Paul Singh, MD, utilizes surgical videos to illustrate the dynamics of a post-occlusion surge and highlights how it can result in anterior chamber instability and posterior capsule rupture.
I. Paul Singh, MD: Hey everybody, thank you so much for joining me. My name is Dr Paul Singh, I'm the president of the Eye Centers of Racine and Scenic Kenosha, in Wisconsin, and anterior segment glaucoma surgeon. I'm excited to share with you 2 cases that we recently discussed at an Ophthalmology Times® roundtable. Our first case that we discussed involved postocclusion surge. One of the limits that we've had for many years with certain phaco technologies was the ability to keep that chamber rock solid. To me, that's the environment that we're working in, so anything we can do to maximize the stability of our environment, keep that chamber stable to give us more room to work in, but also keep that posterior capsule far back so we feel safe in preventing things like posterior capsule rupture as well. Let's talk about what postocclusion surge is and how we can mitigate it, what are some of the new technologies that we have available to us, and what is postocclusion surge?
First, basically when you have irrigation going in the eye, you have a deep chamber because fluid is going in there. When you have an occlusion—so you have your gold tip and you a piece of nucleus stuck to that tip—what's happening? Well, the tip is being occluded, so you're getting no vacuum, meaning you're getting irrigation going in the eye, but because the tip is occluded, nothing is leaving the eye; you have a nice deep chamber, pressures building up in the anterior chamber. What's happened to the actual tubing? The tubing, because no fluid is going back there, collapses. You have a collapse tubing and negative pressure in the tubing, and you have this fluid going in the eye. What happens when it breaks? When you release that break, so when the emulsification occurs and the nuclear piece is then fragmented and gone, that tip opens up. All of a sudden, because you have a negative pressure gradient in the tubing, all that fluid gets out of the eye. When that happens, the pressure drops in the eye, and that sudden decompression, that sudden drop in pressure, because a fluid left through the tubing that just opened up, the pressure can go down and the chamber can collapse. That is what postocclusion surge in a nutshell is.
What does it look like to us? Here's a video showing us what postocclusion surge is. It can be benign sometimes, and we don't notice it, but a way to see post occlusion surge is if you look at the iris, look at the pupillary border. As you get occlusion and you break that occlusion and the piece goes into the tubing, you see that iris go down, bouncing. That can happen subtly where it's very innocuous, but it can be significant enough in some cases where it can actually cause a capsule to come forward as well. Here you can’t see a lot of capsular issues going on because you have a nuclear piece blocking the capsule, but when the nuclear piece is gone, you don't have that protection and that can be scary. As you can see here, when you break in the nucleus, see the postocclusion surge, as soon as the nucleus left the tubing, you can see the iris bouncing. What does that mean clinically? What's the fear that we have? Let me show you a different video. This is an older video of mine, but it shows you what's happening. So, I'm getting that nuclear piece out, this epinuclear piece out, and now watch what happens as this last piece goes into the tubing, ready, boom. Suddenly that piece gets evacuated. Right now, the pressure drops and the capsule came forward into my phaco tip. That caused a posterior capsule rupture. When you have no nuclear pieces protecting the capsule and a postocclusion occurs, that brings a capsule forward and that can cause that small break. The key is not to come out until you put viscoelastic because you want to protect the capsule; you want to protect the vitreous from coming forward. That's why you want to always make sure you're very gentle. Before you come out of the eye as you saw there earlier, I put viscoelastic into the anterior chamber and the bag to prevent vitreous prolapse. I'm being very gentle with my irrigation aspirations from removing as much of the cortical fibers as I can without disrupting the vitreous, the high anterior hyaloid face as well. In these cases, you can put a lens in the bag or in the sulcus depending on how comfortable you feel as well, but I would be very gentle with how much irrigation and how much aspiration you use when you're removing cortical material in the context of a posterior capsule rupture. I'm bringing my bottle height down, bringing the vacuum down, and I'm being very gentle just to make sure. You can see those 2 arrows., that is where the actual break in the capsule is. So, I'm trying to protect it from enlarging, which is why I'm going down on my bottle height, down on my vacuum, swimming gently, and not being afraid to put more viscoelastic into the cap bag. Then here I'm putting a 3-piece IOL just to be safe. Now you probably could have put a one piece in the bag, but I felt comfortable with the 3-piece. I think 3-piece lenses do a great job and the patient did very well. Small things that can happen, but it can lead to more issues if you don't know how to attack it and protect that vitreous from coming forward. In that essence of what we worry about with postocclusion surge is that posterior capsule rupture.
Transcript Edited for Clarity