Questions and Answers

Presiding Physician: Daniel A. Long, MD

Dr Long: Dr Wise, the question came up, when is the earliest you would re-treat with SLT? How long would you wait?

Dr Wise: If I had treated 360o and they really didn’t respond, I’m not sure I would re-treat them at all. If I did 180 and I decided I didn’t get what I wanted after about six or eight weeks, I might do the other 180. But, again, if you don’t get very much response in the short term, re-treatment is probably not going to do a lot. There are people out there who just don’t respond to the laser. The place to consider re-treatments are those patients coming in two or three or four years later.

Moderator: Dr Nichamin, could you repeat or really quickly give us the settings you like to use when you are doing a vitrectomy. You went back and forth between different settings while you were doing your vitrectomy. Could you give us what those settings usually are?

Dr Nichamin: My slides were pretty general. Again, the concept when removing vitreous is to use the lowest possible vacuum that will allow you to effectively bring material into the cutting port, and the highest possible cutting rate. Most modern cutters will cut anywhere from 750 up to 1500 cuts per minute, or faster. The cutting rate is all the way up when removing vitreous and we’re using the lowest amount of vacuum that it takes to actually engage vitreous. That is typically in the 50 to 100 mmHg rate. This is going to depend a little on your system – the type of pump you have and the machine. Again, you want to use as low a vacuum as you can. Then, when engaging lens material, the cutting rate goes down, chop, chop, chop, in order to be able to get that harder material into the cutting port, and your vacuum goes up, sometimes up to 150, perhaps 200 mmHg, just temporarily to engage that material. As you know, we can click over to the side and just have aspiration rather than cutting. That can be effective for engaging a little piece of nucleus, and then kick back to a cutting mode and aspirate that away.

Moderator: We are going to wrap up the morning session now.

At the Crossings: Pediatric Ophthalmology and Strabismus, p. 307

Proceedings of the 52nd Annual Symposium of the New Orleans Academy of Ophthalmology, New Orleans, LA, USA, February 14-16, 2003

edited by Robert J. Balkan, George S. Ellis Jr. and H. Sprague Eustis © 2004 Kugler Publications, The Hague, The Netherlands

Questions and Answers

Refractive update

Presiding Physician: Marguerite B. McDonald, MD

Dr McDonald: How would you use CK, Skip, to modulate astigmatism after PKP? Have you tried that?

Dr Nichamin: That is a very good question. I personally have not treated a patient, but I have two scheduled, and I know of several other surgeons who have attempted treating astigmatism in this setting, and I can share with you, as you might imagine, what you don’t want to do is place the CK probe in the graft/host junction. That is essentially the new limbus for the cornea, and I am aware of several surgeons who have treated post-PKP inside, just inside the graft/host junction on the flat meridian, and they have had good results so far, but very early on.

Dr McDonald: The question is coupling.

Dr Nichamin: The question is coupling with CK, and yes, that’s why we are looking for hyperopic patients. We get an overall steepening, even with the individual astigmatic spots.

Question from Audience:

Dr Nichamin: I don’t know the exact answer to that. But what you can do with CK, because it is so simple, is titrate your treatments. We use intraoperative keratoscopy to apply the spots, round up the mire, actually overcorrect the mire, and we come back and place more spots as necessary.

Dr McDonald: Two questions for Howard and Skip. Number one, what do you think about endolaser cyclophotocoagulation; and two, if you were to have an IOL yourself, which one would you have?

Dr Fine: First, endolaser photocoagulation. We have found this to be an inordinately useful tool. We address almost all our coexisting cataract glaucoma patients with this; we utilize it in all our pseudophakic patients. There are a variety of other uses as well for the endoscope. I know that Dr Richard Mackool operated on one of his parents and had unremitting inflammation. He used the endoscope and

At the Crossings: Pediatric Ophthalmology and Strabismus, pp. 309–311

Proceedings of the 52nd Annual Symposium of the New Orleans Academy of Ophthalmology, New Orleans, LA, USA, February 14-16, 2003

edited by Robert J. Balkan, George S. Ellis Jr. and H. Sprague Eustis © 2004 Kugler Publications, The Hague, The Netherlands

found a hidden residual chip of nucleus. So, I think this is a fabulous technology. We wrote about it in our column in Eye World, and I think it is worth the evaluation of every anterior segment surgeon. The question about which IOL I would want in my own eye would depend on a whole bunch of things. I use about ten different lenses because we customize for each patient, not only the power of the IOL, but also the design and the material, and I would most likely leave the choice of IOL for me to the surgeon who was going to operate on me.

Dr McDonald: Skip, what would you choose?

Dr Nichamin: Very good answer, Howard. I am just gaining familiarity with the endocyclophotocoagulator. In fact, I would like to share with you that I was at the Medtronic booth earlier today and we have set up an evaluation. Once Howard gives something his endorsement, it means a lot to me. I have talked to Dr Mackool on a number of occasions. It has always been of interest to me that the glaucoma academic society, so to speak, hasn’t embraced this technology. I am told that the current iteration of this device is significantly different from the early one which went through some careful study. So, I am very excited about that. I have to beg off that question a little. We use a lot of different lenses. We try to tailor the lens for the patient. I am currently very, very excited about the Tecnis technology that you have heard about. I think that is the wave of the future, and I would probably be leaning toward that type of implant for myself.

Dr McDonald: Another question, is CK permanent? Skip, how do you explain that to your patients?

Dr Nichamin: That’s a very, very good question. Before I got involved with CK, I really took a long, hard long at the data. I personally went through all the threeyear data that were submitted to the FDA. I went and examined patients. I traveled with Marguerite down to Mexicali, Mexico to look at some of Mendez’s own patients. Dr Mendez is the inventor of this technology. We saw patients who were five and six years out. I think if you compare long-term CK data to the natural progression of hyperopia that occurs in this population, it would appear thus far that this is ‘permanent’. Obviously, we only have so much data of a particular duration at this point, but I feel again, in my heart of hearts, that this is a completely different animal from that of non-contact lens thermokeratoplasty.

Dr McDonald: Another CK question, can you perform CK in a post-LASIK patient who is hyperopic, and will CK affect the flap edge and cause gaping there?

Dr Nichamin: Yes. We have treated a number of post-LASIK patients. We have had no flap problems whatsoever. And I would share with you that the other interesting thing about CK is that patients are seeing better than they ought to be, based on their postoperative refraction. Marguerite probably could speak to that better than I. There is some conjecture that we are creating a larger, more functional optical zone than we do with hyperopic LASIK, but these patients are so happy. They just see very, very well. What if you have a hyperopic post-LASIK with a small flap? That’s a problem. You either have to do surface ablation or cut

a new flap on a flat cornea. That’s a problem. So I think CK post-LASIK is wonderful.

Dr Fine: Dan Durrie showed that CK patients had better contrast sensitivity than other modalities than they did preoperatively with the best corrected acuity. So there is something about this technology that is compelling.

Dr McDonald: This one has already been answered. How long does post-op CK last on average? Do you tell your patients anything about the future, that they might ever need a touch-up? Do you ever plant that idea?

Dr Nichamin: I now tell all my refractive patients, myopic patients as well, that if they don’t have surgery today, it is quite possible that they will be coming in to have new glasses in a few years’ time, and that they would be forking out over $300 for new glasses. So, it is important for us to instill in their minds that, although the surgery may be permanent – what we accomplish today with the laser or with a CK – but mother nature is dynamic and your eyes will change. And specifically, with the CK population, these are middle-aged low hyperopes. Typically they were plano and early presbyopes, so they are very frustrated with the fact that one, they were hit with presbyopia earlier than their classmates, and two, now their distance vision is waning in their mid-fifties. And we explain to them that we think the technology we are going to use today is, in fact, permanent, we’re not sure, but we think it is; however, their eyes will progress. Just as we develop gray hair and more wrinkles, their eyes will continue to age, and chances are that they will be back for some additional surgery. They seem to accept it very well if we put that up front.

Dr McDonald: Thank you both so much. We’re going to take our break now.