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State of the art: Intraoperative floppy iris syndrome
John A. Hovanesian, MD, FACS, interviewed David F. Chang, MD, about identifying the condition and management strategies.
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John A. Hovanesian, MD, FACS: Intraoperative floppy iris syndrome has changed the way we think about cataract surgery, and you brought its attention to the world first. Tell us how it came about.
David F. Chang, MD: This was an interesting association that was first suspected by another ophthalmologist in northern California, John R. Campbell, MD, and his staff actually made the connection. He was concerned that some of his patients were not dilating well, and he wanted to know what was different about them. One of the staff members said, “It’s kind of interesting, but a lot of these patients are taking Flomax.” And with that information he asked me if I had seen this.
When I went back and looked at some charts on people who I recalled with floppy irises, there definitely was a connection, although it did not seem to be everyone. So we set out to do some studies to try to determine whether tamsulosin was truly a causative factor, what other factors there were and to just try to define what exactly this syndrome was. That was the basis of our original report and our paper in the Journal of Cataract and Refractive Surgery in 2005.
Dr. Hovanesian: Not everyone who takes Flomax (tamsulosin, Boehringer Ingelheim) develops intraoperative floppy iris syndrome (IFIS). How often does it happen?
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Dr. Chang: I think we have learned that there is a real broad spectrum of severity to this condition, and we ought to think of it as being mild, moderate or severe. If we look at the classic triad of billowing of the iris, of progressive miosis during surgery and of a strong tendency for iris prolapse, it is the most severely affected eyes that manifest all three signs. There are some eyes in which you see just the billowing. There are some in which you just see some billowing and a little bit of miosis, and these would be characterized as being mild to moderate.
I organized a large prospective trial in which we had 10 different centers in the country, and we consecutively enrolled more than 160 eyes of patients taking tamsulosin and having cataract surgery, and when you use these types of definitions, about 90% of all the patients had at least some form of IFIS, even if it was mild. A much greater percentage, though, had the moderate to severe form of IFIS.
Dr. Hovanesian: Since you brought it to the world’s attention, most of us who do cataract surgery have certainly seen this in our patients and are grateful to have at least some fair warning for those tamsulosin patients. Why is it that tamsulosin is more prone to cause IFIS than other alpha blockers?
Dr. Chang: Originally we just saw the connection that tamsulosin is an alpha-1 blocker, and the alpha-1 receptor is well-characterized in the prostate. There are three subtypes of the alpha-1 receptor: 1A, 1B and 1D, and the reason that tamsulosin is the No. 1 prescribed medication for benign prosthetic hyperplasia is that it is selective for the alpha-1A subtype. This receptor predominates in the prostate, and it makes the drug more uroselective, making patients less likely to have postural hypotension compared with the non-selective alpha blockers such as Hytrin (terazosin, Abbott Laboratories), Cardura (doxazosin, Pfizer) or Uroxatral (alfuzosin, Sanofi-Aventis). So it was interesting that in the iris, the alpha-1A subtype is also the most predominant receptor, but if it is going to be blocked by a non-specific drug as well, theoretically tamsulosin, terazosin, doxazosin and alfuzosin should all be about equivalent.
I have been convinced all along that this was far more common with tamsulosin than with the non-specific alpha blockers, and there are several studies now that have supported this, most notably a paper that was published in Journal of Cataract and Refractive Surgery in the fall by Blouin and colleagues that showed retrospectively that among tamsulosin cases vs. alfuzosin cases, the incidence of IFIS was much higher with tamsulosin than with alfuzosin.
More recently, I have collaborated with a basic science group in Europe that has for the first time performed animal studies comparing the effects of alpha blockers on the iris dilator muscle. These experiments are similar to those in which the pharmacology of alpha blockers in the prostrate were studied, and they, interestingly, have shown that tamsulosin has a much greater antagonistic effect on the iris dilator muscle in rabbits than does alfuzosin. So on the basis of this it looks as though there are other alpha blockers that are effective for benign prostatic hyperplasia (BPH) (for example, alfuzosin is also a uroselective blocker), and it appears that these are agents that can treat BPH without causing IFIS to anywhere near the degree that tamsulosin does.
Before surgery
Dr. Hovanesian: When we first became aware of IFIS, the reaction was to stop the tamsulosin some time before cataract surgery. That does not seem to work very well, does it?
Dr. Chang: No. I think we have all seen situations in which patients have been off of tamsulosin for even up to several years and yet still manifest a classic, severe IFIS. So we certainly cannot rely on stopping the drug to make any difference. I routinely now do not have patients alter their BPH medications or stop them, and I would choose instead to rely on surgical strategies to help me through the case.
Dr. Hovanesian: And it also does not seem to matter how long they were on tamsulosin?
Dr. Chang: That is a good question. Several studies have tried to look at whether the dose or duration of the drug had some correlation with the incidence and severity of IFIS, and no one has found any. So at one extreme we have had patients who have been off of tamsulosin for up to 3 years who still show IFIS. There is also a good anecdotal report of a patient who did not have IFIS in the first eye during surgery and then had the other eye done a month later with classic IFIS, with the notable development that he had been placed on tamsulosin 2 weeks after surgery on the first eye. So that is a well-documented case in which taking tamsulosin for just 2 weeks produced a classic IFIS.
Dr. Hovanesian: So if I am a cataract surgeon who has a patient contemplating surgery and we discover that tamsulosin is part of his medication regimen, how should I counsel the patient?
Dr. Chang: I usually tell people that they have been taking a drug that can make cataract surgery a little bit more difficult but that we have some excellent strategies that will allow us to do the cataract surgery with an excellent prognosis and that it is not necessary for them to discontinue the drug. The important thing is that we know about it in advance, and we can anticipate what needs to be done.
Pharmacologic approach, OVDs
Dr. Hovanesian: Are there other measures to optimize the outcome?
Dr. Chang: There are a lot of different ideas for managing IFIS, and people have reported varying success with a number of different approaches. I would divide them into primarily three categories. One is pharmacologic, one is the use of viscoadaptive or specialized viscoelastics, or OVDs, and one is using some type of mechanical dilating devices at the time of surgery. I think it is important for surgeons to be familiar with all of the different methods. You can come up with your own algorithm for how you are going to start managing the case, and then if you need to, you can go to different adjunctive techniques if the pupil is not large enough.
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Let’s start with the pharmacologic approach. Samuel Masket, MD, first proposed using preoperative topical atropine, the idea being to knock out the pupillary sphincter muscle. What has been a wonderful approach, I think, is intracameral alpha agonists. Richard Packard, MD, came up with the idea of intracameral phenylephrine, and later on Joel K. Shugar, MD, MSEE, did some work with intracameral epinephrine, which is a drug that we have readily available in the United States.
My experience has been that with a mild to moderate case of IFIS in which the pupil dilates reasonably well, injecting epinephrine often will improve the pupil dilation. But even if it does not, it seems to tense up the iris dilator muscle, restoring the normal rigidity to the iris during surgery and making it much less likely to prolapse and billow. This is something that you can do on virtually all patients at risk of IFIS, but I would certainly employ this in a case that I expect to manifest mild IFIS. This is a patient who is on tamsulosin but dilates well preoperatively, indicating reasonably good iris dilator muscle function. You want to use bisulfite-free epinephrine, and this is an inexpensive item that you already have in every ophthalmic operating room because this is what gets added to the balanced salt solution bottle.
Dr. Shugar did the work that showed a 1:3 dilution will properly buffer the normally acidic pH of the epinephrine. I take 0.2 mL of the epinephrine and add it in a 3-cc syringe to 0.6 mL of plain balanced salt solution. That gives a 1:4 dilution. You mix it up a little bit and then go ahead and inject that. I have probably done this now in more than 200 cases, both IFIS and non-IFIS with small pupils, and I am certainly convinced there is no danger to using this. I have never seen any deleterious effects, so I think this is safe. You want to use 1:1,000 bisulfite-free epinephrine.
Dr. Hovanesian: So pharmacologic intervention would be appropriate in a mild case. Now, you mention mild vs. presumably moderate or severe cases as measured preoperatively. Is dilation the only characteristic that can indicate the level of severity?
Dr. Chang: Other than having previous experience with the opposite eye, the best way to try to predict who might have mild, moderate or severe IFIS is to evaluate how well the patient dilates immediately before surgery. The smaller the pupil, the more likely it is to be severe IFIS. Another tip is when you first inject some intracameral lidocaine, you will often see the billowing right then and there, and if you start to see billowing already, you should anticipate a more severe degree of IFIS. Finally, if you have a patient who has stopped tamsulosin, or is perhaps on one of the non-specific alpha blockers, if you are going to have IFIS it is much more likely to be moderate or mild.
Dr. Hovanesian: Let’s talk about OVDs and their role.
Dr. Chang: Robert H. Osher, MD, and Douglas D. Koch, MD, were among the first to suggest using the viscoadaptive OVD Healon5 (2.3% sodium hyaluronate, Advanced Medical Optics) because it is so dense a material that it pushes back the iris and pushes the pupil open. This is an effective technique at blocking the iris from either constricting or prolapsing up to the incision. You have to alter your phaco parameters by using a low aspiration flow rate and a low vacuum, and this is not something that all surgeons are necessarily comfortable with.
Dilating devices
Dr. Hovanesian: Dilating devices are the last resort to control the iris movement. At what point during surgery, when you see that billowing and perhaps miosis develop, do you say, “Oh, boy. I need to stop and put one of these in.”
Dr. Chang: If you are going to use a mechanical dilating device, such as a pupil expansion ring or iris hooks, it is nice to do this before you start the capsulorrhexis so there is no danger of hooking the anterior capsular edge. This is where anticipating severe IFIS is helpful and where I probably would just go straight to mechanical devices. I think one advantage of these is that, for most surgeons, they do not require a change in their technique. You do not have the uncertainty of, “Will this case turn into a more severe IFIS case?” You have something that is going to be 100% reliable at keeping the iris open, which is certainly a consideration if you have other co-existing risk factors such as a brunescent lens or pseudoexfoliation or a patient who has only one eye.
I think iris retractors are something that everyone can use, and they deserve a good look. I think initially people found them to be a little difficult to use. They would tent the iris up in front of the phaco tip, and if you were not careful and you overly stretched a fibrotic pupil, you could tear the sphincter so badly that you were left with a permanently dilated pupil.
I favor 4-0 Prolene retractors. These are available through Katena, FCI and Oasis. They are the same girth as an IOL haptic, and that means they are thicker than the typical 6-0 Grieshaber nylon retractors that we all initially tried. This makes them easier to manipulate and faster to place. They should be placed in a diamond configuration instead of a square configuration, which tents up the iris right in front of the phaco tip. You actually place a subincisional retractor through a separate but parallel track made just behind and beneath the clear corneal tunnel incision. This retractor then pulls the subincisional iris down and behind the phaco tip and well out of the way so there is no iris tented up. Meanwhile, the opposite nasal retractor is giving you excellent exposure for placement of the chopper in the contra-incisional quadrant. So the diamond configuration solves the problem of tenting up the iris in front of the phaco tip.
Dr. Hovanesian: Are there any other retractors that you find useful?
Dr. Chang: Those are principally the ones that I use, and I think any of them will work. Pupil expansion devices have also been around for a while, but with IFIS there has a rebirth of interest in these devices. There is the Morcher PMMA ring, the Perfect Pupil (Milvella) and John M. Graether, MD’s silicone pupil expansion ring from Eagle Vision. These can be a little bit unwieldy to insert. Some of them have a thick profile that makes them hard to place if the chamber is a little shallow or the pupil is too small. You have to be careful when you remove them that you do not bump the cornea, and you have to be careful that the edges do not tear the iris. They are also expensive because they are disposable.
My new favorite pupil expansion device is the Malyugin ring developed by Boris Malyugin. This is a 5-0 Prolene ring that is shaped like a square, but at each corner there is a rounded scroll that is used to engage the pupil margin. When placed, the device actually creates a rounded pupil diameter of about 6 mm. MicroSurgical Technology has developed a slick injector system. It is disposable for use with the Malyugin ring and makes insertion and removal easy. Compared with retractors, this cuts down on the amount of time needed to expand the pupil, and you do not have to make multiple paracenteses. It is easy to handle, and this is another way to provide a 100% reliable pupil size throughout the entire case. This ring has a low profile, so I think it is safe to use.
Dr. Hovanesian: Any other tips for surgeons intraoperatively?
Dr. Chang: Overall, you just want to pay a little more attention to core surgical principles. You want to make sure that the clear corneal incisional architecture is good and that you do not have a posterior entry. You want to perform hydrodissection and hydrodelineation a little bit more gently than normal. You may want to see if you can tune down your flow rates and parameters a little bit in these cases. I think those are generally good ideas, but they certainly become more critical when you have a potentially floppy iris.
I think that the main thing is to develop some experience using all of these techniques, and I think you will find that this gives you the confidence going into these cases that you will be able to handle any number of situations. Some surgeons have talked about the staged approach, and I think that makes a lot of sense. Just realize that just because a technique worked on the last four patients does not mean it is going to work on every patient. Be prepared. There is always that patient who surprises you with how severe their IFIS is.
For more information:
- David F. Chang, MD, can be reached at 762 Altos Oaks Drive, Suite 1, Los Altos, CA 94024; 650-948-9123; fax: 650-948-0563; e-mail: dceye@earthlink.net. Dr. Chang receives consulting fees from AMO and Alcon that are donated to the Himalayan Cataract Project.
- John A. Hovanesian, MD, FACS, can be reached at Harvard Eye Associates, 24401 Calle De La Louisa, Suite 300, Laguna Hills, CA 92653; 949-951-2020; fax: 949-380-7856; e-mail: drhovanesian@harvardeye.com.
References:
- Blouin MC, Blouin J, et al. Intraoperative floppy-iris syndrome associated with alpha1-adrenoreceptors: comparison of tamsulosin and alfuzosin. J Cataract Refract Surg. 2007;33(7):1227-1234.
- Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with tamsulosin. J Cataract Refract Surg. 2005;31(4):664-673.
- Chang DF, Osher RH, Wang L, Koch DD. Prospective multicenter evaluation of cataract surgery in patients taking tamsulosin (Flomax). Ophthalmology. 2007;114(5):957-964.