Eyeworld

EW NEWS & OPINION 24 June 2016 by Liz Hillman EyeWorld Staff Writer YES Connect "There are a lot of things you need to pay attention to when you're using the ORA," he said. "The first thing is the ORA has a reticle, which tells you where the different angles are in relation to the eye, so you need to set up your microscope so that the reticle matches the pa- tient's eye. You want to make sure 0 and 180 degrees on the patient's eye matches 0 and 180 degrees on the reticle. It would be very easy to have the microscope oriented so that the ORA was not quite aligned with the patient's eye, so when the ORA reads out a certain axis, it may look like it totally disagrees with your preopera- tive measurements, but it could just be the way the microscope is aligned on the patient's eye." Dr. Weikert also said that the ocular surface must be kept hydrated to protect the corneal epithelium. "If your corneal epithelium gets damaged during surgery, it can throw off your ORA measurements," he said. "This advice goes to any machine," Dr. Weikert continued, "You don't want to blindly trust any device. You want to understand the nuances of it, but you also have to know when things don't make sense. If they don't make sense, you want to understand why." When it comes to choosing to do an LRI or use a toric IOL, Drs. Weikert and Lee said they would prefer a toric IOL in most cases. "I think that incisions are inherently a little bit more unpre- dictable," Dr. Weikert said. "I think incisions made with the femtosec- ond laser are more predictable than with a manual blade, but I think even then, compared with toric lens- es, they're less predictable." Dr. Weikert said he gravitates toward the AcrySof IQ toric IOL (Alcon), but has also used the TECNIS (Abbott Medical Optics, Abbott Park, Illinois). Although he has not had rotational issues with the TECNIS, he noted that some surgeons have and advised those using it to make sure the size of the capsulorhexis is not too large, remove viscoelastic from behind the lens, and leave it a bit under rotated until the end. Dr. Lee uses both of these as well, but leans toward the TECNIS for patients getting a toric in only Orlando, Florida) in order to identify the steep meridian. When she uses the LenSx laser (Alcon, Fort Worth, Texas) for surgery, which can be integrated with the Verion Image Guided System (Alcon), Dr. Yeu creates 12 and 6 o'clock limbal ref- erence marks at the slit lamp as she does not have access to the Verion platform. Dr. Yeu does not use intraop- erative aberrometry currently but did while she was at the Cullen Eye Institute. Calling the results fairly positive, particularly for the information intraoperative aber- rometry can provide in totality, Dr. Yeu maintains that the best corneal measurements are likely those that are captured preoperatively on a naïve cornea, untouched by drops and the pressure changes from a lid speculum. "I reviewed my last 6 months of toric cases leading up to [the ASCRS•ASOA Symposium & Con- gress], and using my preoperative diagnostics, 94% of my toric cases were within half a diopter of refrac- tive residual astigmatism. The Total Corneal Astigmatism (TCA) informa- tion provided through near instan- taneous capture with the Cassini has provided great insight into the cornea's true refractive power and astigmatism. I would love to see how intraoperative aberrometry would compare to that and potentially augment the outcome in my hands because I think that it is a great tech- nology," Dr. Yeu said. Dr. Lee said that while he uses intraoperative aberrometry to help select the IOL's spherical power, he does not change an IOL's toric pow- er based on it. "After putting the IOL in, I use aberrometry to tweak the toric positioning," he said. "It's ideal if it confirms everything is correct, but if there is a significant discrepancy, I rely on my preoperative measure- ments. I also use the aberrometer to help titrate my incisions when performing an LRI." Dr. Weikert offered several pearls for those using intraoperative aberrometry. He uses ORA (Alcon) to confirm his preoperative mea- surements, help align the IOL to the optimal position, and as a tiebreaker when he's determining how much astigmatism he wants to correct. From LRIs and toric IOLs to intraoperative aberrometry, physicians discuss pearls for the young refractive cataract surgeon A fter the preoperative assessment—evaluat- ing measurements for astigmatism in 2 or 3 different ways, ensuring measurements are in agreement, and selecting the plan of action for limbal relaxing incisions (LRIs) or a toric IOL—then it's time to execute the treatment plan and be prepared to manage any surprises at the intra- operative stage. First comes marking the patient for astigmatic correction ahead of surgery. Mitchell Weikert, MD, as- sociate professor and residency pro- gram director, Cullen Eye Institute, Baylor College of Medicine, Hous- ton, said he does a couple of things at this point. He draws a picture of the patient's eye during the preop exam, noting any landmark blood vessels or iris features to use as refer- ence points in the operating room. In the preoperative holding area, Dr. Weikert said his office has weighted markers to place on the eye, but he noted that some of his colleagues will simply use a pen to mark 0 and 180 degrees as reference points. One pearl Dr. Weikert offered here is to mark patients preoperatively while they're sitting because the eye can rotate when they lie down. Bryan Lee, MD, JD, Altos Eye Physicians, Los Altos, California, does not mark the patient and in- stead uses the CALLISTO eye mark- erless system (Carl Zeiss Meditec, Jena, Germany), which has a camera integrated with the IOLMaster (Carl Zeiss Meditec). "I have found it to be accurate and reliable, and skipping manual marking is also great for patient flow," Dr. Lee said. Elizabeth Yeu, MD, Norfolk, Virginia, ASCRS Young Eye Surgeons Clinical Committee chair, uses the iris registration capture from the NIDEK OPD-Scan III (NIDEK, Gama- gori, Japan) and Cassini (i-Optics, The Hague, the Netherlands) to streamline information into the LENSAR laser system (LENSAR, Managing astigmatism at the intraoperative stage T his month's "YES Connect" column continues our series on the man- agement of astigmatism at the time of cataract surgery. In part 1 of this series, which appeared in the May 2016 issue of EyeWorld, we reviewed the components of the preoperative assessment when discuss- ing and planning astigmatism correction. While the importance of planning cannot be overstated, extensive preparation has little meaning without successful surgical exe- cution. In part 2 of the series, we review the intraoperative elements related to achieving optimal astigmatic correction. Mitchell Weikert, MD, along with 2 ASCRS Young Eye Surgeons Clinical Committee members, Bryan Lee, MD, and Elizabeth Yeu, MD, review their strategies for accurate preoper- ative marking and identification of the steep axis of astigmatism, pearls for the effective use of intraoperative aberrometry, as well as choosing between astigmatic corneal incisions and toric intraocular lenses. As is evident in this month's column, intraoper- ative details of astigmatism management cover a wide breadth, from unassuming steps like viscoelastic removal to utilization of evolving technologies like markerless image-guided systems. In next month's column, the final part of the series, we will discuss the postoperative management of astigmatism. Charles Weber, MD, YES Connect co-editor

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