PURPOSE: To compare the visual and refractive outcomes of laser in situ keratomileusis (LASIK) without iris registration, with static preablation iris registration, and with preablation iris registration-assisted intra-ablation with dynamic rotational eye tracking. SETTING: Refractive Surgery Services, Dr. Agarwal's Eye Hospital, Chennai, India. DESIGN: Randomized clinical trial. METHODS: Eyes with myopic astigmatism (cylinder >1.00 diopter [D]) had LASIK using the Technolas 217z100 platform. Preoperative and postoperative assessment included uncorrected and corrected distance visual acuities, refraction, topographic analysis, and a routine LASIK workup. All cases were followed for 6 months. RESULTS: The mean spherical equivalent (SE) was -6.1 D ± 2.4 (SD) with no iris registration, -6.2 D ± 2.3 D with static iris registration, and -6.5 ± 2.2 D with dynamic iris registration (P=.4) preoperatively and -0.27 ± 0.4 D, -0.12 ± 0.4 D, and -0.02 ± 0.35 D, respectively, 6 months postoperatively (P < .001). The mean cylindrical error was -2.05 ± 0.7 D, -2.08 ± 0.5 D, and -2.13 ± 0.7 D, respectively, preoperatively (P=.6) and -0.37 ± 0.2 D, -0.29 ± 0.2 D, and -0.20 ± 0.3 D, respectively, at 6 months (P < .001). Alpins analysis showed comparable target and surgically induced astigmatism between the 3 groups; however, the difference vector, error angle, correction index, success index, and flattening index were best after dynamic iris registration (P < .001). CONCLUSIONS: In myopic astigmatism, iris registration with dynamic rotational eye tracking gave better results than iris registration alone or no iris registration. The worst outcomes were in cases without iris registration.
RCT Entities:
PURPOSE: To compare the visual and refractive outcomes of laser in situ keratomileusis (LASIK) without iris registration, with static preablation iris registration, and with preablation iris registration-assisted intra-ablation with dynamic rotational eye tracking. SETTING: Refractive Surgery Services, Dr. Agarwal's Eye Hospital, Chennai, India. DESIGN: Randomized clinical trial. METHODS: Eyes with myopic astigmatism (cylinder >1.00 diopter [D]) had LASIK using the Technolas 217z100 platform. Preoperative and postoperative assessment included uncorrected and corrected distance visual acuities, refraction, topographic analysis, and a routine LASIK workup. All cases were followed for 6 months. RESULTS: The mean spherical equivalent (SE) was -6.1 D ± 2.4 (SD) with no iris registration, -6.2 D ± 2.3 D with static iris registration, and -6.5 ± 2.2 D with dynamic iris registration (P=.4) preoperatively and -0.27 ± 0.4 D, -0.12 ± 0.4 D, and -0.02 ± 0.35 D, respectively, 6 months postoperatively (P < .001). The mean cylindrical error was -2.05 ± 0.7 D, -2.08 ± 0.5 D, and -2.13 ± 0.7 D, respectively, preoperatively (P=.6) and -0.37 ± 0.2 D, -0.29 ± 0.2 D, and -0.20 ± 0.3 D, respectively, at 6 months (P < .001). Alpins analysis showed comparable target and surgically induced astigmatism between the 3 groups; however, the difference vector, error angle, correction index, success index, and flattening index were best after dynamic iris registration (P < .001). CONCLUSIONS: In myopic astigmatism, iris registration with dynamic rotational eye tracking gave better results than iris registration alone or no iris registration. The worst outcomes were in cases without iris registration.
Authors: Tommy C Y Chan; Kelvin H Wan; David S Y Kang; Tiffany H K Tso; George P M Cheng; Yan Wang Journal: Graefes Arch Clin Exp Ophthalmol Date: 2018-10-27 Impact factor: 3.117