Transcript
Micro-Coaxial Phaco: Putting it all together
www.eyeworld.org
REPRINTED FROM 2008 ASCRS CHICAGO SUPPLEMENT
Supported by an unrestricted educational grant from Alcon, Inc.
A systematic approach to micro-coaxial phaco surgery by Terry Kim, M.D. sizes are being used by an emerging number of surgeons. These can deliver surgical benefits, especially when used in conjunction with the latest technological advances in phacoemulsification.
Rationale for going smaller: Is smaller always better?
“Surgeons have now been given a fully integrated phacoemulsification system to perform micro-incision cataract surgery that will inevitably improve patient outcomes.” Terry Kim, M.D.
The trend toward smaller incision surgery will continue s cataract surgeons, we have always been moving toward smaller and smaller incision sizes, with most of us now using 2.75- to 3.0-mm incisions and achieving great results for our patients. Even smaller incision
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As surgeons, we know smaller corneal incisions induce less astigmatism and can self-seal more easily than their larger counterparts. So in theory, we would be reducing the risk of wound leakage and endophthalmitis. [1] But if the incision size is too small, the surgeon’s ability to manipulate the instruments can be hindered, and the potential benefits are offset. Additionally, the smallest of incisions (1.1 to 1.2 mm) can limit the movement of instruments and necessitate the use of unsleeved instruments, thereby increasing mechanical and thermal trauma to the wound. To address the weaknesses of micro-incisions used in bimanual phaco, some surgeons are suturing their micro-incisions while others are making a third incision for IOL insertion. Both of those options offset any advantages of microincision surgery. An ideal system allows surgeons to perform phacoemulsification through micro-incisions that will capitalize on the benefits of smaller incision sizes without increasing the downside. We found that the INTREPID Micro-Coaxial System using the INFINITI Vision System and the OZil Torsional handpiece (Alcon, Fort Worth, Texas) provides a fully
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A 2.2-mm incision following IOL implantation through a D cartridge and the Monarch III delivery system integrated line of equipment and instruments that has been able to optimize micro-incisional cataract surgery in one overall system.
What the science says Typical phacoemulsification operates with longitudinal jackhammer motion in conventional ultrasound. With OZil Torsional ultrasound, the handpiece amplifies the side-to-side oscillatory motion to the phaco tip, which helps to minimize the stress to the incision. As a result, the side-to-side shearing motion allows for more efficient emulsification of lens material, greatly reduces repulsion, and increases followability. Laboratory and clinical studies have validated the theories as well. In one ex vivo study [2], 15 human cadaver eyes were divided into three groups: group 1 received 2.8-mm coaxial incisions, group 2 received 2.2-mm coaxial micro-
incisions, and group 3 received 1.2mm bimanual micro-incisions. All eyes underwent simulated phacoemulsification using longitudinal ultrasound with standard settings. We evaluated the architecture and integrity of the different wound sizes. Spontaneous wound leakage was present in all eyes that underwent the bimanual technique, in one eye in the standard coaxial group, and in none of the eyes in the micro-coaxial group. Histopathologic examination of the eyes studied revealed India ink penetration in all of the eyes in the bimanual group and no eyes in the micro-coaxial group. The bimanual micro-incisional technique also resulted in more qualitative trauma to Descemet’s membrane and the corneal endothelium as demonstrated by scanning electron microscopy (SEM). As a follow-up to that study, continued on page 8
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Scanning electron microscope examination demonstrates qualitatively greater endothelial cell loss and damage to Descemet’s membrane in the bimanual 1.2-mm incision (A) compared to the micro-coaxial 2.2-mm (B) or standard coaxial 2.8-mm (C) incisions
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Advantages of micro-coaxial phaco by Samuel Masket, M.D.
19.2 mm Hg +/– 4.9 (SD) (median 18 mm Hg, range 11 to 35 mm Hg) in the group with a 2.2-mm square incision and 16.6 +/– 5.2 mm Hg (median 16.0 mm Hg, range 10 to 25 mm Hg) in the group with a 3.0-mm nearly square clear corneal incision. No patient had an IOP less than 10 mm Hg, and there was no evidence of hypotony or wound leakage by Seidel testing in either group. [2] What we have with the 2.2mm incision is a square, stable, astigmatically neutral wound construction – the ideal wound configuration.
“We found both a statistical and clinical significance in the amount of astigmatism in favor of the 2.2-mm incision.”
The ideal system
2.2-mm incision with ClearCut INTREPID knife
Samuel Masket, M.D.
One surgeon’s rationale for using micro-incisions n recent years, there has been an increased concern among ophthalmologists about the wound stability of larger incisions, especially as we have increasing evidence that smaller incisions offer greater ocular stability. Additionally, smaller incisions may be more resistant to deformation caused by patients’ rubbing and/or blinking. When you consider the cataract and IOL implantation incision, the goal is to create a stable, hermetically sealed environment to reduce the likelihood of microbial contamination in order to reduce post-op infection rates. More than a decade ago, Paul Ernest and colleagues proved square surface incision architecture is more resistant to deformation than other types of incisions. [1] Second, but equally important, you want the incision to be as astigmatically neutral as possible. When you consider both of these patient benefits, a smallwidth incision, but one that is square in architecture, should be preferred. With an incision size larger than 3 mm, you are inadvertently creating negative consequences during surgery, such as
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Capsulorhexis with standard forceps through a 2.2-mm incision
corneal striae. Also working near the corneal apex may have negative effects on astigmatism and endothelial cells.
Astigmatism reduction, IOP We evaluated surgically induced astigmatism with two different incision sizes – 2.2-mm and 3.0mm clear corneal incisions. We found both a statistical and clinical significance in the amount of astigmatism in favor of the 2.2mm incision. In the 2.2-mm incision eyes, mean surgically induced astigmatism was 0.11 D, with a range of 0 to 0.375 D. With the 3.0-mm incision eyes, mean surgically induced astigmatism was 0.33 D, with a
range of 0 to 0.75 D. Post-op, we assessed leakage; none required sutures. We also examined the eyes for hypotony and did not find any at the 2- and 6-hour follow-up. (Article submitted to Journal of Cataract and Refractive Surgery.) We recently evaluated 60 patients who had undergone clear corneal cataract extraction with a 2.2-mm incision using the INFINITI system (Alcon, Fort Worth, Texas) and an Ultra sleeve for infusion. We compared the results to those of 10 patients who underwent a nearly square 3.0-mm incision with the Sovereign (Advanced Medical Optics, AMO, Santa Ana, Calif.). The mean post-op IOP was
As a result of that study and others, I prefer to use micro-coaxial phaco in all my cataract surgeries. To make the incision, I prefer to use a diamond blade or steel blades designed to create the perfect 2.2-mm incision, such as ClearCut INTREPID knives (Alcon). For those surgeons who have not yet tried micro-coaxial incisions, the learning curve from a 3.0-mm incision is almost nonexistent. The capsulorhexis with standard forceps is only slightly stiffer through a 2.2-mm incision than through a larger one. In my opinion, surgical instrumentation and phaco fluidics have improved so dramatically, the transition to micro-coaxial is rather simple. When you consider using the INTREPID system with the INFINITI and one-piece aspheric AcrySof acrylic IOL (Alcon), you’ve got a 6 mm lens that can go through a 2.2-mm incision using the new D cartridge and deliver the highest quality vision and visual recovery for our patients. In my opinion, there is no doubt that the square incision architecture, combined with the benefits of the microincision, offers patients the best possible outcomes in today’s cataract surgery. Samuel Masket, M.D., is in private practice in Century City, Calif., and is clinical professor of ophthalmology at the UCLA Geffen School of Medicine, Jules Stein Eye Institute, Los Angeles. He is also the immediate past president of ASCRS. References: 1 Ernest PH, Fenzl R, Lavery KT, Sensoli A. Relative stability of clear corneal incisions in a cadaver eye model. J Cataract Refract Surg. 1995;21:39-42. 2 Masket S, Belani S. Proper wound construction to prevent short-term ocular hypotony after clear corneal incision cataract surgery. J Cataract Refract Surg. 2007;33:383-6.
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Post-op incision size is the true measure of micro-surgery by Alan S. Crandall, M.D.
Cartridge and tip sizes
“It defeats the purpose of micro-incision phacoemulsification if we have to widen or stretch our small incisions in order to insert the intraocular lens (IOL).” Alan S. Crandall, M.D.
A new cartridge eliminates the need to enlarge the wound for IOL insertion s cataract surgeons trend toward smaller incisions, the debate about “diminished returns” has arisen: If 2.4-mm incisions are better than 2.8-mm incisions, are 2.2-mm incisions better than 2.4mm in terms of surgically induced astigmatism and endophthalmitis? Do we get the incremental benefits moving from a 2.2-mm incision to a sub-2.0 mm incision? How small is too small? What is small enough? As the debate grows, there is one thing that every surgeon should agree upon: It defeats the purpose of micro-incision phacoemulsification if we have to widen or stretch our small incisions in order to insert the intraocular lens (IOL). I find it interesting that many who are promoting sub-2.0 mm surgery are also promoting enlarging the incision to insert the IOL. Wound integrity and wound construction still matter.
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My colleagues and I here at the Moran Eye Center, Salt Lake City, Utah, have compared intra-operative and surgical outcome parameters of various angled tips with torsional ultrasound. [1] In this study, we randomized three phaco tips – the mini-flared Kelman tip, the reversed mini-flared Kelman tip, and an angled tip – through a 2.8-mm and a 2.2-mm incision to determine wound integrity. We used the Visante Optical Coherence Tomography (OCT) (Carl Zeiss Meditec, Dublin, Calif.) to look at the wounds on the first day after cataract surgery and at one month out. We then compared the Monarch III system with the D cartridge (Alcon, Fort Worth, Texas) to the C cartridge (Alcon). We found that with the 2.2mm incision, the internal lip of the wound is absolutely sealed with the D cartridge. It doesn’t enlarge the wound. We randomized the tips, and whether we used the 1.1 flared or 0.9 flared, regardless of tip size, the D cartridge does not enlarge the wound. If the wound has enlarged, it’s because I have inadvertently stretched it during surgery. The point is that you’re not stretching or enlarging the incision when properly utilizing the Monarch III system. I’ve delivered all types and sizes of IOLs – from the AcrySof ReSTOR Aspheric (Alcon), to the AcrySof Toric lens (Alcon), to the AcrySof IQ. So far the highest implantation is 27 D but I could go higher. What Alcon has done with the new D cartridge is to change the thickness of the
walls and architecture just slightly so it can better withstand the forces of a rolled-up lens. There’s a lot of technology that’s involved in what we tend to take for granted. Many surgeons have been led to attempt to insert IOLs that are not AcrySof Foldable IOLs through the Monarch C and D cartridges. The implantation of IOLs that are not designed for their respective delivery systems could result in damage to the IOL and/or patient complications. We might use several different types of IOLs in one day – IOLs from Bausch & Lomb, Alcon, Advanced Medical Optics, etc., and our techs have to make sure we are using the right cartridge with the right lens, but ultimately any off-label or non-qualified use of a company’s products is at the surgeon’s risk and liability. We don’t think about the cartridge until something goes wrong and the lens is split or there is a complication. Compared to the C cartridge, the diameter of the D cartridge’s rear opening has increased from 5.5 mm to 6.0 mm (allowing for easier IOL loading with virtually no resistance), and the nozzle tip area is 33% smaller, respectively (resulting in less stress on the corneal incision). As a result, there is better wound sealing with a reduced need for stromal hydration and suture placement. The technique used with the D cartridge is to engage the entire nozzle tip of the cartridge into the lip of the incision while maintaining much gentler pressure on the incision and inserting the IOL into the anterior chamber. The AcrySof
single-piece aspheric lenses have been approved up to 27 D through the D cartridge, and in my hands, can be implanted without wound enlargement into a 2.2-mm incision that seals beautifully. The Monarch III delivery system with the new D cartridge has enabled easier and safer implantation of the AcrySof single-piece aspheric lens models through micro-incisions. We know when we moved from intracap it was a huge improvement in terms of reducing astigmatism and endophthalmitis. So if you’re performing clear corneal surgery through a 2.8-mm incision and your patients are doing well, what’s the motivation to go smaller? My friend and colleague Sam Masket, M.D., points out that micro-coaxial surgery should be less about incision size and more about the benefits of a “square” incision. A 2.2-mm or 2.4-mm blade allows surgeons to make a square incision that seals well and reduces the potential for endophthalmitis. The reduced surgically induced astigmatism gives us even better outcomes for our patients. Alan S. Crandall, M.D., is professor of clinical ophthalmology, vice chair of clinical services, and director of glaucoma and cataract at the John A. Moran Eye Center, University of Utah Health Sciences Center, Salt Lake City. References: 1 Crandall AS. Comparison of various angled tips with torsional ultrasound. Presented at: American Society of Cataract and Refractive Surgery: April 6, 2008; Chicago, IL.
The D cartridge was designed to fit inside a "square" 2.2-mm incision without stretching or distorting that incision; it allows the implantation of aspheric AcrySof IOLs up to 27 D
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Visual advantages using aspheric IOLs in micro-coaxial cases by Satish Modi, M.D.
“But now, with the thinner aspheric optic, we can easily implant up to a +27 D IOL using the D cartridge on the INFINITI through a 2.2mm incision.” Satish Modi, M.D.
The lens design allows implantation through unenlarged microincisions he AcrySof IQ aspheric lens (Alcon, Fort Worth, Texas) has easily become our lens of choice when we are implanting monofocal intraocular lenses. Now the correction for increased aberrations and the improvements in image quality are available on the AcrySof ReSTOR (Alcon). Spherical aberrations (SAs) are the principal HOA that cause a degraded image for the patient. A brief overview of SAs is warranted.
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Understanding SA What is spherical aberration and is it all bad? Rays that are at the center (axial or paraxial rays) are brought into focus on the retina. But SA causes the peripheral rays to be overfocused. This delta between the paraxial rays focusing and the peripheral rays focusing results in a blurred retinal image, and this is created by the SA. As the disparity between the image foci increases, the patient gets rings and blurred focus around lights. SA in the eye
increases incredibly over time. Older patients have higher SAs and that directly results in low image quality, glare, and bad night vision. The cornea has a symmetrical, constant amount of positive SA throughout life, about +0.275 microns. This is compensated for by the negative SA in the crystalline lens when we are young. Unfortunately, this negative SA within the lens decreases over time, so that when we’re in our early 40s, it’s at zero, and then increases over time as we continue to age. This lenticular increase in SA adds to the positive SA already in the cornea, resulting in a further degradation of the retinal imagery. With the AcrySof aspheric, though, we now have a lens that is able to correct for the increased aberrations associated with aging. That’s what an aspheric lens should do – the front or back of the lens surface is modified so marginal rays are at the same pinpoint focus as paraxial rays. This results in clearer images and less blur, which results in better night vision. When we talk about SAs, we need to speak about them in mesopic or scotopic conditions. It’s not a daytime thing. In the old days, we took out a cataract and replaced it with a spherical implant. What we were doing was creating more SA. A study showed higher amounts of SA in pseudophakes as opposed to age-matched phakic subjects. How much SA should one have? Theoretically, zero SA should be ideal. Studies seem to indicate otherwise. Levy et al looked at 70 subjects with supernormal vision and found an average SA of +0.11 microns with a 6mm pupil. [1] Legras looked at people and found the optimal value was not zero but between +0.08 microns and +0.1 microns positive SA. [2] If patients want to have the eyesight of youthful eyes, doctors need to target a slightly positive amount of SA. Of the three aspheric lenses available in the U.S. – the Tecnis (Advanced Medical Optics, AMO, Santa Ana, Calif.), SofPort AO (Bausch & Lomb, Rochester, N.Y.), and the AcrySof IQ – only the IQ leaves a small residual amount of positive SA, approximately +0.08 to +0.1 microns. The Tecnis lens removes ALL of the positive SA and the Sofport removes none of it.
At month one, monocular LogMAR was 0.02. At three months, monocular vision was 0.01. There was an additive effect with binocular vision – most patients saw 20/15 at month one and –0.09 LogMAR by month three
Best corrected distance LogMAR VA for ReSTOR aspheric at one month and three months
Biocompatibility There is nothing more biocompatible than a hydrophobic acrylic IOL. There are extremely low rates of PCO, which provides long-term clarity and lens stability. There’s low inflammation potential in compromised eyes. You don’t need to YAG nearly as much with hydrophobic acrylic IOLs. I’m upset if at seven days post-op the patient’s eye isn’t quiet and totally free of cells and flare. The AcrySof lens has proven biomechanics; it can adapt to different sized capsular bags. The material and design of the lens allows it to readily conform to constricting capsules, easily center in the eye, and provide optimal refractive results.
IQ and ReSTOR lenses in micro-coaxial phaco Before the advent of microcoaxial phacoemulsification, I would need to use a B cartridge (Alcon) and a 3.2-mm incision to put in anything above a +25 D lens. But now, with the thinner aspheric optic, we can easily implant up to a +27 D IOL using the D cartridge (Alcon) on the INFINITI (Alcon) through a 2.2mm incision. Using micro-coaxial phaco, we’re able to implant almost every lens through an unenlarged 2.2mm incision. These smaller incisions tackle concerns about SIA, and reduce post-op wound leakage and potential for infection. continued on page 8
Micro-Coaxial Phaco: Putting it all together—ASCRS Chicago, Show Daily Supplement 5
The role of fluidics in micro-coaxial surgery by Khiun Tjia, M.D. longitudinal ultrasound does not only emulsify the nuclear material by the forward stroke of the metal phaco tip, but also repels the nucleus at the same time. This paradox is in fact the greatest drawback of longitudinal ultrasound. Longitudinal ultrasound depends on high attractive forces – high aspiration flow and high vacuum – to compensate for its intrinsic repulsive forces.
Reducing post-occlusion surge response
“The introduction of OZil and its side-to-side shearing motion of the phaco tip has led to a paradigm shift in fluidics management during micro-coaxial surgery.” Khiun Tjia, M.D.
Efficient micro-torsional phacoemulsification raditional longitudinal ultrasound requires surgeons to use high aspiration flow and vacuum settings to overcome the repulsive effect of the phaco tip’s forward strokes. With micro-incisional phaco, however, fluidics settings have to be decreased to compensate the reduced irrigation flow. This decreases the efficiency and speed of the procedure.
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Irrigation/aspiration flows This decrease in irrigation flow has to be compensated by a similar decrease of aspiration flow. A simple general rule in fluidics management is that one has to balance the total fluid inflow and outflow. Roughly, there is a 30% decrease of irrigation flow if surgeons switch from a Micro sleeve/2.6- to 2.8-mm incision to an Ultra sleeve/2.2- to 2.4-mm incision. A significant decrease of aspiration flow results in a significant decrease of the process of nuclear pieces being attracted to the phaco tip. The speed of the fluid stream (aspiration flow) determines how fast a nuclear fragment is transported to the phaco tip opening. This is particularly important when one realizes that traditional
A high vacuum setting has the potential of increasing the incidence of posterior capsule ruptures. When occlusion of the phaco tip is broken with a high vacuum by the emulsification of lens material on or in the phaco tip, the immediate return of peristaltic pump tubing into its original dimension after being contracted by a high vacuum results in a sudden outflow of fluid from the fluid paths and potentially the anterior chamber. This can lead to a sudden shallowing of the anterior chamber and potentially rupture the posterior capsule. The severity of this surge flow is determined by the height of the vacuum and the compliance or ‘softness’ of the tubing. With softer tubing, more contraction occurs and surge flow is worse. The new INTREPID FMS (Alcon, Fort Worth, Texas) increases the rigidity of the aspiration tubing which reduces the occlusion break surge response significantly. This will help to further reduce tubing contraction, which should increase anterior chamber stability. The introduction of OZil and its side-to-side shearing motion of the phaco tip has led to a paradigm shift in fluidics management during micro-coaxial surgery. High vacuum and aspiration flow appeared to no longer be necessary to obtain efficient and effective emulsification, as there is no repulsion the system needs to overcome. Torsional ultrasound with moderate vacuum and flow settings is still extremely efficient in emulsifying nuclear material of all densities because material is more effectively cut by each shearing movement of the oscillating torsional tip. Formerly, there was a trend toward higher and higher settings to improve the performance of the phaco machines. As mentioned above, the reason to do this is no longer valid with the absence of significant repulsion of torsional ultrasound. In surgical challenges such as continued on page 8
The D cartridge is specifically designed for micro-coaxial surgery
The INTREPID FMS reduces post-occlusion surge by up to 50% with vacuum levels typically used in phaco (300 to 500 mm Hg)
The Monarch III D cartridge has a 33% reduction in nozzle tip (versus Monarch II C cartridge) for ease of micro-incision implantation
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Beginning micro-coaxial surgery by James A. Davison, M.D.
“Having a low energy, high efficiency modality like OZil makes it a very good fit with micro-coaxial surgery.” James A. Davison, M.D.
Learning curves are almost non-existent, making the transition easy and safe echnological advances in phacoemulsification have helped us improve patient outcomes by making the surgery safer while compromising none of our desired visual outcomes. For years, surgeons have looked for various methods to reduce ultrasonic energy used during phaco. We have learned that ultrasonic energy correlates with corneal endothelial cell density loss, so using less energy would therefore be safer. Reduced energy was first introduced in the Legacy and INFINITI pulse and burst modes (Alcon, Fort Worth, Texas), and later with the WhiteStar system (Advanced Medical Optics, AMO, Santa Ana, Calif.). Other methods, such as NeoSoniX (Alcon), AquaLase (Alcon), and Nd:YAG laser all had slight improvements as well. Torsional phaco using the mini-flared tip with the Ultra sleeve, the latest technological advances, combines stable fluidics with a limited irrigation flow while maintaining a secure wound construction and allows IOL insertion through a 2.2-mm incision.
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Oscillatory torsional amplitude creates a lateral tip movement that shears lens material and has proven more efficient in its cutting, thereby reducing the amount of amplitude and thermal energy needed. In traditional phaco, you first impale and cut into the nucleus, then aspirate the emulsified material. The phaco tip will break the impacted nucleus into fragments, but the other nuclear material itself is not really emulsified. The INFINITI Vision System with the INTREPID Fluid Management System (FMS) (Alcon) maximizes the safety of these techniques through a design that utilizes more rigid aspiration tubing that reduces post-occlusion surge.
How micro-coaxial phaco differs The INFINITI with torsional ultrasound uses a more efficient fluidics system in which fluidic turbulence by the vibrating tip is almost completely eliminated. The OZil 12 tip does not “kick” the nucleus material and, therefore, results in less repulsion, increased holding power, and more contact between the nucleus material and the phaco tip. Compared to traditional phaco, torsional itself cuts very efficiently. There is less heat, less thermal damage to the wound, and it is very quiet. In essence, we are delivering less energy into the eye, which allows surgeons to effectively use smaller and more
pristine incisions. That, in turn, means almost no surgically induced astigmatism and faster healing.
Fragment control The ability to control fragments better is a significant advantage of using the INFINITI system. Compartmentalizing the quadrants allows surgeons to organize their removal, minimizing fragment endothelial abrasion. The torsional tip is able to penetrate deeply into the nucleus and keep the nucleus at the tip for emulsification. Also, because you have much less fluid surrounding the phaco tip there is a small clean reservoir, so the thermal cuts become more significant to micro-coaxial surgery. Having a low energy, high efficiency modality like OZil makes it a very good fit with micro-coaxial surgery.
Wound integrity and construction Wound integrity continues to be an integral part of advanced phacoemulsification, and micro-coaxial phaco offers the opportunity for better wound integrity. The OZil 12 tip geometry translates to 50% reduction of stroke within the incision compared to traditional phaco, and there is a two-thirds reduction in thermal energy compared to longitudinal ultrasound. Torsional tip motion uses quadrant aspiration. Advantages to that include a sweeping effect, less fragment repulsion, greater frag-
ment adherence, improved fragment control, improved followability of nuclear material, and improved efficiency ratio of internal work action compared to incisional friction. As we’ve discussed, a traditional phaco handpiece delivers less than 50% effective longitudinal ultrasound energy. Torsional phaco allows us to use 100% effective energy delivery, with more cutting power. If we’re going to stay with larger incisions and high infusion sleeves, we can go to a higher flow rate. With torsional, vacuum levels and flow rates can be raised without affecting efficacy. If we use micro-coaxial incisions, there’s no need to lower the fluidic parameters; they can remain where they would for the incision sizes. In my experience, a 2.2-mm incision made with the ClearCut INTREPID blade (Alcon) feels no different than a 3.2-mm incision with a high infusion sleeve. It’s a seamless transition.
Summary The combination of torsional tip motion, more rigid cassette design, and angled tip design creates the most efficient contemporary phacoemulsification process that enables more surgeons to embrace micro-incisional phacoemulsification. James A. Davison, M.D., is in private practice at the Wolfe Eye Clinic in Marshalltown, Iowa.
QUADRANTS 2 - 3 140 120 100 80 Travel (mm) 60
Time (sec)
40 20 0 Straight Longitudinal
OZil® 12 Longitudinal
Straight Torsional
OZil® 12 Torsional
Torsional phaco with OZil 12 tip reduced quadrant removal time versus longitudinal with a straight tip
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Micro-coaxial OZil with 45-degree mini-flared tip by David Dillman, M.D.
“Other than the cutting phase, the 45-degree tip is never in the anterior/posterior orientation; it’s always on its side.”
45-degree mini-flared Kelman tip with Ultra sleeve
David Dillman, M.D.
The modified Kelman tip offers the most intraocular versatility he best way to take full surgical advantage of torsional technology, by far, is to use a 2.2-mm microcoaxial approach. At that incision size, it’s easy to maneuver the tip into and out of the eye, and once the tip is in the eye, a 2.2-mm incision gives us the most versatility in how to interact with the cataract. If surgeons are going to take advantage of torsional phacoemulsification technology, it has to be in conjunction with using a Kelman or angled tip. When we think about which Kelman miniflared tip to use, we must think about the fluidics offered to us by this combination.
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Using ‘WIN’ In torsional phaco, there is a shearing effect, as the tip moves to the right and left. In other words, 100% of the cycle is devoted to the emulsification process. WIN, or “what’s important now,” simply means at each stage of the cataract surgery, use the tools available to perform the safest and most efficient procedure. For example, a dense lens is going to require some form of cut-
ting/sculpting. Previous versions of the Kelman tip in traditional anterior/posterior orientation have been phenomenal at aiding in the cutting. Angulation will aid greatly in visualizing the tip. The main reason for this is that unlike longitudinal phaco, where movement is forward/backward, in torsional, movement is side-to-side. The interesting thing about torsional is what’s taking place at the actual phaco tip. The oscillation at the hub is combined with the frequency of 32,000 cycles per second. With a standard Kelmanstyle tip, this translates into an actual horizontal excursion as opposed to a longitudinal excursion. The maximum horizontal excursion is 3.5 mills or 90 microns, which is almost exactly the maximum excursion with longitudinal phaco. In my practice, I primarily do phaco pre-chopping. If I cannot do a pre-chop, I’ll perform a quick chop. In pre-chop I prefer to go through a 2.2-mm incision using the rose colored 0.9 mm Ultra sleeve. With torsional phaco, the tip is easily inserted without additional instrumentation needed. In longitudinal phaco, I often had to use a second instrument. I tend to have an aspiration setting of 40 cc/min with a vacuum of 400 and torsional amplitude set at 100. I also prefer to use the 45-degree mini-flared Kelman tip. Once the four quadrants are loose and free, the goal is to get
them out as efficiently and safely as possible. I can place the Kelman tip on its side and slide it in between two quadrants, get a good hold on the one and pull it into the middle, using torsional to move it. The key here is that other than the cutting phase, the 45degree tip is never in the anterior/posterior orientation; it’s always on its side. Depending on the depth, there are many different orientations you can use to interact with the quadrant you’re trying to move. The 45-degree bevel of the tip more effectively repositions lens material so the shearing effect of torsional ultrasound is more efficient than with 30-degree bevel tips.
Pearls for achieving better outcomes I’m a proponent of keeping a second instrument out of the eye whenever possible. I do this to avoid the potential leakage from the side port; incisional leakage is the enemy of fluidics. I find I can bury the tip easily using torsional for the whole process rather than having to start with longitudinal and switching to torsional. The key to that is keeping the angled phaco tip on its side, not in an anterior or posterior position. This helps avoid potential complications of inadvertent contact with the posterior capsule. In torsional, you really want to work at a higher amplitude that delivers the most effective shearing because there is no repulsion at the tip caused by fluidic repul-
sion of the vibrating tip. We can now set and utilize amplitude at 100%. Newcomers to the torsional technology need to remember amplitude is not the same as phaco power. I have found a very short learning curve with torsional. The biggest paradigm shift for me has been that in longitudinal phaco, I was always cognizant of the repulsive force and the need to have a very low stroke length, low phaco power. In torsional, you want to maximize the side-to-side movement and increase the use of power in order to try to bring lens material back to the oscillating tip. You can be more “aggressive” in your settings, and I’ve found I am actually safer with these than I was in longitudinal. A difficult surgery will always be difficult. Because I feel like I am safer and more efficient with torsional, the difficult cases aren’t quite so hard. Flomax patients are a good example. The really ultra dense brunescent cataracts are still challenging for everyone, but the safety of micro-coaxial phaco has made them a little less challenging. You can perform torsional phaco with a 2.8-mm incision and use more traditional Kelman tip designs, but at that larger size, you would be severely compromising the abilities of the torsional component. David Dillman, M.D., is in private practice at Dillman Eye Care Associates in Danville, Ill.
8 ASCRS Chicago, Show Daily Supplement—Micro-Coaxial Phaco: Putting it all together Using aspheric IOLs– from page 4
Systematic approach– from page 1 we examined the effects of different OZil settings on post-op wound architecture. [3] We evaluated 100% fixed OZil and 70% OZil/30% longitudinal settings using either 2.8-mm or 2.2-mm incisions on human cadaver eyes. Gross, histopathologic, OCT, and SEM examination demonstrated no noticeable differences in corneal wound architecture or integrity in the four groups. When compared to the longitudinal phaco results, neither torsional nor the mixed torsional/longitudinal settings induced any additional adverse effects to these incisions.
Putting all the pieces together At this ASCRS meeting [4], we presented a clinical study comparing various intra-op and clinical parameters during torsional phacoemulsification. Using the INFINITI system and the OZil Torsional handpiece through a 2.8-mm incision in right eyes and a 2.2-mm incision in left eyes, we performed phacoemulsification using only 100% torsional in 30 patients with bilaterally similar cataracts. In the 2.8-mm incision eyes, we used a 0.9-mm tapered Kelman tip with a 30-degree bevel, and in the 2.2-mm incision eyes, we used a 0.9-mm miniflared Kelman tip with a 45degree bevel. We chose these tips to maximize the fluidic performance for the corresponding incision sizes. We analyzed accumulated ultrasound energy usage, BSS usage, change in central corneal thickness (one day postop), and change in endothelial cell count (six months post-op). The two parameters that showed a statistically significant difference between the two groups were: 1) the amount of energy used (cumulative dissipat-
ed energy or CDE), which was found to be higher in the 2.8-mm incision eyes, and 2) change in endothelial cell count, which also showed a higher percentage loss in the larger 2.8-mm incision eyes. We concluded that 2.2-mm micro-coaxial phacoemulsification with continuous torsional ultrasound and the 45-degree bevel mini-flared tip was as safe and effective as standard coaxial techniques, but may also provide more favorable clinical and intraop characteristics that may benefit patients post-op. In my opinion, surgeons have now been given a fully integrated phacoemulsification system to perform micro-incision cataract surgery that will inevitably improve patient outcomes as a result. Terry Kim, M.D., is associate professor of ophthalmology, Duke University School of Medicine, Cornea and Refractive Surgery, Duke University Eye Center, Durham, N.C. References: 1 Masket S. Coaxial 2.2-mm microphaco technique reduces surgically induced astigmatism in study. Ophthalmology Times. 2006;31:41-2. 2 Berdahl JP, DeStafeno JJ, Kim T. Corneal wound architecture and integrity after phacoemulsification evaluation of coaxial, microincision coaxial, and microincision bimanual techniques. J Cataract Refract Surg. 2007;33:510-515. 3 Jun B, Berdahl JP, Kuo AN, Cummings TJ, Kim T. Corneal wound architecture and integrity after OZil and mixed phacoemulsification: evaluation of standard and microincisional coaxial techniques. Poster presented at: The Annual Meeting of the ASCRS, April 2007; Chicago, IL. 4 Berdahl JP, Jun B, DeStafeno JJ, Kim T. Intraoperative and clinical comparison of the OZil torsional handpiece through microincisional and standard clear corneal cataract wounds. Paper presented at: The Annual Meeting of the ASCRS, April 7, 2008; Chicago, IL.
We’ve been implanting premium lenses since December 2003. The single most important thing we’ve found with patients who invest in premium lenses is that they all want to be able to read without glasses. They brag to their friends and family about it. We have found that only the ReSTOR implant consistently provides this ability. The ReSTOR is an apodized diffractive lens. When using it, there are only two caveats that have to be discussed pre-op – rings and reading distance. Multifocal IOLs are pupil-dependent and the patients who complain about rings around lights are those with small scotopic pupils. Because the ReSTOR has an outer refractive distance zone, those patients with larger pupils don’t seem to complain as much about rings and halos. More importantly, with the ReSTOR, you’re giving them an effective +3 D add. So they’re reading at 12 to 13 inches, but they’ve been used to moving things down to their lap as they became more presbyopic. We tell our patients that they will have to “act younger” and start holding things closer! For those who require acute intermediate vision (using a computer, playing bridge, or looking at a musical score), we suggest an OTC +1.50 pair of readers; most do not need them after several months.
Aspheric ReSTOR We conducted a prospective Phase IV study on 25 patients implanted bilaterally with the ReSTOR aspheric and compared them to patients implanted with the regular ReSTOR. We had a lot of exclusionary criteria – no significant astigmatism, presumed BCVA was good, no planned LRIs, etc. Among other things, we looked at LogMAR at one and three months, monocularly and
binocularly. At month one, monocular LogMAR was 0.02. At three months, monocular vision was 0.01. There was an additive effect with binocular vision – most patients saw 20/15 at month one and –0.09 LogMAR by month three. We also did aberrometry on the patients using a 3.5-mm and 5-mm pupil aperture. With both the regular and aspheric ReSTOR at 3.5 mm, there was 0.01 microns – no appreciable difference or benefit. But SA is NOT a function of photopic vision or a small pupil – it comes into play with an enlarged pupil, in mesopic or scotopic conditions. When we looked at the 5-mm pupil, SA increased to 0.15 with the regular ReSTOR, but was only 0.06 with the ReSTOR aspheric lens. That translates directly into results. At post-op day one, only 6% of the regular ReSTOR patients saw 20/20; 43% of the aspheric ReSTOR saw 20/20, with 85% of the aspheric eyes seeing 20/30. By day 90, 100% of the aspheric eyes were 20/30 or better. Right now, we’re using 100% aspheric ReSTOR. It’s been a huge step forward in design, and we now have reached a critical mass where potential patients are coming in to the office asking for this lens by name. Satish Modi, M.D., is assistant clinical professor of ophthalmology, Albert Einstein College of Medicine, Bronx, N.Y., and is in private practice at Seeta Eye Centers, Poughkeepsie and Fishkill, N.Y. References 1. Levy Y, Segal O, Avni I, Zadok D. Ocular higher-order aberrations in eyes with supernormal vision. Am J Ophthalmol. 2005;139:225-8. 2. Legras S, Chateau N, Charman WN. Assessment of just-noticable differences for refractive errors and spherical aberration using visual simulation. Optom Vis Sci. 2004;81:718-28.
The role of fluidics– from page 5 weak zonules, a posterior capsule rupture, or floppy iris syndrome, torsional ultrasound allows us to adjust the fluidics parameters to maintain low pressure fluctuations and reduce turbulence. Another advantage to lower fluidic settings is that a dispersive viscoelastic is not aspirated and may further protect the delicate intraocular structures during complicated cases.
Ideal incision size In my opinion, micro-incision cataract surgery should be guided by the ideal incision size through which the IOL of your choice can be injected.
For AcrySof (Alcon) single piece lenses, the new Monarch (Alcon) D cartridge allows easy and reproducible injection through 2.2mm incisions without any significant wound stretch. I believe one of the biggest hurdles we as surgeons had to overcome when switching to micro-coaxial phacoemulsification in the past was the learning curve of the IOL injection with the C cartridge. Because that cartridge was designed for in-the-bag insertion through a larger incision than we are currently using, initial attempts at the 2.2-mm incisions may have resulted in failed IOL injections.
I currently recommend my fellow surgeons who want to reduce their induced astigmatism to switch to the following microcoaxial procedure: 2.2 HP2 ClearCut INTREPID knife (Alcon), 0.9 Ultra sleeve, 45-degree Kelman mini-flared tip, INTREPID FMS with continuous OZil amplitude and moderate fluidics settings. The mini-flared Kelman tip has been specifically designed for micro-coaxial phaco procedures. It has a thin shaft that allows more irrigation flow into the eye, compared to other micro-tips and tapered tips. The efficiency of the 45-degree bevel enhances emulsification, ensuring that the anterior
chamber remains extremely stable. Our cataract group has expressed a growing interest in multifocal and toric IOLs. Astigmatism management has therefore become a major focus to develop a successful refractive cataract surgery practice. The INTREPID Micro-Coaxial System with OZil Torsional and the D cartridge has very quickly become our preferred procedure. Khiun F. Tjia, M.D., is an anterior segment specialist at the Isala Clinics, Zwolle, The Netherlands.
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