Publication Exclusive: Expert panel debates preferred strabismus surgery techniques

At the annual American Association for Pediatric Ophthalmology and Strabismus meeting in New Orleans, OSN Pediatrics/Strabismus Section Editor Robert S. Gold, MD, led a round table discussion on surgical approaches to correcting strabismus. Each of the participants had a different approach to correcting esotropia in patients with a large disparity in distance/near vision, some operating on the near angle, some on the distance angle and some with nuanced differences in the amount of correction to perform. Then the panelists took a new look at plication vs. resection for strabismus surgery, an idea that is not new, but one that is getting more consideration as an alternative to resection.

Robert S. Gold, MD: We will start by talking about surgical treatment for accommodative esotropia with a high accommodative convergence/accommodation (AC/A) ratio, that is, a distance/near disparity with a basic component that requires surgery.

The question is, how do you approach this patient? Which muscle and what angle do you operate on?

Scott E. Olitsky, MD: To me, it is fairly straightforward. I operate on the near angle always. I operate on the medials when they have not been operated on, but I do not think that matters. You can normalize the AC/A ratio regardless of which muscle you work on.

Gold: Do you get overcorrections?

Olitsky: I have more undercorrections than overcorrections. I understand people’s concern about exotropia, but I do not think it happens often. Certainly there is no higher risk in my experience than for any other strabismus we treat.

What does not conceptually make sense to me is, if you are worried about exotropia, which I do not think you need to be, why operate on an in-between angle in which you would still potentially get an exotropia and an undercorrection at near? That is not something I have ever really looked at doing

Anthony P. Johnson, MD: I typically operate for the distance angle and adjust for the patient with a high AC/A ratio. I probably see that high AC/A ratio in fewer than 10% of the esotropes I see. And I see more overcorrections than Scott does. It is disturbing to get those overcorrections, so I have evolved into being a little bit less aggressive and more willing to accept an undercorrection of the AC/A ratio than converting the patient into an exotrope.

Kenneth P. Cheng, MD: I will take the middle of the road here. Generally I tend to operate more toward the near angle of deviation, but not quite all the way, depending on how large the distance/near disparity is. I have been fortunate not to see too much in the way of overcorrection, but I do have patients whose eyes are straight at distance but need a bifocal to keep their eyes straight at near.

The one thing I do that I think makes a difference is to operate on the medials. If a patient has a fixation preference, as most of these patients do if they have decompensated, I will still operate on the medials on both eyes, but I will do more on the non-fixating eye than on the fixating eye. Even if the patient has had strabismus surgery once before, I will still redo the medials to avoid the laterals on those patients. I cannot say that I have tried it the other way around and whether it makes a real difference, but I am happy with my results.

M. Edward Wilson, MD: I agree somewhat with what Tony said. I have seen overcorrections. They are few in number but memorable. So I do not go all the way to operating on the near angle.

Another reason I do not is because the distance measurement is often consistent because of the distance angle. If the patient changes accommodative effort, it does not change the measurement much, whereas the near measurement can change a lot. It changes based on the attractiveness of the target. It changes based on small distance if the patient pulls it to near. So I have been happy with operating for the distance angle and then fudging up by 1 mm if the near is 10 prism diopters (DD) greater, 1.5 mm if it is 15 DD greater and 2 mm if it is 20 DD or more greater because sometimes the near deviation will go up to 70 DD. So I do not keep adding. I add 2 mm to my formula when the measurement is 20 DD or more. And that seems to have worked pretty well. If you do a relatively larger number than distance, you are going to get them correct most of the time. There are more undercorrections than overcorrections, but I just want to avoid those overcorrections.

Click here to read the full cover story published in Ocular Surgery News U.S. Edition, August 10, 2015.