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Innovations | Jan 2016

Entering a New World of Cataract Surgery

A novel approach offers increased reproducibility and improved workflow.

It seems that today there are two worlds of cataract surgery.

One world is limited by what is medically indicated and without alternatives. Here, the goal is to perform as many cataract procedures as possible within a given timeframe and budget. Optical rehabilitation is handed over to the optician or optometrist. The background for this world is that statutory health insurance reimbursement is continually dropping over time, while the number of patients with cataracts is increasing and will continue to increase in future, as the baby boomers are aging.

In the other world of cataract surgery, along with prioritizing the safety of the procedure, refractive correction increasingly targets spectacle-free visual function in both daytime and nighttime and at all distances. Each procedure is individually customized. In this world, no cost or effort is considered too high in order to achieve the best performance and meet the demands of the self-paying or privately insured patient.

A NEW TECHNOLOGY

My clinic implemented the Centurion Vision System (Alcon) into our cataract surgery practice in January 2015. In the past 12 months, this system has proven to me that it can be a worthwhile investment for clinicians and patients alike. Other manufacturers offer similar solutions, and some technology providers set up compatible arrangements of components from multiple manufacturers with the same goal of bringing refractive cataract surgery closer to perfection.

All elements of the Centurion Vision System, including the LuxOR Microscope, the Centurion phaco machine, the Verion Image Guided System, and the LenSx femtosecond laser, combine to improve the surgeon’s performance and outcomes. The system incorporates multiple integrated and logical innovations and, at the same time, closes the loop between diagnostics, surgical planning, perfomance, and postoperative quality control.

An image-guided approach. If a patient opts for a premium cataract treatment, this includes premium diagnostics, premium performance in the OR, and implantation of a premium IOL. The Verion Image Guided System is used to plan and navigate the procedure. The reference unit, which, in my setup, is positioned next to the IOLMaster (Carl Zeiss Meditec), measures the optical, visual, and geometric axes of the eye, the pupil margins and corneal radii, and a variety of landmarks on the limbus and iris for the eye tracking system (digital marker) that is optionally incorporated in the LuxOR microscope.

AT A GLANCE

• In refractive cataract surgery, priorities include safety, refractive correction targeting spectacle-free visual function in daytime and nighttime and at all distances, and a fully customized procedure for each patient.

• A premium cataract treatment should include premium diagnostics, premium performance in the operating room, and premium IOL implantation.

• New technological advances are making surgeons’ refractive cataract surgery goals easier to achieve.

Originally, I was reluctant to give up my preferred microscope; however, I found that it was not a problem to adopt the new microscope incorporating the Verion Digital Marker. The digital marker works like an eyetracker once it has recognized the landmarks identified by the reference unit. Thereafter, the system produced robust and reproducible results.

There is no need for ink marking, and this facilitates work flow significantly. Before we adopted the Verion system, every patient had to be marked with an inked toric marker prior to topical peribulbar anesthesia. In my practice, one out of four procedures includes either toric IOL implantation or astigmatic keratotomy. For each of these patients, I had to leave the OR to do the marking. Now, the data from the Verion Reference Unit are transferred wirelessly to the digital marker in the OR, and I simply have to bring up the patient’s ID in order to make the data available.

Coaxial alignment of the eye with the optical pathway of the microscope is a precondition for accurate digital marking. The system can be used to guide a manual capsulorrhexis with regard to size and position (centered on either visual axis or line of sight). Toric and multifocal toric IOLs can be easily centered. It is important to note, however, that significant conjunctival chemosis or bleeding can interfere with the eyetracker, and eye tilt can lead to false axis identification. In my experience, however, the system is reliable and consistent in 98 of 100 cases. I have been driving a car with a heads-up display for more than 5 years now, and I no longer would want to drive a car without it. Finally, I have a similar system in my OR. The digital marker in my microscope uses the Verion data in order to help me navigate with an integrated display.

The reference unit can be used for postoperative axis control of the toric IOL. This is useful for both documentation and fine-tuning of surgical nomograms, as it delivers objective data. This is how quality control works. The postoperative checkup closes the loop.

Femtosecond advantages. The LenSx laser can also be fed by and matched with the Verion data. The laser performs all the cutting portions of the cataract procedure, including creation of corneal incisions, arcuate incisions at the right positions, a capsulorrhexis centered on the optical or visual axis as customized by the surgeon, and nucleus fragmentation. All of this is done with robotic precision before the surgeon has even touched the eye with an instrument.

Two features of the femtosecond laser technology are without comparable alternatives: (1) the capsulorrhexis and (2) the arcuate incision. With the data from the reference unit, both the arcuate incisions and the capsulorrhexis can be centered and performed with robotic precision and reproducibility.

I do not use the laser for the corneal incisions, as I like to have a little bleeding of the perilimbal vessels to facilitate early sealing of the wound. The nucleus fragmentation is nice to have but is not of additional value, in my opinion; additionally, this feature can add risk because the gas bubbles can blow up the capsular bag and reduce visibility in the surgery field.

A phaco upgrade. Last but not least is the core element of the Centurion Vision System: the phaco machine. After all, regardless of whether the procedure is refractive or medically indicated, guided or laser-assisted, the lens must be emulsified by ultrasound and aspirated with an efficient I/A system. With the Centurion, fluidics are governed by a computer-guided injection system (Fluid Managment System [FMS]) that replaces the gravity-driven, high-IOP irrigation with sensor-controlled physiologic irrigation pressure. With conventional I/A systems, the bottle height is typically set at 100 cm H2O, corresponding to an IOP of 74 mm Hg. With the FMS, the surgeon has the choice to tell the system what level of IOP he or she is willing to tolerate for the patient’s eye.

Typically, I use an IOP of 30 mm Hg (corresponding to 40 cm H2O) for routine procedures. As a result, in my routine cataract procedures, I use only one-third of the fluid I would use with a conventional machine. Quite simply, less fluid equals less stress. One factor to note is that the machine uses most of the irrigation solution for its own calibration. The irrigation solution packages used by the FMS are specially designed and can be provided only by Alcon; however, it should be mentioned that the Verion phaco machine can also run with coneventional gravity-driven irrigation bottles.

With the combination of low pressure, sensor-controlled injection fluidics and the gentle power of the OZil balanced phaco tip, the anterior chamber remains stable at all times, with no surge and no bouncing of the cornea, iris, or capsule. Thus, the procedure remains under the surgeon’s control.

CONCLUSION

Regardless of whether cataract surgery is performed as though on an assembly line or with a customized target refraction of ±0.50 D, new technological advances are making surgeons’ refractive cataract surgery goals a reality. Innovations in cataract surgery will continue to have an impact on both worlds described at the outset of this article, and clinicians should be encouraged to consider exploring what kind of environment they want to operate in and precisely how they can get there.

Omid Kermani, MD
• CEO and Consultant in Cataract and Refractive Surgery, Augenklinik am Neumarkt, Küln, Germany
o.kermani@augenportal.de
• Financial disclosure: None

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