Objective: To assess efficacy, safety, predictability, stability, and changes in corneal higher-order aberrations (CHOAs) and contrast sensitivity (CS) after a femtosecond laser for LASIK and standard LASIK for myopia.
Design: Prospective, randomized, comparative clinical study.
Participants: Two hundred eyes of 100 consecutive patients who underwent LASIK treatment using the VISX S2 laser system. A femtosecond laser for flap creation was used in 100 eyes (50 patients; spherical equivalent [SE], -2.85+/-1.79 diopters [D]), and a mechanical microkeratome was used in 100 eyes (50 patients; SE, -2.90+/-1.63 D).
Methods: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, CS by means of the Functional Acuity Contrast Test, and CHOAs by means of custom software linked to topography were evaluated preoperatively and 6 months after treatment.
Main Outcome Measures: Efficacy, safety, predictability, stability, CHOAs, and CS were evaluated before and after surgery at 6 months' follow-up.
Results: At 6 months postoperatively, UCVA was 1.0 or better in 100% of the eyes. Efficacy indexes were 1.07 for the femtosecond laser for LASIK patients and 1.00 for LASIK patients. No eye lost > or =1 lines of BCVA; for the femtosecond laser for LASIK group, 24 eyes gained 1 line, and 18 eyes gained > or =2 lines; for the LASIK group, 18 eyes gained 1 line. The femtosecond laser for LASIK group showed a percentage of eyes (98%) within the 0.5-D range in SE higher than that of the LASIK group (92%). For a 3.5-mm pupil, CHOAs' root-mean-square (RMS) increased for both the femtosecond laser for LASIK (2.21-fold) and LASIK (2.81-fold) groups. For a 6-mm pupil, CHOA RMSs were increased significantly after femtosecond laser for LASIK (4.18-fold) and LASIK (5.07-fold) surgeries (P<0.01). Contrast sensitivity improved only in the femtosecond laser for LASIK group at the highest spatial frequency (18 cycles/degree; P<0.01) after surgery.
Conclusions: A femtosecond laser for LASIK surgery is an effective and, in this series, safe procedure for treatment of myopia. The improvements in UCVA and CS after the femtosecond laser for LASIK are related to the differences in postoperative CHOAs found with femtosecond and microkeratome flap creation.
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http://dx.doi.org/10.1016/j.ophtha.2006.07.019 | DOI Listing |
Phys Chem Chem Phys
January 2025
Theoretical Physics Section, Bhabha Atomic Research Centre, Mumbai-400085, India.
Extensive research on ultrashort laser-induced melting of noble metals like Au, Ag and Cu is available. However, studies on laser energy deposition and thermal damage of their alloys, which are currently attracting interest for energy harvesting and storage devices, are limited. This study investigates the melting damage threshold (DT) of three intermetallic alloys of Au and Cu (AuCu, AuCu and AuCu) subjected to single-pulse femtosecond laser irradiation, comparing them with their constituent metals.
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January 2025
Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, P. R. China.
Optical metasurfaces have found widespread applications in the field of optoelectronic devices. However, achieving dynamic and flexible control over metasurface functionalities, while also developing simplified fabrication methods for metasurfaces, continues to pose a significant challenge. Here, the study introduces a PCM-only metasurface that exclusively consists of voxel units crafted from different phases of phase-change materials.
View Article and Find Full Text PDFKlin Monbl Augenheilkd
January 2025
Department of Ophthalmology, Pallas Kliniken, Olten/Bern/Zürich/Dübendorf, Switzerland.
Background: Extended monovision is a novel mix-and-match approach that has been recently introduced. It involves implanting an aspherical monofocal intraocular lens (IOL) for distance vision in the dominant eye, and a bifocal extended depth-of-focus (EDOF) IOL in the nondominant eye. The target refraction for the nondominant eye is - 1.
View Article and Find Full Text PDFNano Lett
January 2025
Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, California 94720, United States.
Ultrafast near-field optical nanoscopy has emerged as a powerful platform to characterize low-dimensional materials. While analytical and numerical models have been established to account for photoexcited carrier dynamics, quantitative evaluation of the associated pulsed laser heating remains elusive. Here, we decouple the photocarrier density and temperature increase in near-field nanoscopy by integrating the two-temperature model (TTM) with finite-difference time-domain (FDTD) simulations.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
School of Physics, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 611731, China.
Ultrashort laser pulses are extensively used for efficient manipulation of interfacial spin injection in two-dimensional van der Waals (vdW) heterostructures. However, physical processes accompanying the photoinduced spin transfer dynamics on the all-semiconductor ferromagnetic vdW heterostructure remain largely unexplored. Here, we present a computational investigation of the femtosecond laser pulse induced purely electron-mediated spin transfer dynamics at a time scale of less than 50 fs in a vdW heterostructure.
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