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Round table: Surgical solutions to strabismus in infants and adults
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The Early vs. Late Infantile Strabismus Surgery Study established that children with infantile esotropia who underwent early intervention, between age 6 months and 2 years, had better stereoscopic vision than children who underwent surgery at a later age. The final report of the study was published in 2005, and debate continues almost 15 years later regarding the optimal timing of “early” surgery.
The OSN Pediatrics/Strabismus Board Members, led by Section Editor Robert S. Gold, MD, tackled this debate, as well as other questions of esotropia management in children and adults, in a round table discussion at the American Association for Pediatric Ophthalmology and Strabismus meeting in San Diego.
Source: Rudolph S. Wagner, MD
Rudolph S. Wagner, MD: The timing of surgery for infantile esotropia has varied over the years. At one time, 18 months or later was the norm; at another time, there was a push to operate sooner, at 6 months or even earlier. There is often variability in the first 6 months, and the important thing is to establish that the deviation is stable. Sometimes if I observe inferior oblique overaction, I wait to see what happens over time. Once I have consistent measurements, I am OK with doing the surgery. On average, I would say I end up doing most of those surgeries around 1 year of age.
Courtney L. Kraus, MD: I find that I do not see these children much earlier than 6 months of age, with pediatricians being inclined to watch them for the first couple of months of life before referring them. I like to see them at least twice to get an idea of the kind of angle I am dealing with. I target 9 months to a year for surgery and really try for before a year to see if I can improve their chances of fusion. I do always counsel parents that this may be the first of a couple of surgeries, given that they will show up later with inferior oblique overaction or dissociated vertical deviations.
Douglas R. Fredrick, MD: One thing I fear about early intervention is consecutive exotropia. I find consecutive exotropia is challenging to repair later. Operating too early risks overcorrection as well as missing the inferior oblique overaction, which often occurs between 6 and 12 months of age. For me, I would say operating between 10 months and 12 months is my target as well; I do not consider that “early” intervention.
Jordana M. Smith, MD: One thing I would say about timing is that I am cautious about operating on babies who I know are amblyopic. I have a long conversation with parents about patching or atropine for amblyopia and the importance of trying to correct their amblyopia before I do a procedure. I always do a minimum of two exams, but sometimes the amblyopia corrects quickly and sometimes it takes 6 months. On average, I operate at 9 to 12 months, maybe later if we’re struggling with amblyopia. But my preference is to do bilateral medial rectus recessions as opposed to a unilateral medial rectus recession and lateral rectus resection for esotropia. So, I try to fix someone who I know is amblyopic first.
Roundtable Participants
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Moderator
- Robert S. Gold, MD
- Kenneth P. Cheng, MD
- Douglas R. Fredrick, MD
- Courtney L. Kraus, MD
- Jordana M. Smith, MD
- Rudolph S. Wagner, MD
- Roberto Warman, MD
- M. Edward Wilson, MD
Kenneth P. Cheng, MD: The only thing I do differently that might be a little unusual is that if the patient has hyperopia, +1.5 D or even +2 D, I will put that patient on Phospholine Iodide (echothiophate iodide, Wyeth) eye drops, just to make sure that there is not any accommodative component. Typically, there is not. It is pretty easy to pick out these patients as real infantile esotropia patients, but the trial gives me that second examination, and there is no harm done. Then I will take them to surgery. With the referrals and the time it takes to get an appointment, it is rare to have somebody come in and be ready for surgery after two visits before 6 months of age, but I do not shy away from operating on somebody between 6 months and a year.
M. Edward Wilson, MD: I would differ a little bit. I do not think there is any reason to delay surgery once you have established that it is a constant esotropia, it is a stable angle, and the eyes are anatomically otherwise normal. My concern is with the length of time they remain constantly esotropic. Most of these patients’ eyes are not crossed in the nursery. They become crossed at 2 to 3 months of age. As soon as I am comfortable that the angle is stable, I find that if I can make the eyes straight, the child’s development improves, and the child starts to better meet developmental milestones. So, I would operate as early as things are stable — often that is around 6 months of age. For a stable 6-month-old child, I am not going to wait until the first birthday; I do not see a reason to do that.
Roberto Warman, MD: An important issue is the magnitude of the angle of deviation at presentation. The PEDIG studies showed that a 20 D deviation in the early stage often goes away. For a 40 D esotrope, I agree with you. I have operated early, and I have operated late. I am not sure there was any difference. However, it is the 20 D esotrope that I want to watch. Another thing is, for those who are not demonstrating preferent fixation and I am waiting and observing, I do put them on alternate patch, at least 1 hour a day. One, the parents want something done. Two, it avoids some contracture of the medial while I am waiting.
Robert S. Gold, MD: I have found over the last 10 years or so that parents do not want to hear that word “surgery” until you have seen the child at least more than once. When you see a 6-, 7- or 8-month-old child who obviously needs surgery and it is the first visit, parents are skeptical. It is a difficult conversation: “Hi, how are you? Your child needs to have eye muscle surgery.” So, I agree that more than one visit is needed, and if there is any concern at all about amblyopia, I do patch and do alternate patching as well to keep the child a cross-fixator. That is a change I have made in my practice over the years. In the past, the child’s second visit often would have been the presurgical visit, but now that is more often the third visit. I see them maybe a month later, maybe several weeks later, to watch them closely.
Cheng: I would add that the characteristics of real infantile esotropia are so fixed — the large angle strabismus, the cross fixation — that if you see a child with a smaller angle, 20 D or less, or a strong fixation preference in amblyopia, those are red flags that this is not simple infantile esotropia and you need to look further for either an accommodative component or other cause of deviation, for example, sixth nerve palsy. Those are also the patients, I have found, who do not do as well long term as the typical large angle esotropia case.
Wilson: We know the common patterns, and if it is a variable angle, if it is a child who is developmentally abnormal, if there is a strong amblyopia component, I will follow the case and tell the parents that we are going to need to see how it evolves. But I have no problem if the parent brings the child in and it is a large angle esotropia that I know needs to be fixed and they are looking for someone who will do something, then I am confident enough to say, “We’re going to schedule surgery.” Sometimes there is a sigh of relief because if you send them away, cautiously saying we need to see you two or three times, that might not be serving the family as well. They may go find another doctor.
Fredrick: For the younger children, say the 4- to 6-month-old who has a large stable deviation, I will offer Botox (onabotulinumtoxinA, Allergan) chemodenervation. Having trained on the West Coast, I am comfortable with Botox. In my experience, the risk of an overcorrection, the consecutive esotropia, is lower with Botox. So, if I am being pressed or feel that somebody wants to have surgery early or intervention earlier than what I am normally comfortable with, then I offer to proceed with Botox chemodenervation, even though I know it might take a second set of injections to get the eyes straight. But that is another modality you can offer.
Wagner: I agree with Ed. Once you have identified that this is a surgical infantile esotropia, it is your obligation to explain to the parents the benefits of surgery along with the risks. After spending a few minutes with the patient and family, you can tell whether they are going to accept that immediately or not. Most of the time, if you explain it well and you are confident in the proposed surgery, they will accept your decision.
Maximum medial rectus recession
Gold: Let’s move on to how much recession and how many muscles you incorporate in your surgical management. What is your maximum medial rectus recession amount for alternating esotropia, whether it is infantile or some other, and when do you go to a third or even a fourth horizontal muscle?
Warman: Through the years I have become more conservative, particularly with small children. I do not like to do more than 5 mm to 5.5 mm on the medials. If I feel I need a third muscle, I would rather go in and do the third muscle because long term, if you do the 7 mm, they are going to go exotropic (XT), not all of them, but enough. For the older child, say 3 years old, you have more leeway. My limit is 7 mm, which I do not often do on a medial, but I do sometimes.
Wilson: In the congenital/infantile esotropia group of disorders, I do just two muscles initially and I do up to 7 mm as the maximum. We looked at our cases a few years ago in which we operated on two muscles initially in children younger than 1 year of age, and we found that there was no greater need for a second surgery in those with more than 80 D of deviation than in those with 50 D to 80 D. So, it seems that in that condition, the response is directly related to how much deviation you have. I do not add a third muscle unless it is needed later. That does not apply to large angles in older children.
Kraus: I would say my max is 6.5 mm, but that might be splitting hairs. I also only start with two muscles, not because I think they are more likely to go XT but because there are probably equal numbers who will be either undercorrected or overcorrected. Leaving myself with the laterals is a nice option for both over- and undercorrections.
Smith: I agree. My max is 6 mm to 6.5 mm for children a year old or younger. I do not tend to go over 6 mm even if they are a little older, and I only do two muscles. I always do cycloplegic refraction in these patients, and if anything makes me think the axial length is particularly short, then I will decrease my maximum medial rectus for recession.
Kraus: My senior partner, David L. Guyton, MD, has advocated for placing medial rectus recessions greater than 6 mm on a permanent suture, which is not something that I have personally adopted, but he has worked on many more slipped muscles than I have.
Cheng: I never heard of using a permanent suture if you are going to go way back. My personal observation is that some of these patients, now in their 20s, develop an adduction deficit, and if you have to go back to operate for consecutive XT, you find that muscle is significantly recessed. But when you look back at the charts, you do not see these adduction deficits early on or over years of following them, but long term, when they hit adulthood, a lot of these patients with XT have adduction deficits, possibly due to some molding or modeling changes in the healing patterns, some slipping of the muscle. So, for some time now, I have limited my recessions to 6 mm, and I have been happy with the results.
Wagner: I also do not like to do more than 6.5 mm, but one of the things I have learned is that people measure differently. What is 7-mm recession for one person might be 6 mm for another. I tend to measure right after I have removed the muscle from the insertion after it has been secured with the sutures. I measure from the inside edge of the insertion, going posteriorly. Some people measure from the front of the insertion. The point is that there is individual variability.
Cheng: Rudy is 100% right. You can make this number anything you want, but it is the consistency of measuring that is key. I tell residents that all the tables and whatnot are guidelines, but in their own hands, they will have to use their own sort of nomogram, a key point being taking measurements the same way every time.
Fredrick: Depending on the age, I would say 6 mm for younger patients, maybe 6.5 mm if they are a little bit older. I also use forced ductions to help define. Sometimes you do forced duction testing and the medials are tight, and you get a big bang for that buck. So if I put it back 5.5 mm and it is still tight, I will let it go back another 0.5 mm before I tack it down, not using a traditional hang back method, but just letting it be 0.5 mm farther back, having placed the sutures posterior to the original insertion.
Gold: I am glad to hear your perspectives on the two-muscle approach vs. the three- or four-muscle approach because it is still a topic of debate. I would rather have the patient be a little undercorrected than be way overcorrected in that postop period. I make it clear to the parents that there is a chance, whether it is 20% or 25%, whatever it is throughout the lifetime, that the child may need more than one surgical procedure.
Wilson: If you have done two muscles to start and some months later you have a residual esotropia, especially if it is a little bit variable, one pearl is that these kids with congenital/infantile esotropia are not as capable of developing an accommodative esophoria. In other words, they will cross with less accommodative effort than normal kids. That residual crossing after your first surgery might respond to +1.5 D or +2 D glasses, even if a normal child could have handled that and not crossed. Instead of jumping to a second surgery on the laterals, prescribing glasses, even when the hyperopia is modest, is a good second step.
Smith: I tell parents of young patients with infantile esotropia that, based on studies, 50% to 80% of these children will need an additional surgery. I think introducing that concept early helps if you do have continued need for either a second procedure or more therapy with glasses because the parents know right from the start that this is not a one-time type of intervention.
Wilson: I would caution that parents might imply that the first surgery is a shot in the dark, that we do not know how to dose our surgery. I would make a slight change and say, “We have a lot of information about what your child has. The first thing we need to do is do the surgery for the crossing, but there are other things, some ‘late bloomers,’ that are going to show up and that will need to be addressed. When the child looks to the side, the eye may start to go up. When the child is inattentive, one eye may drift up or out. These things are coming. They may not be significant, but they may require more procedures.” So, you are setting up the second surgery and predicting the future. This is better than saying, “Well, we need surgery now, but you know there’s an 80% chance of a second surgery,” and then it sounds like we are imprecise. We are not. We are actually predicting the future.
Small angle corrections in teens, adults
Gold: What is your approach to small angle strabismus problems in teens and adults with previously treated disease? With these small angles, esotropia in particular, these adults may be having double vision and do not want prisms but still want something done.
Kraus: Diplopic patients who do not want to wear prisms? That is a problem that I encounter more frequently than I would like to, especially when the patient shelled out for the multifocal IOLs with the enhancements so they could be glasses-free and now they have a 3 D to 4 D esotropia and they are symptomatic. I have a conversation with those patients that my preference would probably be prisms but I understand that they want to be glasses-free, so that puts them in a boat in which they need to have surgery. I tell them the pros and the cons. The risks for over- and undercorrection are high when you are operating for such a small angle, but if you use an adjustable suture, I think it is fair to at least offer that option. But I put it on them to choose. It is not something I relish operating on, but I think it is a way to approach the patient.
Fredrick: For a small angle horizontal deviation, Botox is a great first step for a couple of reasons. One, it can demonstrate to the patient what it could be like if they were to have surgery. The Botox sometimes can last a long time; it does not necessarily have to be repeated every 3 months. It also is a step before doing surgery, which can be perceived as something intermediate between an optical or medical therapy and a surgical therapy. I think it improves the therapeutic alliance I have with a patient by offering something before surgery.
Gold: What unit dose do you use for small angles?
Fredrick: Usually 5 units is about right. The smallest I have ever used is 2.5 units, and I only use 7.5 units for bigger angles. It often depends on whether the patient has had previous surgery. I tell patients that I do not have a table that tells me exactly how much to apply, and they accept that, but it is easy to do in the office and I think it is low risk.
Kraus: Are you more inclined to get overcorrection or undercorrection?
Fredrick: If I get an overcorrection, it is almost always temporary, as I have had only one permanent overcorrection with Botox in 25 years. So, I warn them about that. I try not to just chip away at it. If I am going to use Botox, I will give what I think would be an adequate dose.
Gold: Is anyone doing the partial tenotomy procedure, whether it is in the office or in the OR for these small angles?
Wilson: For adults, usually elderly patients, with small vertical deviations and who do not want to wear prisms, the partial tenotomy is a good option, and I do not do it in the office. I take them to the operating room with the patient under topical anesthesia so I can snip across the tendon. The superior rectus muscle is the most common. I have the patient sit up and I measure, then I have them lay back down and I snip a little more. It is titratable. You do not get much of anything until you get 50% or more across the muscle, but then every snip gets you more and that works pretty well. It probably has less risks of an overcorrection than if you take the whole muscle off and try to pull it up to a small recession. That is probably a little riskier for an overcorrection.
Kraus: I use that technique but only for vertical deviations.
Wagner: Yes, it can be effective in those cases, and adults with diplopia often prefer surgery over prisms.
- Reference:
- Simonsz HJ, et al. Strabismus. 2005;doi:10.1080/09273970500416594.
- For more information:
- Kenneth P. Cheng, MD, can be reached at 100 Bradford Road, Suite 320, Wexford, PA 15090; email: kpchengmd@me.com.
- Douglas R. Fredrick, MD, can be reached at New York Eye and Ear Infirmary of Mount Sinai, 310 E. 14th St., 319 South Building, New York, NY 10003; email: douglas.fredrick@mssm.edu.
- Robert S. Gold, MD, can be reached at 790 Concourse Parkway South, Suite 200, Maitland, FL 32751; email: rsgeye@gmail.com.
- Courtney L. Kraus, MD, can be reached at Wilmer Eye Institute, 615 N. Wolfe St., Wilmer 230, Baltimore, MD 21205 email: ckraus6@jhmi.edu.
- Jordana M. Smith, MD, can be reached at University of Arizona College of Medicine, 1501 N. Campbell Ave., P.O. Box 245017, Tucson, AZ 85724; email: jsmith@eyes.arizona.edu.
- Rudolph S. Wagner, MD, can be reached at Doctors Office Center, Suite 6100, P.O. Box 1709, Newark, NJ 07101; email: wagdoc@comcast.net.
- Roberto Warman, MD, can be reached at Miami Children’s Hospital, 3200 SW 60th Court, Suite 103, Miami, FL 33155; email: rwarman@eyes4kids.com.
- M. Edward Wilson, MD, can be reached at Albert Florens Storm Eye Institute, 167 Ashley Ave., Charleston, SC 29425; email: wilsonme@musc.edu.
Disclosures: The round table participants report no relevant financial disclosures.