Lecture: Pupil Management in Modern Cataract Surgery

In this lecture, Dr. Malyugin shares his experiences with pupil management in cataract surgeries.

Lecturer: Dr. Boris Malyugin, Professor of Ophthalmology, S. Fyodorov Eye Microsurgery Complex Federal State Institution, Moscow, Russia


DR MALYUGIN: Hi. My name is Boris Malyugin. I’m from Moscow, Russia. And I will be happy to share with you my experiences with pupil management in cataract surgery. First of all, a little bit about myself and the institution. So this is the Fyodorov Eye Microsurgery Institution, as shown here. And you actually see the main building. We have an educational facility, we have clinics, and a place where our patients can stay, short term. Actually, we have the major facility in Moscow, and also we do have affiliations all over Russia, as shown here. This is the European part of Russia, which is much more populated than the Asian one. And we see that the biggest number of clinics we do have located — is in the European part of the Russian Federation. And this is how these clinics look like. There are ten of them, including some smaller outpatient clinics overall. I’ll talk about cataract surgery. We need to keep in mind several critical aspects of that surgery. We need to talk about optimal instrumentation and settings. We need to talk about proper surgical maneuvers and visualization. Capsular stability and keeping capsular integrity. And of course, IOL design and fixation methods. There are many of them to be kept in mind. However, I will focus today on visualization, which is one of the major things in cataract surgery to be discussed. Visualization is very much decreased when we do have our problems with corneal transparency. But also, the other major factor is the size of the pupil, as shown here. Very small pupil does not allow us to visualize what’s going on behind the iris, and does not give us a good access to the lens and to the lens capsule and capsule content. For years, it was a big issue for cataract surgeons, and even for the ancient cataract surgeons. And as you can see here, iridectomy was one of the options at that time, to have a good access to the lens, to be able to extract it from the eye. Later on, pharmacological substances were used. One of them is belladonna, or as you know it, atropine. And it was introduced to ophthalmology by Karl Gustav Himly in his seminal work, which was published in 1831. Small pupil is not only a geometrical issue. It’s also an indication of various systemic and local comorbidities. Because it is very much associated with zonular pathology, blood-aqueous barrier disruption, intraocular pressure spikes, and so forth and so on. And it is also known for its association with the increased complication rate, such as iris trauma, capsular rupture, vitreous loss, inflammation, et cetera. And it is known that 1 millimeter of pupil which is abnormal, subnormal, 1 millimeter of pupil miosis increased the complication rate by roughly 10%. There are several techniques that can be used to manage small pupils in cataract surgery. I do think that stepwise approach is the most logical and appropriate one. We start with of course topical mydriatics. But also we follow with intracameral injection of phenylephrine or epinephrine into the anterior chamber. Following by viscodilatation, because we know that the deepening of the anterior chamber actually increases the size of the pupil. After that, posterior synechiolysis can be done. If posterior synechiae exist. And if the pupil is fibrotic, we need to stretch it in order to expand it. And then we need to decide about pupil expansion rings and hooks. Intracameral mydriatics are very effective, as shown here. Right after an intracameral phenylephrine injection, we see that the pupil starts to open, and we have a very nice size of the pupil. And this is another case of a patient with pseudoexfoliative syndrome, and as shown here, the pupil starts to open, but at some point it stops, and we don’t have a good access, and we don’t have a good pupil dilation. We don’t have a good access to the lens. Intracameral mydriatics to be used: 1% phenylephrine, or a combination of phenylephrine and lidocaine. In Europe, there is Mydrane, which is a combination of phenylephrine, tropicamide, and lidocaine, which is injected intracamerally. And also, there is another option of utilizing combination of phenylephrine and non-steroidal antiinflammatory agents, which is delivered to the anterior chamber by continuous irrigation throughout phacoemulsification procedure. And this is the publication, showing that we can not only sustain the pupil dilation during the surgery, but also decrease the postoperative pain. However, it is to be mentioned that the pupil is very small at the very beginning. So this pharmacologic combination will not give you pupil expansion. It should just give you sustainability of the pupil size throughout the procedure. As already mentioned, posterior synechiolysis is one of the options. And usually these synechiae are very loosely attached to the anterior capsule, as shown here, and it’s very easy to break them with a side port instrument. And with this maneuver, the pupil expands. The other option is to utilize peripupillary membranectomy. And this is the pupil stretching technique, when we use two instruments, and stretching the pupil in the opposite sides, and by doing that, we sometimes have been able to see and to visualize the pupillary membrane, which is attached to the posterior surface of the iris. And then by removing that membrane, either with microcapsulorrhexis forceps, or especially designed forceps, it’s possible to release this membrane, which is constricting the pupil. Not allowing it to expand. And then after removing that membrane, it is possible to have much better pupil dilation. And of course, you may see there is some bleeding from the pupillary margin happening here. However, this is usually not very significant, and can be blocked by viscoelastic or increasing the pressure in the anterior chamber. Sometimes pupillary membranes are so intense that you’re having trouble finding a good spot to introduce the instrument into the posterior chamber. And also, this bimanual technique is quite useful. By holding the membrane with the right hand and stabilizing the iris with the left hand, I’m helping myself to remove this membrane away from that iris. One of the options to get rid of the pupillary membrane is fragment it with microscissors, as shown here. This is a 25-gauge instrument that is introduced through the main incision, and we can also introduce it through the side port incision from different angles, in order to cut this membrane. This is a membrane which is now being fragmented, with the help of the scissors, and again, with cutting this membrane into pieces, it’s possible to remove this membrane, more or less successfully. There is another option, which is shown here. Actually, we see here very thick fibrotic membrane, which is about 1.5 to 2 millimeters wide. And in order to expand the pupil, we need to reach this area of relatively elastic tissue, and for that, we need to cut all the way through that membrane, in order to get this significantly fibrotic tissue to be broken in several pieces. And then by that it’s possible to expand the pupil. And of course, when we are cutting the iris tissue, what we can expect is bleeding, as shown here. Which can be managed by diathermy of the iris vessels. This is another option, which is mechanical pupil dilation. Iris hooks are widely utilized for that purpose. And it’s shown here by holding the iris in four points. We may have a very nice square pupil, allowing us to have an access to the lens material, allowing us to stabilize the pupil. We have to keep in mind that we don’t have to overstretch the pupil or overexpand the pupil, because at the final moments of the expansion, the iris, as shown on this cross sectional image, with OCT, the iris is lifting now above the plane of the anterior lens capsule, and you may have difficulties with introducing instruments into the anterior chamber. This is another great instrument, which is a capsular hook. Specially designed for the purpose of not only expanding the pupil if necessary, but also to keep — and support the weakened zonule apparatus, as shown here. So that device is resting on the equator of the capsular bag, and there is a gap in between the tip of the device and the anterior capsule. So there is no stress on the anterior capsulorrhexis edge, and there is no chance that the membrane will be — that the capsule will be ruptured by rhexis radialization. So this is how these devices work. And again, you see that the pupil was not perfectly wide. However, now we are expanding the pupil, and at the same time, supporting the capsular bag, and supporting missing zonules. And having a double effect of expanding the pupil and having a good support of stabilization of the capsular bag during the procedure. The Assia Pupil Expansion Device is another option, as shown here. This is a scissor-like instrument that — each of these instruments is introduced through the paracentesis, and catching the iris in two points, and this is more or less similar to what we have with iris hooks. However, it is much better, because actually you reduce the number of incisions needed for this expansion by a factor of 2. You need only two paracenteses, instead of 4 in the case of iris hooks. This is how the device works. It’s a plastic disposable version of the APX 200 pupil expansion device. And you see that by releasing the string, the branches of that device with the hooked elements catches the pupillary margin, and you have a very nice square pupil at the end of the procedure. However, we don’t like square pupils. Why is that? And the answer is quite simple. Because given the same size of the pupil, this perimeter of the square is much longer than the perimeter of the circle. And that’s why, when we do have square pupil, there is always a tendency to overstretch the iris tissue. And this is where the iris rings come into place. And there are several pupil expansion rings that were being introduced during the course of the history of cataract surgery. Perfect Pupil, Graether Ring, and some others, and most of them sharing more or less the same concept of having fixation elements on the outer side of the ring that catches the iris margin, and holds the margin in place. So this is the device that I introduced into clinical practice, more than 10 years ago. Which is based on the concept of the circular elements that are located — and the corners of this device — and these circular elements are coming from the lens that we were using for many years, in the Fyodorov Institution, that was rigid PMMA lens, that was used for extracapsular cataract extraction. And actually, this principle was quite successfully used by us for catching the anterior capsule and using the anterior capsule for fixation of intraocular lens. And then finally we came up to the concept of the pupil expansion. What is good with this device is that actually in spite of the square shape, you actually have 8 points of iris fixation, because there are — in addition to the fixation points that are located at the corners of the device, there is one more point in the middle, when the thread goes from the upper portion of the iris to behind the iris. So it’s actually equal to 8 iris hooks. And that is why the pupil is almost round, rather than being square. Which you may expect from the square shape of the device. And we were partnering with MST to produce these nice devices, which are having different sizes. 6.25 and 7 millimeters. And a special holder, and the special injector that I use to insert and remove the ring, in and out of the eye. As shown here. This is the injection process. And the ring expels from the injection device. And at the same point, catching the distal and two side scrolls with the iris, and then what you need to do is to engage the last scroll, proximal scroll, which is located closer to the main incision, and then place the device properly and center it. Removal is also quite straightforward. If you just disengage the distal scroll, located contralaterally to the main incision, and lift a little bit the proximal scroll, above the iris plane, and then catches this scroll with the hook of the injector device, and then retract it inside the injector tube, as shown here. And at the end of the procedure, you can see that the pupil becomes constricted again. It’s very nice and round. So there were several improvements, some modifications, such as Osher/Malyugin ring manipulator, specially designed thinner hooks that allow us to more reliably insert and remove the device from the eye. And actually, my personal preference is a small ring. Especially with very small and fibrotic pupils. However, for intraoperative floppy iris syndrome, I do believe that the bigger one works much better. As well as for the surgeon preferring divide and conquer or phaco flip, rather than phaco chop procedures. First publication on the Malyugin ring was by David Chang, who showed that it is quite useful in intraoperative floppy iris syndrome, which I will be talking about a little bit later on. As shown here, the pupil is not very small, but actually, we can see the iris going through the main incision, and it is incarcerated into the paracentesis, and you anticipate some issues to happen here. And this is one of the clinical cases, showing how the pupil starts to constrict throughout the procedure. And there is a propensity of the iris to prolapse into the phaco and side port incisions. And this is a progressive pupillary constriction during surgery. And the billowness of the iris, which is fluctuating under the irrigating currents. And obviously we need to do something here, in order to avoid complications and issues in that case. The iris is now being repositioned with viscoelastic, introduced through the main and side port incisions. And you can see that the pupil is quite small and very flaccid here. So this is another clinical case. When the femtosecond laser-assisted capsulotomy and lens fragmentation was being done. And again, we started with a relatively decent size of the pupil at the beginning of the procedure. However, as we are proceeding with the phacoemulsification, the pupil is now progressively constricting, and again, we see there is some billowing of the iris, which is having a tendency to go into the main phaco needle, to the phaco needle. And we have to be quite cautious of not catching the iris in that case by irrigating, aspirating it, into the phaco needle. As shown here. The reason for that syndrome is the antagonist, the use of antagonist, of alpha 1 adrenergic receptors, such as tamsulosin, or Flomax, that changes the dilator smooth muscle anatomy, as shown here. This is the normal thickness of the dilating muscle, which is taken from the cadaver eye, and this is the thickness of the muscle dilating the pupil from the subject, taking tamsulosin, and we see that there is a marked thinning of that muscle, and there are some other mechanisms involved, including the degradation of the nucleus that are shared in between the dilator muscles and the pigment epithelium, which was shown on the experimental model. And the result of that is quite devastating, as you see here. In a retrospective study, it was more than 12% of complications. Some of them quite significant, with a partial loss of iris tissue, giving quite significant functional and also cosmetic result. And the question is: Can we anticipate intraoperative floppy iris syndrome? And the answer is yes. Because when we do have a pupil which is initially suboptimal on the patient having tamsulosin, there is almost 4-fold increased chance of having intraoperative floppy iris syndrome, as opposed to the person having very wide and well dilated pupils. So by judging the size of the pupil preoperatively and intraoperatively, you can actually anticipate this intraoperative floppy iris syndrome to happen. And the other question: Whether intraoperative floppy iris syndrome is associated with medications used for benign prostatic hyperplasia. And as you can see here, intraoperative floppy iris syndrome was observed in 12.6% of cases. However, there was a substantial amount of female patients showing that syndrome, that are obviously not taking tamsulosin. And this is another paper showing that intraoperative floppy iris syndrome is obviously higher with men. However, it can also be seen in women as well. The prevalence of that syndrome with men is almost 5 times bigger than in women. Why is that? Because there are some other medications involved. One that I used for arterial hypertension, that are having angiotensin II-type receptor blockers. And also with some medications used for anxiety disorders. They are also associating with that syndrome. As shown here, there are several drugs associated with this syndrome, however, not all of the patients are having any kind of drugs. There is a substantial amount of patients that are not using any kind of drugs. This of course may happen with them. From my point of view, intracameral injection of mydriatics is the way to go. And these are two already mentioned in the description of the stepwise approach, as you may see here. The other option is to use the mechanical pupil expansion devices. This is the patient with intraoperative floppy iris syndrome, and as soon as the viscoelastic left the anterior chamber, you see that the iris becomes billowing. Under the irrigation currents. And the pupil starts progressively constricting and prolapsing through the side port incision. And obviously to be on the safe side, we need to do something such as use the pupil expansion ring, and as shown here, as soon as you insert viscoelastic, you see that the pupil becomes quite big again. So you may expect that with the smaller ring, you will not be able to have a good hold of the iris. So the bigger one is — the 7 millimeter ring is much more useful in intraoperative floppy iris syndrome. And in fact, in spite of the minor depigmentation of the area, corresponding to paracentesis, this case was completed quite successfully. And of course, good innovations always stem from other innovations. As shown here, there are several other pupil expansion rings that are currently available on the market. First to be mentioned, one that is from India. This is 5-0 nylon with indentations, used to catch the iris tissue, and this is a planar structure. And this, with the latest hexagonal version, with the positioning holes that are helpful to manipulate the device, insert and remove it from the eye. Nitinol wire, which is a thin metal wire, can also be used for that purpose, as shown here. This is the three-dimensional structure that is used to insert — that is used with the special insertion device, as shown here — and it is now injected inside the anterior chamber, and the instrument, such as a fork-shaped spatula, is used to etch the iris with the fixation element of the device, and as a result, we have a 7 millimeter square — almost round — pupil. And you see how these devices can be removed from the eye, in the manner opposite to what you’ve just seen in the previous video clip. So you use the instrument, disengage the device from the iris, with the positioning elements, one by one, and then you may use forceps, or use the same injector that was used for introducing the ring into the eye, catch one of the sides of this ring, and then remove that device from the eye, as shown here. In that video clip. Although not all devices are similar, and you have to keep in mind that the profile of X-pand is slightly bigger than that of the Malyugin ring, and you have to keep in mind that while manipulating it inside the anterior chamber. So this is another device made of soft polyurethane, and again, it can be used with an injection system, and these are triangular side port elements. They are triangular corner elements that are used to engage with the iris tissue. Having special holes, you can utilize Sinskey hook in order to catch the iris with the corner elements. And actually, you can use the same injector device in order to insert — remove the I-Ring from the eye. This is another, made from polyurethane. Oasis Iris Expander, which is shown here, and again, it utilizes the special pockets that are used to engage with the iris tissue. Malyugin Ring 2.0 is the newest version of the pupil expansion device, having thinner thread, 5-0 polypropylene, a new injector, and a new holder. Being utilized here. Basically, the technique of insertion and removal — quite the same. This is 2.0 version. 7 millimeters in size. And as you can see here, it is easy to insert and remove, with more or less the same technique shown for the classical version. And actually, you can use this injection device to remove the expansion ring from the eye. And as soon as the viscoelastic is removed from the eye, you see that the pupil regains its shape and size. What is good is that the thinner thread gives us much better flexibility. There is much less force needed to compress the two ends of the device, and also by utilizing thinner thread, we increase the gap that is shown here, so it’s much easier to remove. Both versions, I think, should be in the surgical armamentarium, because the thicker classical version is better to use with very small and very fibrotic pupils, and 2.0 is indicated in moderately dilated pupils or patients with floppy iris syndrome, when there is no need to forcefully open the pupil, because the pupil easily goes back and forth during the course of the procedure. So I do believe that with the latest advances with ocular pharmacology and pupil expander devices and designs, we should be happy with the options currently available for small pupil cataract surgery. And I thank you very much for your kind attention.

December 11, 2019

Last Updated: October 31, 2022

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