Lecture: Surgical Strategies: Strabismus

Unique complex cases require careful planning and consideration of many factors by the surgeon. In this webinar we will illustrate unique cases, discuss preoperative assessments, and demonstrate interesting surgical videos for cases with Dissociated Vertical Deviation, esotropia with myopia, resurgeries and strabismus with foveal ectopia.


Dr. Sumita Agarkar, Shankar Netralaya Eye Hospital, Chennai, India
Dr. Suma Ganesh, Dr. Shroffs Charity Eye hospital, Delhi, India
Dr. Andrea Molinari, Hospital Metropolitano, Quito, Ecuador


DR GANESH: Welcome, everyone. To our webinar on surgical strategies: Strabismus. So we have a very, very highly qualified and very highly knowledgeable faculty here. Dr. Sumita Agarkar, Dr. Andrea Molinari, and we will be speaking on dissociated vertical deviations, esotropia with myopia, resurgeries, surgical strategies, and strabismus with foveal ectopia. Dr. Andrea Molinari is the director of a fellowship program in pediatric ophthalmology and strabismus from Hospital Metropolitano, Quito, Ecuador. She’s the associate professor of Universidad Central Del Ecuador, the past president of the Latin American society of pediatric ophthalmology, vice-president of the strabismus organization, and Orbis volunteer faculty. Dr. Sumita Agarkar is the head of department of pediatric ophthalmology and adult strabismus, Sankara Nethralaya, medical research foundation, Chennai, for 21 years, the executive member of the strabismus and pediatric ophthalmology society of India. She’s the lead ophthalmologist Orbis REACH Project coordinator. And myself, I’m Dr. Suma Ganesh, the head of pediatric ophthalmology at the eye hospital in New Delhi and Orbis volunteer.

DR MOLINARI: Okay. Well… Okay. So first let me thank Orbis for having me again in these fantastic educational events that Cybersight is organizing. And I really enjoy participating in these events. Especially with such good friends as Dr. Suma and Dr. Sumita. And the first of today’s topics will be the surgical management of esotropia with high myopia. And this is a very interesting topic, and a very interesting type of strabismus. Sometimes a little challenging to resolve. Let me start my presentation with a case presentation. This is a 38-year-old female that was referred to our department by an anterior segment surgeon, because the patient was almost blind due to dense bilateral cataracts that she presented with. Her vision was only count fingers at 10 centimeters. And she was referred because the anterior segment surgeon had difficulty in trying to perform cataract surgery on her, due to her eye position and her orbits. The eyes were stuck in an inward and downward position. As you can see in these pictures of her nine different gaze positions, the patient could hardly abduct the right eye, cannot abduct the left eye, and the elevation of the eyes was also impossible. So the patient didn’t come with glasses, but she referred to being a myope. We could not refract the patient, because of the dense cataracts. So we’ll start with a question. What axial length do you estimate in the eyes of this patient? Due to the clinical scenario? 24 to 28 millimeters, 29 to 32 millimeters, 33 to 36 millimeters, or more than 36 millimeters? We’ll give you 30 seconds. And see what most of you think. Do we have any results yet? Okay. Okay. So it was pretty… Even… Most of the responses. Let’s close this and go ahead. This patient had the largest eyes I have ever seen in a patient. Lawrence, I cannot advance my presentation.

DR MOLINARI: Yeah. Let me see. Now we go. So this patient had 37 millimeters on her right eye. And 38 millimeters on her left eye. As you can see here, the orbit was mostly occupied by her globes. There was no other space left for anything else in this orbit. Usually patients with esotropia associated with high myopia have globes larger than 30 millimeters. So in a coronal cut of an orbital image of a patient like this, where would you expect to find the extraocular muscles? Would you expect to find the superior rectus nasally displaced, the lateral rectus inferiorly displaced and the IR temporally displaced, the lateral rectus inferiorly displaced and the superior rectus nasally displaced, or the lateral rectus only inferiorly displaced? Let’s have a couple of seconds for your answers. We can see the answers — okay. Lateral rectus inferiorly displaced and superior rectus nasally displaced. Exactly. And that’s what happened here. As you can see here… The lateral rectus were inferiorly displaced. And the superior rectus were also very much nasally displaced. And this muscle displacement is what produces the clinical picture of these patients. Because the superior rectus, being nasally displaced, loses its capacity to elevate the eye, and this is why these patients have such a hard time trying to elevate their eyes. And the inferior displacement of the lateral rectus also produces that the lateral rectus loses its abducting capacity, and therefore the medial rectus gets contractured, and this is why these patients have the esotropia. So there are several techniques that you can use, in order to reposition or to relocate these displaced muscles. And you could use all of them. But which one would be your preferred? This is like a survey to see what’s the preference of the audience. Repositioning of the lateral rectus. The Yamada technique. The Yokoyama technique. A partial Jensen. Or an R and R, recess resect, plus myoscleropexy. We’re going to talk about each of these techniques. But I’m curious to see which is the most popular technique among our audience today. Oh, that surprises me. R and R plus myoscleropexy and Yokoyama was the second most popular one. So we’ll keep going. We’re going to talk very shortly about each of these techniques. The first one of these techniques was described in 1997. This one here — positioning the lateral rectus path by a German author whose name is really difficult to pronounce. Dr. Krzizok, together with the famous Dr. Kaufmann, also from Germany. This technique involved putting the lateral rectus in a more physiological position. Placing a suture 8 to 10 millimeters from the muscle insertion and placing the muscle in a more physiological position. You can see this technique employed in this young boy. This type of strabismus can also be seen in very young patients. Here you can see how the patient, when trying to abduct the eye, depressed the eye. This eye was -16 diopters of myopia. And you can see when he tries to abduct the eye, the eye goes down, because the inferiorly displaced lateral rectus acts as a depressor, and not as an abductor. And after the surgery, you can see how the abduction is much better and the esotropia is corrected. Another technique is the Yamada technique, that consists of hemitransposing both the half of the superior rectus and the half of the lateral rectus, 7 millimeters from the limbus, halfway between the two muscles. This is not a myopexy technique. But the result is the same. It moves the displaced paths — muscle paths — to a more physiologic position. I would say one of the most popular techniques is the Yokoyama technique. The sutures — the lateral rectus with the superior rectus, 15 millimeters away from the limbus. Not from the limbus, sorry. From the muscle insertion. Which is not very easy. Going as far back as 15 millimeters. It’s really difficult. And this is why I wanted to show you this. What I do — and this was also recommended by Dr. Yokoyama. I place a first non-absorbable suture 10 millimeters from the insertion. And then I pull these threads and try to get further back 15 millimeters from the insertion. And that way, it’s easier for me to place the sutures so far back. The partial Jensen’s procedure was published in the Journal of AAPOS in 2004. It’s very similar to Yokoyama procedure, in the sense that it unites also the border of the lateral rectus and the superior rectus with the only difference that in these cases, the muscle is split. Either in half or less than half, in this picture. And lately, the recess-resect with myoscleropexy is one of the latest techniques, and its efficacy is larger. The myoscleropexy improves the efficacy of the procedure. So let’s go back. Would you add to one of the procedures we described before a weakening procedure of the medial rectus? Yes or no? Can we see the answers now? Yes, okay. Good. So now we’re going to see what happened with this patient. What was the surgery performed? As you can see in this picture, that is the superior rectus. And you can clearly see how it is nasally displaced. And the lateral rectus is inferiorly displaced. This is the lateral canthus. And you see how the muscle is displaced inferiorly. So what did we do? Remember, this patient had a very large eye, 37 millimeters in her right eye and 38 millimeters in her left eye. So what we did is — trying to do a Yokoyama procedure with such a large globe was very difficult. Because I couldn’t reach to unite the lateral rectus with the superior rectus. So in this case, what I did was a hemi-Jansen procedure, splitting the muscle not one half, but one third, because I wanted to preserve the anterior segment irrigation. You can see the vessel I tried to avoid. So that’s why I split only one third of the muscle and one third also of the lateral rectus and united it. And in this case, the medial rectus was very tense. As you will see, the traction test was very positive. But in these cases, where the globes are so large, it’s very difficult to perform a large medial rectus recession. Because it’s difficult to get so far back. There is no space. And the sclera is so thin. So what I did — and this was an advice from my former mentor, Dr. Kristina Ugrin from Argentina — is I just hooked the muscle, placed it on a Miostat, and went back as far as possible, and just cut the muscle free, after cauterizing the borders, and let the muscle go back. And here you can see how the forced duction test was positive before the myectomy and it got much better after the myectomy. So at the end, what was done in this patient was a free myectomy of 6 millimeters on the right medial rectus, and 8 millimeters on the left medial rectus. Remember, this was the worst eye. And Jensen on one third of the lateral rectus and the superior rectus. The patient had 10 diopters of residual esotropia after the surgery. Eye movement was still very limited, but at least the cataract surgery could be performed. And here is a picture of how the patient looked before and after surgery. Finally, to conclude, there is a very interesting paper that compared the efficacy of the different procedures. In this paper, published by some Chinese colleagues, they compared three different techniques. The Yokoyama procedure, and they established that this procedure alone can correct up to 40 diopters of esotropia. Yokoyama plus medial rectus recession can correct up to 80 prism diopters of esotropia, and the most powerful of the procedures, the one performed in my patient, a partial Jensen’s procedure plus recession of both medial rectus — it can correct more than 100 prism diopters of esotropia. So to conclude, in these patients with high or progressive myopia and esotropia, repositioning the muscle paths by the different techniques that we just showed will help in improving the ocular alignment. Medial rectus weakening is not necessary in all patients. But should be performed if the medials are tight on forced duction tests. And a thorough eye examination and imaging of the patient before surgery will be very useful for choosing the surgical strategy. Thank you so much for your attention today. And let me stop sharing my screen, so we can see if there are some questions. I would be very happy to answer them.

DR GANESH: That was an excellent presentation, Dr. Andrea. What a lovely case. And the way you managed it so well. There are no questions yet, but I have a question. I don’t understand: How did you do the medial rectus myectomy? How did you grade it at 6 to 8 millimeters and how was it performed?

DR MOLINARI: I hooked the muscle, placed it on a myostat and tractioned it. I went back as far back as possible and cut it after cauterizing the muscle to prevent bleeding. Because the muscle goes back, and then you cannot control bleeding if it starts bleeding. Usually these muscles are compressed between the orbital wall, the nasal wall, and the globe. And sometimes these muscles are fibrotic. You can cut them, but you will not see them retracting very far back. Into the orbit. And in these cases, cutting the muscle will not give you a lost muscle with a huge overcorrection. As you can see, this case was even undercorrected, not overcorrected. So you can do this with confidence. You understand the way I did it, right?

DR GANESH: Yes, two questions. One is: Which muscle do you tackle first? MR or Jensen’s?

DR MOLINARI: Which muscle I tackle first when doing a Jensen’s procedure? The superior rectus or the lateral rectus? Is this the question?

DR GANESH: No, is it better to go in for the medial rectus recession first, or the Jensen first?

DR MOLINARI: I would do the medial rectus first. In order to let — to free the positive duction test. And then it’s easier to do the Jensen or the Yokoyama or whatever procedure you want to do.

DR GANESH: And how would you manage under and overcorrection as well as vertical deviation after surgery?

DR MOLINARI: That’s a very good question. Sometimes this is very difficult. Actually, I don’t remember having overcorrection in these cases. I had undercorrections. But not overcorrections. Well, how would I manage that? What you can do is you can place more sutures. For example, in the case I showed, that had 10 diopters of left esotropia, well, 10 diopters is not much. If I had more undercorrection, what I would do is — since I cannot do anything more on the medial rectus, what I would do is go to the myopexy that I did between the lateral and superior, and add one more suture, posterior to the one I already placed. This will help you to abduct the eye a little more.

DR GANESH: Okay. Where exactly did you reinsert the one third superior rectus and lateral rectus? How many millimeters from limbus? I think you had said 15.

DR MOLINARI: That’s the Yokoyama procedure. In the Jensen procedure, I place it like… Between 8 and 10 millimeters.

DR GANESH: Okay. So there’s another question. Myectomy — tendon elongation of the medial rectus may solve the problem? What do you think about it?

DR MOLINARI: Yes, tendon elongation of the medial rectus may solve the problem. Yes. You’re right. For example. But tendon elongation with what? With artificial tissue, like Tutoplast, like they do with a thyroid orbitopathy? Or I remember one very nice paper from Dr. Ramesh, I think it was, Kikunaya, using the muscle. But in this case, you cannot use another piece of muscle, of lateral rectus, because you’re using it for the myoscleropexy between those. So yes, you could do that. I find that this myectomy was the easiest, faster procedure to do. Elongation of the medial rectus — maybe you can do it with myotomies. On the border of the muscle. But no, I prefer the technique I used. But it’s a possibility. Yes.

DR GANESH: There’s another question. Do you see exotropia with high myopia?

DR MOLINARI: Exotropia with high myopia? I see it. But usually it’s a sensorial myopia in the cases where I see it.

DR GANESH: Would you use the Yokoyama?

DR MOLINARI: In an exotropic patient? No, I would not.

DR GANESH: Another question. Did you tackle both the eyes at one sitting or one eye at a time?

DR MOLINARI: No, no, no, both eyes in the same sitting. If you are sure you have the imaging — I always ask for orbital imaging in these patients. If you see that the muscle paths are displaced, you have to tackle both at the same time.

DR GANESH: I think there are many more questions. You may have to answer it.

DR MOLINARI: I will answer.

DR AGARKAR: Yes. So DVD is an oculomotor anomaly. The non-fixing eye tends to drift upwards. It also abducts and extorts. And it is commonly associated with infantile esotropia, but is known to occur with exotropia also. It can be latent or manifest, symmetric or asymmetric, comitant or incomitant. And very often associated with nystagmus. So this is a patient. You can see under the cover, the eye has gone up. Not only gone up, but also if you see carefully… The eye is coming down. And coming in. And as we dissociate these eyes further… DVD not only becomes manifest, but also stays manifested. As the dissociation increases. And as you can see, both eyes tend to come up. Because this entity does not follow the Hering’s law the way we are taught. There is another interesting phenomenon in these DVDs. You can see that DVD is manifest, but as you put a neutral density filter in front of the other eye, you can see the eye actually coming down to take up the fixation. This is called Bielschowksy’s phenomenon, as you can see in this image. What causes it? Pathophysiology is a little uncertain, but Dr. Brodsky has proposed that DVD is a dorsal light reflex. Dorsal light reflex is usually a primitive reflex, which is a righting reflex. And it is used to keep the position of the lower animals in place. But dorsal light reflex — which is usually suppressed in human beings, but if there is early onset strabismus, say in infantile esotropia, it manifests even in human beings, and it probably is one of the theories — some feel that it is a compensating mechanism to dampen the nystagmus. Particularly the cyclo-vertical component of nystagmus. So when should you offer surgery to these patients? Usually when it is cosmetically unacceptable. It’s a large manifest DVD. Occasionally it does cause anomalous head posture, and head tilts are often what the anomalous head posture — which is usually seen in the clinic — and of course, if there is a horizontal surgery to be planned, horizontal deviation in association with nystagmus — in DVD — then you would probably combine a DVD correction at the same time. As you can see, this child has a manifest DVD in the left eye and also has a left head tilt to compensate for that. This time, probably, we need surgery, along with exotropia surgery. Now, problems with the measurements. With DVDs. There is no clear endpoint. As you can see in the previous video, the more you dissociate, your angles tend to increase. So some of the strategies, which you can adopt to correctly measure these patients, is you can use the prism undercover measurements. Where you slip a prism just underneath the cover, and then see the endpoint is where there is no corrective downward drift of the eye. If there is asymmetric DVD, you can do this in either eye, individually. And measure it individually. Sometimes reversal also can be taken as endpoint. And it is important to discuss with the patient that surgery will make DVD better, but will not eliminate it completely. It’s important to see that, especially when you’re offering surgery. So this is a patient. Again, I’m going to show it in a small screen, because this video is not playing properly in full screen. As you can see, this child has DVD in the right eye. And you actually put the prism under the cover and remove the cover. There is no fixational movement. Seeing downward fixational movement. And you may actually remind the child to see all the time at the fixation target. And you should quickly see the first movement. Still coming down. That means you still need to neutralize. And this point, as you can see, there is actually a smaller deviation and no vertical. So this you can consider as your endpoint. So whatever factors allow you to make vertical decision making — when we have to decide whether the DVD is symmetrical or asymmetrical — most of the time, even if DVD can be asymmetrical, it is almost always bilateral. And surgery in fact should be considered in both eyes, and appropriately told to the parents. If there is any inferior oblique overaction coexisting, that should be noted, and of course, if there is a horizontal strabismus with a coexisting pattern, that also should be factored in, in your surgical plan. So these are the various options, which have been — technically, you can operate on superior rectus, you can operate on inferior oblique, and sometimes very rarely you could do some surgeries on inferior rectus also. Especially unilateral cases, where vision is very poor, and patients do not allow you to operate on the other eye. Then sometimes you may have to consider doing a unilateral surgery. But most of the DVD surgeries are likely to be bilateral. So superior rectus recession. Effective for moderate DVD. Asymmetrical DVD may require asymmetrical recession. And it is very effective. You can see this is slightly asymmetrical. The left eye is a little bit manifest, compared to the right eye. So I did an asymmetrical recession, and this is on the second or third post-op date. This is the picture at six weeks. Where he looks well aligned. And I would like to quote this paper here, which compares bilateral symmetric, as well as asymmetric superior rectus recession. And two of the co-authors in this paper are our moderators today. So they included the results of patients who have DVD of at least 10 PD or more, with no oblique dysfunction. And reported a success rate of 63%. In either group. And what age at surgery or magnitude of preoperative DVD, presence or absence of horizontal strabismus, or asymmetry, or surgical technique, particularly, did not modify the success rate. So yes, if you have a moderate 10 to 15 PD bilateral and there is no oblique dysfunction, bilateral SR recession is probably the surgery of choice. But as I said earlier, you can make it better. Like in this case. My earlier patient. But you cannot eliminate it. As you can see, the DVD is still there in the left eye. Even though he looks good. Aligned good with glasses. Faden or posterior fixation on superior rectus is effective for small angle DVDs. It is technically difficult and carries a little bit of risk of perforation, especially in inexperienced hands, but if it’s a very small magnitude DVD, probably you can look at posterior fixation on superior rectus. Sometimes posterior fixation can be combined along with superior rectus recession. To tackle a slightly larger DVD. Now, surgery on inferior oblique are indicated in DVDs where there is a coexisting inferior oblique overaction. Both anterior transposition as well as inferior oblique recession, which produces a slight anteriorization, have been described to correct DVD, and again, this can be combined with a horizontal surgery. Thank you, Dr. Suma, for sharing this picture. As you can see, this child has a DVD as well as a V pattern as well as inferior oblique overaction and esotropia. And I think she underwent bilateral medial rectus recession, with inferior oblique anterior transposition, and you can see a very, very gratifying postoperative result. Beautifully aligned eyes and almost no DVD. This is how you would do an anterior transposition. This is a short video of my colleagues. So here, inferior oblique is isolated. And we usually pass the suture after disinserting the muscle. But you could do it before also. And this is — inferior rectus is hooked on the hook. And you can put it parallel, bunching up the muscle. And you can close. But that is how you would do it. Inferior oblique transposition. Now, in 2016, Stager et al. described nasal transposition of the inferior oblique, where the inferior oblique is sutured near the nasal border of the inferior rectus, which converts it effectively to a depressor and intorter. It is related to less antielevation, which is seen and sometimes problematic with anterior transposition of inferior oblique. And this has been studied in DVD, and this paper from Egypt has shown it to be as effective as inferior oblique anterior transposition. In DVD. In fact, anteronasal transposition was seen to be more effective in primary position DVD and had less antielevation effect in this paper, which was published in 2016. If there are patterns along with DVD, again, A pattern is a very common association, and this may require surgery with superior rectus recession, with posterior tenectomy of superior oblique, combined with a horizontal surgery. And it produces fairly good results. Helveston syndrome, which comprises a triad of exotropia, A pattern, and DVD, this kind of surgery probably requires recession of the horizontal muscles, combining it with posterior PTSO as well as inferior oblique anterior transposition. So here you can — it is possible to correct both the horizontal as well as vertical correction. In the same setting. So this is another patient of ours. Who had a small exotropia. And he underwent A pattern. Exotropia was rather small. But he had a DVD, as well as A pattern. And he did undergo both PTSO, as well as inferior oblique anterior transposition. He’s a relatively happy patient, postsurgery. Thank you for your attention.

DR GANESH: Thank you, Dr. Sumita. That was an excellent presentation. A question to you: How do you confirm inferior oblique overaction in DVD?

DR AGARKAR: One, you can look at the fundus, and look at further macular extortion. Which is more likely to be with inferior oblique overaction. The overelevation is more in abduction compared to adduction, in true inferior oblique overaction, compared to DVD, and often it will have a true hypertropia in the side gazes, compared to DVD. So that’s when we’re looking at differentiating between DVD and inferior oblique overaction.

DR GANESH: I think somebody has asked to explain PTSO. I think in India, we use the word… PTSO is…

DR AGARKAR: Tenectomy of the inferior oblique. So if you have A pattern as well as exotropia, sometimes if you want to correct the A pattern, that will in fact worsen the DVD. So you combine — for A pattern, you would do A pattern with exotropia and DVD — is a fairly common combination. Association which is seen. So to correct everything in one sitting, it gives very gratifying results if you could combine all three together. That you correct the horizontal for exotropia, you do a posterior tenectomy of superior oblique for A pattern, and you also combine it with an inferior oblique anterior transposition or inferior oblique recessions, to take care of DVD at the same sitting.

DR GANESH: Do we do — IOAT, if the inferior oblique overaction is 2+. That’s the question. If there is a 2+ IO overaction and DVD.

DR AGARKAR: Yes. Anterior transposition. But I would probably not do the classical anterior transposition, where it is 1 millimeter in front of the inferior rectus. But I would in fact keep it at the level of what they say is — I would not go really anterior, but parallel to the inferior rectus.

DR GANESH: There’s a question. The patient has a superior oblique overaction. But would you still do SR recession or IOAT in Helveston syndrome?

DR AGARKAR: I think Helveston syndrome needs all four obliques. Classical triad of Helveston syndrome includes exotropia, A pattern, and DVD. So I think it makes sense to do superior rectus recession, inferior oblique anterior transposition, which will take care of the DVD —

DR GANESH: I also would agree with that. But again, I think there’s a question: Would you consider inferior rectus tucking in DVD?

DR AGARKAR: I have personally no experience with inferior rectus tucking. But there are a few papers. And especially in unilateral DVDs or nearly blind eyes, where the eye is never going to move up or the other eye is always going to be the dominantly fixing eye, probably a vertical recess/resect has been described for DVD. And may work in that situation. But yes, inferior rectus plication or inferior rectus recession has been tried for small angle DVDs.

DR GANESH: What correction following DVD surgery? I don’t think so.

DR AGARKAR: I have heard of them developing hypertropia following anterior oblique transposition, and that has happened. That has been described also. Anteronasal transposition is supposed to be more effective that way. It will give less amount of antielevation syndrome compared to —

DR GANESH: The questions have been taken care of. I think some questions are repetitive. I think you can just reply personally to the person. Yeah. Dr. Andrea, you’re around? Yeah. So any questions? So that we can proceed to my talk? I think… I think DVD — have you had any lid — if you do both the superior rectus recess and the IOAT together, sometimes there is still residual DVD. Have you done superior IOAT and again done superior rectus recession, Dr. Sumita?

DR AGARKAR: Sorry, I was not —

DR GANESH: Okay, sorry. It means if there is a residual DVD even after doing an inferior oblique anterior transposition, would you go back and do a superior rectus recession again?

DR AGARKAR: No, probably I would revise inferior oblique anterior transposition. Maybe do a little bit more further weakening or transpose it to the nasal side. Rather than tackling superior rectus. Because sometimes that can really add on to the… Taking care of both the elevators. It is a little bit risky.

DR GANESH: Dr. Andrea, would you go ahead?

DR MOLINARI: What you can also do is resecting the transposed — anteriorly transposed inferior oblique. And this will give you more action if you need more efficacy.

DR GANESH: I have done both the elevators, in a few cases, where I found that it was still — especially when the DVD sometimes is more than 15 to 20. We’ve had to add on another surgery. The only thing is — what I found is there’s lid retraction in a few cases. I got in one case a lid retraction. Just cosmetically not looking very good. But I think, Dr. Andrea, what you are saying is right. We can go back and maybe transpose it. I think I’ll share my screen. Any other questions? I think Dr. Sumita, you can take it from…

DR AGARKAR: Yeah. I hope I am audible and visible. My presentation is visible? Okay. I’ll begin my talk, and first of all, I would like to also thank Orbis and Cybersight for giving us this opportunity to hold so many webinars during the COVID breakdown. And I think it has been a real learning experience. And I’ve interacted with so many mentors, and I feel obliged and I feel so thankful to Cybersight for giving me this opportunity. I’ll be speaking on reoperation strategies in strabismus. We know that reoperations in strabismus surgery has its own set of unique challenges. Proper planning is required. Taking into account the measurements, incomitancies, and the versions. It should also take into account the laxity of the muscles. So the common post-op misalignments are undercorrections, overcorrections, slipped muscle, missed muscle, or the development of a new strabismus problem. So the history is very important. You need to elicit the history of childhood strabismus, which strabismus was documented, records from prior surgery can be invaluable, and what type of surgery is performed, how long the eyes remained straight, and if there are any old photos. So the first step would be whether the surgery should be done on a previously operated muscle. Or should we go and operate on a fresh unoperated muscle? The second step is to think whether it’s an undercorrection or an overcorrection. Assess the incomitance patterns and also the limitations of rotation. So if there is undercorrection, you could rerecess or resection of antagonist. If there’s overcorrection, advancement or recession of the muscle. The first case is a boy with face turn to the right. Both eyes medial rectus recession had been done. Lateral recession in childhood, and now he presented with an exotropia that had been there for 16 years. But there was no history of diplopia. He preferred his left eye because the vision in the left eye was better. There was 70 prism base in exotropia. There is incomitancy. And this measurement was the same. The first thing you see is: Is it a slipped muscle? A medial rectus muscle? So the best tool which is available is the dynamic MRI to rule out whether it’s a slipped muscle. So this medial rectus was found to be posteriorly placed. And on adduction, also we found that there is an increased bulk of the left medial rectus muscle belly on adduction. So what are the causes? There could be a stretched scar syndrome. This was popularized by Ludwig and Chow in 1999. Where you could get late secondary strabismus with variable degrees of muscle underaction, which occurs months up to years after the primary procedure, and this is thought to result from improper wound healing with stretching of the scar tissue intervening between normal muscle tissue and the sclera. So you do the tendon step test, where you sweep the muscle hook back and forth and identify the step — you feel a bump here — which is created by the tendon-muscle junction and the fibrotic tissue. Here you can see the fibrotic tissue or the scar tissue is seen under the hook. The hook is easily seen. And you can see in the muscle it is not seen. So this would help us to find out the muscular junction. So the first strategies. Whenever there is overcorrection like in this case, there is limitation of rotation and there is incomitance. So we do a dynamic MRI. To check for slipped muscle, or disinserted muscle. So we’ll go back to the previously operated muscles. That’s what we did in this case. Where we went back to the medial rectus. We advanced it from the insertion. And placed it up to the insertion. And a resected lateral rectus was recessed, 9 millimeter. The important thing is: You have to keep the patient — there is a tendency to exo drift. So the best result would be to keep it — esotropia overcorrected around 6 to 10 prisms. But there was a small amount of residual exo. The dynamic MRI helps us to rule out whether it’s a slipped muscle. So now in a slipped muscle, in this case, there was no slipped muscle, but if there was a slipped muscle, it would look like this. But this attempt at adduction in the left eye — there is a fusiform swelling of the posterior belly of the left medial rectus. But anteriorly you can see there is an empty capsule. So it does not show any contractility. This would be very useful when we do dynamic MRI. We should inform whether we can see the contractility or not and whether there is a fusiform swelling of the posterior belly. This helps us to differentiate from a slipped muscle and a posteriorly placed muscle or a scar tissue, stretched scar. If you have a slipped muscle, then you trace the empty capsule posteriorly to reach the true muscle fiber. The muscle, then you clamp it, hold it with a clamp, and you recover the slipped muscle. This is another case where she had complaints of diplopia. There was a head tilt to the left, there was limitation of adduction, elevation, and depression. 50 exotropia with 30 left hypotropia, limitation in elevation, and limitation in depression. So recovering third nerve palsy with left hypotropia. Maximum lateral rectus recession 12 with 8 millimeter medial rectus recession with SO tenectomy. Now there was a -4 abduction deficit. A large recession was planned of the lateral rectus. Maybe that’s why there was a limitation in abduction. So the second strategy is: If you have a consecutive ET, an advancement should be done. Third strategy. If there is overcorrection, no incomitance, you operate on fresh muscles. In this case, consecutive exotropia, a lateral rectus recession or consecutive esotropia, medial rectus recession. Fourth strategy. If there are undercorrections and no incomitance, you strengthen the antagonist. If there is medial rectus recession, you would go to the antagonist and do a lateral rectus resection. Or you would resect the medial rectus. After prior horizontal surgery, now one is dealing with the vertical problem, you treat the vertical strabismus like a fresh case as long as there is no limitation of rotation. This is the fifth strategy. In this case, you have DVD. It occurs after four years of medial rectus recession surgery. This is a case which is referred by a colleague, and was originally referred one week after the surgery. Said that the surgery was uneventful, but found that on first postoperative day, there was the left eye looks small, there was a consecutive esotropia, the limitation in abduction and limitation in elevation. Both eyes, lateral rectus recession was done 9 millimeters, with left eye medial rectus resect 6 millimeters, left eye inferior oblique recession and left eye inferior rectus recession. This was the pre-op pick sent to me. This had a 70 exotropia with 40 left hypertropia. So the surgical plan was correct. The three recti were done, along with left inferior oblique recession and right IR recession. So what happened? Now there was overcorrection, there was limitation in upgaze and abduction. FDT was positive, so we decided to go ahead and see what the muscles need. The surgical plan was: Is it inferior oblique adherence syndrome? The eye is hypotropic and esotropic, not going upwards? The elevation is limited. We do an FDT and find out. Also the left eye medial rectus and lateral rectus, there was limitation in abduction also. And recess the inferior rectus, same eye, if there is adherence syndrome. And Botox the medial rectus. So we went ahead, and this is the… So what we found — that the medial rectus was — the inferior rectus was tight, but not as tight as expected. And you can see that the elevation is limited. But not as tight as expected. Thinking that it would not go up at all. And the medial rectus was also — when we tried the medial rectus, that medial rectus was also — we found that there was tightness of the medial rectus also. You can see that the medial rectus is very tight. So we decided to — media limbal peritomy. And we decided to see what has happened to the medial rectus. It was shifted downwards, it was resected, and it was found to be shifted downwards and was placed near the inferior rectus. As if a half transposition downwards had been done. Half to full transposition downwards had been done. Wondering whether this was the cause for the hypotropia, that the medial rectus was shifted downwards, and the inferior rectus. So the plan was changed, and I decided to do a recession of the medial rectus. Because it was tight. And transpose it upwards, because it had been transposed down. Transpose it to its normal position upwards. And recessed it around 3 to 4 millimeters. Then we went back to the inferior oblique to find out whether there was inferior oblique adherence syndrome. This is an edited video, but there was a lot of fibrosis near the inferior rectus and inferior oblique. We had to find out whether it was fibrotic tissue or muscle. So we passed the hook back and forth and found out this was just scar tissue and not any — it was not any muscle fiber. So this is how we traced the muscle backwards to find out where the inferior oblique was. And found that the inferior rectus — not much fibrosed. Of course, this was one or two weeks after the surgery, we had gone back. So it was quite clean. And this is why we decided to cut this tissue and this was a fibrotic tissue. We found that the inferior oblique was placed in the recession area where they had placed it, and ruled out — this could not be the reason for the elevation deficit. And left it with Botox to the inferior rectus. So gave Botox to the inferior rectus. And hoped that she would do well. This was corrected, but there’s still hypotropia of 6 millimeters — prism diopters. But the right eye was there. And the elevation had improved. There was still some amount of underaction of the right inferior rectus. So my question is: What will be the next step? Can we have the questions? We repeat Botox on the left inferior rectus immediately? Or we do a right eye inferior rectus advancement on an adjustable immediately? Because there was a scleral show, and that was appearing as if the inferior rectus had gone back? Or we do it after 4 months? We do the inferior rectus advancement after 4 months? Or we do a left inferior rectus recession after 4 months, as is it the third recti surgery? 30 seconds for answering. And then we will be leaving it open to discussion to the panel. So many of them — repeat after 4 months. Advancing inferior rectus of the right eye. And the next is left inferior rectus recession after 4 months. And the third is repeat Botox immediately on the left. So… It’s different. So… I’ll just say… We can discuss on the panel, again, and it’s open to discussion. Just want to complete my presentation. Saying that: I did go immediately for the surgery. Because I thought it put inferior oblique adherence and I thought I could release the tissues, fibrotic tissues. And maybe we could have waited for summer time. Because the main indications for immediate surgery is lost muscle or large overcorrection after superior oblique tuck, or large vertical deviation induced by surgeries. The conclusion is we have to be prepared to modify the surgical plan based on intraoperative findings. And we know that despite the best preoperative evaluation and surgical techniques, we still get surprises and we may have to do repeat surgeries and we have to know how to manage them. Mild overcorrection and undercorrections may be treated non-surgically by the use of prisms and orthoptics. Thank you. Any other questions? I’ll leave it open to the panel. Most of them are saying we should go after 4 months.

DR MOLINARI: Yes, I agree with that too. There are some questions from the audience here. Dr. Vidhya says when to go ahead with resurgery to correct consecutive ET or XT?

DR GANESH: If you have a slipped muscle, of course you will go immediately. But if it’s not a slipped muscle and there is no limitation of movement, I think I would wait. Initially if there’s a consecutive ET, you can do an alternate patching, or you could wait or do alternate occlusion — you would also give a trial of hyperopic glasses, you would also do cycloplegic refraction, check if there are any plus glasses, after two or three months, what I find is most of them drift. And if you have an esotropia of 10 to 15 prisms, most of them drift back. In 2 to 3 months. I have had patients who have waited for six months, and they have become orthotropic. So I think I would observe and wait.

DR MOLINARI: There is another very interesting question. Dr. Sumita, you wanted to add something to that comment? You have to unmute yourself.

DR AGARKAR: If it’s consecutive ET or XT and there is no slipped muscle, there is no limitation of movements, I would wait. I would definitely wait.

DR MOLINARI: Another very interesting question. If you have a 3-year-old, for example, who has a severe amblyopia in his right eye, and had surgery on the right eye, and then had an overcorrection, would you operate on the amblyopic eye again, or on the better seeing eye? Touching fresh muscles? Vision 20/125 in the right eye, 20/30 on the left eye.

DR GANESH: So this means a child of an infant — maybe esotropia? If they are amblyopic, I’m assuming this, because it is not specified, and now it’s gone into consecutive esotropia. If there’s no limitation of movement, the motor part is okay. And I think the sensory part — we have to work on the amblyopia part. We have patch the eye and ensure that the vision improves. Because we have a vision therapy setup, we do focus on antisuppression exercises and fusional exercises. But if still there is exotropia remaining, then if my distance deviation is more than my near, then I would tackle the lateral rectus. If it is a consecutive esotropia and my near deviation is much more, then I would definitely go and advance the medial rectus. This is my plan of action.

DR MOLINARI: Good. There are many other questions. There is one interesting question. If you used local anesthetic bupivacaine, and I don’t know your opinion on that, but for example, I would like to answer this. Because I use local anesthetic in all my patients, together with a general anesthetic. It helps me. And especially in reoperations. And I’ll tell you why. Because reoperations, as you might know, are very bleedy. They bleed a lot. And if you use local anesthetic with epinephrine, this will help you not only in controlling the bleeding, but also in dissecting the tissues that are stuck together or cicatricial. So I use local anesthetic a lot. And I don’t use bupivacaine alone. I use a combination between lidocaine and bupivacaine, half and half. And this also helps in the postoperative comfort.

DR GANESH: Yes. I have seen you doing it. When you had mentored me, and I think that is a good option. I do not practice it so much now. I make phenylephrine 2.5% and put it before the surgery. Phenylephrine 2.5% shows me that it is not much of bleeding. But I have witnessed that the bupivacaine injections which you inject really helps. It also helps in separating the tissues out very nicely. I have seen that.

DR MOLINARI: Good. Do you want us to keep answering questions? Dr. Sumita wants to say something.

DR AGARKAR: I wanted to ask you: Would you still use bupivacaine even if you’re planning for an adjustable suture? Because that has a slightly delayed…

DR MOLINARI: That’s a very good question. When I perform adjustable sutures, I use only lidocaine. Without bupivacaine. But I still use lidocaine. We have a couple of minutes left. Excuse me, Dr. Sumita?

DR AGARKAR: I was saying general anesthetic is not very good for postoperative pain. Supplementing with a little bit of local anesthetic, at the end of surgery, even in children, it makes them very, very…

DR MOLINARI: Yeah. And usually I don’t do it at the end of the surgery. I do it before the first cut. If you avoid that the nociceptors start firing, that will give you better postoperative comfort. Because if you place the anesthetic after you did the surgery, the nociceptors, the receptors that are responsible for transmission of the pain stimulus, have already fired. So it’s not so effective. We don’t have too much time left.

DR GANESH: I think you will have to — I will answer the questions separately. I think we have our next talk by Dr. Andrea.

DR MOLINARI: If I’m allowed to share my screen, I will share my screen now. And I will start with this presentation. Which is a strabismus associated with foveal ectopia. As you all know, the fovea is usually located 3 millimeters… Sorry, 3 disc diameters temporal to the optic disc, and approximately 0.5 millimeters inferiorly. This will produce an angle of torsion in between 4 and 8 degrees. But what happens when the fovea is located in a different place? For example, it should be placed there. And we see in this case, that it lies in another place. In these cases, you might find very typical forms of strabismus, that are sometimes very challenging to manage. And foveal ectopia can be congenital, in chorioretinal coloboma, FEVR, Norrie’s disease, and toxoplasmosis, it can be acquired after macular translocational surgery, or trauma. Cases of FEVR that produce peripheral retraction, the same seen in Norrie’s disease, and chorioretinal scars, where the scar is not so large that it will destroy completely the fovea, but it will displace it, like in this case. This patient with this scar had VA of 20/40, because this was displaced temporally and produced an esotropia of 10 prism diopters. These cases are commonly associated to strabismus and amblyopia. It has always to be looked for. Foveal ectopia can also be seen after macular translocation surgery, where the retinal surgeon displaces the retina upwards or downwards, in order to put it away from the choroid that is sick or is damaged. And this will produce a very disturbing torsional diplopia that is sometimes very difficult to correct. ROP, as I said, or sequelae of ROP, is in my experience the most common cause of cases of foveal ectopia, and in these cases, a nasal dragging can be seen or a temporal dragging, which will produce that the fovea is nasally displaced or temporally displaced. In nasal dragging, you usually can find a pseudoesotropia, as you can see in this patient. This patient looks esotropic, but when you perform the cover test, the patient had 70 prism diopters of exotropia. And in this case, you will find pseudoexotropia. This patient had 25 prism diopters of esotropia. And let me end with this very interesting case. This young lady was born full term, and she consulted me, because she saw that her eyes were inward displaced. And at the exam, yes, 35 prism diopters of esotropia could be seen by Krimsky test. And she had a previous history of a right inferior oblique weakening procedure for a right hypertropia of 12 prism diopters done when she was much younger. But what was very interesting to see was the cover test. Look here. When she fixes with her right eye, the eye goes up. And now she fixes with her left eye. And then again with her right eye. And then with the left eye. So by performing the cover test, it could be established that she had no horizontal deviation at all. And she had a vertical right hypertropia of 45 prism diopters. And this is how her fundus on her right eye looked. She had this fibrosis here. Very peripheral. At the superior temporal quadrant, that produced this dragging of the fovea from this place to this place. Curiously, she had a very good visual acuity in that eye. 20/40. And this was explained when looking at the OCT of the right eye. Here you can clearly see how the fovea was displaced superotemporally. Yes. Sorry, superonasally. And you can see that the foveal architecture by OCT was very, very good. And that explained the good vision in that eye. So what to do with a patient like that? She had by cover test 45 prism diopters of right hypertropia. But a Krimsky test — she had 35 prism diopters of esotropia. So I talked to her during the hours previous to the surgery. She said that she could — she had no diplopia. She did not complain of diplopia. But she could see in her visual field that there were two different images. But she simply ignored the image of the right eye. So I explained to her that the results could be very unpredictable. But she was very keen to get this surgery done. So we decided to proceed with a very conventional R and R. 5 millimeters of medial rectus recession and 5 millimeters of lateral rectus resection. The recession with an adjustable suture, fortunately. And I say fortunately, because a few hours after the procedure, you can see that there was — she was way overcorrected. But fortunately I had the adjustable suture, and this was after the first adjustment. She was still a little bit exotropic. And this was after the second adjustment. And since she was satisfied with this eye position, this is how she remained. This was the 5 postoperative day. And 2 months after surgery, she was still happy. Not diplopic. So what have I learned with this case? And with all the other cases I have seen? The foveal ectopias — it might induce atypical forms of strabismus that are really challenging to manage. There are many different causes that can produce a foveal ectopia. The presence of strabismus — and let me say also that in my experience, the most common cause of foveal ectopia is now sequelae of ROP. The presence of strabismus and amblyopia are very common in these cases. Nasal dragging will produce more commonly a pseudoesotropia, and temporal dragging will produce more commonly a pseudoexotropia. And it is very important if you decide to surgically treat these patients — explain to the patients that their results might be very unpredictable. Let me end my presentation first by thanking you for attending this webinar, but also to those of you who are enthusiastic about strabismus, I would like to invite you to the next ISA meetings this year, that will probably be virtual in Paris, in April. And next year, that — this will probably be seeing us person to person in Cancun, Mexico. With this, I’ll end my presentation. I don’t know if we still have some time to answer any… Some questions. You tell me, Dr. Suma. Unmute yourself, please. You’re still muted.

DR GANESH: Do you measure this kind of pseudostrabismus by cover test or centering the corneal reflexes?

DR MOLINARI: I measure it with both methods. With Krimsky and with the cover test. Usually what the patient wants is the correction they see by Krimsky test, not by cover test. So I aim to correct the patients with what I find by Krimsky test.

DR GANESH: Okay. In the previous talk, I asked you whether you would inject bupivacaine into the medial rectus if there is consecutive exo? I think this is for the resurgeries. I have not injected bupivacaine. But asking whether you would inject bupivacaine into the medial rectus.

DR MOLINARI: I have not experience with that type of injection. Because you need a large — we don’t have bupivacaine in concentrations more than 0.75%. And if you use this concentration, you need very large amounts of anesthetic to inject. In order to get a result that’s an effective result. So I have no experience. But if I had bupivacaine that is 1% or 2%, which is the one that Dr. Alan Scott uses, I would try it. Yes, why not?

DR GANESH: There’s a question — what did you do to correct the hypertropia?

DR MOLINARI: In the case I just showed?

DR GANESH: Yes. There’s a question.

DR MOLINARI: Well, the patient had no apparent vertical deviation. She had a vertical deviation when the cover test was performed. But cosmetically, she had no vertical deviation. This is why I did not address that deviation. These are cases that are really difficult to treat. Because one thing is what you find in a Krimsky test. The appearance of the patient. And the other is what you find by performing a cover test. And usually those two tests give you very different results. But the patient consults you, because what they see in the mirror, which is the Krimsky test…

DR GANESH: Yes, I would go for Krimsky test rather than what you would do for the cover test.

DR MOLINARI: But the most important point of this presentation, the most important learning point, is that the result you will get is very unpredictable. If you aim for the typical tables that you find you have to do for 30 diopters, so much recess, so much resect, be sure that the result will be totally different. So be prepared about that. Using adjustable sutures is a very good way to avoid difficult surprises.

DR GANESH: And the last question on eccentric fixation. How do you measure? Of course. And how do you plan the surgery? If in these cases…

DR MOLINARI: Eccentric fixation usually unfortunately have low vision. Because the fixation is not near the fovea. So in these cases, diplopia can occur, but it’s not so common to occur. So it is very important always to listen to the patient, and listen to what they are more concerned about. And try to correct what they are more concerned about. You can still perform surgery in exotropia… In peripheral… In eccentric fixation. But also, results there will also be unpredictable.

DR GANESH: Yes, I think in these cases, it is important to do an adjustable. Because what happens is we do not know exactly the eye — what part of the eye is exactly used for fixation.

DR MOLINARI: Yeah, sorry, Dr. Suma. Go ahead.

DR GANESH: I was just saying that you need to do an adjustable. Because otherwise it’s quite unpredictable, and sometimes what happens is that they use a small amount of eso for — you have corrected the exo, and sometimes what happens is they use a small amount of eso and it looks overcorrected.

DR MOLINARI: There’s also a question here from Pilar from Spain, and she asked if I use direct Krimsky or inverse Krimsky test. Placing the prism over the — I usually place the prism on the good seeing eye. Always. Yeah. Which will be here inverse.

DR GANESH: Modified Krimsky. Yeah. There is another… Okay. I think most of the questions have been…

DR MOLINARI: Answered.

DR GANESH: Answered, yeah. And there’s one question. The rest I have to answer. There’s one on… Would you do rerecession in undercorrection? I have very rarely done rerecession. Unless the recession has been very less. Because sometimes whenever you have a resurgery, the recession is already around — if you have the surgical notes, it’s around 8 to 9 millimeters. And so to go in again, and it will cripple the muscle. It’s better to do one rather than cripple the recessed muscle if it has already been done, 7 to 8 millimeters, already.

DR MOLINARI: Let me answer the last question, if possible. There was a question on how young can a patient present a heavy eye syndrome? And let me tell you that in the case that I showed, where we did the technique of elevating the lateral rectus — this patient had a little bit over one year old. I have seen very young patients with heavy eye syndromes. Because there’s another question here. What is the cause of 25 prism diopters in a -8 diopter myopic patient, age 10 years, and how we can treat it? Well, if the patient has — because a -8 is not so myope, I would perform or investigate about axial length in this patient. Maybe in this case, a bilateral medial rectus recession will solve it. If there is no vertical deviation when the patient looks to the sides, I will do a conventional surgery. I will not do any of the techniques that I described today. So it’s almost 10:30. I think we can finish now.

DR GANESH: The rest of the questions maybe could be answered… There are a few more questions which are coming up. I can answer them separately over the email. Lawrence, can we do that?

>> I can send those to you today, Dr. Suma.

DR GANESH: Yes, a few more questions coming in. It was a wonderful session. There were so many questions and great presentations by everyone. Thank you so much. Thanks, Cybersight and Lawrence too. Lawrence, you want to make any announcements?

>> Nope, I just wanted to say thank you all, and I will be in touch, and thank you, everyone, for joining.

DR MOLINARI: Well, thank you, Lawrence, and thank you to my friends, Suma and Dr. Sumita. And hope to see you soon again. Bye!

DR GANESH: Bye. Thank you so much.

Download Slides

Dr. Molinari’s slides
Dr. Agarkar’s slides
Dr. Ganesh’s slides

January 8, 2021

Last Updated: October 31, 2022

4 thoughts on “Lecture: Surgical Strategies: Strabismus”

Leave a Comment