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Saturday, April 26, 2014 ASCRS News Today © 2014 Novartis 2/14 VRN14003JAD-B PI IMPORTANT SAFET Y INFORMATION FOR THE VERION™ REFERENCE UNIT AND VERION™ DIGITAL MARKER CAUTION: Federal (USA) law restricts this device to sale by, or on the order of, a physician. INTENDED USES: The VERION ™ Reference Unit is a preoperative measurement device that captures and utilizes a high-resolution reference image of a patient's eye in order to determine the radii and corneal curvature of steep and at axes, limbal position and diameter, pupil position and diameter, and corneal reex position. In addition, the VERION ™ Reference Unit provides preoperative surgical planning functions that utilize the reference image and preoperative measurements to assist with planning cataract surgical procedures, including the number and location of incisions and the appropriate intraocular lens using existing formulas. The VERION ™ Reference Unit also supports the export of the high-resolution reference image, preoperative measurement data, and surgical plans for use with the VERION ™ Digital Marker and other compatible devices through the use of a USB memory stick. The VERION ™ Digital Marker links to compatible surgical microscopes to display concurrently the reference and microscope images, allowing the surgeon to account for lateral and rotational eye movements. In addition, the planned capsulorhexis position and radius, IOL positioning, and implantation axis from the VERION ™ Reference Unit surgical plan can be overlaid on a computer screen or the physician's microscope view. CONTRAINDICATIONS: The following conditions may aect the accuracy of surgical plans prepared with the VERION ™ Reference Unit: a pseudophakic eye, eye xation problems, a non-intact cornea, or an irregular cornea. In addition, patients should refrain from wearing contact lenses during the reference measurement as this may interfere with the accuracy of the measurements. Only trained personnel familiar with the process of IOL power calculation and astigmatism correction planning should use the VERION ™ Reference Unit. Poor quality or inadequate biometer measurements will aect the accuracy of surgical plans prepared with the VERION ™ Reference Unit. The following contraindications may aect the proper functioning of the VERION ™ Digital Marker: changes in a patient's eye between preoperative measurement and surgery, an irregular elliptic limbus (e.g., due to eye xation during surgery, and bleeding or bloated conjunctiva due to anesthesia). In addition, the use of eye drops that constrict sclera vessels before or during surgery should be avoided. WARNINGS: Only properly trained personnel should operate the VERION ™ Reference Unit and VERION ™ Digital Marker. Only use the provided medical power supplies and data communication cable. The power supplies for the VERION ™ Reference Unit and the VERION ™ Digital Marker must be uninterruptible. Do not use these devices in combination with an extension cord. Do not cover any of the component devices while turned on. Only use a VERION ™ USB stick to transfer data. The VERION ™ USB stick should only be connected to the VERION ™ Reference Unit, the VERION ™ Digital Marker, and other compatible devices. Do not disconnect the VERION ™ USB stick from the VERION ™ Reference Unit during shutdown of the system. The VERION ™ Reference Unit uses infrared light. Unless necessary, medical personnel and patients should avoid direct eye exposure to the emitted or reected beam. PRECAUTIONS: To ensure the accuracy of VERION ™ Reference Unit measurements, device calibration and the reference measurement should be conducted in dimmed ambient light conditions. Only use the VERION ™ Digital Marker in conjunction with compatible surgical microscopes. ATTENTION: Refer to the user manuals for the VERION ™ Reference Unit and the VERION ™ Digital Marker for a complete description of proper use and maintenance of these devices, as well as a complete list of contraindications, warnings and precautions. 85342 VRN14003JAD-B-PI EWDN.indd 1 3/6/14 1:27 PM by Michelle Dalton EyeWorld Contributing Editor Cornea Day topics range from nomograms to glaucoma T he 2014 Cornea Day pro- gram featured presentations on topics ranging from advances in cataract surgery for the corneal surgeon, to videos exemplifying the benefits of using viscosurgical devices and staining materials for better visuali- zation. Calculating nomograms with femto lasers With 50% of all patients presenting for cataract surgery having "at least 0.75 D of astigmatism," choosing how to correct that astigmatism is becoming more of an issue, said Kendall Donaldson, MD, Miami. Studies have shown that for astigma- tism levels of 2.25 D or higher, toric IOLs are preferred, but at lower levels there's not much statistical difference in outcomes between toric and limbal relaxing incisions (LRIs). "We know from the Nichamin nomograms that we need to treat with-the-rule astigmatism differently from against-the-rule," she said. Although there are no published nomograms when using the femtosecond laser, "if you're using the Donnenfeld or Nichamin nomograms, subtract about 33% from your manual nomograms," she said. Some tips for success when using the femtosecond laser: patient selection, managing patient expecta- tions, and "select and personalize your nomogram with continual outcome analysis." Dry eye and LASIK compatibility The etiology of dry eye is "not per- fectly clear," and the neurotoxicity of the excimer laser results in a cyclical process of "inflammatory dessication of the ocular surface," said Elizabeth Yeu, MD, Norfolk, Va. Several factors increase the risk of dry eye complications/complaints in the postop LASIK patient, including low Schirmer's scores, preop contact lens wear, ocular allergies, among others. "An older age and female gen- der may confer a greater risk," she said. Race may also play a role, as chronic dry eye after 6 months is seen more frequently in Asian eyes than in Caucasian eyes, she added. Postop dry eye will peak between 1 week and 3 months after LASIK, and will be "considerably worse" if preop dry eye exists, she said. She suggests tear film break-up time be more than 8 seconds and preop dry eye be mild before considering LASIK in these eyes. In general, she suggested treat- ing preop dry eye medically first, then procedurally, which may in- clude thermal pulsation or chalasis cauterization. "If dry eye does not resolve, these patients will be poor candi- dates for LASIK," he said. Include posterior corneal measurements Douglas D. Koch, MD, Houston, stressed to attendees here that "if you measure only the anterior cornea," there will be over- and un- dercorrection, depending on which IOL is chosen and whether astigma- tism is with-the-rule (WTR) or against-the-rule (ATR). If the ATR is on the front cornea, it will be steeper horizontally and will not create much of a change on the back surface, but a WTR astigmatism (steeper on the posterior surface) can result in as much as 0.9 D difference. "I try to leave patients with 0.4 D of WTR astigmatism. That gives them good uncorrected vision for many years," he said, adding the importance of accounting for the impact of effective IOL toricity of IOL power and anterior chamber depth. Two nomograms to use are the Holladay II or the Abbott Medical Optics toric IOL calculator. "Don't forget to factor in surgi- cally induced astigmatism," he said. He has proposed a nomogram that ups the threshold from 1 to 1.7 D of WTR and lowers by 0.7 D in ATR. The "holy grail" for perfecting nomograms would be the ability to measure the posterior corneal with either Scheimpflug or optical coherence tomography, he said. Using femto laser in glaucoma patients Surgeons are well aware that IOP spikes occur during phaco, often exceeding 60 mm Hg, but advanced phaco machines will address these fluctuations. Malik Y. Kahook, MD, Aurora, Colo., said that few publica- tions currently address IOP changes related to femto cataract surgery. "The literature suggests a modest rise in IOP during suction and treatment," he said. The potential benefits of femtocataract in pseudoexfoliation patients are that there is "less manipulation of the lens and lens zonules and less phaco energy, so there's less stress on the zonules," Dr. Kahook said. "One caveat is that the laser needs a pupil dilation of 4.8 mm and in some cases of pseu- doexfoliation, that is not possible." Avoid femtocataract in these patients when there is a functioning bleb, or when there is a drainage device and functioning bleb, he said. "Consider the condition of the bleb and tube position preopera- tively," he said. EW Editors' note: Dr. Donaldson has no related financial interests. Dr. Koch has financial interests with Abbott Medical Optics (AMO, Santa Ana, Calif.) and Alcon (Fort Worth, Texas). Dr. Yeu has financial interests with companies including AMO, Alcon, Allergan (Irvine, Calif.), Bausch + Lomb (Rochester, N.Y.), and TearLab (San Diego). Douglas D. Koch, MD, discusses with-the-rule and against-the-rule astigmatism.

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