Eyeworld

EW REFRACTIVE SURGERY 60 October 2015 in the progression toward the best possible quality of vision for patients and corresponding higher levels of patient satisfaction. It also provides a platform for future growth. iDesign, in addition to wavefront aberrometry, performs full-gradient corneal topography, autorefractometry, pupillometry, and keratometry. Right now, this provides the surgeon with additional data from a single device and makes it possible to automatically incorpo- rate true keratometric data into the treatment plan, rather than relying on user input of the Ks to adjust laser pulses in the periphery to com- pensate for the cosine effect. We can certainly envision a time when the entire corneal shape could be incorporated into treatment algo- rithms. Such a topo-assisted wave- front-guided procedure would allow for correction of optical aberrations based on the entire eye and bring us to the point of correcting smaller increments of higher-order aberra- tions. This is a significant advance- ment in laser vision correction and one that should get ophthalmolo- gists excited again about performing LASIK. Our expectation is that visual results like those seen in Europe will speak for themselves, generating positive word-of-mouth referrals for refractive practices and taking visual quality and patient satisfaction to new heights. EW Editors' note: Dr. Donnenfeld is in private practice, Ophthalmic Consul- tants of Long Island, Rockville Center, N.Y. He is a trustee of Dartmouth Medical School and a clinical professor of ophthalmology, New York Univer- sity. Dr. Schallhorn is global medical director, Optical Express, professor of ophthalmology, University of California San Francisco, and in private practice. Drs. Donnenfeld and Schallhorn have financial interests with Abbott Medical Optics. Contact information Donnenfeld: ericdonnenfeld@gmail.com Schallhorn: scschallhorn@yahoo.com by Eric D. Donnenfeld, MD, and Steven C. Schallhorn, MD Wavefront aberrometry goes high resolution to improve results and patient satisfaction W hen custom ablation was first introduced commercially a little more than 12 years ago, it represented a great improvement in visual out- comes compared to convention- al laser vision correction. LASIK outcomes were already quite good at that point, making it easy to forget just how much better they have become, thanks to advances in abla- tion profiles, aberrometry, tracking and registration, and custom treat- ment algorithms. For example, ablation zones have become larger and better blended. From simple pupil tracking, we've progressed to more advanced iris registration and compensation for cyclotorsion and pupil centroid shift so that wavefront-guided treatments can be delivered more accurately on the cornea. Early Shack-Hartmann aberrom- eters captured relatively few data points (less than 100, in some cases) and then fit them to Zernike polyno- mials. The WaveScan system (Abbott Medical Optics, Abbott Park, Ill.) moved to Fourier-based algorithms to provide a more detailed repre- sentation of the wavefront using about 240 data points. Each of these changes improved refractive results and quality of vision, increased patient satisfaction, and reduced the need for enhancements. Now, with the introduction of the WaveScan's successor, the iDesign Advanced WaveScan Studio, treatments can be even more high resolution, incorporating data from up to 1,257 Shack-Hartmann spots, depending on pupil size. This dra- matic increase in the number of data points improves treatment accuracy. The new system can also measure wavefront error across a broader dynamic range, meaning that more highly aberrated eyes and those with greater amounts of spherocylinder error can be captured and treated. Custom ablation continues to evolve Postoperative monocular and binocular uncorrected visual acuity (UCVA) was excellent, with most eyes seeing better than 20/20 (n=10,132 eyes of 6,148 patients). Source: Steve Schallhorn, MD/Optical Express Monocular and Binocular UCVA 20/16 20/20 20/25 20/40 81.8% 91.5% 93.7% 97.4% 97.5% 99.2% 99.6% 99.8% 100% 80% 60% 40% 20% 0% Monocular Binocular Study results Beginning in 2013, after an anal- ysis showed that out-of-the-box results with iDesign were better than WaveScan results with highly refined nomograms, Optical Express surgery centers in Europe began using iDesign for all custom laser vision correction cases. There is now a sig- nificant body of data on results with the higher-resolution aberrometer. In a recent analysis, there were 10,132 eyes of 6,148 patients treated with iDesign at Optical Express centers that fall within the approved U.S. indications (myopes with up to 5.0 D of astigmatism). The mean age of this large cohort was 33.1 years (range: 18 to 66). Mean preoperative sphere was –3.09 D (–0.25 to –10.75 D) and mean cylinder was –0.80 D (0.00 to 5.00 D). Predictability of the manifest spherical equivalent was very high, with 96.6% of eyes within 0.50 D and 99.5% within 1.00 D. Uncor- rected visual acuity (UCVA) was ex- cellent, with 82% of the eyes seeing 20/16 monocularly without glasses after surgery and nearly all seeing 20/20. Most eyes had no change in best corrected visual acuity (BCVA), while about one-third experienced gains in BCVA compared to preoper- ative levels. When asked about their vision without glasses or contact lenses, 94.2% of patients reported being "satisfied" or "very satisfied." These are the kind of results that U.S. surgeons can expect to achieve with the current-release software for treating myopic patients. Natural progression Whereas in the past, 20/20 vision might have been the goal of laser vision correction, our current goal is to surpass 20/20 in as many patients as possible. The only way to do that consistently is to treat the intrinsic irregularities of individual eyes with customized treatment plans. The latest evolution of wavefront aber- rometry technology is a natural step

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