Choice of phaco technologies depends on fluidics, control

Economic considerations also affect a surgeon’s selection of a phaco system.

Recent years have seen the introduction of several new phaco technologies, as well as wholesale upgrades to existing phaco systems. Burst mode ultrasound, improved fluidics and new non-ultrasound modalities are among the options now available to surgeons striving for reduction in thermal energy and for the best possible control of the intraoperative environment.

Understanding the new phaco technologies is important, but it can be difficult for surgeons to distinguish among all the options now offered: Which are truly advances and which are techno-hype?

For this article, Ocular Surgery News spoke to surgeons from across Europe and the Asia-Pacific region to learn what they require in a phaco system and where they have found it most reliably. Recurring themes in the interviews were the surgeons’ desires for excellent fluidics and for phaco systems that are potentially adaptable to a microincision technique.

The B&L Millennium System

After using a variety of phaco systems, Graham Barrett, FRACS, FRACO, switched to the Bausch & Lomb Millennium Phaco System 6 years ago. He said he became interested in it because it combines a venturi pump with simultaneous dual linear control of ultrasound and aspiration.

“I felt that the system offered the potential for improved efficiency and control,” he said. “A venturi system is more responsive than a peristaltic system and therefore more suitable for surgeon control in a dual linear system.

“This indeed has proved to be the case and remains the major reason why I still use the Millennium and believe it remains the state of the art in phaco systems today,” he said.

Dr. Barrett said the Millennium technology has focused on improved fluidics, featuring accessories such as the Micro-Flow phaco needle, which he said reduces the likelihood of incision burns while allowing use of a fully sealed 2.6-mm incision.

“The needle, combined with the 28 kHz handpiece, is powerful and efficient, capable of dealing with extremely hard nuclei using relatively low power settings,” he said. “To me, the most important features of a phaco system are optimized fluidics and control. The Millennium phaco system in my mind meets these requirements.”

The ability to control vacuum is also helpful when using the phaco axe technique, Dr. Barrett’s preferred surgical technique, which is similar to a quick-chop.

Vacuum levels required for embedding the phaco tip and cracking the nucleus are different from that needed for removing fragments. However, with the Millennium system and Micro-Flow needle, Dr. Barrett said he can use the same settings throughout surgery — 70 mm Hg to 140 mm Hg — controlled in a linear fashion.

“Personally, the need to be able to control vacuum in a linear fashion is no different than the need to control ultrasonic energy in a linear fashion for optimum outcomes in phacoemulsification,” he said.

The software controlling the ultrasound on the Millennium system has pulse and burst mode phaco options. But Dr. Barrett said this is not too important to him because the Micro-Flow needle has allowed so-called “cold” phaco for several years.

“My personal experience is that pulse may be helpful in extremely hard nuclei. But generally, the intermittent nature of the application of ultrasound in both pulse and burst is somewhat less efficient and, in my hands, slows down the removal of material to some extent,” he said.

The interrupted nature of burst and pulse mode phaco also alters the aspiration rate, which can be helpful in reducing rapid occlusion break, although the characteristic is more problematic with peristaltic-type pumps, he said.

“Most surgeons accept that venturi systems provide more control and are more efficient in cortical removal during irrigation and aspiration. The same characteristics are available to surgeons during removal of the nucleus by using dual linear control of ultrasound and vacuum,” he said.

In addition to the good fluidics of the Millennium system, Dr. Barrett said the system is modular, allowing upgrades to be added, such as the Concentrix pump and enhanced vitrectomy modules.

“The economics of having a single multi-user machine for anterior and posterior segment surgeons is extremely attractive. … Similarly, the availability of the Concentrix pump, which can operate in a flow-priority manner similar to a peristaltic system, is helpful in an environment catering to different surgeons,” he said.

Alcon Legacy

Khiun Tjia, MD, an ophthalmologist in Zwolle, Netherlands, said he switched to Alcon’s Legacy phaco system in 1993 because, at the time, it was the only completely upgradable system.

He said he has stayed with the Legacy because of the latest upgrade to the system, the AdvanTec, a digital ultrasound driver providing more efficient use of ultrasound.

“Not only [is it] more efficient, [but also] more precise, more predictable and more reliable, meaning low power is true low power, which comes in useful … because you do not lose contact with the nuclear material,” he said.

He explained that a phaco system’s holding force is dependent on the attractive forces of vacuum and aspiration as well as repelling forces, mainly the result of ultrasound.

“If you can control these repelling forces accurately, that is a useful tool for this kind of efficiency, not only on the low end, but also on the high end, during sculpting,” he said.

When using a divide-and-conquer surgical technique, Dr. Tjia said, the Legacy Advantec produces a true stroke linearity from 0% to 100% power in contrast with previous ultrasound drivers or other systems.

“That means I can really attack a nucleus of any kind of hardness up to dark brown or black, of which I was not confident using older systems. The AdvanTec ultrasound driver … makes a clear difference,” he said.

Dr. Tjia said grooving with harder nuclei is normally avoided because there is no aspiration flow during occlusion. This increases the risk of thermal injury, particularly when a lot of energy is being continuously used.

“Using pre-occlusion mode, when it senses near occlusion, the Legacy will start pulsing. Pulsing during grooving is already one way to avoid excessive heating, but by doing continuous with pre-occlusion mode, you have the best of both worlds because you can have the most efficient, effective high-power settings,” he said.

“Where I had to do normal, medium-hard cataracts, I had to do five or six passes each down to the floor of a groove, I now need three, two and sometimes just once because you can go in all the way like in a phaco chop,” he said.

During grooving, Dr. Tjia uses a microflared Kelman 45° tip with 50 mm Hg vacuum pressure and 15 mL/min flow. During quadrant removal, 425 mm Hg vacuum and 50 mL/min flow is used with maximum power of 30% to 40%. With 40% power, even the hardest nuclei will be emulsified in a very controlled manner, he said And according to Dr. Richard Mackool, the wound temperature with sleeve compression will not exceed 100° F, which is significantly lower than other systems, Dr. Tjia said.

“Unlike other systems, that is enough to emulsify any kind of nucleus. … In older systems, with harder cataracts, the delivered energy was not always what you asked for. With the digital ultrasound driver it, you get what you want, which has made a tremendous difference in ultrasound control,” he said.

Alcon Infiniti

In terms of ultrasound and settings, Alcon’s latest system, the Infiniti Vision System, has many differences from its predecessor, particularly in respect to fluidics, according to one experienced user.

Richard Packard, MD, an ophthalmologist in Berkshire, England, and a clinical investigator for numerous phaco systems, said the Legacy vacuum has been exceeded by the Infiniti by more than 50%. Also, although the ultrasound driver is the same, power modulation capabilities are more extensive on the newer unit.

Dr. Packard said he had performed about 25 cases using a prototype of the Infiniti system, which the company made available to its clinical investigators. He is anticipating the device’s return to his practice for further evaluation.

He said the system has a micropulse option similar to the WhiteStar on Advanced Medical Optics’ Sovereign phaco system. Short, spaced bursts of ultrasound energy and rest, which can also be adjusted by the surgeon, provide efficient nuclear breakup without excessively heating the tip. The phaco power can be adjusted in this micropulse mode in a linear manner similar to conventional phaco, he said.

“It means that because you are inducing only minimal tip heat increases, you can use this system safely for bimanual microincision phaco,” he said.

Dr. Packard stressed that the Infiniti is not an upgrade to the Legacy. Rather, it is a completely different phaco machine. The pump mechanism has had all of the compressible tubing removed, which eliminated almost all of the compressibility, he said.

“When you get an occlusion break, you do not get surge. That’s because of the tubing … and because of the cartridge, which is totally rigid so nothing can collapse inside of it,” he said.

As there is almost no buildup of energy in the system, Dr. Packard said much higher vacuum levels and flow can be used, although the rates are somewhat dependent on the tip being used by the surgeon. The 19-gauge tip would use lower, flatter vacuum than the 21-gauge microtip, although up to 600 or 700 mm Hg can be safely used, he said.

“The first time I used this machine in the lab … we really cranked it up. It was extraordinary to see how stable the chambers were,” Dr. Packard said. “Of course, what it also means is that everything happens very quickly. Although the chamber is stable, you may not want to use those settings.

“But, it does mean that whatever settings you do use, whatever settings a surgeon chooses to use, what they do will be dramatically safer and more consistent,” he said.

Dr. Packard said the Infiniti also has a feature, called AquaLase, that can break up a nucleus using pulsed water jets. He said AquaLase is effective for soft to medium cataracts, but does not work as well as ultrasound for harder cataracts.

“As we move towards an era where there will be more refractive lens exchanges, using a system like this, where it makes it almost impossible to break the posterior capsule, gives you an added level of safety in combination with the great fluidics,” he said.

Dr. Packard said the Infiniti also features a “power wash” mode, allowing the AquaLase tip to be maneuvered right up to the capsule to clean the capsule, a feature he said could be particularly useful for bimanual phaco.

OS3 system by Oertli

For some surgeons, a company’s commitment to its products can be a deciding factor in their choice of a phaco system. Detlev R.H. Breyer, MD, an ophthalmologist in Düsseldorf, Germany, has been using Oertli’s OS3 phaco system for about 2 years.

He began using it after touring Oertli’s manufacturing facilities in Switzerland, an opportunity afforded to him because he is a former student and now a faculty member of the Ophthalmosurgical Winter Academy in Schruns.

“It was an impressing experience to watch the perfectionism and enthusiasm for quality of the employees. … I haven’t been disappointed by their products,” he said.

Dr. Breyer, who also performs vitreoretinal surgery, was further impressed by the company’s vitreous cutter and single-use instruments.

Regarding the OS3, he said the variability of the machine and control afforded by its foot pedal, as well as the ergonomics of its titanium handpieces, are reasons he prefers this system over others. He noted that the six piezo crystals contained in each phaco handpiece, the cool phaco mode, easy handling and system reliability are additional aspects he feels are important for a system to provide.

“I now routinely use the cool phaco mode and the powerful venturi pump,” Dr. Breyer said. “I start with a divide-and-conquer technique for the first split of the nucleus to create space in the capsular bag and then change to stop-and-chop to continue.

“I’m the only surgeon [in my practice], but by using various settings with different nuclear sclerosis settings and by developing bimanual cool microincision phaco, I of course have to use the multi-modal memory settings, which I can easily change using my foot pedal,” he said.

IOLTECH Pentasys

Carlos Verges, MD, PhD, an ophthalmologist in Barcelona, used the Sovereign phaco system with WhiteStar technology for more than 1 year. But he began using IOLTECH’s Pentasys phaco system within the past year, mainly because the system incorporates both peristaltic and venturi pumps.

“I am still using this combination, but after having changed some of the parameters to further improve the fluidic system,” he said.

He said he needs equipment that can provide the requisite software and fluidics for his current microincision surgery technique. Additionally, he requires an efficient vitrectomy system with cutting speeds above 800 cuts/min. The Pentasys allows 2,500 cuts/min.

Dr. Verges said he also prefers ultrasound phaco to sonic phaco because ultrasound provides the cavitation effect needed for improved phaco effectiveness.

“Also, new micropulsed software reduces the mass-rejection effect, allowing lower flow and vacuum parameters. The final outcome is a reduction in hydrodynamic trauma and an overall improvement in the surgical treatment,” he said.

Dr. Verges has been using a bimanual, microincision surgical technique with a quick-chop cracking procedure for all of his surgical cases for over a year. His routine depends on his own customized instruments manufactured by Rhein Medical and E Janach. For his surgical routine, he said the provision of two pumps — peristaltic and venturi — to use simultaneously during surgery is critical.

“During surgery, while I’m using the peristaltic pump, intraocular pressure values can be adjusted using the IOP module,” he said. “This way I can program my settings with 24 mL/min flow and 225 mm Hg vacuum, adjusted to a chopper that irrigates 55 mL/min. With these parameters I can perform a safe, efficient surgical technique adaptable to all types of cataracts,” he said.

Another advantage, Dr. Verges noted, is the ability to adjust fluidics parameters on the peristaltic pump based on surgical requirements, while the pressure control directly upon the aspiration line allows more rapid surge compensation.

The micropulsed ultrasound has additional advantages, he said. There is reduced heating of the phaco tip, while there is no rejection effect, which keeps lens fragments at the tip. This also allows reduced vacuum and the use of 21- and 22-gauge needle tips, he said.

Dr. Verges said a study conducted at his clinic measuring temperature increases at the tip showed the Pentasys system produced a temperature increase of only 2° C, while conventional ultrasound produced an increase of 8° C.

The system provides efficient diathermy, and surgical parameters can be customized to meet the needs of different surgeons, he said. In cases of capsular rupture, a strong optic fiber allows identification of remaining vitreous or identification of the sulcus through retroillumination, which is useful when stitching a lens to the sulcus, he said.

AMO Sovereign with WhiteStar

Alessandro Franchini, MD, has been using the Sovereign phaco system with WhiteStar technology for more than 2 years in his Florence, Italy, practice. Initially, he worked with a prototype system that allowed switching phaco-on and phaco-off time as desired to identify the best standard parameters for various techniques and cataracts of various nuclear hardness. He now uses the standard commercially available system.

Dr. Franchini said he has been interested in small-incision cataract surgery for more than 10 years. He began working with an Er:YAG laser for cataract extraction in 1993, and in 1994 he developed his first bimanual technique.

He said it is necessary to reconsider the cataract extraction process and adapt it to working through the narrower incision, performing all phases of the operation through watertight incisions.

“In my opinion, the fundamental point is to avoid the presence of outflow in all phases of the operation [because it] may create dangerous anterior chamber collapse,” he said.

This has led to the development of new surgical instruments, such as blades to make the 1-mm trapezoidal tunnel, appropriate capsulorrhexis forceps, irrigating choppers and irrigating and aspirating cannulae, all of the same diameter.

“For this reason, I think that we still have to define what is the best technique to use in the bimanual technique,” he said.

Dr. Franchini said that one of the most important aspects a phaco system should have to be useful in performing a microincision cataract extraction is the ability to produce low increases in temperature at the tip compared to standard ultrasound. This makes it possible to work without the phaco sleeve covering the tip while maintaining two watertight incisions.

WhiteStar produces rapid bursts of ultrasonic energy between rest periods, which allow the tip to cool and eliminate the need for outflow from the anterior chamber. In standard pulsed phaco, the rest time is not sufficient to adequately cool the tip, leading to a progressive increase in temperature.

Dr. Franchini confirmed the low temperature increase of the WhiteStar in a study he performed. The study was done in vitro in a closed chamber of 2.5 cc of water using standard conditions of use.

In the study, the WhiteStar and an Er:YAG laser produced a similar temperature increase of around 2° to 3° C after 30 seconds, maintaining the temperature under 42° C. He said this is important because the first corneal changes causing wound burns occur at approximately 45° C.

“This is the first machine with which it is possible to reach what has been the dream of all ophthalmologists working in anterior chamber surgery: to perform the operation through a 1-mm incision in patients with every kind of nuclear hardness in the same amount of time as using standard ultrasound,” he said.

Regardless of the parameters and techniques used, Dr. Franchini said that when using the WhiteStar, the effective phaco time is five times less than using a standard pulsed phaco. Despite this, there has not been a decrease in the efficiency of the machine, he said.

“In fact, the use of only transient cavitation (the most efficient part of the cavitation energy), the decrease of the turbulence in the anterior chamber and the improvement in holdability and followability guarantees an efficiency similar to the efficiency guaranteed by a standard phaco machine,” he said.

“We have a significant improvement in corneal clarity on the first postoperative day and a significant decrease in the corneal stromal thickening the day after surgery.

“Furthermore we have a decrease in endothelial cell density loss that is above all linked to the decreased number of particle impacts generated by the decreased chatter in anterior chamber,” he said.

Mediphacos Regency 2020

For some surgeons, a system’s reliability and capabilities must also come with a cost-effective price.

Eduardo França, MD, an ophthalmologist in Belo Horizonte, Brazil, has been using the Regency 2020 phaco system since 1997. He noted that the system’s cost, use of autoclavable tubing and portability contributed to his decision, and he still uses the machine today because of those factors. However, he originally selected the system because of the stability its Anterior Chamber Anti-Surge System provides.

“A good phacoemulsification machine must maintain good chamber stability, even in high vacuum and flow parameters,” he said, noting the lightweight handpiece, control of ultrasound delivery during surgery and reliable costs remain important as well. “These requirements are almost fulfilled with the Regency 2020.”

For routine cataract surgery, Dr. França said he prefers to use a quick chop or vertical chop technique with low ultrasound, high vacuum and a high flow rate. Depending on nuclear density, only minimal changes in the technique are required.

“The use of microtips provided by the Regency 2020 allow me use of high vacuum and flow levels, which are important in my current surgical technique. I use pulse mode to impale the nucleus before chopping it,” he said.

Dr. França noted that the Regency is a quality portable system that is easy to transport, eliminating the need to purchase additional systems.

“I can travel to other cities and use just one machine in several surgical centers,” he said. “Working in a developing country, we must always focus on surgical costs without losing quality.”

Appasamy Galaxy systems

For K. Premraj, MS, DO, an ophthalmologist in practice in Tamil Nadu, India, cost effectiveness is also a concern.

Dr. Premraj began performing phacoemulsification in 1993 using a 3M phaco machine. Currently, he operates at four hospital sites, each requiring a separate unit. In 1999, he switched to a Bausch & Lomb Millennium system and then bought a Mentor Phaco System in 2000.

About 2 years ago, he bought two Appasamy phaco systems — the Galaxy 1 and the Galaxy 2 — to fill the need for phaco systems in the two remaining hospital sites.

The Galaxy 1 system combines a peristaltic pump with effective phaco energy capable of pulsing between 1 and 8 pulses/sec. It is capable of vacuum levels of 5 to 500 mm Hg and aspiration of 1 to 40 cc/min during both phacoemulsification and vitrectomy. The vitrectomy feature is capable of up to 900 cuts/min.

The Galaxy 2 system combines a venturi pump with phaco capable of 1 to 8 pulses/sec. It is also capable of vacuum levels of up to 350 mm Hg for both phacoemulsification and vitrectomy, which is also capable of up to 900 cuts/min.

Dr. Premraj said he bought the two Appasamy systems mainly because they are cost-effective and reliable, filling the need for efficient delivery of phaco energy and good fluidics, the most important considerations in performing phacoemulsification, he said.

“Both Galaxies do well in both aspects. They are comparable to any high-end systems,” he said.

“If you want to compare them to the Millennium, [the Galaxy systems] do not have four crystal handpieces and the computer programmability has fewer features. But if you look at it from [the standpoint of] value for the money, it is excellent,” he said.

Dr. Premraj prefers using a quick-chop or a stop-and-chop surgical technique. The two Galaxy systems have good followability and effective burst mode capabilities for handling hard cataracts, he said.

Also, because he operates at several sites in multisurgeon practice settings, he selected the Galaxy systems because of their multisurgeon programming features.

Pulsar Minimal Stress

Roland Seufert, MD, an ophthalmologist in practice in Bergisch Gladbach, Germany, began working with the Pulsar Minimal Stress system 6 years ago, after a local Optikon dealer introduced him to it. He said he was immediately impressed with the anterior chamber stability the Pulsar provided, producing no surge even when he used aggressive parameters such as 500 mm Hg of vacuum with 50 cc/min of flow.

“The Pulsar is a flexible system for standard procedures as well as for modern techniques like bimanual phaco,” he said.

One aspect Dr. Seufert said he particularly likes about the Pulsar phaco system is its programmability, allowing extensive control using primarily the foot pedal.

“I don’t like preprogrammed systems,” he said. “I want to rule the phaco system, not be ruled by the system. I want a system I can rule with my footswitch. With its dual linear footswitch, the Pulsar in this point is perfect.”

For standard cataract cases, Dr. Seufert uses a surgical technique he said is similar to back-chopping. Using high vacuum, he takes hold of the lens and cracks it from behind. The fragments are then vacuumed out of the chamber.

“I initially need a high vacuum to grab the lens. With my dual linear footswitch, I don’t have to fear starting phaco too early because phaco is separately controlled in the second plane of the footswitch. That saves time and improves safety,” he said.

Vacuum levels of up to 500 mm Hg are controlled by the up-and-down movement of the pedal, he said. The side-to-side movement controls the phaco power.

The Pulsar system also incorporates features such as pulse mode ultrasound for preventing thermal injury.

However, Dr. Seufert said, the Minimal Stress system is the most important feature of the Pulsar. This allows control of the tip stroke to be maintained regardless of nuclear density or handpiece efficiency, he said.

“That means, the stroke of the phaco tip is absolutely controlled during the surgery, which means less energy is needed,” he said. “This is an advance you only can evaluate when you try it out. The Minimal Stress minimizes thermal effect in the incision. This is why the Pulsar was the first system used for bimanual phaco some 6 years ago.”

Editors’ note

Although numerous attempts were made to contact them for this article, Ocular Surgery News regrets that it was unable to contact surgeons using Corneal’s OPENphaco system, Paradigm Medical’s Photon Laser Phaco system and STAAR Surgical’s Sonic Wave phaco system.

For Your Information:

• Graham Barrett, FRACS, FRACO, can be reached at 2 Verdun St, Nedlands WA 6009, Australia; +(618) 93-810-872; fax: +(618) 93-821-171; e-mail: barrett@cyllene.uwa.edu.au.
• Khiun Tjia, MD, can be reached at Heerderweg 14, 8161 BM EPE, Zwolle, Netherlands; fax: +(31) 578-629-940; e-mail: k.tjia@isala.nl. Dr. Tjia has no direct financial interest in the products mentioned in this article.
• Richard B. Packard, MD, can be reached at 12 Clarence Rd, Windsor, Berkshire SL4 5AG, England; +(44) 1753-829204; fax: +(44) 1753-831185; e-mail: eyequack@vossnet.co.uk. Dr. Packard is a consultant for Alcon on the Infiniti Vision System.
• Detlev RH Breyer, MD, can be reached at Augenärzte, Gemeinschaftspraxis, Day Clinic am Hofgarten, Stresemannstrasse 7-9, D-40210 Düsseldorf, Germany; +(49) 211-601-5000; fax: +(49) 211-135-381; e-mail: detlev.breyer@web.de.
• Carlos Verges, MD, PhD, can be reached at the Departamento de Oftalmología, Institut Universitari Dexeus (UAB), Edifici Planetarium, C. Escoles Pies, 103, 0817 Barcelona, Spain; +(34) 93-254-54-20; e-mail: cverges@cverges.com. Dr. Verges has no direct financial interest in the products mentioned in this article.
• Alessandro Franchini, MD, can be reached at the Azienda Ospedaliera Careggi, Viale Pieraccinc, 17, 50139 Firenze, Italy; +(39) 55-42-77-550; fax: +(39) 55-42-22-679; e-mail: alessandrofranchini@yahoo.it. Dr. Franchini has no direct financial interest in the products mentioned in this article. He is a paid consultant for Advanced Medical Optics.
• Eduardo França, MD, can be reached at 737, Grao Para St, 2nd floor, Belo Horizonte MG, Brazil ZC 30150-341; fax: +(55) 31-3241-5454; e-mail: eduardo@coa.com.br. Dr. França has no direct financial interest in the products mentioned in this article.
• K. Premraj, MS, DO, can be reached at Prems Eye Hospital, 118 A, Bazaar Rd, Saidapet, Chennai - 600 015, Tamil Nadu, India; fax: +(91) 44-24-32-16-15; e-mail: premraj1952@hotmail.com.
• Roland Seufert, MD, can be reached at Dolmanstr. 10, Bergisch Gladbach, 51427, Germany; +(49) 2204-301480; fax: +(49) 2204-301529; e-mail: seufert@augen-zum-arzt.de. Dr. Seufert has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.

• Advanced Medical Optics, makers of WhiteStar Technology for the Sovereign System, can be reached at 1700 E St. Andrews Pl, Santa Ana, CA 92799; (800) 449-3060; fax: (866) 872-5635; Web site: www.amo-inc.com.
• Alcon, makers of the Legacy and Infiniti phaco systems, can be reached at 6201 South Freeway, Fort Worth, TX 76134; +(1) 817-293-0450; fax: +(1) 817-568-6142.
• Appasamy Associates, makers of the Galaxy 1 and Galaxy 2 phaco systems, can be reached at 20, SBI Officers’ Colony, First Street, Arumbakkam, Chennai - 600 106, Tamil Nadu, India; +(91) 44-2475-7363; fax: +(91) 44-2475-4721; Web site: www.appasamy.com.
• Bausch & Lomb, makers of the Millennium phaco system, can be reached at 1400 N Goodman St, Rochester, NY 14609; +(1) 585-338-5212; fax: +(1) 585-338-0898; Web site: www.bausch.com.
• IOLTECH, makers of the Pentasys phaco system, can be reached at Ave. Paul Langevin, BP5, 17053 La Rochelle, Cedex 9, France; +(33) 5-46-44-8550; fax: +(33) 5-46-44-8560; email: ioltech@ioltech.com.
• Mediphacos Ltda, manufacturer of the Regency 2020 phaco system, can be reached at Rua Mestre Luiz, 31, Belo Horizonte, MG, 30330-070, Brazil; (800) 31-1111; fax: +(31) 3225-8648; Web sites: www.mediphacos.com.br or www.ferrararing.com.
• Oertli Instrumente AG, makers of the OS3 phaco system, can be reached at CH-9442 Berneck, Switzerland; +(41) 71-747-4200; fax: +(41) 71-747-4290.
• Optikon SpA, maker of the Pulsar Minimal Stress system, can be reached at Via del Casale di Settebagni 13, 00138 Rome, Italy; +(39) 06-888-8355; fax: +(39) 06-888-8388; Web site: www.optikon.com.