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Contact Lenses || Optics and Lens Design
摘要： Some aspects of contact lens design and optics are rarely applied nowadays, as they are less relevant to modern practice, but readers may still need to refer to them. They are available at: https://expertconsult.inkling.com/, whereas the more relevant topics are included here. The appendix, available at: https://expertconsult.inkling.com/, also describes various equations that are used in contact lens work, while the online resources include programs relating to both the optics and to lens design. There are two main aspects to be considered when dealing with the optics of contact lenses: the effects on the wearer of the optical differences from spectacles and the necessity for the practitioner to understand the components which affect the back vertex power (BVP) of the contact-lens/liquid*-lens system. There is some overlap of these two aspects, but for the sake of convenience they are discussed separately in the first two sections of the chapter. In the second section a set of approximate rules is included, the use of which should permit practitioners to make quick and reasonably accurate estimates of changes in power caused by altering certain lens parameters. The Cartesian sign convention2 is used throughout. For further understanding of the basic principles involved, readers are referred to the works of Bennett (1985), Tunnacliffe (1993), Freeman and Hull (2003), Douthwaite (2006) and Rabbetts (2007).
关键词： Lens Design,Astigmatism,Optics,Bifocal Contact Lenses,Power Variations,Contact Lenses,Ocular Refraction,Aberrations,Spectacles
更新于2025-09-23 15:23:52
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Aberrant hiPSCs-Derived from Human Keratinocytes Differentiates into 3D Retinal Organoids that Acquire Mature Photoreceptors
摘要： Human induced pluripotent stem cell (hiPSC)-derived three-dimensional retinal organoids are a new platform for studying the organoidogenesis. However, recurrent genomic aberration, acquired during generation of hiPSCs, limit its biomedical application and/or aberrant hiPSCs has not been evaluated for generation of differentiated derivatives, such as organoids and retinal pigment epithelium (RPE). In this study, we efficiently differentiated mosaic hiPSCs into retinal organoids containing mature photoreceptors. The feeder-free hiPSCs were generated from the human epidermal keratinocytes that were rapid in process with improved efficiency over several passages and maintained pluripotency. But, hiPSCs were cytogenetically mosaic with normal and abnormal karyotypes, while copy number variation analysis revealed the loss of chromosome 8q. Despite this abnormality, the stepwise differentiation of hiPSCs to form retinal organoids was autonomous and led to neuronal lamination. Furthermore, the use of a Notch inhibitor, DAPT, at an early timepoint from days 29–42 of culture improved the specification of the retinal neuron and the use of retinoic acid at days 70–120 led to the maturation of photoreceptors. hiPSC-derived retinal organoids acquired all subtypes of photoreceptors, such as RHODOPSIN, B-OPSIN and R/G-OPSIN. Additionally, the advanced maturation of photoreceptors was observed, revealing the development of specific sensory cilia and the formation of the outer-segment disc. This report is the first to show that hiPSCs with abnormal chromosomal content are permissive to the generation of three-dimensional retinal organoids.
关键词： genomic aberrations,keratinocytes,photoreceptors,retinal organoids,hiPSCs
更新于2025-09-23 15:22:29
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Repeatability of wavefront measurements in pseudophakic eyes; Reproduzierbarkeit von Wellenfrontmessungen bei pseudophaken Augen;
摘要： Higher- as well as lower-order aberrations influence uncorrected visual quality after successful cataract surgery. Different techniques are used for measuring ocular wavefront aberrations, such as Hartmann–Shack aberrometers, laser ray tracing aberrometers, and automatic retinoscopy. The aim of our study was to assess the repeatability of a Hartmann–Shack aberrometer measurement in a pseudophakic study population. Methods This prospective study included patients who underwent cataract surgery 1 month prior to recruitment. Three consecutive Hartmann–Shack measurements (WASCA, Carl Zeiss Meditec AG, Germany) were performed after pharmacological dilation of the pupil. Results In total, 156 eyes of 156 patients were included. Repeatability of measurements was good in pseudophakic eyes for all Zernike polynomials up to the fourth order. The median values of the SD of all three measurements ranged between 0.042 and 0.125 for the Tecnis intraocular lens (IOL) and 0.028 and 0.148 for the CT Asphina 409MP IOL. Intraclass correlation coefficients ranged between 0.793592 and 0.97955 for the Tecnis IOL and between 0.673894 and 0.989172 for the CT Asphina 409MP IOL. Conclusion Postoperative unsatisfactory image quality, sometimes reported by patients, despite good defocus and astigmatism values calls for examination of higher-order aberrations. Hartmann–Shack measurements with the WASCA offers good repeatability in pseudophakic patients and, therefore, fulfills this task.
关键词： Repeatability,Higher-order aberrations,Hartmann–Shack aberrometry
更新于2025-09-23 15:22:29
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Compact IR synchrotron beamline design
摘要： Third-generation storage rings are massively evolving due to the very compact nature of the multi-bend achromat (MBA) lattice which allows amazing decreases of the horizontal electron beam emittance, but leaves very little place for infrared (IR) extraction mirrors to be placed, thus prohibiting traditional IR beamlines. In order to circumvent this apparent restriction, an optimized optical layout directly integrated inside a SOLEIL synchrotron dipole chamber that delivers intense and almost aberration-free beams in the near- to mid-IR domain (1–30 mm) is proposed and analyzed, and which can be integrated into space-restricted MBA rings. Since the optics and chamber are interdependent, the feasibility of this approach depends on a large part on the technical ability to assemble mechanically the optics inside the dipole chamber and control their resulting stability and thermo-mechanical deformation. Acquiring this expertise should allow dipole chambers to provide almost aberration-free IR synchrotron sources on current and ‘ultimate’ MBA storage rings.
关键词： integrating magnetic and photonic synchrotron beamline components,multi-bend achromat storage ring,infrared synchrotron beamline,bending-magnet source,optical aberrations
更新于2025-09-23 15:21:21
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Irregular Astigmatism and Higher-Order Aberrations in Eyes With Dry Eye Disease
摘要： Visual disturbances were included in the de?nition of dry eye disease in the 2007 Dry Eye Workshop report. As a result, quality of vision (QoV) in dry eye patients has received increased attention. Corneal topography and wavefront sensors have been used to objectively and quantitatively evaluate optical quality, with data showing increases in irregular astigmatism and higher-order aberrations (HOAs) in dry eye patients. Furthermore, ocular optical characteristics are in?uenced by the tear ?lm, which constantly ?uctuates over time. Therefore, dynamic quantitative assessments of optical quality with continuous measurements are essential to understanding QoV in dry eye patients. This review summarizes what is known and what advances have been made in evaluating and understanding QoV in dry eye patients. In particular, corneal topographic and wavefront analyses, conducted both overseas and in Japan, are described.
关键词： wavefront sensor,dry eye,higher-order aberrations,corneal topography,irregular astigmatism
更新于2025-09-23 15:21:01
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A study on the effects and visibility of low-order aberrations on laser beams with orbital angular momentum
摘要： Laguerre–Gaussian-like laser beams have been proposed for driving experiments with high-intensity lasers. They carry orbital angular momentum and exhibit a ring-shaped intensity distribution in the far field which make them particularly attractive for various applications. We show experimentally and numerically that this donut-like shape is extremely sensitive to off-axis wavefront deformations. To support our claim, we generate a Laguerre–Gaussian-like laser beam and apply a selection of common low-order wavefront aberrations. We investigate the visibility of those wavefront deformations in the far field. Under use of established tolerance criteria, we determine the thresholds for the applied aberration and compare the findings with simulations for verification.
关键词： tolerance criteria,Laguerre–Gaussian-like laser beams,orbital angular momentum,far field,wavefront aberrations
更新于2025-09-19 17:13:59
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Five-year outcomes of small-incision lenticule extraction vs femtosecond lasera??assisted laser in situ keratomileusis
摘要： To compare the long-term refractive and visual outcomes and the corneal higher-order aberrations of contralateral eyes of patients who received small-incision lenticule extraction (SMILE) in one eye and femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK) in the other eye.
关键词： small-incision lenticule extraction,femtosecond laser–assisted laser in situ keratomileusis,myopic astigmatism,corneal higher-order aberrations,SMILE,FS-LASIK,myopia
更新于2025-09-19 17:13:59
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[Laser Institute of America ICALEO? 2017: 36th International Congress on Applications of Lasers & Electro-Optics - Atlanta, Georgia, USA (October 22–26, 2017)] International Congress on Applications of Lasers & Electro-Optics - Adaptive optics for intra-volume engraving of glass with ultra-short laser pulses
摘要： Within the frame of high precision ultrafast laser processing of transparent materials, we report here on the use of adaptive optics as a tool for intra-volume laser engraving of glass. With the active monitoring of the laser beam wavefront, the repartition of the above-threshold energy in the focal volume is actively detected. Therefore, the elongation of the laser-induced modification due to longitudinal spherical aberration can be minimized or emphasized on demand. Indeed, the industrial adaptive optics set up, made of a wavefront sensor and a deformable mirror, permits the management of each wavefront aberration as RMS values of chosen Zernike polynomials coefficients. This technique allows the control of the processing of transparent dielectrics, whatever the index of refraction and the depth are. This study addresses the precise correlation between wavefront distortions and intra-volume modifications in borosilicate glass obtained with a 300 fs Yb-doped fiber laser running at 1030 nm. The effects of the 3rd and 5th orders of longitudinal spherical aberrations on the laser-induced marking of the bulk are investigated with the purpose of precisely controlling the length of the interaction volume in the illuminated dielectric material. We show here a minimization of the total length of the marking by 65% at 600 μm in depth, from the natural wavefront to the optimized one, close to the diffraction limit.
关键词： wavefront distortions,ultra-short laser pulses,intra-volume engraving,adaptive optics,glass,longitudinal spherical aberrations
更新于2025-09-16 10:30:52
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Factors predicting successful customized excimer laser treatment in irregular corneas
摘要： Purpose: To identify factors associated with a successful wavefront-guided customized treatment (WG-CT) with an excimer laser in highly aberrated corneas. Setting: VISSUM Alicante Spain. Design: Retrospective consecutive noncomparative case series. Methods: Treatment was performed with the WG-CT Amaris excimer laser using the ORK-CAM software for the calculation of the ablation profile. Eyes of patients with significantly aberrated corneas, including postrefractive and keratoplasty procedures or high irregular astigmatism with significant higher-order aberrations (HOAs) that had WG-CT were included. Refractive outcomes, HOAs, and visual outcomes were recorded. Statistical analysis was performed to identify factors associated with technical (based on HOAs) or refractive outcome success. Results: The study included 55 treatments of 51 eyes (35 patients). The postoperative uncorrected distance visual acuity was 0.2 logarithm of the minimum angle of resolution or better in 72% of the eyes, and the postoperative residual manifest refraction spherical equivalent was ±0.50 diopter in 56% of the eyes, whereas 11% of the eyes lost 1 line or more in corrected distance visual acuity. Successful reduction in the total root mean square (RMS) of HOAs occurred in 36 eyes (65%), and these eyes had a significantly higher preoperative RMS of HOAs (1.45 ± 0.93 μ vs 0.91 ± 0.34 μ, P = .003) and preoperative coma-like aberrations (1.09 ± 0.83 μ vs 0.55 ± 0.28 μ, P = .001). In multivariate analysis, posthyperopic treatment eyes were less likely to achieve refractive outcome success (odds ratio = 0.09, P = .02). Conclusions: WG-CT in highly aberrated corneas had a limited refractive predictability. Eyes with preoperative coma-like aberrations are more likely to benefit from a reduction in HOAs. Post-hyperopic treatment is associated with a higher rate of refractive surprises.
关键词： excimer laser,refractive surgery,irregular corneas,wavefront-guided customized treatment,higher-order aberrations
更新于2025-09-16 10:30:52
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Ocular Aberrations and Corneal Thickness-Intraocular Pressure Relationship One Year after Laser in situ Keratomileusis (LASIK) Enhancement with An Aspheric Ablation Profile
摘要： Objective: To evaluate the effect of an aspheric LASIK refractive enhancement performed by relifting the original flap on the higher order aberrations (HOA) of the eye and the relationship between central corneal thickness (CCT) and intra-ocular pressure (IOP). Methods: Consecutive case series of 30 eyes requiring refractive enhancement from 1804 uncomplicated primary LASIK procedures performed in 2012. Flap relift and wavefront optimized ablation (Wavelight Allegretto Eye Q 400 Hz excimer laser) were performed in all cases. Pre-and post-operative examination included Shack-Hartmann aberrometry for 3 mm and 5 mm pupil sizes, CCT and IOP. Postoperative results at 1 year were compared to baseline values. Results: Changes in average values of coma, spherical aberration (SA), trefoil, CCT and IOP were not significant. Linear regression revealed significant associations between change (y) in trefoil and pre-enhancement value of trefoil for 3 mm pupil (0.828x-0.045, r=0.722, p<0.001), coma and pre-enhancement value of coma for 5 mm pupil (y=0.281x-0.030, r=0.501, n=30, p=0.048), SA for 3 mm pupil compared with change in CT (y=0.0080-0.0009x, r=-0.378, p=0.0392), and SA for 5 mm pupil compared with change in CCT (y=0.0035x-0.0541, r=0.524, p=0.0029). Also there was a significant association between IOP and CCT both pre-(IOP=0.0313CT-3.3, r=0.740, p<0.0001) and post-enhancement (IOP=0.0243CT-0.018, r=0.675, p<0.0001). Conclusion: LASIK enhancement with an aspheric ablation profile did not significantly impact on the average values for HOAs, IOP or CCT. For individual cases, the likely shift in magnitude of coma, trefoil and SA can be estimated and, the change in SA is correlated with changes in CCT. The change in the abscissa value linking IOP with CCT may be an indication of changes in biomechanical properties of the cornea in the central region.
关键词： High order aberrations (Hoas),LASIK enhancement,Wavefront,Intraocular pressure (IOP),Excimer laser,Wavelight allegretto,Corneal thickness
更新于2025-09-16 10:30:52