, here’s my response. My response is exploration. Your findings now. Verbal history given from the patient can often be incomplete and erroneous. From office records, you can get an idea of what muscles have been operated, but as far as where they are now, don’t depend on operative reports. Muscles are where you find them at your exploration. And that’s true whether it’s your prior surgery, and it’s your report you’re reading, or another ophthalmologist’s report. And it’s really very easy to make these determinations yourself. You can see in the upper picture that you can just make a limited incision — easily closable — put a hook under the muscle of interest, and with a caliper, you can determine where it is. It’s either a muscle that’s never been operated, that’s where this lateral rectus appears to be, or it’s one that has been operated, probably resected, and put back. In the lower picture, you can use, again, hook the muscle, and you can see just by how easily the tissues move whether it’s a fresh muscle or not a fresh muscle, and what its vitality is. So I would really advise you not to depend on either history or past reports. Everything you encounter in a complex case is going forward. Not going backward. And that’s been a very useful parameter for me. All right. We talked about rotations. And rotations can either be full or limited. If, in order to correct the — whatever the misalignment is — the muscles that you might use seem to do their job very well, you can go back on them, but it’s often much easier to use unoperated muscles in your usual number of millimeters for that size deviation. If there are no limited rotations, you do not have to alter what you would do for a fresh case. So that’s called the Cooper Doctrine, named after a prominent strabismologist of several years ago, Dr. Cooper, and it comes in very handy. Here are two items from my experience, when it comes to working with full rotations. If you want to go back on a previously resected muscle, that’s fine. You can resect it more. But remember to check the forced ductions intraoperatively, as well as — I hope you’ve done — preoperatively. When it comes to recessing a previously weakened recessed muscle, the result can be unpredictable, and you risk postoperative limitation. So if you determine that a previously recessed muscle is at somewhere near the conventional limit of where we typically leave recessed muscles, be very careful about doing it again. You might use an adjustable suture here, even if you don’t favor them for routine cases. Or you might look around for other options. So now here’s question two. It doesn’t involve an adult. It’s a patient, now 12 years old, but with a history of infantile esotropia, of 70 prism diopters. In which the surgeon chose recession of the medial recti, 6 millimeters. Pretty close to the usual maximum for a small child. On that muscle. And added a third muscle. A resection of 8 millimeters. Now, throughout this, we may be talking about resection, but everybody should understand that more recently, we are frequently doing plications to tighten rectus muscles, rather than resections. So what we say about resections is essentially the same for plications. So here at age 3, for this rather large esotropia, three muscles were chosen. Another choice could have been 7 millimeters or 7.5, for both medial rectus muscles, but that might not have gotten 70 prism diopters either, and it also would have involved a third muscle, so that it seemed better to not do that much recession. Now, at age 3 years, after what was successful surgery, accommodative ET supervened, and was now a new problem. And my experience has been: this happens a large number of times. After a perfectly good correction of infantile esotropia, at a later time, accommodative esotropia supervenes, and despite correction that was good for several years, finally at age 12 years, optical compensation by glasses was not enough to prevent decompensation of that accommodative esotropia, and now we have much more modest measurements, slightly bigger at distance than at near, reflecting the fact that recessing the previous medial rectus operation was a more powerful one than the resection effect. Abduction and adduction are full, and there are no inferior or superior oblique under or overactions, and no associated deviation. So now we have a pure example of a patient who ought to have another operation, and there are no limited rotations, but with three muscles operated. So now we come to the question: what would be a good plan here? We have a choice of repeating recessions on the medial recti, receding one of them and resecting the lateral, and in this case, it could be the right eye, since the right lateral rectus had not been operated. And we have a chance to use a fresh muscle. We can do a resection procedure on both, in which case the left one would be — the left lateral rectus would be a repeat resection. Or resect only the right, on the right lateral rectus. So how will we vote here? Okay. So the results seem to favor resection of only the right lateral rectus. Not much sentiment for re-recessing the medial recti on both sides. Certainly not much for wanting to recess — re-recess — even one of the medial recti. And that would be my choice as well. I would, I think, this being my case, I think what I did was I actually resected the right lateral rectus and re-resected a moderate amount the left lateral rectus. I could have done only a resection on the right lateral. That would have worked. But you heard me say if the medial recti were just about at the limits of a safe recession, why would we want to re-recess both of them? And for that matter, why would we re-recess even one of them? So certainly choices C and D would seem to be the better ones. And here is what I did. I followed the Cooper Doctrine for the most part, as much as I could. I resected the right lateral 5 millimeters and re-resected the left lateral 3. Could I have done it all on the right lateral rectus? Probably. In which case I would have had to do more than the total of 8 millimeters you see here. Why didn’t I do 4 and 4? Well, there was a small incomitance in right gaze, reflecting the fact that the left lateral rectus had been operated, and so I tried to balance what I would get in both lateral gazes to a small amount. I’m not sure that was important, but it certainly did no harm to the case. It was a good outcome. All right. So now let’s get to — away from rotations that are full. To rotations that are not full. And I describe them only as limited until they are analyzed. There are three principal reasons why a rotation would not be full. One is: It’s the weakness of the muscle responsible for that rotation. Another is: There’s a restriction to that rotation. Probably involving the muscle on the other side of the eye, the antagonist muscle. And the third one would apply to such things as Duane Syndrome, where you have anomalous co-contraction and anomalous innervation of the muscles. So we’re not gonna deal with that last situation, so much as we will with these first two. The weakness and the restriction. Well, first of all, if there’s a limited rotation, we have to understand where it is. In this picture, the patient looking up to the right appears to have what we would call an overacting left inferior oblique. If you look at the picture just below that, if you cover that eye, you see that it is something involving the oblique, because the right superior rectus action, elevation of that eye in abduction, works pretty well. So this would not be an apparent overaction of the inferior oblique, because of a Hering’s Law effect on the yoke muscle to a limited right superior rectus. Here’s the same patient. And now she’s looking down and to the left. And depression in abduction is limited. The right eye is probably the fixing eye in that view. And when you cover that fixing eye, you see that the patient still can’t depress, even in primary position. So you know that this is not a weakness of the right superior rectus you’re dealing with. It’s some weakness or restriction involving the left inferior rectus. So until you sort out where the rotation is limited, in this kind of — in this manner — you really haven’t analyzed things. So how do we then further analyze limited rotations? I’m again calling them limited. Well, the forced duction or traction test is our gold standard, but for what? For restriction. The forced duction test doesn’t tell you anything about muscle strength. And although we call it a forced duction test, it really should be done passively. Not with force. You can probably force an eye to go anywhere you want it to, tearing conjunctiva in the process. But it should be done in a more gentle manner. And when you’re doing a forced duction test on the vertical rectus muscles, it’s important not to push the eye back into the orbit with the forceps, because that puts the rectus muscles on a slack, and you want them to be at their tightest. So if anything, you try to prolapse the eye a little bit. For the oblique muscles, they are their tightest when the globe is back. So there you tend to try to push the eye back a little. And for the oblique muscles, you’re probably familiar — I won’t discuss it further here — with the peculiar traction test, where the eye is grasped in two places, and torsionally rotated, while moving through the vertical field below, and torted with the two forceps. So now, if the forced duction test tells you nothing about the strength of the muscles, how do we tell that? Well, there’s a test called a force generation test. Where we can either measure the force with a very fancy device called a strain gauge instrument, or we can do it in an indirect manner. Actually, the forceps on the globe, although I label it here as direct, is not really direct. So with the same forceps that you use for a forced duction test, where you are trying to move the eye where the patient cannot, in a force generation test, you try to hold the eye in a position away from where you’re gonna ask the patient to move it. And then ask the patient to move it in the suspected direction where the rotation was limited. You can feel in your grasp on the forceps the transmitted muscular contraction action of the muscle, trying to get to where you are now preventing it, and you can get a judgment of force generation that way. Another way you can do it is by saccadic velocity determination, which not everybody has. You put electrodes on — and this is a modified electromyogram, where using the eye as a battery, so to speak, with the positive pole forward, and the negative pole backward, as the eye rotates toward a certain one of these electrodes, it gives you a positive deflection, and when it rotates away, it gives you a negative deflection. And if you look at the left tracing, the lower one, you’ll see that the patient gets a very nice — what’s called a square wave. A very nice brisk looking to the right, and a very nice brisk looking to the left, and the velocity recordings are normal. That’s the tracing above. Whereas, in another case, you can see that in the upper trace, you don’t get a nice square wave. You get rather a weak and wiggly wave that tells you that there’s not much active force, and the velocity trace, which is calculated below, bears that out. So suppose you don’t have that machine, and suppose you can’t get a forceps on a patient’s eye. Well, another way you can do it is with a saccadic velocity drum. A saccadic velocity drum generates saccades, which are rapid eye movements that are caused by good muscular action. They’re not following movements. So if you take the drum — in this case, you see that the drum — we want to assess the elevation force of this patient, who has a demonstrable limitation of rotation upward of the left eye. If you take the patient into downgaze, and move the drum so that you generate what should be an upward movement, you can observe the movement, and if it’s saccadic, if it’s the usual way that we respond to saccadic movements, you get a good idea that there is active force there, and if it’s a weak or floating motion, you don’t — you get an idea that it’s floating. Now, suppose you don’t have an optokinetic drum. You can do this another way. Give the patient a light to fixate in the distance, and put up a prism. In this case, you would put the prism base-down, since you’re trying to assess elevation. Interpose a prism base-down, in front of the eye, whose superior rectus you’re trying to evaluate. And the patient ought to make a very brisk refixation movement. And if that doesn’t happen, that’s another sign that there’s a limited rotation, usually attributed to that eye. Now, in that case, you should have done the forced duction beforehand, because you wouldn’t be doing force generations — or you would be, but you wouldn’t get the same information if the patient has a restriction, if the saccadic velocity — if you have it — if the optokinetic drum or if the fixation with the prism doesn’t give you a brisk elevation, if there’s also a restriction, you can have a restriction and a weak muscle, and that is a special consideration. Now, here’s a big clue. If you have a — if you can’t do any of these tests, that we’ve mentioned, for limited rotation, but now you have a patient whose eyes were essentially straight in the primary position, and now in the right hand picture, where you’re eliciting left gaze, the right eye adducts fully, and the left eye goes nowhere, absolutely nowhere… That’s very unlikely to be a weakness. It could be a restriction. In this case, I’m showing you a Duane Syndrome. But the point is: Any limited rotation that leaves you with what look like straight eyes in the gaze position, in the primary position, that’s very unlikely to be a weakness. It’s either a co-contraction effect, or it’s a restriction. So there’s something where, if you have no instruments or no opportunity to use them, you can get at least the preliminary idea. If I showed you the rest of this patient’s motility, you would see very clearly that it was a left Duane’s, with the typical features of narrowing on adduction and upgaze, upshoot. Okay. So for limited rotations, as we said before, we try to see what’s going on with previously operated muscles, by looking to see where they are and not depending on operative reports or history. So the other point of this slide is to show you — or to explain to you — that you have your tentative plans worked out as to what you might do. You may needed to be creative, as we’ll discuss later, but you have a tentative plan. And it does involve exploring all muscles that you thought were previously operated, and certainly those that you might use again, and you should explore them all and have all the information you need, before you operate on any one of them. If your plan depended on some two muscles — it doesn’t matter which they are — and when you approach the first one, you can’t accomplish it, because it doesn’t look or feel or be uninvolved by scar to an extent that you would find important — you have to go looking around somewhere else. If you do something to the first muscle, and you come upon a situation that you can’t work with at the second muscle, that’s even a more difficult thing to be creative about. So any of the muscles that you think you might use — look at them before you work on any of them. If you think they’re fresh, be sure they’re fresh. Use limited incisions. Pick up the overlying tissues to make sure they’re not bound down. And then, knowing everything you can, you can work. And none of that information is gonna come from either operative reports, prior history, or patient office records. I can’t stress that too much. All right. So you’ve done all these good things, as I’ve suggested. And you determined there’s a restriction. Forced ductions tell you that. Well… The first thing I would recommend doing is do your conjunctival incisions, separate the conjunctiva from the underlying muscle and whatever adhesions are on it, and if that improves the forced duction test, you certainly want to recess that conjunctiva, when you reattach it. If you bring it back to where you started with, and tightly suture it, you’re gonna recreate part of your — at least part of your adhesions. If you have a restriction and nothing happens to change it, with the conjunctiva recession, and you’re planning to use it, put your suture in, and disinsert it. If that improves the restriction, then you have a plan to do something with that. Typically a weakening procedure. You don’t really have a good quantitative scheme as to how many millimeters, based on the deviation. So there’s a case where, whether or not you like adjustable sutures, that’s a good case to use an adjustable suture. The point is: You cannot have a scheme for — I do so many millimeters for so many prism diopters of deviation, when it comes to either restrictions or weaknesses. There you have to improvise, and one of the more favorite tools when we improvise is an adjustable suture. I personally am not a big fan of adjustable sutures. I do not use them routinely, even in adults. I do use them in special situations, this being the typical one. Okay. Now, suppose you have a normal forced duction, and you’re dealing with a weakness. And you can identify the muscle principally involved in what was a weak rotation. You wanna look for intracapsular slippage. If it was operated on before, it may be that the suture was put in to capture the capsule, and didn’t capture the muscle itself. In which case, you will not have a true loss. You will have a visible slippage, within the capsule of that muscle. A true loss is rare, although if it’s going to happen at all, it will be on your medial rectus muscle. If it’s only a minor slippage, I usually don’t try to fix it. I will prefer to try to fix this, again, according to the Cooper’s Doctrine case, where you can use the muscle on the opposite eye, or the antagonist of that muscle, and just do it as if it were a fresh case. If it’s a major slip, there you have to capture the muscle and bring it back, typically to where it might have started originally. That is to say, its original insertion site. And then you have to do something adjustable on the other muscle. Now, if you’ve already worked on the other muscle, and you haven’t done it adjustably, and now you discover that you have a major slip on this one, then you have to go back and readjust the muscle you already worked on. And this is why it’s important to look at all the muscles you might use, before you do either one. You should have known about a major slip, intracapsular, or a loss, before you did work on any other muscle. And this is a good example of why. Now, there’s such a thing called a stretched scar. And whether a stretched scar is really a stretched scar, or whether it’s an intracapsular slip that has scarred in is debated a long time and in many places. But here, it would be one and the same. If you have what looks like a stretched scar or an intracapsular slip, you would want to work on that muscle, put it back at its anatomic place, and try working on other muscles in order to solve the deviation. You have to think on your feet, at the time, and be creative. We’ll get to that again in another context. So now we come to another question. We’ve discussed weak muscles, weak rotations, and restricted rotations. What is the best way to characterize things? Which of the following does not tell you — differentiate between a weak rotation or a restriction? A forced duction test? A force generation test? A saccadic velocity recording? Or just judging whether the deviation is bigger with one eye fixing, or the other eye fixing? What we call a primary or secondary deviation? So we’re interested in which of these four does not give you any information or sufficient information. I want to take this off. All right. So our result is in favor of primary versus secondary deviation as not giving the appropriate information. And that is the correct answer. A forced duction test tells you restriction yes or restriction no. It gives you no information by itself about weakness. A force generation test tells you weakness yes, weakness no. And doesn’t give you any particular information about restriction. The combination of these tells you what you really want to know. Saccadic velocity tells you weakness, as does force generation, but nothing about restriction. Primary versus secondary deviation tells you neither one. The eye that doesn’t have the embarrassed rotation, when it fixes, will give you the bigger deviation than when the other eye is the fixing eye, whether or not it’s a restriction or a weakness. So everybody got that one, and that’s very important. We talk about — the neurologists who see cranial nerve disorders talk about the primary and secondary deviation as pointing to the eye with the paresis. Yes, it does. It points to the eye with the paresis. But it doesn’t tell you anything about restrictions, which is the context we’re looking at. Okay. So those are the major issues. What are some of the other things that I use as my planning? It’s usually very safe to operate on a third rectus muscle, or to reoperate on up to three rectus muscles, or at least up to two rectus muscles that have been done before. Even in elderly people, where you’re concerned about arteriosclerosis, in my experience, third muscle — third rectus muscle procedures are usually okay. I’m very wary of doing a fourth rectus muscle. If something seems to call for operating what would be a fourth rectus muscle, I either do it in the most limited way possible, which could be either by microscopically isolating its feeder vessels, which I don’t do, or maybe doing a limited central tenotomy, which I lately have been doing, but I usually have to adjust the plan, and think of something else to do. So here: Beware the fourth rectus. And we’ve already discussed the second of these. Give priority to the primary position, and the lower field, over that of the upper field. We’ve covered that one. When you operate on vertical rectus muscles, if there’s an alternative that will not make fissure widths unequal, or that will equalize fissure widths that are already unequal, look for that alternative. If it’s an alternative. If it’s not a reasonable alternative, then you just have to deal with the fissure width in another way. If the limited rotation involves the better seeing eye, and in order to make the case come out so the primary position is good, so that a little above, a little below, and a little to the left and right would be good, you may be forced to operate on the better-seeing eye, and include that, really, in your informed consent discussion. Very important. All right. So now we have one more creativity question. This is the patient I dealt with. The history was: left superior oblique palsy. And I had the other doctor’s records. And even though I don’t like to rely on it for my surgical plan, I could rely on it from the history in this case. And the history indicated — and the other doctor’s operative report — and I emphasize that I look at the other doctor’s operative report — there had been a recent left inferior oblique myectomy for that left superior oblique palsy, and a recession with adjustable suture on the yoke right inferior rectus stated to be 2 millimeters, with the right lower lid attachments divided, and I presume that was not to generate a lower lid sag problem. And that’s why I have it in italics. Postoperatively, with the other doctor, the patient had vertical diplopia. And a wide palpebral fissure on the right eye, which she didn’t have pre-op, and now a right hypertropia, and limited depression of the right eye, in all gazes. Okay. You should be starting to get a picture here. Left superior oblique palsy. Yoke inferior rectus, modest right inferior rectus, adjustable procedure, now a right hypertropia, and limited depression of the eye that had the inferior rectus recession. Okay. So here’s the way she looks when I see her. Not before the other doctor. This is now presenting to me. And what we can see is a left eye that doesn’t elevate quite as well. The upper central picture. A right hyper in primary, the middle central picture. And an eye that can’t get down in primary — in the straight-ahead downgaze. Now, I would have gone through all of the maneuvers I told you. Forced duction test, force generation test, by one or another method, and here I am, and I need a plan. So let’s see. Here’s my plan. One of my choices is: Look at the right inferior rectus. Clearly it seems to be a problem. Despite the report of a modest recession and adjustable suture. I could recess and adjust the right superior rectus. Okay. And if I work on either muscle, I don’t want to go into — I don’t want to do too much to the attachments below. You’ll see why in a minute. Anyway, here’s my… So there’s my plan. Let’s vote. Who would do what? So what I see is that there’s a distinct preference for advancing the right inferior rectus. Now, I could have done just the right superior rectus. That would take care of the right hyper. But really, the suspect muscle was this one. So what I did was… My plan, my plan was what the audience has said. Advance the right inferior rectus. And it was to avoid the right lower lid attachments. Why? Because I needed something to address not only the right hypertropia, but I needed something to address the right lower lid reattachments. And that was another reason not to just work on the antagonist right superior rectus. So let’s see what I did. Here’s my operation. Despite a reported very limited recession of the right inferior rectus, I found it to be attenuated, and with a very indistinct reattachment. I looked there first. Because I knew I was gonna do something about that. What now? What do I do now? Weakening the right superior rectus doesn’t take care of the lids. I advanced what I call the right inferior rectus in quotes. Without dissecting away the right lower lid attachments. Why? Because in advancing the right inferior rectus, I was depending on those attachments to help me elevate the right lower lid margin. This was invented by me, or thought of by me, only having looked at — initially — that badly attenuated right inferior rectus, which I had no reason to suspect. Okay? So now I have a right inferior rectus that’s fragmentary, put back where I wanted it, in order to get the upper lid up. But how am I going to get that eye down to the primary — down to primary position? Can I depend on that right inferior rectus? Probably not. So what I did was a right inferior oblique anterior displacement, as you can see on the right in the diagram, before the reattachment, and instead of putting it just lateral to the right inferior rectus, I put it right over the right inferior rectus. I was not expecting to get depression from this. I was expecting to get an eye with a better right lower lid position, and better in the primary position. So let’s see what happened. Here she is beforehand. The upper picture on the left shows her right hyper and primary position, in primary position, and her wide palpebral fissure. The lower picture, 18 months later, shows an eye that’s not hypertropic anymore, and a very good lid position. Look at the pictures on the left. The preoperative picture, pre-my operation, shows a right eye that can’t get down, and the lower picture shows an eye that gets down very well. Now, did that come from the right inferior oblique anterior transposition? No. Here’s what I think happened: When you find — or when you can’t find the muscle, or you find the muscle in very bad shape, use it anyway. And include some of its surrounding tissues. Because you may be fooled by what you think is an essentially non-working muscle that can work. And what I thought was a fragmented very weak inferior rectus is what I think was responsible for the improved depression, once I put it in its anatomic position. And so the big message there is: Use what you can, and you may be surprised by how well it does. Now, here’s some last creativity. Here’s a patient, an adult patient, who had esotropia in childhood, one operation at age 10 years, no operative report. This is my history. Vision: 20/25 in the right eye, and in the left eye, due to a very dense amblyopia, finger counting vision at 10 feet, and an exotropia measuring over 100 prism diopters. I can’t even tell you how many. But the light reflex was well onto the sclera. There was an A pattern, and overaction of all the oblique muscles, which we probably recognize as a pseudo-overaction. What am I gonna do with this lady? Here she is. Primary position, huge exo. Big exo in upgaze, big exo in downgaze. Full rotations to both sides. What am I gonna do for this? Let’s go to question five. Huge XT, one good eye. Here are the choices. Huge recession on the lateral rectus, huge R and R on the eye that can see, huge R and R on the eye that can’t see, or huge resection of both medial recti, or none of these? And if you have none of these, what else are you gonna do? You’re not gonna tell me but let’s see. So please cast your votes. We’re coming to the end. Okay. Let’s go to the votes. And here they are. We don’t have 100% of people voting here. But: Huge R and R, left eye, or none of these. Okay. You cannot do anything for this patient that involves a huge lateral rectus recession on the left side, without substantially limiting that procedure. Or that abduction. So what I did here… Was none of these. Now let me tell you what I did. You have to have something you can do. That should say question 5. Excuse me. The oblique muscles, in addition to being antagonist vertical rotators, are antagonist torsional rotators. We know that. But they are synergistic abductors to the eye that’s already abducted. I took advantage of that fact by doing big weakening of both the superior oblique, by a complete tenotomy, and the inferior oblique, by a big anterior transposition, together with a conventional recession/resection procedure, a conventional maximum, on the left eye. Nothing on the right eye. It was the only good-seeing eye. So now you have the pre-ops and the post-op. Compare the two central pictures in the middle. Her exo is very well fixed. Compare her abduction. The middle row on the right side of your screen, both pre-op and post-op. And you can see that I didn’t limit her abduction at all, because I didn’t do excessive surgery on the lateral rectus, or excessive tightening of the left medial rectus. What I got was lessening of the abduction effect from tight oblique muscles. I operated four muscles on one eye. Is that dangerous? We said we wouldn’t operate a fourth muscle. But what we really said was we wouldn’t operate a fourth rectus muscle. The inferior obliques carry no nourishment to the anterior segment. So that’s my way of treating that situation. A huge exotropia. With a non-seeing eye. Here’s another patient who had the same procedure. On the left, he’s pre-op. Here is he on the right. He was a former assistant in my hospital, who told me that his social life vastly improved after this operation. Here are two more patients. On the upper one, you can see pre-op. On the left screen. The primary position on the left one of the post-op views — it’s not completely straightened, but he was very happy with it. Much better than his pre-op. And you can see on the right hand upper picture that he can still abduct. Same thing below. Preoperative position, big exotropia, straight ahead primary post-op, no limitation of abduction. Another patient, same thing. Pre-op, post-op, and retained ability to abduct. So now I’m gonna just close this by repeating what I told you before. The message is: Spot the patient’s big issue in each case. When the two eyes can see, it’s usually diplopia. In both cases, it’s typically cosmetic. Understand you can’t fix everything. In that lady that I did — in these patients that I did all the obliques on, I didn’t care about A patterns, V patterns, or torsional consequences. I didn’t get into any. Be ready to make trade-offs and adjust your plan based on what you see when you’ve explored things. And try to get a creative solution for what you have to do when you can’t carry out your plan. Well, that’s the message. I enjoyed sharing this with you. And now, if there are questions, we can handle them. All right. So should I read the question? Okay. So the first question is: if the conjunctiva is totally damaged while doing repeat surgery, will amniotic membrane transplantation help? I’ve not done that. Typically it will help. If the conjunctiva is badly damaged, it’s probably better to excise it and leave some bare sclera, as long as you cover the insertions of the muscles. If you can’t accomplish that, you probably could use amniotic transplantation. Would not be a bad idea. What type of conjunctival incision is preferred for resurgery? Typically, a limbal incision, if I’m planning to do an adjustable suture, or if I anticipate scarred conjunctiva. If it’s reop, where rotations are normal, and the conjunctiva is in good shape, I prefer a fornix incision, even if that’s a reoperation on that muscle. What is the Cooper Doctrine? The Cooper Doctrine said that if rotations are normal, and you have — then you can treat the patient as though they’ve never had surgery, by either — by working on previously non-operated muscles, or a previously non-operated eye. Does an MRI help in planning resurgery? Yes, it probably helps. If you need to have a lot of time to make a plan. Typically, I find looking at the muscles to be a very adequate substitute for MRI. And since I don’t have the kind of MRI that Dr. Joseph Demer uses, I wouldn’t be able to get the same results he does. So I’m content to just look at the muscles. Another question is: is operating on the same muscles — does it increase ischemic chances? It probably does, but not in a way that causes problems. There are several studies of iris fluorescein angiography that show that there is delayed flow to previously operated muscles, but not in complete flow. Mostly delayed flow. Delayed flow is not enough to cause a problem. In my experience. How did depression improve? I assume it goes to the last case I showed you. What I thought was an inferior rectus muscle that didn’t work had some elements — enough elements in it that it did work — and advancing it, instead of disregarding it or doing something else, gave me a result better than expected. How long after surgery could a muscle slip? Typically that happens within a day or so, because you haven’t had the suture into the muscle. Then the rest of the question is: if aligned after surgery with a late deviation, is that not more likely to be a stretched scar, rather than a slipped muscle with scarring of the sheath? The answer is yes. It will… The inferior oblique, anterior transposition… Why did it improve… Why did I do the inferior oblique anterior transposition? Well, I didn’t know that the inferior rectus reposition would work. And I wasn’t trying for better depression. I was using the inferior oblique anterior transposition just to bring the eye down into primary position. What maximum amount of… Was the R and R? No, I’m sorry. What maximum amount of R and R in this case? I didn’t do an R and R, so I can’t answer that question. I didn’t do a recession on either the inferior rectus or the superior rectus. In the last case… I didn’t do that, so I have no answer for it. The oblique muscles typically are abductors, as well as torsional rotators and vertical rotators. And they are not antagonists for abduction. They are synergists for abduction. And weakening both, especially when they’re tight, from a longstanding deviation, allows you to weaken their abducting effect. And if you combine that with a recession/resection of the rectus muscles, in this case, it gives us enough without limiting abduction. Transposition of the… Um… That didn’t occur to me in this case. But I wasn’t worried about comitance. I was really just worried about not weakening abduction and getting a good primary position deviation on the big exotropia. Operating the good eye can reduce the recurrence by Hering’s law? Yes, it can, but I wouldn’t want to operate on a good-seeing eye, when the patient’s other eye only saw finger-counting at 10 feet. In big exotropia, with one operated eye, you touch the… Not four obliques. Only the obliques of the eye — of the amblyopic eye. This is not an operation that takes me to the good eye. Will I touch even though they have no hyperfunction? Yes. In order to achieve what the patient has as the big problem, which is how they look, I’m trying to get that eye to primary position. And when that eye doesn’t see well, I’m not worried about disturbing binocularity in other gaze positions. How to decide on millimeters, when I’m doing repeat surgery? Very difficult. If I’m advancing a muscle to its original insertion, I have to depend on another muscle, to get the millimeters I want. And I will do that as an adjustable suture. What do we mean by stretched scar? It’s a scar that weakens with time, undergoes more fibrosis, and spreads out, fills in the weakened scar with more fibrotic muscle attachments, and looks like a stretched scar, rather than just an intracapsular slip. How much exodeviation is introduced by operating on the obliques? I can’t tell you by just operating on the obliques, but by doing that together with a conventional maximum resection/recession, recession of the lateral rectus and maybe 7 or 8 millimeters tightening of the medial rectus, you can get anywhere from 60 to 85 prism diopters, and you have a satisfied patient, even if you don’t have a perfectly orthotropic patient. What is the time between the two strabismus surgeries? Well… In most of the cases, the first surgery that was done was done several years ago. And so there’s no… I don’t have a reason to wait any further. If you’re talking about a second operation on a case without a restriction or a weakness, I would do it as soon as I was sure that the patient had healed from the first operation. So that would be any time from six weeks on. Do I think that working on the two abductors is enough to fix the… Is enough to treat the large angle amblyopia? No. Doing the two abductors alone is not. There are situations where I have done that, but not in this situation of the very large exotropia. In a patient with an inferior oblique adherence syndrome, what do I prefer? Steroids or Botox? If the adherence syndrome is permanent, I would prefer surgery to either of the other two. If it’s something I thought were recent, it would be Botox. Botox on a restriction… I’ve not found to be helpful. I would try steroids. But typically, surgery is what’s needed. I’ve answered that already. How much R and R for the XT. Have I reoperated a recessed inferior oblique? Yes, I have. I find it and I anterior transpose it. That’s true whether it’s my prior surgery or somebody else’s, and it’s true in any kind of case. I’ve answered that already. You can get anywhere from 60 to 85 or more. The incidence of DHD operating for infantile esotropia… Well, that’s not part of this thing, but I’ll answer it, if you would like. The incidence of DHD is anywhere from 40% to 60%. In huge XT, do I operate only on the obliques? No. I’ve already covered that. I’ve already covered the amount of maximum I would do. Tight horizontal muscles will induce pseudo-overaction. Should we touch the obliques, then? Well, in the case I’m talking about, you are touching them, whether or not they are pseudo-overacting, as they typically are. You tend to weaken them if they are true or pseudo-overacting, but that has nothing to do with the reason for doing it. If I operate on the obliques plus the horizontals, what will the amount of R and R… We’ve answered that already. I’m glad so many people are interested in that. That is important. What are your plans in a huge ET in a non-seeing eye? Hm. Well, weakening the obliques is not the answer. I probably would weaken the inferior… The medial rectus, maybe as much as 9 or 10 millimeters. I would resect the lateral rectus, probably 10 to 12 millimeters. I would see where that takes me. I would be ready to settle for some loss of abduction. And if I had undercorrected, I would have to do either a marginal myotomy of the medial rectus, without further recession, combined with or instead of a plication or further resection of the lateral rectus. And I would probably in that case — would put that on an adjustable suture. One more. Sometimes large resections of medial rectus lead to poor cosmetic result, with lingering redness of the muscle. How can I avoid that? Well, I think it’s important, when you’re doing the medial rectus muscle, to separate its attachments of its overlying capsule to the under surface of the plica. The main problem that I find with large resections or, for that matter, recessions of the medial rectus is not lingering redness. It’s more likely a recession of the caruncle, which gives a very hollow look in that area. And that I find is the most serious cosmetic result. I don’t know if there’s time for more. All right? The heavy eye syndrome… Large exotropia… Well, first of all, you usually don’t get a large exotropia in the heavy eye syndrome. You more typically get a large esotropia. And it’s thought that’s because the muscle — the globe herniates, between the superior and lateral rectus. And there you would do a procedure that incorporates some or most of the superior rectus and lateral rectus, by moving one toward the other, and suturing them to each other, not necessarily into the sclera. This would take a long time to answer. So I think in the interests of time, I’m going to have to decline. I’m glad to have been with all of you. I’m very delighted that so many questions arose. And that so many of you registered to do this. I think this will be helpful to you. I believe Orbis makes it possible and wishes you to give subsequent feedback, or further questions on this. And if any of them are directed toward me, I would be happy to try to answer them. So I wish all of you a pleasant day or evening. I’m not sure where you’re… Thank you.

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June 9, 2017

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