EyeWorld Asia-Pacific March 2011 Issue

March 2011 13 EW FEATURE delivers high-resolution images from basically the top of the cornea to the posterior capsule,” Dr. Fishkind said. “Nobody else does that.” The images developed by the system are 3D. “It literally three-dimensionally delineates the structures that are going to be treated—the lens, the capsule, and the cornea and then it models them,” Dr. Fishkind said. “In that model it then gives you an image that has very high-resolution and is confocal.” He stresses that the image is in real-time with low signal to noise. “If you’re trying to treat things with micron accuracy you can’t have noise that disrupts the image so that image isn’t perfect,” he said. He points out that both LenSx and Optimedica use an OCT approach instead. “The issue with OCT is that it scans really well in a very narrow band,” Dr. Fishkind said. “So, for OCT we all know that you can scan the cornea and the iris but that’s about it. If you want to scan the iris to the capsule or the capsule to the bag you have to reset the scan.” As a result, he points out that neither the LenSx nor the Optimedica offers real-time images, which Dr. Fishkind feels translates into less accuracy. With the LensAR system, the docking system is brought down to the patient’s eye and a low-degree of suction is used to stabilize the device. After the fluid interface is filled the laser goes through a series of steps to create a model of the eye. A predetermined algorithm for segmenting the lens is loaded. Typically this is pie-shaped segments but that can be overridden. Then the surgeon programs in the capsulorhexis and centers this over the central visual axis, which has been determined by analyzing the corneal curvature and macular red reflex. “Now the capsulorhexis is centered where you want it, on the one thing that you can never find: the visual axis,” Dr. Fishkind said. “So, that’s a big plus right there.” The surgeon can then tell the laser what type of incisions they want and where to place these as well as the paracentesis. If the patient has residual cylinder after IOL implantation, any necessary limbal relaxing incisions can be carved. The cataract itself can then be treated by the laser. “It doesn’t care whether the cataract is 4+, 5+, 3+, or 2+; it will treat it,” Dr. Fishkind said. “That’s another differential between LensAR and all of the others—I have not yet seen a paper where they are showing hard lens treatment.” Once the lens is segmented, the capsulorhexis, paracentesis, and incisions made by the laser, three dots are created to indicate where the lens should be placed. Then the patient is ready for surgery. “There is really no incision until the incision is opened,” Dr. Fishkind said. The surgeon then sits down to open the incision and go about removing the already segmented nucleus. They can use whatever kind of phaco procedure they would like. “With a soft nucleus you can just go in with an irrigation and aspiration tip and you scrape over the fragments and they pop out and you suck them up,” Dr. Fishkind said. After the nucleus is out and all the incisions are made, the lens is centered on the rhexis. “This is accurate to 1/100th of a micron and is now centered on the visual axis,” Dr. Fishkind said. The surgeon then removes the viscoelastic and finishes up the case. So far, Dr. Fishkind has found results with the laser to be very promising. When he recently looked at 110 cases, he found that in grade one cataracts there was a 93% reduction in CDE (cumulative dispersed energy), in grade 2 a 95% reduction, in grade 3 a 73% reduction, and in grade 4 a 40% reduction. Currently, the LensAR only has 510K approval for capsulorhexis creation but Dr. Fishkind is hopeful that the rest will soon follow. Emerging Technolas technology The fourth femtosecond cataract system, the Technolas workstation 520F, centers on an existing femtosecond laser system, which has already been on the market for several years, according to Frieder Loesel, PhD, chief strategy officer, Technolas Perfect Vision GmbH, Heidelberg, Germany. “I think that the key difference or uniqueness of our system is that we have taken the refractive workstation and expanded it [for use] in the lens by basically adding image-guided technology,” he said. “We’ve also added an in-line OCT device, which allows for basically live OCT imaging for guiding the beam, for planning the surgery, and also for tracking the procedure as it happens during the various steps of the laser cataract procedure.” For the cataract procedure, dubbed CUSTOMLENS, the femtosecond laser source has also been ramped up. However, the beam path remains the same. “We’re using the proven beam path of the Technolas workstation and have expanded its range from already going deep in the anterior chamber,” Dr. Loesel said. “We were able to go down into the anterior chamber already but now we’ve expanded it with some upgrades in the optics to go down to the end basically of the lens.” The same area from the endothelium of the cornea to the posterior surface of the capsule base is covered by the system’s in-line live OCT. Dr. Loesel sees the ability to do live OCT as a distinguishing feature. “We have the capability of really doing a live view of the OCT during the surgery and I can only guess from videos which I have seen from competing devices and some appear to stop their imaging during the procedure,” he said. Dr. Loesel sees live imaging as quite helpful since it enables the surgeon to track the process. Also, like the LenSx laser, the Technolas Perfect Vision system uses a curved interface, something it has been doing with its work station from the beginning. “The cornea is gently adapted in an anatomically correct way to the curvature of the applanation interface,” Dr. Loesel said. Having this already in place on workstations has enabled the company to quickly adapt to cataract removal where it is important to distinguish specific anatomical parts within the anterior chamber. Dr. Loesel also sees the fact that the new femtosecond cataract system is part of an already functioning workstation as another distinguishing factor. “Besides the cataract procedure we can also do the flap, we can do the unique INTRACOR procedure for intrastromal presbyopia correction, and we can do what we call the CUSTOMSHAPE class of procedures, which include various kind of corneal transplant cuts or tunnel cuts for intracorneal rings,” Dr. Loesel said. In addition, the workstation can also make astigmatic relaxing incisions. For the cataract procedure the Technolas system works from the posterior to the anterior of the eye, beginning first with lens fragmentation. It then moves to the anterior capsulotomy and then on to the primary and secondary incisions. If desired, the surgeon can also perform a limbal relaxing incision or an astigmatic keratotomy. “We have the unique position of having a cataract and refractive laser, so you could also consider combining in the same session the cataract procedure and also a refractive treatment,” Dr. Loesel said. Surgeons could cut a flap in the cornea for a bioptics approach or might pair cataract surgery with the INTRACOR procedure. “Having this combination of possibilities is at the moment just [touching] the tip of the iceberg,” Dr. Loesel said. So far 20 patients have been treated with the CUSTOMLENS procedure, but because the larger system has already been in use Dr. Loesel does not think that it will be long before this is available. “We are pretty confident that we will be able to roll this out with the global availability next year pretty swiftly,” he said. Overall, Dr. Loesel sees the fact that there is good competition in the femtosecond cataract field as a plus here. “Competition is always good for driving a field and bringing additional tools and thus advantages to the modern surgeon,” he said. “We believe that this field will develop very quickly.” EW Editors’ note: Dr. Slade has financial interests with Alcon (Fort Worth, Texas, USA/Hünenberg, Switzerland). Mr. Raetzman is area president in the United States and vice president of global marketing at Alcon. Mr. Forchette is president and CEO of Optimedica (Santa Clara, Calif., USA). Dr. Fishkind has financial interests with LensAR (Winter Park, Fla., USA). Dr. Loesel is chief strategy officer at Technolas Perfect Vision GmbH (Heidelberg, Germany). Contact information Fishkind: wfishkind@earthlink.net Forchette: mforchette@optimedica.com Loesel: f.loesel@technolaspv.com Raetzman: Melissa.Mota@AlconLabs.com Slade: sgs@visiontexas.com