نتایج جستجو برای: induced higher order aberration
تعداد نتایج: 2649586 فیلتر نتایج به سال:
It is known that the depth of focus (DOF) of the human eye can be affected by the higher order aberrations. We estimated the optimal combinations of primary and secondary Zernike spherical aberration to expand the DOF and evaluated their efficiency in real eyes using an adaptive optics system. The ratio between increased DOF and loss of visual acuity was used as the performance indicator. The r...
Spherical aberration arising from deviations of the thickness of an optical disc substrate from a nominal value can be compensated to a great extent by illuminating the scanning objective lens with a slightly convergent or divergent beam. The optimum conjugate change and the amount and type of residual aberration are calculated analytically for an objective lens that satisfies Abbe's sine condi...
purpose: the aim of this study was to compare higher-order aberrations between personalized treatment (pt) versus personalized treatment advanced (pta) photorefractive keratectomy (prk) for myopia and myopic astigmatism. methods: in this clinical trial, 80 eyes of 40 patients who met inclusion criteria were enrolled. they underwent prk using pt or pta algorithm randomly. higher-order aberration...
PURPOSE To simulate the effects of decentration on lower- and higher-order aberrations (LOAs and HOAs) and optical quality, by using measured wavefront error (WFE) data from a cat photorefractive keratectomy (PRK) model. METHODS WFE differences were obtained from five cats' eyes 19 +/-7 weeks after spherical myopic PRK for -6 D (three eyes) and -10 D (two eyes). Ablation-centered WFEs were co...
The common marmoset, Callithrix jacchus, is a primate model for emmetropization studies. The refractive development of the marmoset eye depends on visual experience, so knowledge of the optical quality of the eye is valuable. We report on the wavefront aberrations of the marmoset eye, measured with a clinical Hartmann-Shack aberrometer (COAS, AMO Wavefront Sciences). Aberrations were measured o...
OBJECTIVE To evaluate the aberration and visual quality differences between myopic and astigmatic eyes before and after contact lens application by using corneal aberrometer and low- contrast sensitivity chart. METHODS Eighty eyes of 40 patients were included in this study. Patients were divided into two groups as myopic (40 eyes, n=20) and astigmatic groups (40 eyes, n=20). We used aspheric ...
Semantic models are presented for two simple imperative languages with higher order constructs. In the rst language the interesting notion is that of second order assignment x := s, for x a procedure variable and s a statement. The second language extends this idea by a form of higher order communication, with statements c ! s and c ? x, for c a channel. We develop operational and denotational ...
PURPOSE To determine whether Hartmann-Shack wavefront sensing detects differences in optical performance in vivo between poly(methyl methacrylate) (PMMA) and foldable acrylic intraocular lenses (IOLs) and between clear corneal and scleral tunnel incisions and whether optical differences are manifested as differences in visual performance. SETTING Department of Optometry, University of Bradfor...
The next major space-borne observatory, the James Webb Space Telescope, will be a 6.6M field-biased, obscured, three-mirror anastigmat (TMA). Over the used field of view, the performance of TMA telescopes is dominated by 3(rd) order misalignment aberrations. Here it is shown that two dominant 3(rd) order misalignment aberrations arise for any TMA telescope. One aberration, field constant 3(rd) ...
We explored the impact of the eye's higher-order aberrations on subjective refraction comparing two classes of methods for estimating refractive state, one based directly on the wave aberration defined in the pupil plane and another based on the retinal image plane. The method defined in the pupil plane chose the sphere and cylinder that either minimized the wave aberration root mean square or ...
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