Eyeworld

EW REFRACTIVE 62 April 2018 makes the ablation profile smoother. The ablation profile is described as a three dimensional model with vol- ume and xyz coordinates, based on a curved corneal surface where each position is equidistant in the three dimensional space. The smoother, optimized corneal surface created by smart pulse technology accelerates visual recovery." Outcomes Twelve months postoperatively, 88% of patients achieved 20/20 uncor- rected distance visual acuity (UDVA). The UDVA was the same or better than the corrected distance visual acuity (CDVA) in 93% of the eyes. UDVA was within one line of CDVA in 98% of cases. The postoperative UDVA was 20/25 or better in 97% of the study eyes at 12 months. A gain of one line of CDVA was noted in 52% of the patients, and there was no change in 41%. No patients lost two or more lines of Snellen, and 5% lost one line. The preoperative mean spherical equivalent was –4.11 ± 1.28 D, and cylinder was –1.12 ± 1.11 D. Twelve months after the treatment, the mean spherical equivalent was –0.07 ± 0.14 D, and the cylinder was –0.11 ± 0.35 D. "The attempted versus achieved spherical equivalent refraction shows a tight line in the scatter- gram, achieving a mean –4.18 ± 1.27 D (range: –2.11 to –7.25 D)," Dr. Arbelaez said. "In terms of accuracy, we have 100% of the patients with ±0.50 D and 100% with ±1.00 D. In terms of stability, the percentage changed was assessed by the mean spherical equivalent over 0.50 D change, over the weeks and months after surgery. It showed very little or no variation during the year of follow-up." Pre-/postoperative values for spherical aberration were –0.11 preoperatively/–0.16 postoperatively. Horizontal coma was 0.04/0.02; ver- tical coma was 0.01/0.00; horizontal trefoil was 0.03/0.03; vertical trefoil was 0.03/0.02; and RMS was 0.31 preoperatively/0.34 postoperatively. "The combined procedures demonstrated high safety and effica- cy, however, a longer follow-up will be required to confirm the benefits of the combination of a transPRK with an Xtra procedure," Dr. Arbelaez said. EW Editors' note: Dr. Arbelaez has finan- cial interests with Schwind eye-tech- solutions. Contact information Arbelaez: drmaria@muscateye.com laser in a continuous single setting, to ablate the surface epithelium and stroma simultaneously. The epitheli- um thickness profile was 55 µm cen- trally and 65 µm peripherally. "We used an asymmetrical offset centra- tion in all of the patients," she said. "But we also used an asymmetrical pattern of the profile of the Amaris to correct all the patients covering the scotopic pupil. If we don't have an asymmetric profile, there can be part of the scotopic pupil without correction. Mitomycin-C (MMC) 0.02% was applied between 30 and 60 seconds following a nomogram, based on the depth of stromal abla- tion." CXL was carried out using the KXL Avedro system (Waltham, Mas- sachusetts) using riboflavin (VibeX Rapid) with a soaking time of 90 seconds. The UV power was 30 mW/ cm 2 , the treatment time was 76 seconds, for total energy delivered of 2.3 J/cm 2 per eye. Accelerated CXL may offer corneal stabilization, and it is more comfortable for the pa- tient and surgeon as it is performed more quickly. "Corneal geometry is a fullerene dome," Dr. Arbelaez said. "SPT uses a geometric model of the cornea that is based on a three dimensional fullerene structure that realistically portrays the corneal curvature and Combining continued from page 61

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