Questions and answers

Questions and Answers

Moderator: The first question is: “Do you avoid LASIK completely if a patient has guttata?” and, also, I’d like you to address, “Do you look at it differently if the patient is 25 years old versus say 55 years old?”, and, also, “Do you look at the patient differently, male versus female, since we know Fuch’s is more prominent in females?”

Karl G. Stonecipher, MD: Experience usually means you’ve done it before and either had a good experience or a bad one. So, in my hands or series or however you want to look at this, I have operated on people with guttata before. I don’t think it is a good idea because their flaps don’t stay as well, and there is definitely a male versus female issue in that females tend to be drier and they end up having more problems with slipped flaps. I would think that, if you are really thinking about what we are doing here, someone brought it up in one of the chats on the ISRS the other day. Don’t feel that you have to operate on everyone who walks through the door. I think Dan alluded to this early on and I’m accentuating that. That is, we really need to say “No”. There are a lot of people to whom you can say no. It’s just hard, especially if you are trying to feed a laser that you own yourself. Number two, if someone else has a better toy, send them over there. I have just started doing that lately, telling the patients, “I chose to have this laser and we have four different lasers. This is not the thing to do and I think this is better.” So referring these guys out, as Dan said, a lot of times will get you just as many patients as if you try treating them and end up with a problem. Today, to answer your question, guttata I pretty much leave alone. I just don’t think it is worth the risk.

Moderator: Any other comments?

Ronald R. Krueger, MD, MSE: One thing that I do with guttata patients is to tell them that they have the condition, that that could potentially prevent them from having the surgery. I measure the pachymetry, look at their topography. I send them home with a bottle of Muro for a few weeks and then when they come back I check the pachymetry again and look at topography and see if there is any difference, the same with the manifest. If I see any thinner corneas or something from using the Muro, then I will assume that there is some kind of subclinical edema and not treat them. But if I don’t see any real change, I will go ahead and treat them, and I haven’t had any problems with that.

Moderator: Does anyone else dare to operate on patients with guttata, or do we avoid them completely?

Dr Krueger: I avoid LASIK on them, but I have done several with PRK successfully.

Wavefront and Emerging Refractive Technologies, pp. 111–114

Proceedings of the 51st Annual Symposium of the New Orleans Academy of Ophthalmology, New Orleans, LA, USA, February 22-24, 2002

edited by Jill B. Koury

© 2003 Kugler Publications, The Hague, The Netherlands

Moderator: Do you look at a 25-year-old differently from a 55-year-old in this situation? Or do you lump them together?

Steven Schallhorn, MD: I think that, in the older patient, I am more inclined to see if there is any clinical or even subclinical evidence that the endothelium is not working properly. Kind of like what Ron was talking about.

Dr Krueger: I would avoid LASIK anyway.

Paolo Vinciguerra, MD: I think we have to look to the endothelium, of course, not just looking for guttata, but if there is polymegathism or polymorphism, the number of cells. There are many other factors in deciding whether to treat those cases or not. In looking at the Orbscan pachymetry map, is this pachymetry map homogeneous or not, or is there local dyshomogeneity that can play a different role in deciding whether or not to treat those cases.

Moderator:What is the best treatment for postop hyperope with visual blur or distortion?

Dr Vinciguerra: First of all, why he has blur, because of a small optical zone, he has high eccentricity, decentrated, he has some remaining optical aberration outside, he has interface problems, he has striae.

Marc Michelson, MD: The hyperopes can be really tricky for a number of reasons. One is that you can treat a mild or moderate hyperope and they can come back with 20/30 vision and are not happy, and you refract them manifest and they are +1.00, repeat a cycloplegic refraction and they are still +2.00 or +3.00. So then you have to decide if you can retreat them, and what are you going to use. And you have to be very careful because I think that, in those situations, you have to be very conservative. Sometimes a small touch-up, maybe even 50% retreatment of the residual manifest refraction, the lowest amount sometimes makes these patients very happy. So you don’t want to fall into the trap of retreatment on a hyperope, going and chasing the cycloplegic refraction, because you can end up creating excessive myopia.

Dr Schallhorn: The other thing is centrations. I find that centration of the hyperopia is very important. Generally, smaller optical zones are used for hyperopia because you have such a large transition zone. I would also look carefully at the centration.

Daniel S. Durrie, MD: Just to add to that, our laser is getting a lot better at hyperopia. And as we are getting more lasers approved in the USA that have wider blend zones....Paolo has worked on this with Nidek and with the same laser over probably a fouror five-year period of time, just by making the true optical zone larger and larger now. Lasers have 6, 6.5 mm of true optical zone before they hit their blend zone. I think we can do a lot better on hyperopia. So if you have someone who has a large pupil or someone who is a pretty picky patient, you may want to wait until your lasers are upgraded, because if you do them with some of the original broad-beam lasers with small optical zones, you are just forming little bumps and they don’t see very well and there is not a lot you can do about it afterwards.

Question from the audience: I have just one other comment with regard to treating

hyperopia. I find it is very important as to what the Ks are. If the average Ks are already steep, you are not going to be able to continue to steepen them further. That is one of the important things, where they were before the initial treatment, preoperative Ks.

Dr. Stonecipher: What is your cut-off? What do you steepen them to?

Question from the audience: I don’t try to take anyone past +4 now, no matter where they are. If the desired refraction is going to take them beyond about 47, 47.5, I tell them that I probably am not going to be able to get all their treatment done.

Dr Stonecipher: I’m at the same level; 47, 48 is about my cut-off.

Stephen G. Slade, MD, FACS: Interestingly, if you look in Barraquer’s book from back in the 1950s, he said the same thing, that the cornea won’t tolerate being steepened past, I think he said, 49.

Dr Vinciguerra: My idea is that more than the K readings is the corneal eccentricity. Because that gives you an idea of the gradient. Because you can have normal corneas with 46, 47, but you can have keratoconus with 45 eccentrically with terrible vision just because of the different eccentricity. So, increasing the gradient of the curvature is much more important than the absolute K reading, and it is very easy. Topography gives you this value.

Ioannis G. Pallikaris, MD: Age is very important in our decision. Patients of over 40 and with less than 3 D is all for me now. I use secondary procedures. Patients younger than that, I have to go for better lasers. From the clinical point of view, just wait for the approval.

Question from the audience: Now that we have lasers with tracking mechanisms and we can choose our point of centration of the ablation, it is always a puzzle for me, and I’d like to know from the staff here, what sort of pearls, what sort of wisdom can they pass on to us about if we can choose a point to center on. Obviously, we saw some of the early Orbscans there that showed cones that weren’t quite in the middle of the cornea, and I think it was Dr Pallikaris, or maybe Dr Vinciguerra, who talked more about flattening nasally, and hyperopes are naturally flatter nasally. How does that influence your choice of centration?

Dr Durrie: This is a question that we have never really answered. I think with wavefront devices and those things, it is time for someone to start doing randomized prospective trials with different centration points in each eye looking at quality of vision. Because yes, we do almost everything on the pupil, the center of the pupil. But there is an awful lot of evidence to say, especially in hyperopes, that we should be a little bit nasal, maybe we shouldn’t be on the corneal apex, maybe we should be halfway between, but as we are moving along with this diagnostic technology, I would like to ask if that can be revisited a little. I think most of us are afraid to go away from the center of the pupil because we don’t have any data to support that, and we certainly don’t want to cause vision problems in the long term.

Dr Vinciguerra: In this way I think that, if those corneae have more flattening nasally, I

don’t recommend doing different centration because a decentration is a terrible problem in any kind of patient, but with a Merocel sponge, and a little bit with BSS, you can push a little bit of fluid just nasally, so that the ablation rate reduces just focally and leaves the same pattern that you have, but you have a little less ablation pattern nasally.