Speaker: Ronald R Krueger, MD, Cleveland Clinic
Session: Femtosecond LASIK: Tips for Optimizing Visual Outcomes and Avoiding Complications
Typically, the things to know is that when the femtolaser comes down and hits the cornea at a creative burst that ultimately separates the tissue, there’s a lot of energy being posited. And it’s possible for the bubbles that are being created to sort of coalesce and to create something called an opaque bubble layer. And the opaque bubble layer can block your pupil. It can degrade a little bit of the laser quality during the surgery, and so you want to try to avoid that.
And some of the laser companies have actually developed a pocket, where it sequesters some of the bubbles into this pocket and comes out of where the flap is created. And some have created a canal, where it actually, like a chimney, allows the bubbles to go out to the outer surface. And some use low enough energy pulses that it really doesn’t make very many bubbles, and they don’t have any canal or pocket.
One of the systems that I use, called a Visiomax, actually not only makes flaps, but does a procedure called SMILE. And SMILE is a new procedure, kind of like a laparoscopic LASIK, where you make a small incision, and you make an anterior and posterior layer to the exact shape of the prescription you want to change. And then you just pull that lenticule of those two layers created and pull that out, and that changes your refraction through a small incision instead of a large flap.
Intraoperative complications with SMILE come into three categories — that which is happening during the laser application, that’s happening during the dissection when you separate the lenticule, and then that which happens during the extraction when you take the lenticule out. So all the intraoperative steps, but three categories.
And essentially, during the laser part the things to be concerned about is a suction loss — the opaque bubble layer that I mentioned, or areas where the pulses don’t actually ablate, and they create black spots where the ablation doesn’t occur, and even things like decentration. If you’re off-center and then your entire refractive pattern is in this lenticule that’s now no longer centered, it’s going to affect some of the clinical outcomes.
Is that if you have a suction loss on the very first pass of the femtosecond laser, then that’s going to stop you from doing the small procedure, because we can’t re-dock and get it exactly in the same place.
But if you have it in the second layer, the anterior-most layer, which is a flat or plane layer, planar layer, then you can simply re-dock it and apply it, and it will go in the same pathway. And the system allows you to do that pretty easily if you need to.
And then, finally, during the extraction the real key point is you want to take this whole lenticule out of the eye. And if you take it out, the first thing you need to do is lay it on top of the cornea and look at it and say, is it all there?
And if it looks like there’s a section that’s missing, you need to go back and get that section and then piece it together with the original and say, OK, now I have the whole piece. Because if you leave a lenticule, or piece of a lenticule behind, then you’re going to have some irregularity in your refractive outcome.