EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/153099
36 EW FEATURE February 2011 Diagnostic technologies for cataract surgery August 2013 Picture continued from page 34 steepest meridian is located. It also eliminates the necessity of preoperative diagnostics. "I think this approach may prove to be the key to achieving emetropia in the future," he said. iTrace snapshot Another system being used for preoperative registration is the iTrace. Dr. Yoo said that while the iTrace is a topography system that is not made for marking, it is a viable application of the device. "The iTrace gives topography that's overlaid on the photograph of the cornea and the limbus," Dr. Yoo said. "You can see some individual patient characteristics on the photograph with the patient's topography overlaid there." For example, she said, there may be some iris crypts or nevi that are particular to the patient's eye, or there may be some limbal vessels that you can see and use as markers. "The nice thing is because you can see them with the topography overlaid on top, you can mark the axis of astigmatism based on these anatomic landmarks," Dr. Yoo said. As Kevin L. Waltz, MD, partner, Eye Surgeons of Indiana, Indianapolis, explained it, the Zaldivar Caliper system on iTrace shows the practitioner either a black and white or LET'S TALK SOLUTIONS Accutome's AccuSharp™ Guarded Ophthalmic Knives ofer superior sharpness and safety at an afordable price. It provides sharps protection for you, your staf and your budget! Call today or use the QR Code to trial the AccuSharp Guarded Knives. color image of the eye and then superimposes the topography on top of that. "It puts marks on the same image so you have reference marks on the sclera or the iris to your IOL orientation," he said. It will also take into account surgically induced astigmatism on the screen. "It will show you where your astigmatism started and with your surgically induced astigmatism where it will end up," he said. There's a second system that can be used with the iTrace, called the Osher Marking System, Dr. Waltz said. "This uses a high-definition color image and has a different set of marking functions," he said. "It's the same idea, where you can mark the axis preoperatively according to reference marks on the eye." While the Zaldivar system is on all of the iTraces that are currently available, the Osher system is only on the more recent ones but can be added on to the older models as a software upgrade, he explained. Dr. Yoo views the iTrace system as far more accurate than traditional ink marking methods. "For the surgeons who feel, 'I'm getting good results, I'm accurate with doing it freehand,' if you have the device you can confirm that you are indeed accurate," she said. "What we noticed is that with freehand, we weren't as accurate as we thought." There are a lot of variables when marking freehand including the type of pen used and damage to the marking devices, which can get slightly bent over time, making the iTrace system a valuable alternative. Callisto system sketch www.accutome.com/accusharp-guarded-trial-request 3222 Phoenixville Pike, Malvern, PA 19355 USA • 800-979-2020 • 610-889-0200 • FAX 610-889-3233 • www.accutome.com Another markerless system, the Callisto Eye and Z Align, uses a slightly adapted IOLMaster (Carl Zeiss Meditec), according to Oliver Findl, MD, Department of Ophthalmology, Hanusch Hospital, Vienna. "It's a red-free photograph that shows very nicely the vessels of the conjunctiva and those at the limbus," Dr. Findl said. "This photograph is then imported in the computer, which is connected to the microscope and the laser system in the operating theater." With this system the eye is also tracked. "This means that if I lose the eye during surgery, the alignment is going to track with the eye movement," Dr. Findl said. This helps him to fine-tune the lens positioning at the very end of surgery. When Dr. Findl conducted a trial comparing the system to the conventional marking approach in which a fine mark was placed at the limbus, he found that the results