Round table: Refractive lens exchange techniques advance with experience

Refractive surgeons who routinely practice refractive lens exchange discuss techniques, challenges and the future. Part 1 of two parts.

William F. Maloney, MD: For this round table on refractive lens exchange, I invited only surgeons who have extensive first-hand, long-term experience with the procedure. We want to emphasize techniques and technology that are currently available, which you are now using and that our readers can begin using now.

Refractive lens exchange is a viable procedure right now, regardless of future technology, because it builds on the remarkable success of today’s cataract surgery. I feel it is a mistake to await whatever accommodating IOL may become available before considering refractive lens exchange.

In this issue we present part 1 of the round table. A second part will run in an upcoming issue.

Why now?

William F. Maloney, MD, is Ocular Surgery News Cataract Surgery Section Editor. He can be reached at 2023 West Vista Way, Suite A, Vista, CA 92083; (760) 941-1400; fax: (760) 941-9643; e-mail: williammaloney2000@ yahoo.com. Ocular Surgery News was unable to confirm whether Dr. Maloney has a direct financial interest in the products mentioned in this article or if he is a paid consultant for any companies mentioned.

The first thing that I want to talk about is, “Why now?” It’s been more than 20 years since the idea of refractive lens exchange as a treatment for myopia was proposed, by Versella, from Bologna, Italy, in 1980. In the modern era, he was the first. At that time, the ophthalmic community wisely recognized that the techniques and technology were not ready for refractive lens exchange to be consistently successful.

After a decade of talking about it and a slowly developing increased interest, there has suddenly been a surge of interest in lens-based refractive technique in the past year — in particular refractive lens exchange.

Some say this is really a phenomenon of demographics more than anything else — that this surge in interest is from a large group of LASIK surgeons targeting the now-presbyopic baby-boom generation. A stampede toward the next new thing. If that’s the case, we must be cautious.

The question is: Is all of this current interest in refractive lens exchange occurring for the right reasons? Is this procedure ready, or is this phenomenon just because some are looking for the next hot topic?

I. Howard Fine, MD: I think it’s for the right reasons. Several important things have pushed us in that direction. First, as LASIK was developed and used over the past 10 years or so around the world, we’ve become increasingly aware of optical aberration associated with the changes in the curvature of the cornea. Some patients saw 20/20 in a darkened lane but were unhappy for a variety of other reasons that had to do with optical aberration as a result of abnormal corneal curvature. This led to attempts at wavefront technology, blended zones and other things.

But simultaneous with this, there have been developments in IOL technology. That turned us in the direction of reevaluating vision. We have to credit Art Ginsberg for his insights and the developments that he has contributed to how we measure functional vision.

The bottom line at this time appears to be contrast sensitivity. It is through the measurement of contrast sensitivity that we have come to recognize that Snellen visual acuity is not a good measure of functional vision. As Jack Holladay is fond of saying, you can have 20/20 visual acuity in a darkened lane and not see a truck in a fog.

The contrast sensitivity functional vision testing done with sine-wave gradients gives us a spectrum of visual function not unlike audiometry, which measures all of the frequencies within the hearable range at different intensities. This gives us sine-wave gradients at different contrast levels, which describes for us the whole spectrum of our functional vision. In fact, recently the American National Standards Institute recommended that we change our measuring of vision from Snellen acuity to contrast sensitivity.

As we age, the spherical aberration of the human lens changes from negative to positive, compounding the spherical aberration of the eye.

I. Howard Fine, MD, is a Board member of Ocular Surgery News. He can be reached at Drs. Fine, Hoffman and Packer, 1550 Oak St., Suite 5, Eugene, OR 97401; (541) 687-2110; fax: (541) 484-3883; e-mail: hfine@finemd.com. Ocular Surgery News was unable to confirm whether Dr. Fine has a direct financial interest in the products mentioned in this article or if he is a paid consultant for any companies mentioned.

Dr. Maloney: Is it fair to say that that is a lens pathology? That the lens without a cataract — or with what we have traditionally categorized as nuclear sclerosis or “early” cataract — is a pathological condition with visual disturbance previously undiagnosed by Snellen acuity standards?

Dr. Fine: Absolutely. What’s wrong with my eyes, doctor? It’s the lens that’s wrong, not the cornea.

Interestingly, the spherical aberration in the cornea is constant throughout life. If you look at patient populations, this is true for well over 90% of them. They all have positive spherical aberration. But as we age, the lens changes in a way to compound the spherical aberration of the cornea. So the cornea is constant throughout life. The eye changes throughout life in a parallel fashion to changes in the lens.

That’s why we are confronted with patients have mild cataracts who say, “I know I read the chart well, but I can’t drive at night,” or “I don’t see well in a fog,” or “I don’t see well when it rains.” Spherical aberration has degraded their vision.

Dr. Maloney: I know all of us here are now much more aware of these visual complaints. The emphasis is shifting from Snellen acuity, which is quantitative, to functional acuity, which is qualitative. As this process unfolded in my practice, I learned to ask specific qualitative questions about the patient’s functional vision, and believe me, they tell me about a great many frustrations and difficulties that I had previously been overlooking.

Presbyopia: surgical solutions

R. Bruce Wallace III, MD: There is another element, and that’s correcting presbyopia. LASIK is weak at that.

Dr. Fine: The aging lens is going to degrade no matter what you do to the cornea, and there is not yet a true cure for presbyopia in the cornea, so the cornea is not where we’re headed. Refractive lens exchange is where we’re headed.

If you look at treatments for refractive errors today, children are treated with spectacles, teenagers with contact lenses, young adults with refractive corneal surgery by and large, middle-aged adults with bifocals, senior citizens with cataract surgery. You can combine those three last steps with a refractive lens exchange.

R. Bruce Wallace III, MD, is Ocular Surgery News ASCs Section Editor. He can be reached at 4110 Parliament Drive, Alexandria, LA 71303; (318) 448-4488; fax: (318) 448-9731; e-mail: rbw123@aol.com. Ocular Surgery News was unable to confirm whether Dr. Wallace has a direct financial interest in the products mentioned in this article or if he is a paid consultant for any companies mentioned.

It’s going to be a triple win. Patients can enjoy a predictable refractive procedure with rapid recovery that addresses all of the refractive errors including presbyopia and, importantly, never develop cataracts. That means they will never develop positive spherical aberration in their lenses. The surgeon will benefit because he can offer those procedures without the intrusion of private or government insurance and establish a less disruptive relationship with patients. And I honestly believe the driving force will be the government. When they realize that they will experience a decreased financial burden from the expense of cataract surgery, as increasing numbers of baby boomers opt for refractive lens exchange, ultimately reaching Medicare coverage as pseudophakics, the government is going to be one happy camper.

Dr. Wallace: Along with what Howard said about contrast sensitivity, I think aberrometry will move us toward lens surgery. Right now that’s the hot topic for custom ablation for LASIK. But once surgeons realize where the aberrations really are, and that they are going to get worse in patients’ eyes if they have corneal surgery, we’re probably going to counsel patients differently. We will tell patients, Well, you can have a corneal surgical procedure that is a good procedure. But this aberrometry shows that most of the aberrations in your eye, at over 50 years of age, are in the lens. And they are going to get worse. Does it really make sense to do an operation on the cornea?

We are challenged now by corneal refractive surgery patients when they come back needing cataract surgery, so it’s probably better to just avoid corneal surgery and move straight to the lens in patients that qualify with their refractive surgical correction needs.

And many are looking for more than just distance correction or even monovision, they are looking for distance and near vision in both eyes. We only can really do that with a lens.

Dr. Fine: Yes, what you said is important. We tend to think of developing cataracts as though they are nothing until they are surgical candidates. But there is morbidity associated with precataract changes in the lens as we age. The aberrometries document that.

Dr. Maloney: I couldn’t agree more. What we have classified as cataract, using Snellen criteria, is actually the end stage of a much longer process of lens changes. We are only now starting to appreciate the cumulative visual impairment associated with the earlier “precataract” stage of this process. The closer we look, the more significant this visual impairment appears.

Start with cataract surgery

Dr. Wallace: Getting back to the original question of what can we do now, the first step that most surgeons should consider is committing to refractive cataract surgery.

Cataract surgery is where it starts. Surgeons must commit themselves first to refractive cataract surgery, measuring outcomes on a regular basis, discussing desired refractive outcomes with each patient, finding out what they are looking for and being proactive at correcting astigmatism so that there is less than 1 D of cylinder after surgery. They must work hard on being a consistent, predictable lens surgeon.

Having a refractive cataract surgery team is really critical. It’s not the surgeon working in a vacuum but the whole practice working together and measuring goals together. That’s how we get to the point where we feel comfortable going to refractive lens exchange.

Dr. Maloney: You are right, Bruce. And the key word you used is “commit.” It’s one thing to do cataract surgery and hope to get some refractive benefit for your patient. It’s a very different thing when you sit down in front of that cataract patient and say, “I can offer you a procedure that will eliminate your need for glasses,” and know you can deliver. And the next step is saying that to a patient who doesn’t have a cataract. The only way to get that necessary deep sense of confidence is a lot of first-hand experience with the cataract patient to whom you’ve made that commitment. That’s absolutely the best training ground.

I am concerned that there are surgeons out there who don’t appreciate the need to take the active step in that direction but who just feel, “Well, what’s the difference if I have a cataract patient with a 20/30 cataract and then suddenly there is a 20/20 eye?” I feel it’s a big difference. When the cataract is removed from the equation completely, the refractive results must be near perfect every time. That takes a great deal of attention and preparation. The technology is not new, the surgical techniques are not different, it is the intolerance for any complication or for any error in outcomes that is new. This change is palpable and should not be taken for granted in the transition to refractive lens exchange.

Dr. Fine: Both of you have mentioned the key word, commitment. It is really a commitment. It’s not an accident, and it’s not a once-in-a-while thing. It requires commitment.

Dr. Maloney: We’ve talked about the advantages of refractive lens exchange. One that should be emphasized is that we are building on the proven long-term results of today’s cataract surgery, which is probably the most successful surgery in the history of medicine. That is our starting point. There is no other technique with that kind of long-term track record in the refractive arena. We are not going to have any technology-related unfortunate surprises with this technique.

Kurt A. Buzard, MD, is a well-known refractive surgeon. He can be reached at 7135 W. Sahara Ave., Las Vegas, NV 89117; (702) 362-3900; fax: (702) 362-7405; e-mail: kurt@buzard.com. Ocular Surgery News was unable to confirm whether Dr. Buzard has a direct financial interest in the products mentioned in this article or if he is a paid consultant for any companies mentioned

The only thing that can hold us back is a surgeon who takes for granted the transition. We have to constantly reinforce that, the need to commit to acquiring the skills and updating the skills to today’s state-of-the-art level before crossing the 20/20 threshold.

Dr. Fine: This surgery not only restores but enhances, and there is no other refractive surgery that does that.

Kurt A. Buzard: MD: But the people who are doing LASIK for patients in their 50s must begin looking at the early lens-induced changes that occur, like lenticular astigmatism. When you see lenticular astigmatism of more than 0.5 D, you should begin asking yourself, “Is that the beginning of a cataract?” Far too many LASIK surgeons are operating on 50-year-old patients with the beginnings of cataracts, and then a year or 2 later they have cataracts.

Moreover, surgically induced complications with LASIK, both in terms of dry eye and epithelial erosions at the time of surgery, are much higher than in younger patients. If you truly know your complications and look at the early stages of cataract, many more patients would be having clear lens exchange than are currently having it.

Retinal detachment reassessment

Dr. Maloney: I want to move on to the potential disadvantages of the technique. One of the lingering concerns is the perceived potential for retinal detachment in myopes. Richard Packard recently summarized the literature and did a lot to neutralize some of the initial negative impact of Joseph Colin’s publication of some years ago.

Dr. Fine: Yes. Richard Packard showed that some surgeons who have done a lot of refractive lens exchange in young high myopes have not had a retinal detachment rate as reported by Dr. Colin. He furthermore showed that the average incidence in young high myopes of lattice degeneration is low, somewhere around 15%. In Dr. Colin’s patient population it was high, around 60%, which is an unusual patient population.

And the third consideration is that Dr. Colin’s patient population had about a 65% YAG laser capsulotomy rate, which is unheard of today as well. So these things make us look again at the high myope as a potential refractive lens exchange patient.

Dr. Maloney: This is worth emphasizing. Capsular opacification and the need for YAG laser following refractive lens exchange will be dramatically reduced, if not eliminated, in the next few years. David Apple’s studies have shown that square edge lens design is addressing this issue effectively.

Dr. Buzard: I don’t know if it’s well known that many of those cases in Dr. Colin’s study were extracapsular cataract extractions. They weren’t done with small incisions.

I did a large study and found that my retinal detachment rate in young myopes is between 0.1% and 0.4%. I have reviewed this with other surgeons around the country, and that’s a normal rate. With normal small-incision surgery and a good surgeon who does the case quickly without a lot of trauma, you don’t have an increase in the rate of retinal detachments.

Dr. Fine: But there are other things present in a myopic eye that are independent of how well the surgery was performed. The most important of which is the fact that if you look at the location of the vitreous face in a phakic, high myopic, young patient, compared to a pseudophakic, high myopic, young patient, there is quite a forward movement of vitreous face. And that presupposes to an increased rate of retinal detachment.

There may be an acceptable risk level there, but I think it’s going to be partially dependent on lens style.

Dr. Wallace: Well, it’s going to be more comfortable for us to work in hyperopia rather than myopia until this issue is fully resolved. We generally get retinal consults on patients that have greater than 4 D or 5 D of myopia with longer axial length measurements, simply because we have to protect ourselves and our patients. Some of these people need prophylactic care, or they may just be high risk in the first place, and we wouldn’t elect to do their lens surgery, at least not initially. I think that’s the best way to go for now.

As we have procedures that become more precise, and we don’t see the trampolining of the posterior capsule during surgery, with more controlled fluidics, I think this will be less of a need. But for right now that’s what we’ve been doing with these myopes.

Dr. Maloney: I find patient selection is important. I’m highly unlikely to choose a young football player that’s –10 D to have a refractive lens replacement, not only because he is prepresbyopic but because this patient’s lifestyle is more likely to create a retinal detachment. Most of the patients in my practice that are high myopes and refractive lens exchange candidates are 45 years and older and tend to have a lifestyle that’s at less risk for retinal detachment.

Dr. Fine: We’ve done some 8 D to 10 D hyperopic patients that were in their 20s, Bill, and they are fabulously happy.

Dr. Maloney: Hyperopia is a whole other issue, and we’ll get to that.

Dr. Buzard: We looked at the few retinal detachments that we had, and our data correlated with other people who have found that the real risk for retinal detachment is in myopia of between 5 D and 8 D. In really nearsighted people the vitreous is already detached, and the risk is much lower.

The two patients I had in my refractive study that had retinal detachments were both about 6 D. I’ve done a lot of 15 D and 20 D and 30 D. I have a 20-year-old who was 35 D nearsighted. He’s never had a problem with his retina. It’s the people who are in that midrange that are the problem.

Surgical technique

Dr. Maloney: Let’s move on to technique. Although we’re dealing with lenses that have less lens opacity and are probably less dense than the traditional cataract lens, these very long and very short eyes do present some unique problems of their own.

I want to first talk about the specific phaco technique for soft lensectomy in these eyes. Is there anything that works better in the lensectomy for these patients than in a cataract patient?

Dr. Fine: For short eyes, I like to do the capsulorrhexis using microincision capsulorrhexis forceps. Right now I’m using the ones manufactured by ASICO. The chamber remains fully stable with these capsulorrhexis forceps. You can do it through a 1.2-mm incision.

I then do cortical cleaving hydrodissection and hydrodelineation just as I do in any other case.

For the high hyperope, I use a chop instrument to score the lens. Without counterpressure, I crease the lens about halfway or more through with the chop instrument. I make a cruciate groove in two directions. And then with a bevel-down technique and no phaco power, I just pick those quadrants out of the capsular bag at the level of the capsulorrhexis and then turn the bevel up and remove the epinucleus. Because of cortical cleaving and hydrodissection, there is very little left to do with the capsule.

In myopes, where we have a strong desire not to trampoline the vitreous face, I now do all my refractive lens exchanges with a bimanual microincision technique. I use two 1.2-mm incisions. I do capsulorrhexis as I’ve described. I do cortical cleaving and hydrodissection. I usually do not do hydrodelineation.

I then hydrodissect the lens out of the bag into the plane of the capsulorrhexis. Then I use the irrigator in one hand through a 1.2-mm incision and the phaco needle in the other hand, and I carousel the lens in the plane of the capsulorrhexis. In almost all cases, I can do it with zero phaco power. It will come out just through fluidics alone.

Dr. Maloney: Is there any place for the tilting or flipping techniques that you use for cataracts in this approach?

Dr. Wallace: I think so. This may be where one of the departures comes in for standard cataract surgeons. They may be challenged by this spongy lens material that doesn’t chop or crack easily. So they have to look at other ways, as Howard pointed out, of prolapsing the material, maybe through the capsulotomy. For the younger patients that’s the technique I use.

I use the cortical cleaving and hydrodissection. Then I remove the nuclear material with the epinuclear setting on the phaco. And I use a Connor wand as a second instrument through the side-port incision that has a blunt, bulbous tip to move the spongy material around. It also helps me protect the posterior capsule toward the end of the procedure. I can get underneath the phaco tip and avoid contact. This is crucial at that part of the procedure.

When I get into a little firmer nuclei, I do a hemiflip. I bisect the nucleus and then remove each half.

I would say that firmer nucleus occurs about the age of 50 to 55 years. So patients in that 50 to 55 age group could go either way depending on how the nucleus feels.

But a lot of surgeons may feel out of their comfort zone when dealing with these softer nuclei. It seems like it would be easier, but in some ways it’s more difficult because it’s unfamiliar.

Dr. Fine: I think you are right, Bruce. It’s more difficult because it is less predictable. A 2+ or 3+ grade nucleus will always behave the same. For those patients, you do your usual technique that you are already good at. The thing that makes the soft ones hard is that they are unpredictable.

Dr. Buzard: When you use a clear corneal incision, I think you have a less stable chamber. I use that blue line incision. It gives me a more stable chamber. I totally agree with you two. I think hydrodelineation is a great technique. These nuclei are usually soft. They hydrodelineate really nice.

I do a modification of the chip-and-flip technique. I go in and then lollipop up. Usually you can crack a soft nucleus like that and then just chip it. The little piece in the middle is hydrodelineated away, and it will pop up easily through the capsulorrhexis.

If you routinely use your phaco tip to take thicker epinuclear material away, which I do, then you are already familiar with that technique. So the hydrodelineation and hydrodissection allows me to take that little piece out in the middle and then do the epinucleus really quickly.

Dr. Maloney: As a common denominator among all of these, there is clearly a recognition that in these refractive lens replacement patients we have to be extremely conscious of keeping the phaco away from the capsule. We cannot afford to have capsular rupture in these cases.

Dr. Fine: That’s correct. This is a more formidable procedure because these patients will be less tolerant of a complication.

Dr. Maloney: Yes. If you break the capsule, at the very least you are going to have a refractive power change because of the different anterior-posterior position of the lens. You open the door for risk of cystoid macular edema and retinal detachment. So it has to be avoided at all costs.

I think in different ways we have all gravitated toward techniques that will accomplish that without damaging the cornea, even as we move closer to the cornea, because the lens is softer and we use adequate viscoelastics.

In my experience, the best phaco approach to truly eliminate the possibility of capsule rupture is supracapsular. I have used this technique exclusively since 1996 for both cataract and refractive lens exchange. When the phaco process is relocated away from the capsule, the risk of rupture is dramatically reduced and eventually eliminated.

There are several iterations of the supracapsular approach. Dave Brown’s flip technique is popular with many cataract surgeons, but I would mention that a soft lens may not readily flip. It may be better to simply sublux and rotate out of the bag in some of these cases. Either way, the key is to move the lens out of the bag before phacoaspirating the lens material.

Dr. Buzard: Also, little things that may not matter in normal cataract surgery can matter here, like the size and position of your capsulorrhexis. If one edge of the lens gets outside of the capsulorrhexis it will cause a little change in refraction. So much more detail toward getting everything perfect is necessary.

Dr. Wallace: I agree with you. If you can get those lenses overlapped by just a touch of capsule all the way around, they stay centered better and there is less posterior capsular opacification, as David Apple has shown. All these little things add up.

To address the capsulorrhexis issue I’ve been using a capsulotomy diameter mark on the central cornea, a 6-mm mark. That helps because with the corneal magnification, staying just inside the line I end up with a fairly consistent 5-mm capsulotomy.

IOL selection

Dr. Maloney: Let’s talk about IOL selection. I want our readers to know exactly what IOLs you are using now for these patients.

Dr. Buzard: When we’re approaching refractive surgery it is important to consider the issue of enhancement. A lot of people use limbal relaxing incisions. But if down the road the patient has astigmatism, it’s not convenient to do in the office and it’s harder to enhance.

In a similar way, the choice of the original lens is important. If the lens is going to be hard to remove, that will limit your options for enhancement. So if I want a multifocal lens I use the Array (Advanced Medical Optics), but normally I use a STAAR IOL. And I’ve been happy that Alcon has now come out with an extended range on their lenses. So I just recently used a 39 D lens. That’s fabulous.

I use piggyback lenses when I have to, but I am not eager to do so. The extended range with the Alcon lens and the lower ranges with the STAAR have been helpful in my practice.

Dr. Fine: I think Bruce and I both favor Array multifocal IOLs. Overwhelmingly, that’s what we use for our refractive lens exchanges because it addresses presbyopia as well.

And we are getting excellent achieved vs. anticipated spherical equivalent using the IOL Master for biometry.

With binocular Arrays to correct presbyopia, in our study nearly 100% of the patients had visual acuities of at least 20/40 and J5, meaning they could drive and read without correction.

Dr. Maloney: How effective is their design in terms of PCO inhibition?

Dr. Fine: Within a short period of time, AMO will be introducing OptiEdge Arrays, which will improve that.

With the standard Array lens, we do YAG laser capsulotomies earlier than we normally would, because small amounts of PCO degrade vision more with an Array than they do with a monofocal IOL. We’ve gotten great results and very happy patients with that lens. And it’s very predictable.

As Kurt suggested, for high myopes we frequently use a STAAR AQ5010, a three-piece, 6.3-mm optic diameter, 14-mm haptic diameter with polyamide haptics that are stable for those big eyes. We also use that lens for refractive surprises because we can implant that through a 2.5-mm incision into the ciliary sulcus with great ease on top of another IOL. It comes in powers from –4 D to +4 D.

In some instances we’ve used other lenses. In patients who are unconcerned about presbyopia we’ve used the Pfizer Tecnis IOL, and they are routinely pleased with the quality of their vision.

Dr. Wallace: My lens of choice for just about all refractive lens procedures is the Array. It’s important with this lens to talk to patients up front about what to expect, what their new vision system is going to be like. As long as they know going in that the rings around lights at night are expected and that they diminish over time, they are happy. Their near vision takes time, but for the younger patients not long, usually a day or two. Cataract patients take longer.

But the Array lens with the right patient education and the right patient selection, particularly for hyperopic presbyopes, has been a winner for us.

For all of us using these technologies, we have to start with recognizing that presbyopia is a real problem. This is not minor in a person’s life. It’s a real inconvenience for patients to go through. We have to be committed to the fact that presbyopia must be overcome.

Dr. Maloney: We will talk more about patient selection and education, as well as about our surgical approaches to presbyopia, in the second part of this round table in an upcoming issue.