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EW SHOW DAILY 14 Saturday, May 6, 2017 by Rich Daly EyeWorld Contributing Writer ASCRS News Today various superior abilities of topogra- phy-guided LASIK. For instance, its results are accurate and reproducible regardless of the size or location of the pupil. The technology provides "excellent peripheral data; it is derived from the cornea, where most aberrations arise; and it can measure highly aberrated eyes, in eyes where wavefront sensors have problems measuring." It may facilitate repairs of ab- normalities, which is its primary use outside of the U.S. Some U.S. sur- geons have begun to use it off-label for that purpose. "It may become our best repair tool," Dr. Stulting said. Patients who are not candidates for topography-guided LASIK are those from who you cannot capture good images. Dr. Stulting said it is not a high-volume method of treat- ment given the work involved. "So if you're going to do this, plan to do it yourself and become involved or have someone else in your practice who is going to do that," Dr. Stulting said. The planning for topography- guided treatment is the same in normal eyes for selecting the images and capturing the images. The difficulty occurs when the refractive astigmatism is different from the topography-detected astigmatism. When they are different then algo- rithms are needed to ensure both correct spherical equivalent is used and the correct corneal astigmatism is selected to be treated. Stephen Slade, MD, Houston, said topography-based ablations are normalizing a cornea, rather than customizing a cornea done with wavefront-guided treatments. T he spreading technology of topography-guided laser surgery is at least theoret- ically superior to wave- front-guided treatments, according to a presenter at the first Refractive Day during the 2017 AS- CRS•ASOA Symposium & Congress. "We have the ability with topography-guided LASIK to tell our patients that they might expect uncorrected visual acuity at least as good as and perhaps better than their preop best corrected visual acuity for the first time," said Doyle Stulting, MD, PhD, Atlanta. Dr. Stulting cited research that found normalization of topography may improve visual outcomes even in normal topography eyes. A study of the recently approved Contoura Vision (Alcon, Fort Worth, Texas) ex- cluded eyes with previous refractive surgery and those with abnormal corneas. That study found post- op corrected visual acuity in 16% achieved 20/10 or better and 31% gained at least one line of visual acuity compared to best spectacle corrected. Research also indicated a 12-month postop improvement in visual symptoms. "So we can tell our patients that they have a good chance of having better quality of vision with LASIK than they have with their correc- tion at present—something that we weren't able to do years ago," Dr. Stulting said. Topography-guided LASIK or PRK may become the standard of care—instead of wavefront-guided LASIK that some consider the stan- dard of care, he said. That expectation stemmed from He prefers topography-guided treatments especially for patients who are expecting to have cataract surgery, which gives him more treat- ment intraocular lens options. "We've had good results with it for regular patients and we've had good results for it from aberrated eyes, which is an exploration," Dr. Slade said. Refractive Day also included the first Steinert Refractive Lecture, which was delivered by Douglas Koch, MD, Houston, regarding the challenges of IOL calculations with postop and ectatic corneas. Dr. Koch noted that current lim- itations have left surgeons making many assumptions about posterior corneal power. Surgeons can better factor in the posterior cornea by measuring it in very limited zones, extrapolating posterior corneal curvature using a population average of the posterior to the anterior, and using that to cal- culate total corneal cover. However, there are atypical cor- neas—after refractive surgery, after keratoplasty, ectasia, and with toric IOLs—in which the extrapolation can cause larger errors. Accurate measurement of the posterior cornea can be done with tomography—with Scheimpflug technology and with OCT devices —or directly with the Cassini LED topographer (i-Optics, The Hague, the Netherlands). "The concept is you measure the posterior cornea on an eleva- tion-based method, you add that to the anterior, and you get total corneal power," Dr. Koch said. Dr. Koch said as corneas get better—and less RK is used—then measures of the posterior cornea should improve. Other continuing measurement challenges include patients with keratoconus, post-DSEK, and astig- matism. "The steeper the front, the more the back counteracts it," Dr. Koch said. EW Editors' note: Dr. Stulting has finan- cial interests with Johnson & Johnson Vision (Santa Ana, California), Alcon (Fort Worth, Texas), Avedro (Waltham, Massachusetts), RxSight (Pasadena, California), and others. Dr. Slade has financial interests with Alcon, Bausch + Lomb (Bridgewater, New Jersey), Clarity (Pleasanton, California), and Carl Zeiss Meditec (Jena, Germany). Dr. Koch has financial interests with Alcon, J&J Vision, Bausch + Lomb, Clarity, and others. Topography-guided LASIK, PRK superior to wavefront-guided treatment? Dr. Stulting said topography-guided refractive procedures may become the standard of care over wavefront-guided procedures. However, "it's not a magic bullet," he said. Per the U.S. Food and Drug Administration's definition of bio- logicals, there are other treatments that fall into this category, including allogenic serum and amniotic mem- brane, he said. Other presentations focused on newer treatments for dry eye, such as neurostimulation and newer med- ications. EW Editors' note: Dr. Fram has financial interests with Alcon (Fort Worth, Texas), Johnson + Johnson Vision (Santa Ana, California), and other ophthalmic companies. Dr. Garg has financial interests with Alcon, Allergan (Dublin, Ireland), and other ophthal- mic companies. Dr. Jeng has financial interests with Alcon, Avedro (Waltham, Massachusetts), and other ophthalmic companies. Dr. Neff has financial inter- ests with Sun Ophthalmics (Princeton, New Jersey). Dr. Jacobs has no financial interests related to her comments. Cornea Day continued from page 12

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