Since the inception of phacoemulsification in the late 1960s, an evolutionary process has occurred in development of the technology. This has been driven by the need to make the operation safer and more predictable, but also by industry with the hope of inducing surgeons to buy newer phaco machines.
The journey began with nonlinear phaco and heavy nonautoclavable magnetorestrictive handpieces attached to collapsible silicone tubing and relatively crude pumps. Forty years later, we now have before us a dazzling array of new and enhanced phaco machines offering the possibility of better and safer surgery through increasingly smaller wounds.
This article looks at three modern machines with which the author is familiar in order to unravel the mysteries of what is on offer: the Infiniti Vision System (Alcon Laboratories, Inc., Fort Worth, Texas), the Stellaris Vision Enhancement System (Bausch & Lomb, Rochester, New York), and the WhiteStar Signature Phacoemulsification System (Advanced Medical Optics, Inc., Santa Ana, California). The question to be addressed is: Is it worthwhile to upgrade to the latest generation of phaco machine?
THE INFINITI
The Infiniti, introduced in 2004, has been around the longest of the three machines discussed here, and it already has an established position. Many innovative features, from its graphic user interface (GUI) to new power modulations and better fluidics control, set new industry standards. The Infiniti has continued as a platform for development since its introduction.
Although the concept of torsional phaco was originally described in Japan in 1969, it did not become commercially available until 2006 when Alcon introduced its Ozil technology on the Infiniti. The side-to-side movement of a curved phaco needle is claimed to be a more efficient way of removing nuclear material than traditional longitudinal phaco. Certainly in my experience there is little or no repulsion from the phaco tip and improved followability with lowered fluidics parameters. Ozil works well in both continuous and microburst mode.
Alcon has been pushing the idea of coaxial surgery through a 2.2-mm incision, and the company's Intrepid tubing was introduced on the phaco cassette to facilitate this procedure. The tubing is more rigid than the previous type, and it certainly makes for more stable chambers when smaller incisions are used with lower amounts of irrigation fluid entering the eye.
Alcon recommends the use of its new Ultrasleeve with a variety of tapered and flared phaco needles. In fact, the fluidics control with this tubing is such that this author uses a standard 30° non-ABS Kelman tip with the 2.2-mm incision.
Although it is not yet released commercially, there is also a Nanosleeve. With a mini-flared tip, the Nanosleeve has allowed surgery safely through a 1.8-mm incision (Figure 1). The 45° tip works best here, as it seems to minimize clogging by pieces of harder nucleus. The release of Alcon's D-cartridge for IOL insertion has meant that the wound does not need to be enlarged for lens delivery into the eye with either a 2.2- or 1.8-mm incision when combined with the Monarch III (Alcon Laboratories, Inc.) or Duckworth & Kent (Hertfordshire, England) injectors. Insertion through a 2.2-mm incision is straightforward, with no need to learn a wound-assisted insertion technique.
THE STELLARIS
Bausch & Lomb introduced the Stellaris last year as the successor to its well-established Millennium Microsurgical System. The main thrust behind the Stellaris is to provide a platform for either biaxial or coaxial microincision cataract surgery (MICS); however, a number of additional features will also assist all users.
A new touchscreen allows easy and faster setup compared with the Millennium. There are new cassettes for both vacuum- and flow-based pumps, and the Advanced Flow Module (Figure 2) allows the surgeon to change from a peristaltic to a Venturi approach in mid-case. A new footpedal with Bluetooth wireless technology has dual-linear control like its predecessor. This is probably more important when used with the Venturi pump to allow an extra measure of control.
The phaco handpiece is also new, with six piezoelectric crystals that are claimed to provide smoother power delivery. The tip excursion has been increased by 25%, meaning that power settings must be reduced in comparison with the Millennium. I found that it was not necessary to use more than 25% pulsed phaco power, and most of the time 16% was the maximum setting. Custom Control software to shape the wave of ultrasound pulses is now available in Version 2.
The connections for irrigation and aspiration lines now have a luer lock to prevent inadvertent disconnection during surgery. For coaxial MICS, a new tip married to a new thin sleeve has been introduced. The inner diameter of this needle is 0.5 mm, and thus high vacuum levels are essential to make it function efficiently, whichever pump is used. Despite my preference for Kelman-style needles, this tip seemed to work well for me with all types of cataract.
The Stellaris' EQ Fluidics Management Technology is said to more precisely control the balance of aspiration and irrigation. In practical terms, the chambers are extremely stable when using either the flow or vacuum systems with the new MICS tip. On the vacuum pump, the company recommends using its StableChamber tubing. This is a mechanism to introduce resistance to fluid outflow, incorporating a narrow section of rigid tubing with a mesh to prevent large pieces of nucleus from clogging it. In my hands, this seemed to slow down events when combined with the added resistance of the MICS tip. I found its use counterproductive.
The Stellaris works extremely well as both a biaxial and a coaxial MICS platform (Figure 3). The 20-gauge straight and Kelman tips have been used in combination with the author's irrigating chopper with both flow and vacuum cassettes, producing stable chambers.
To complement the MICS approach, Bausch & Lomb recently introduced the Akreos MI60 IOL. This hydrophilic lens can be implanted through a 1.8-mm incision using a disposable one-hand injector and a wound-assisted technique with countertraction. For those who prefer not to use this approach, the coaxial MICS sleeve and tip work well with a 2.2-mm incision and the same lens and insertion system.
THE SIGNATURE
Last year, Advanced Medical Optics launched the Signature as a successor to its Sovereign Phacoemulsification System, which had introduced the groundbreaking WhiteStar Technology phaco power modulation. All other phaco machine manufacturers have subsequently copied the use of micropulsing.
The GUI on the Signature is wholly new, with an easy-to-read screen and simple setup instructions that make this process much quicker than before. A new, one-step auto-loading cassette accompanies the Signature system. This cassette allows the surgeon to change from peristaltic to Venturi fluidics in mid-case.
The Chamber Stabilization Environment (CASE) control of fluidics was introduced on the Sovereign to minimize postocclusion surge while allowing the safe use of high vacuum levels and flow rates. The problem was that the time at maximum vacuum was only 500 milliseconds, which did not allow for chopping of hard cataracts and was generally less efficient than the previous occlusion mode. On the new machine, this problem has been addressed with a longer up-time allowed by Fusion Fluidics management. In a novel feature, the fluidics response to occlusion can be programmed dynamically by moving a cursor on the touchscreen. Thus, once surgeons become familiar with the machine, they can truly customize their settings.
To further customize settings, a Surgical Media Center is available (Figure 4). This is a dedicated laptop computer that takes feeds from the microscope's video camera and the phaco machine. It overlays the video not only with a display of the in-use phaco parameters but also a graphic timeline of machine performance. This means that the frame-by-frame response of the machine in relation to activity in the anterior chamber can be analyzed, which should prove useful for all surgeons across all levels of experience.
Although the handpiece for conventional phaco is unchanged, one with transverse tip movement has been introduced. The combination of lateral and longitudinal tip movement in the Ellips handpiece is supposed to eliminate tip clogging and reduce repulsion similarly to torsional phaco on the Infiniti. At the time of this writing, it was not yet available on the Signature machine to which I have access. (For more on the Ellips, see Transversal Phaco Offers Range of Safety Benefits)
The Increased Control and Efficiency (ICE) pulse-shaping technology on the Signature is the same as on the Sovereign. It is notable that with the Signature, there is a punch at the start of a pulse to enhance cutting. The pulse-shaping technology on the Stellaris does the opposite, starting lower and becoming stronger. In practice, I perceive little difference between the two approaches.
Used with the current yellow sleeve through a 2.2-mm incision, the Signature works well with little chamber fluctuation. As with the Sovereign, it is also a good machine for biaxial MICS (Figure 5). At present, Advanced Medical Optics does not have a lens that fits through a 2.2-mm incision, but there are plans for the new one-piece Tecnis to be injected through this size incision.
CONCLUSION
As surgeons, we are fortunate to have such a sparkling array of technology to enable us to operate more safely with better visual outcomes for our patients. Having used all three machines to a greater or lesser extent, there are certain features that stand out on each, which are listed in the Take-Home Message.
Richard B. Packard, MD, FRCS, FRCOphth, is in practice at The Prince Charles Eye Unit, King Edward VII Hospital, Windsor, Berkshire, England. He states that he is a consultant to Alcon Laboratories, Inc., on the Infiniti Vision System; to Bausch & Lomb on the Stellaris system; and to Advanced Medical Optics, Inc., on the Signature system, but he states that he has no financial interest in any products mentioned. Dr. Packard may be reached at +44 1753 860441; eyequack@vossnet.co.uk.
