Search results for "Lenses"
showing 10 items of 294 documents
Refractive index and equilibrium water content of conventional and silicone hydrogel contact lenses
2006
Prova tipográfica (In Press)
Analysis of the possible benefits of aspheric intraocular lenses: review of the literature.
2008
We reviewed recently published studies that analyzed the visual and optical quality in eyes with different spherical and aspheric intraocular lenses (IOLs). Recent studies focused on visual quality metrics, such as visual acuity and contrast sensitivity, under photopic and mesopic lighting conditions and optical metrics, such as wavefront aberrations, especially spherical aberration. The results in this review were used in an attempt to understand whether there is a visual and/or optical benefit of implanting aspheric IOLs over implanting spherical IOLs.
Analysis of the depth of field of integral imaging displays based on wave optics.
2013
In this paper, we analyze the depth of field (DOF) of integral imaging displays based on wave optics. With considering the diffraction effect, we analyze the intensity distribution of light with multiple micro-lenses and derive a DOF calculation formula for integral imaging display system. We study the variations of DOF values with different system parameters. Experimental results are provided to verify the accuracy of the theoretical analysis. The analyses and experimental results presented in this paper could be beneficial for better understanding and designing of integral imaging displays.
In vitro optical performance of a new aberration-free intraocular lens
2014
To assess the optical performance of the new EnVista intraocular lens (IOL). Four aspheric IOLs were evaluated; the new EnVista is one amoung them. This IOL, similarly to the Z-Flex HB and the Bi-Flex 1.8 667AB ones, has a neutral aspheric design, whereas the fourth IOL under test (AcrySof IQ IOL SN60WF) presents a negative spherical aberration (SA). The IOL’s aberration patterns were measured in vitro, by setting them up on an optical bench. From these aberration-pattern data, the modulation transfer function (MTF), the average modulation values, and the points spread function (PSF) were calculated. Furthermore, in order to assess the potential optical quality that these IOLs would yield o…
Optical quality comparison between 2 collagen copolymer posterior chamber phakic intraocular lens designs
2014
Purpose To compare the optical quality in vitro of 2 designs of the Visian Implantable Collamer Lens phakic intraocular lens (pIOL) for different powers and optical apertures. Setting University of Valencia, Valencia, Spain. Design Experimental study. Methods The Nimo TR1504 deflectometry device was used to measure the V4c pIOL, which has a smaller optic diameter, and the V5 pIOL, which has a larger optic diameter. The pIOLs were measured for −3.00 diopters (D), −6.00 D, −9.50 D, and −10.50 D at different optical apertures from 3.00 to 6.00 mm depending on the IOL power and model. The root mean square of higher-order aberrations (RMS HOAs) was analyzed. The Strehl ratio, point-spread functi…
In vitro optical performance of nonrotational symmetric and refractive-diffractive aspheric multifocal intraocular lenses: impact of tilt and decentr…
2012
Purpose To evaluate the optical quality of Acrysof Restor SN6AD1 refractive–diffractive +3.00 D and Lentis Mplus LS-312 nonrotational symmetric +3.00 D aspheric multifocal intraocular lenses (IOLs) and analyze the effect of tilt and decentration. Setting University of Valencia, Valencia, and University of Murcia, Murcia, Spain. Design Experimental study. Methods An artificial model eye was used to measure wavefront aberrations of both IOL models. The modulation transfer function (MTF) and point-spread function (PSF) were calculated for a 5.0 mm pupil and under 5 situations: centered, 0.2 mm and 0.4 mm decentered, and 2 degrees and 4 degrees tilted. Results The refractive–diffractive IOL had…
Tolerance to rotation of toric monofocal and bifocal intraocular lenses. A theoretical study
2018
Abstract This manuscript aims to evaluate the tolerance to rotation of a toric monofocal and a toric bifocal intraocular lenses with different cylinder powers. Theoretical designs based on wavefront aberrations were created to simulate a toric monofocal and a toric bifocal intraocular lens. Cylinder power ranged from −1 D to −6 D, in steps of −1 D. Tolerance to rotation was estimated by the visual Strehl ratio based on the optical transfer function (VSOTF) metric. Tolerance to rotation for both monofocal and bifocal intraocular lenses decreased when the cylinder power increased. For the bifocal design studied, the tolerance to rotation was larger for the near focus than for the far, however…
A review of Devenir Soi by Jacques Attali: through the lenses of liberalism and Buddhism
2015
Purpose – The purpose of this paper is to reinterpret Attali’s worldview through the lenses of liberalism and Buddhism by mobilizing the relevant literature, beyond the mere book review. This paper is an essay based on the book “Devenir Soi” by Jacques Attali, published in France in 2014. These analytical grids were chosen, because freedom and self-realization are two themes that pervade the book. Design/methodology/approach – After presenting the book structure, the objective and the methodological approach, we uncover Attali’s interrogation, namely how to free oneself from the omnipresence of evil, the withering away of the State and growing xenophobic populist self-entitlement. We make …
Analysis of the angular acceptance of surface plasmon Bragg mirrors
2007
International audience; We analyze an important aspect of the behavior of surface plasmon polariton (SPP) Bragg mirrors: the dependence of the angular acceptance for reflection on the incidence angle. By means of leakage radiation microscopy, both in direct and Fourier space, we observe that the angular acceptance diminishes for increasing incidence angles. This effect, which can considerably affect the design of devices based on these elements, is shown to be the consequence of the decrease of the bandgap width with increasing incidence angle. (c) 2007 Optical Society of America.
Ortokeratoloģijas lēcas dizaina ietekme uz acs aksiālā garuma izmaiņām.
2020
Maģistra darbs ir uzrakstīts angļu valodā uz 59 lapaspusēm. Tas satur 24 attēlus, 3 tabulas un 85 literatūras atsauces. Pētījuma mērķis bija novērtēt miopijas kontroles ortokeratoloģijas lēcu formas un optiskās zonas platuma ietekmi uz miopijas progresijas mazināšanu. Darbā tika analizēti 12 bērnu ar augstu miopijas pakāpi ortokeratoloģijas rezultāti, iegūti kopā no 19 acīm. Tika salīdzinātas acs aksiālā garuma izmaiņas, bērniem nēsājot parastas ortokeratoloģijas lēcas un lietojot specializētās miopijas kontroles ortokeratoloģijas lēcas. Rezultāti parādīja, ka specializētās ortokerotoloģijas lēcas daudz efektīvāk samazina acs aksiālā garuma palielināšanos nekā parastās lēcas. Atslēgas vārdi…