Results of nonpenetrating glaucoma surgery discussed

Practitioners provide insight on variations in this surgical treatment modality for glaucoma. Part 2 of a two-part round table discussion.

Ocular Surgery News Europe/Asia-Pacific Edition convened a round table of experts to discuss nonpenetrating glaucoma surgery at the International Glaucoma Symposium in Barcelona. An international panel of ophthalmologists discussed their experience with nonpenetrating deep sclerectomy, viscocanalostomy and the techniques’ many variations.

In last month’s issue, we presented part 1 of the round table, including discussion of anatomy and manual techniques, the use of implants, postoperative monitoring and the use of sutures. In part 2, participants discuss antimetabolites, indications for surgery, complications and long-term results.

The moderator of the round table session was Philippe Sourdille, MD, of Nantes, France. The participants were Giorgio Marchini, MD, Alfredo Mannelli, MD, Paul Palmberg, MD, Richard Parrish, MD, Roberto Carassa, MD, and Christophe Baudouin, MD, PhD.

Long-term results

Philippe Sourdille, MD: What can we say about long-term results with these procedures? Dr. Carassa, you have presented 5-year follow-up in your patients.

Philippe Sourdille, MD, is the director of the Clinique Sourdille in Nantes, France. He can be reached at Le Chaigne, 16120 Touzac, France; +(33) 545-21-25-51; fax: +(33) 252-83-87-19; e-mail: philippe.sourdille@wanadoo.fr. Dr. Sourdille is a paid consultant for Cornéal.

Roberto Carassa, MD: We have presented at the most recent American Academy of Ophthalmology meeting the long-term results of our prospective analysis, one arm analysis, in viscocanalostomy. We have 80 patients with a follow-up up to 60 months. By considering the success rate, and looking at survivor curves in patients with pressures below 21 mm Hg with no additional therapy, no goniopuncture, no needling, no 5-FU, no nothing, we are still getting a pressure below 21 mm Hg in 62% of the patients after 60 months. That’s quite interesting.

If we are looking at a pressure below 16 mm Hg, the figures go down, and we are around 28% below 16 mm Hg with no additional therapy.

We are still not confirming what we saw at the very beginning, that viscocanalostomy leaves the eye with a physiological pressure, let’s say, between 14 mm Hg, up to 18 mm Hg in most cases. We are not reaching low pressure and that’s obviously a limitation.

Alfredo Mannelli, MD: What is the rate of IOP decrease after gonio-puncture and viscocanalostomy? I think the fact that goniopuncture after viscocanalostomy is more difficult than in deep sclerectomy, this is probably one of the reasons you do not get lower IOP at long-term follow-up.

Dr. Carassa: We perform goniopunture in roughly 5% to 7% of our treated cases, in cases with elevated IOP and a patent intrascleral lake. You are going to get a sudden decrease in pressure in the majority of these cases.

At the very beginning, we tried to do goniopuncture even though there was not an elevation in pressure, and we got very little effect. That may be related to the fact that, if we have a closed system, with the flap closed and pressure within the lake, goniopuncture or no goniopuncture, the membrane will not make a big difference as in an open system, such as in deep sclerectomy.

Dr. Sourdille: I think one of the major reasons for having an implant to keep the space open is to make the goniopuncture efficient. Then you will have a convex trabeculum on gonioscopy. Then you have some place where aqueous can go, whether is it in the suprachoroidal space or subconjunctival. So that is a major reason for using an implant.

Dr. Mannelli: I would like to stress again the importance of goniopuncture for long-term results. I perform gonio-puncture in 40% of cases, mostly because I have a low pressure goal. It’s absolutely important. We achieved a 33% decrease in IOP after goniopuncture 2 years after surgery.

If you need a low IOP and long-term control, you have to perform goniopuncture very often, but it’s not a complication, in my point of view.

Christophe Baudouin, MD, PhD, can be reached at Auinze Vingts hospital, 28 Rue de Charenton, Paris 75012 France; +(33) 1-49-09-55-08; fax: +(33) 1-49-09-59-11; e-mail: arepo@worldnet.fr. Dr. Baudouin has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.

Christophe Baudouin, MD, PhD: I have not tabulated my own long-term results, but my feeling is quite similar to my previous experience with standard trabeculectomy. If done in the mid-term, goniopuncture may work instead of medical treatment. This may be explained by the fact that in this kind of surgery, the main mechanism of failure would be at the level of the outflow, whatever the technique, penetrating or nonpenetrating.

Giorgio Marchini, MD: I think it will be confusing to our readers if we don’t specify the difference between viscocanalostomy and deep sclerectomy. They are two totally different interventions. My experience is similar to that of Dr. Baudouin’s because I have had failure with deep sclerectomy the first year after an intervention, and it is quite similar to that after trabeculectomy. Viscocanalostomy always works well in the beginning.

Our long-term results are only out to 3 years for a consistent group of patients. After 2 years we have a 30% reduction of IOP with all the applications, the goniopuncture and the needling. I have to specify that to massage the bleb is not correct in deep sclerectomy, after goniopuncture.

Richard Parrish, MD: To talk about long-term success without discussing the indications of the procedure may be confusing for the reader. I don’t think anyone here would recommend this for surgical intervention in a patient with normal-tension glaucoma, based on the results that have been discussed here.

If you’re talking about long-term success in high-pressure glaucoma, is there a difference between operating on patients like Robert Stegmann’s compared to those with normal tension glaucoma? I think we’re all impressed with his results in patients with preoperative pressures that were quite high. I recall the mean was about 50 mm Hg, not typical of North American glaucoma patients. Perhaps some of the differences in success depend on who you choose to operate on. To talk meaningfully about your success, you should talk about who you’re likely to be successful in.

Dr. Sourdille: What does the term “physiological pressure” mean for a patient who has a glaucomatous optic neuropathy? The physiologic pressure of such a patient is closer to 10 mm Hg than to 18 mm Hg. This is why we, the deep sclerectomy team, are in favor of subconjunctival filtration. That is because from our experience, we know that we can achieve long-term low pressures, that means in the 10 mm Hg or 12 mm Hg range, only if we have subconjunctival filtration, which is slightly different from trabeculectomy — thick conjunctivas, but hypovasculature of the conjunctiva, a quiet eye, no hyperfunctioning bleb, no cataract — or at least less than 10% at 5 years.

I have 6 years follow-up of my patients. I follow most of them personally, and I know that the ones who do well are those who did well at 1 or 2 years with some conjunctival filtration. There may be 10% or 15% of those without filtration who will do well, probably because they have diffuse uveal reabsorption of aqueous, not only intrascleral. But this is why I wanted to insist so much on technical aspects, because how we achieve, how we monitor the patient, is critically important, not for the first or second year, but for the long-term results.

Paul Palmberg, MD: In discussing long-term success, Mermoud and Carassa in particular have given us nice 5-year numbers, and we have to compare that to the alternatives. We in the “control group” now have 10-year results of primary surgery with either 5-FU or mitomycin. In these patients at 5 years, 91% of the people are under 21 mm Hg, and 62% are under 16 mm Hg without added medication.

That’s a bit more than perhaps you’re getting with viscocanalostomy, but perhaps only a little bit lower, with an average pressure of between 10 mm Hg and 11 mm Hg, only a little lower than Mermoud’s 12 mm Hg, in which he is also using antimetabolites.

Antimetabolites

Dr. Palmberg: How important are antimetabolites for the success of the procedures you’re talking about, particularly deep sclerectomy where you’re trying to get a bleb?

Dr. Sourdille: Mitomycin-C. Who uses it, how, and what is the complication rate, as compared to trabeculectomy? Where should we apply mitomycin-C? Who has experience with mitomycin-C in non-penetrating surgery?

Dr. Carassa: I am not using antimetabolites in viscocanalostomy.

Dr. Mannelli: Nor am I.

Roberto Carassa, MD, can be reached at Ospedale San Raffaele, via Olgettina 60, 20132 Milan, Italy; +(39) 02-2643-3591; fax: +(39) 02-2641- 2912; private surgery: +(39)02-7733-1542; fax: +(39) 02- 7631-1438; e-mail: carassa@tin.it. Ocular Surgery News could not confirm whether Dr. Carassa has a direct financial interest in the products mentioned in this article, or if he is a paid consultant for any companies mentioned.

Dr. Carassa: I choose to work on viscocanalostomy as a possible alternative in terms of complications, mechanism of action, a clear difference when compared to trabeculectomy. I think that we have to clarify to the readers that deep sclerectomy is different from trabeculectomy. By hearing certain things from this round table’s participants, if you have a procedure that is nonpenetrating but requires peeling of the membrane, and strict postop management, and sometimes in half of the cases goniopuncture is required, it is going to require antimetabolites, and therefore the difference with trabeculectomy becomes smaller and smaller, and thus it makes me less interested in deep sclerectomy.

In my clinical practice — and we will come back to that when we will talk about indications — I am working with viscocanalostomy in specific cases without the use of antimetabolites. And let’s say that viscocanalostomies are roughly 10% of the procedures that I’m doing, then 85% of the procedures are mitomycin in all the other cases.

I’m doing viscocanalostomy when the eye is feasible for that type of procedure. I’m using mitomycin drops in hard cases, and I’m doing deep sclerectomy with mitomycin-C in all the risky cases in which a trabeculectomy can have side effects. When I’m using mitomycin/deep sclerectomy, I am doing the first flap, and then I apply mitomycin 0.3 for 3 minutes and then I continue the procedure, and this is one of the ways to get a lower pressure with external filtration.

Dr. Mannelli: I would like to answer the indirect question from Dr. Carassa. It’s absolutely true, we are reducing the difference between deep sclerectomy and trabeculectomy, and, in fact, we are having better results in terms of long-term IOP control. That’s why we are reducing the difference, but we are still having fewer complications, and that is important. I am starting to use antimetabolites because of just the same philosophy. I have not been using any antimetabolites over the years, but I have started to think that antimetabolites can be a useful tool to achieve long-term IOP control. So I am starting to use mitomycin-C in nonpenetrating surgery, but I do not have enough postop control to discuss this further.

Dr. Sourdille: What are your indications, Dr. Mannelli?

Dr. Mannelli: High-risk patients, such as secondary glaucoma, except from pigmentary and pseudoexfoliative glaucoma, and previous surgeries, and young age.

Dr. Carassa: And when you need very low pressures.

Dr. Baudouin: I use the same indication as for trabeculectomy. If I identify a risk factor for fibrosis, I will use mitomycin-C. If not, I don’t use mitomycin-C. So, of course, the same indication, a classical indication.

Dr. Sourdille: What about advanced disease?

Dr. Baudouin: Not really, because with my technique I may obtain a low-pressure rate. Therefore it’s not really necessary to use that and to undergo a risk for the conjunctiva with atrophic blebs, if I am not sure that there is really a risk of fibrosis. It’s not for me. It’s not a way to achieve a lower pressure. The way to achieve a low pressure is with a good dissection. But that can’t always be achieved.

Dr. Marchini: For me, the same indications. I take into consideration young patients, previous operation, complicated cases and race.

Dr. Sourdille: My indications are equivalent. I started that 6 years ago. At that time, everyone told me I was crazy to use mitomycin-C. I am happy to say that many people are now moving to that. My first indication is low-pressure glaucoma, to be sure, because I am not confident that the operation itself will be sufficient to achieve reduction of 7 or 8 mm Hg.

It is notable that publications on viscocanalostomy and deep sclerectomy indicate the lowest number as 10 mm Hg, apart from antimetabolite use, whereas with trabeculectomy we have numbers below 10 mm Hg. This to me is the reason trabeculectomy results in a lower IOP on average, because it includes lower results that are not present in the nonpenetrating surgery group.

I would like to add congenital glaucoma as an indication for use of mitomycin-C, as I have seen Peng Khaw do at Moorfield’s in London, and I think most of us have moved from scleral application to subconjunctival applications.

Now we come to wound healing control. We have covered the newer techniques for application of mitomycin-C. I still have one question left for the faculty. Would you consider using what Peng Khaw has recommended, application of mitomycin-C distant from the limbus? Roberto, you mentioned the fact that you were using it under the superficial flap. Would you give up this application or continue it?

Dr. Carassa: There is an interesting randomized controlled study that was presented a couple of years ago that was showing differences between applications of mitomycin-C below the flap or just over the flap. The difference is related to the fact that what we want is to block proliferation at the scleral and Tenon's level, and that means that we need to make contact with the conjunctiva and with the episclera.

The study demonstrated that if we are also using mitomycin-C below the flap, we are giving some more advantage in terms of a decreased production of aqueous at the ciliary body level. Obviously, this would increase some sort of complications. And also decrease the pressure.

It was interesting that in this study it was speculated that if you really want low pressure, they suggested to use mitomycin-C both ways, up and down. Usually, I want to expose the conjunctiva and episclera at first. Then if you want to add something you can also use it below the lower, less superficial flap.

Complications

Dr. Sourdille: Now we come to complication rates of nonpenetrating surgery as compared to trabeculectomy. Dr. Carassa, would you like to start?

Dr. Carassa: Talking about viscocanalostomy, we are in the process of publishing the randomized controlled trial in which there is a comparison between complication rates. Let’s say that viscocanalostomy and deep sclerectomy are pretty much the same. They are safe procedures. Looking at complication rates postop, the only thing that makes some difference with trabeculectomy is that there is some blood in the anterior chamber, which we’re seeing more with viscocanalostomy than with trabeculectomy.

On the other side, in our study with trabeculectomy, we were using 5-fluorouracil in the postop and suturelysis, and we certainly had all the problems that trabeculectomy had, like choroidals. Using postop 5-FU we had superficial problems, corneal epithelial defects, 20% with hypotony in the postop period, and so forth.

Nonpenetrating surgery is a safe procedure, and the complication rate mostly is affected by intraoperative events, like small punctures of the Descemet’s membrane. But from a safety profile, it’s very safe.

Alfredo Mannelli, MD, can be reached at IMO Barcelona, C/munner 10, Barcelona 08022 Spain; +(34) 93-25-31-500; fax: +(34) 93-41-71- 301; e-mail: alfredomannelli@ hotmail.com. Dr. Mannelli has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies entioned.

Dr. Mannelli: I cannot give numbers, but I have almost every kind of complication except endophthalmitis and flat anterior chamber. I’ve had choroidal detachment, even in my malignant glaucoma cases. So this surgery is not exempt from complications, but the feeling is absolutely clear that the complication rate is much lower than after trabeculectomy.

Dr. Baudouin: I agree with both of you. It would be wrong to assert that there are no complications of these procedures. There may be some complications but at a low rate. It will sometimes take the form of micro- or macroperforation during the surgery, and this may change the prognosis. But a small perforation is not really an issue for the future, and we can avoid many flat anterior chambers.

Dr. Marchini: In our prospective study the difference is clear. The number of complications in the deep sclerectomy group is only 4%, and these are minor complications. On the other hand, there was a 15% rate of complications in the trabeculectomy group. This is the main advantage of this type of surgery. But in my opinion, the first complication is to incorrectly perform the intervention during surgery. This is the main complication; it’s a difficult surgery.

Dr. Sourdille: We are currently reviewing our complications at 5 years plus. The big difference in long-term complications obviously is the rate of cataract. We have below 10% cataract rate at 5 years, which is really low in relation to the age of the population we are operating on. These are primarily elderly patients. The rate of cataract is definitely much lower in the long-term, and I agree with colleagues in what has been said of early complications.

Dr. Palmberg: And we have wonderful data from the Advanced Glaucoma Intervention Study to help us compare this. It’s a 1.78 risk factor for getting cataract if you do a trabeculectomy vs. laser trabeculoplasty. And so these people frequently listed two eyes of the same person. It is a quite good indication of the difference. It turns out to be about 30% cataract vs. 15% in the other eye, which would be the natural rate of cataract development in these patients, who average 68 years old at the beginning of that study. There’s virtually a doubling of the risk.

Importance of inflammation

Dr. Sourdille: I would like to ask Christophe Baudouin, one of the world's experts on the ocular surface, to tell us, do we need a virgin conjunctiva for surgery? How do we diagnose troubles in the conjunctiva, and how does that relate to the success of surgery?

Dr. Baudouin: The ocular surface is an important factor in glaucoma patients that is neglected. Glaucoma is a disease consisting of three important levels: the ocular surface, the trabeculum and the optic nerve. Several studies have shown that an inflammatory ocular phase may influence surgery, whatever the mechanism of that inflammation might be. There are many direct and indirect animal in vitro and in vivo studies showing that there is inflammation in patients who have had long-term glaucoma treatment.

One of the major questions raised is the respective role of the active compound and of a protective agent that may influence this inflammation, the preservative benzalkonium chloride. And we have not fully answered this question because there are many factors that may influence the ocular surface.

However, we know that noninflammed conjunctiva will have a much better prognosis, and this is probably the most important revelation in the studies conducted by Stegmann. There's a major difference in his series of South African patients without any previous medical treatment as compared with our patients in the United States, or in Europe, in which a large majority of U.S. and European patients have had treatments for many years before surgery.

Giorgio Marchini, MD, can be reached at Lungadige Panvinio 1, Verona I-37121 Itlay; +(39) 45-80-72-340; fax: +(39) 45-80-72-025; e-mail: giorgio.marchini@ univr.it. Dr. Marchini has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.

In our lab we have developed a different way of assessing this inflammation. By using confocal microscopy, immunofluorescence studies and more recently flowmetry, we can both determine the existence of inflammation and quantify this inflammation. There is no doubt that there is a strong correlation between the inflammation of the ocular surface and previous treatments.

The second question is, will these findings influence our surgery and our indications? Certainly not by moving to primary surgery, because there are many medical treatments that are very efficient in reducing IOP and altering glaucoma progression. But improving the tolerance of drugs, and the development of preservative-free drugs is certainly a good way. We have conducted many in vitro and in vivo studies showing that using nonpreserved drugs may really improve the level of inflammation in the conjunctiva of patients.

Currently we only have beta-blockers that are available without preservatives. We need to extend the variety of drugs available without preservatives.

Dr. Palmberg: You've made an important point. One of the reasons that we got away from miotics was to avoid the small pupil, but the other was the four drops of benzalkonium chloride a day. And for those of us who get patients at the end of the line, we know that if they were on six drops a day for many years, that our success was really very much reduced, at least before we had antimetabolites, and even then it has an influence.

I would hope that physicians who are treating patients, if the patients happen to get the side effects, the physician will try to find alternatives for their patients. Maybe laser trabeculoplasty, or going on to surgery, if they can't control the pressure. We should not have people with fairly red eyes and say, "Take this or go blind." That's not the best way to manage those patients. It's not necessary.

Dr. Sourdille: But how can we improve the prognosis, when we see a patient who is a potential candidate for surgery and who has a conjunctiva with destroyed epithelium and the absence of goblet cells?

Dr. Baudouin: This is one of the most difficult questions. Some attempts have been made to reduce the quantity of benzalkonium chloride preoperatively by using nonpreserved drugs as much as possible. This is one way.

We have compared inflammation levels after a few weeks of removal of preservative, and we found that the inflammation is rapidly reversible. So it's possible to obtain the return of very natural conjunctival epithelium. The inflammation may decrease rather quickly after removal of toxic drug preservative.

Or we can add something to the conjunctiva before surgery, and two studies have been published. One by Moorfield's about using fluorometholone preoperatively. We have done also a prospective study concerning a nonsteroidal agent, and we found we can reduce inflammation satisfactorily. However, neither of these studies has shown a better prognosis for surgery because it's very difficult and it must be conducted for several years prospectively. But on the inflammatory pathway, we can reduce it efficiently after a few weeks.

Dr. Palmberg: With regard to fluorometholone, one would have to be careful that it wasn't raising the pressure. If it were used for 10 days or less you wouldn't expect a problem.

Indications

Dr. Sourdille: Are the indications for surgery different in nonpenetrating as compared to trabeculectomy? Dr. Baudouin?

Dr. Baudouin: My indications for this surgery are not different from those for trabeculectomy. My question is surgery or no surgery? If I decide to do surgery, after that, anatomical concerns may modify my choice of technique.

The only exception is for end-stage glaucoma. I don’t feel confident with standard trabeculectomy in this case, except if I have no other choice. I may do surgery in those cases because of a lower risk of deep hypotony in the first postop days. Of course, in cases where the indication is clear, and especially in patients who are obviously losing their remaining vision, it’s an indication for surgery. I didn’t change my indications with the development of this technique.

Dr. Sourdille: Could you clarify when you do a trabeculectomy? We understand that in some cases we’ll consider surgery as indicated. Could you clarify when you do trabeculectomy and when do you do nonpenetrating, apart from end-stage glaucoma?

Dr. Baudouin: Apart from end stage, the indication will depend on the location of the resistance to aqueous outflow. In case of pretrabecular, I will choose trabeculectomy.

Dr. Mannelli: My indication is exactly the same, except for closed or occludable angles. These are the only cases where I do perform trabeculectomy. That’s no more than 5% of my filtration surgery.

I would like to distinguish between the indication for deep sclerectomy and deep sclerectomy with mitomycin. I use deep sclerectomy for normal-tension glaucoma too, but I do not use mitomycin because, to me, mitomycin does not have to reach lower IOP, just to maintain it in the long-term follow-up. If I have a patient with virgin conjunctiva, older age, I do not use mitomycin in this case. Just before deep sclerectomy.

Paul Palmberg, MD, PhD, can be reached at Bascom Palmer Eye Institute, Box 016880, Miami, FL 33101 U.S.A.; +(1) 305-316-6386; fax: +(1) 305-326-6474; e-mail: ppalmberg@ med.miami.edu. Ocular Surgery News could not confirm whether Dr. Palmberg has a direct financial interest in the products mentioned in this article, or if he is a paid consultant for any companies mentioned.

Dr. Carassa: For viscocanalostomy, we need strict indications. I’m using this surgery in no more than 10% of my patients. I need patients with open-angles, high initial pressures, good visual fields. And the majority of cases are pseudoexfoliative glaucomas and are intolerant to drops.

Other cases in which I think viscocanalostomy can be useful are cases where I do not want a bleb, even though the patient needs lower pressure. These are cases of blepharitis, or contact lens wearers. In this case, I hypothesize that it’s better to have nonpenetrating surgery, viscocanalostomy, eventually adding drops in the postop period.

I am using viscocanalostomy in previously unoperated eyes. Deep sclerectomy is used in the indications that were mentioned before. I use antimetabolites in all my deep sclerectomies. In these cases, I do not need virgin eyes, and I tend to use it in cases that would be high risk for trabeculectomy, such as vitreous in anterior chamber and so forth. In secondary glaucomas and in advanced cases, in other cases, I may use mitomycin.

Dr. Palmberg: I just want to clarify something. When you said a good visual field, you didn’t mean a normal visual field. Mild damage?

Dr. Carassa: Yes, mild damage. You can hypothesize also normal visual field with elevated pressure not controlled with drops. That’s the best case.

Dr. Marchini: One thing to add to the previous indications is that when we need a very low postop pressure, in my opinion mainly after long-term results with nonperforating trabecular surgery, I think this may be better than trabeculectomy. Advanced and normal-tension cases also, but those are cases in which there may be more complications. This is a difficult problem.

Dr. Sourdille: In cases of open but narrow-angle, or angle-closure, chronic angle-closure, I always combine a surgical peripheral iridectomy through a reverse corneal incision at the site of surgery.

A second thing is, I think we now have a choice, when we hesitate to use antimetabolites, to do it after surgery, combined with goniopuncture if we have any suspicion of a re-elevation of IOP. Or if we want to lower the pressure, if we are about 14 mm Hg to 15 mm Hg, if we are operating on low-pressure glaucoma. If we want to have a pressure of 10 mm Hg, we can decide this after the surgery in the first month or two.

I think Dr. Carassa, and Dr. Mannelli agree on that also. And Dr. Baudouin, we are coming closer to individual treatment for a given patient.

Dr. Palmberg: I would like a clarification. You say the pressure is 14 mm Hg. You may be talking about using 5-FU injections. I would thinkthey’re not gong to make the pressure go down unless you also then cut some stitches or do something to reduce your scleral resistance. The 5-FU and mitomycin keep you from getting additional resistance, but at least in the experience that I have, which is now 21 years with 5-FU, having been the first person to use it, administering it never brings the pressure down, but it can keep it from going up further.

So I would think you have to couple that with something like cutting a stitch.

Dr. Sourdille: I couple that with goniopuncture to add more aqueous. This is specific to nonpenetrating. You have one more thing do to before addressing the conjunctiva. So we agree on the indications.

Conclusions

Dr. Sourdille: We have made clear that we should remove the external trabeculum. We have made clear in deep sclerectomy that we should use implants. We have made clear the differences between viscocanalostomy and deep sclerectomy, especially in terms of IOP-lowering mechanisms, and I would like especially to thank Roberto Carassa for that.

We have heard that we can consider earlier surgical treatment with nonpenetrating surgery should the diagnosis of glaucomatous optic neuropathy be well established with different clinical and paraclinical measurements.

Richard K. Parrish II, MD, can be reached at Bascom Palmer Eye Institute, 1638 NW 10th Ave., Miami, FL 33136 U.S.A.; +(1) 305-326-6474; e-mail: rparrish@ med.miami.edu. Ocular Surgery News could not confirm whether Dr. Parrish has a direct financial interest in the products mentioned in this article, or if he is a paid consultant for any companies mentioned.

We have highlighted the importance of different applications of mitomycin-C when we think that there is a need. We have mentioned the importance of the conjunctiva for the success of surgery. Additionally, we have tried to mention the possible treatments in case of problems with the conjunctival epithelium. And finally, for the time being, the only anti-metabolites that we can use are 5-FU and mitomycin-C.

Is there anything that you would like to add, any final comment?

Dr. Palmberg: We need to constantly examine the long-term results of whatever we do to find out what we've been doing wrong. I've noticed two things with mitomycin that are terribly important. One is, don't leave the operating room without the pressure about 10 mm Hg or higher. You cannot use the old strategy of performing a regular trabeculectomy, getting a pressure of 3 mm Hg or 4 mm Hg and leaving the OR. Mitomycin never causes hypotony, but it will preserve any hypotony you produce. You now have a strategy of adjusting the scleral flap resistance to what you want to live with, and then these drugs may help you to preserve that status.

Just as cataract surgery evolved with newer wounds, foldable lenses, continuous tear capsulorrhexis, there have been improvements in filtering surgery, and if you don't understand them, your patients suffer. If we pay attention to where our complications come from, with nonpenetrating surgery we can make surgery not only effective, but much safer for our patients, and, therefore, more beneficial to the patient.

Dr. Sourdille: And safety for nonpenetrating surgery would certainly be the final word of the symposium.

Thank you very much.