Eyeworld

iTrace Surgical Workstation "We have found the iTrace Surgical Workstation [Hoya Surgical Optics, Chino Hills, California] very useful because it calculates which model of IOL is right for each patient," Dr. Srivastava said. "Again, you can use limbal vessels for reference and the machine tells you how many degrees from the reference point to place the IOL. You use the gauges to digitally mark two or three points before the IOL is placed and can check the postoperative position. The iTrace offers a toric IOL check and enhancement for after surgery, so if you think your toric IOL is not in the right axis, you can still rotate it by checking aberrometry after surgery." Intraoperative aberrometry is used in addition to preop biometry to minimize refractive error and help determine IOL power selection and placement. According to Dr. Srivastava, "Image-guided systems, as of today, are still more reliable than intraoperative aberrometry in terms of toric positioning. However, without guidance, and toriCAM will use them as reference points to mark my IOL placement intraoperatively. When using toriCAM, you no longer have to mark at 90 degrees and 180 degrees. You can mark anywhere on the cornea and toriCAM will use the mark as a reference point. You take a photo with the app and it will tell you where the mark is and use it as a gauge to mark the toric IOL placement, together with a Mendez degree gauge," he said. Image guidance systems Digital image guidance systems are an interesting new option in the eye surgeon's armamentarium that use anatomic reference points to accurately identify the target axis for toric and multifocal IOL placement and guide surgery. Dr. Srivastava uses the VERION Image Guided System (Alcon, Fort Worth, Texas), which allows the surgeon to pho- tograph the eye preoperatively and use reference points from the image such as limbal and scleral vessels and features of the cornea and iris to create a digital overlay during live surgery. The target axis is projected into the right microscope ocular to guide surgery. The VERION incor- porates an eye-tracking navigation system that compensates for eye movements and cyclotorsion. "Many different companies are now offering these types of systems. We use the VERION that uses ana- tomic data and provides gauges on where to position the toric IOL," Dr. Srivastava said. "There is a display inside the operating microscope that is within the surgeon's view, and the guidance system guides us based on the vessels and the iris architecture. The toric positioning guidance sys- tem shows us if we are on or off axis. You do not necessarily need to mark the eye because it is a purely auto- mated procedure and there are no problems associated with the subjec- tive evaluation of marking. We can center the rhexis on the visual axis, which gives us a full overlap and guides us for manual capsulorhexis, if you do not use femto." I would not rely on image-guided without a marking backup because sometimes the technology is better in theory than reality." EW Editors' note: Dr. Srivastava has no financial interests related to his comments. Contact information Srivastava: samaresh@raghudeepeyeclinic.com The VERION system helps with intraoperative alignment of the IOL without depending on preoperative or intraoperative manual markings. Source (all): Samaresh Srivastava, DNB " Automated systems are the way to go, since manual marking has some issues with patient comfort and IOL centration. In our clinic, we use both methods for the majority of our patients. " —Samaresh Srivastava, DNB EW CATARACT 47

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