Background And Objective: To identify the relationship between preoperative parameters and postoperative overcorrection or undercorrection in eyes with myopic astigmatism treated with wavefront-guided laser in situ keratomileusis (LASIK), and to develop an advanced surgical nomogram.
Patients And Methods: A retrospective chart review of 468 eyes that underwent wavefront-guided LASIK for myopia with astigmatism with the Alcon LADARVision 4000 (Alcon Laboratories, Fort Worth, TX), of which 235 had flaps created by microkeratome (OneUse; Moria Surgical, Doylestown, PA) and 233 by femtosecond laser (Intralase; AMO, Santa Ana, CA). Manifest sphere, cylinder, and spherical equivalent were recorded preoperatively and 3 months postoperatively. Various parameters from patient records were analyzed to identify which had greatest influence on outcomes.
Results: Manifest spherical equivalent was the most important predictor of surgical overcorrection, with the second being spherical aberration. In both groups, there was a statistically significant (P < .0001) correlation of spherical aberration with the amount of overcorrection. Using these two parameters, compensatory nomograms were derived.
Conclusion: Surgical overcorrection in wavefront-guided LASIK for myopic astigmatism correlates positively with the amount of spherical equivalent treated and preoperative spherical aberration. Nomograms incorporating spherical aberration may improve accuracy of outcomes.
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http://dx.doi.org/10.3928/15428877-20110303-01 | DOI Listing |
We theoretically demonstrate that ponderomotive interactions near the electron cross-over can be used for aberration correction in ultrafast electron microscopes. Highly magnified electron shadow images from SiN thin films are utilized to visualize the distortions induced by spherical aberrations. Our simulations of electron-light interactions indicate that spherical aberrations can be compensated resulting in an aberration-free angle of 8.
View Article and Find Full Text PDFSpecimen-induced aberrations limit the penetration depth of standard optical imaging techniques in vivo, mainly due to the propagation of high NA beams in a non-homogenous medium. Overcoming these limitations requires complex optical imaging systems and techniques. Implantable high NA micro-optics can be a solution to tissue induced spherical aberrations, but in order to be implanted, they need to have reduced complexity, offering a lower surface to the host immune reaction.
View Article and Find Full Text PDFIn the last few years, new ways of structuring light have emerged, with the potential to be used in a wide variety of applications, including materials processing, micro-particle manipulation and charged particle acceleration. One of these techniques is the structured laser beam (SLB). The important advantages of this beam are the simple generation principle using spherical aberration and the potentially infinite propagation range.
View Article and Find Full Text PDFOphthalmic Physiol Opt
January 2025
Northeastern University College of Science, Boston, Massachusetts, USA.
Purpose: To assess longitudinal changes in optical quality across the periphery (horizontal meridian, 60°) in young children who are at high (HR) or low risk (LR) of developing myopia, as well as a small subgroup of children who developed myopia over a 3-year time frame.
Methods: Aberrations were measured every 6 months in 92 children with functional emmetropia at baseline. Children were classified into HR or LR based on baseline refractive error and parental myopia.
Photodiagnosis Photodyn Ther
January 2025
Department of Ophthalmology, Shanghai Tenth People's Hospital, School of Medicine, Tongji University Shanghai, 200072, China.. Electronic address:
Purpose: This retrospective study aimed to investigate the subjective and objective visual outcomes following Small Incision Lenticule Extraction (SMILE) surgery in high myopic patients with varying axial lengths (AL).
Methods: The study enrolled 113 highly myopic patients (202 eyes) who underwent SMILE surgery at Shanghai's Tenth People's Hospital from July 2021 to September 2023. Patients were classified into three groups based on the axial length before surgery: Group A (AL < 26mm, 62 eyes), Group B (26mm ≤ AL < 27mm, 88 eyes), and Group C (AL ≥ 27mm, 52 eyes).
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