نتایج جستجو برای: coma aberration
تعداد نتایج: 16755 فیلتر نتایج به سال:
purpose: to investigate the relationship between higher-order aberrations (hoas) and contrast sensitivity function (csf) in myopes. methods: in this cross-sectional study, hoas and csf were measured in myopic eyes over a 6-mm pupil. pupil diameter was measured in photopic condition. the correlation between hoas and csf was investigated using multivariate linear regression analysis. results: sev...
Optical disks are read out by focusing a beam of high numerical aperture (NA) through the substrate. Deviations of the thickness from the nominal value result in spherical aberration; tilting the substrate results in coma. Exact analytical expressions for the rms aberration per micrometer thickness mismatch (for spherical aberration) and per degree tilt (for coma) are derived. The paraxial esti...
By generalizing the wave aberration function to include plane symmetric systems, we describe the aberration fields for a combination of plane symmetric systems. The combined system aberration coefficients for the fields of spherical aberration, coma, astigmatism, defocus and distortion depend on the individual aberration coefficients and the orientations of the individual plane symmetric compon...
PURPOSE To examine the effect of misalignment (decentration and tilt) of intraocular lenses (IOLs) on retinal image quality using a water-immersed model eye with corneal spherical aberration adjusted to the values found in normal human eyes (spherical aberration 0.25 μm; pupil diameter 6 mm). METHODS Three types of IOL holders were prepared. The first was without decentration or tilt, the sec...
The precision and work efficiency of the distributed repeat projection lithography machine (DSW) directly affect special requirements large-scale integrated circuit production process. In order to improve exposure imaging accuracy projection, paper proposes object image difference in-situ detection (AMF) technology based on particle swarm optimization. article analyzes basic principles this usi...
PURPOSE To use a large wave-front database of a clinical population to investigate relationships between refractions and higher-order aberrations and between aberrations of right and left eyes. METHODS Third- and fourth-order aberration coefficients and higher-order root-mean-squared aberrations (HO RMS), scaled to a pupil size of 4.5-mm diameter, were analyzed in a population of approximatel...
PURPOSE To evaluate the correlation between refractive error and higher-order aberrations (HOAs) in patients with myopic astigmatism. METHODS HOAs were measured using the Zywave II aberrometer over a 6 mm pupil. Correlations between HOAs and myopia, astigmatism, and age were analyzed. RESULTS One hundred and twenty-six eyes of 63 subjects with mean age of 26.4±5.9 years were studied. Mean s...
purpose: to study the distribution of ocular higher-order aberrations (hoas) and mesopic pupil size in individuals screened for refractive surgery. methods: ocular hoas and mesopic pupil size were studied in 2458 eyes of 1240 patients with myopia, simple myopic astigmatism and compound myopic astigmatism and 215 eyes of 110 patients with hyperopia, simple hyperopic astigmatism and compound hype...
It is well known that the aberrations of the cornea are partially compensated by the aberrations of the internal optics of the eye (primarily the crystalline lens) in young subjects. This effect has been found not only for the spherical aberration, but also for horizontal coma. It has been debated whether the compensation of horizontal coma is the result of passive mechanism [Artal, P., Benito,...
The effects of geometric residual aberrations such as coma B2 and two-fold astigmatism A1 on the contrast in aberration corrected high resolution transmission electron microscopy (HRTEM) images are investigated on single-walled carbon nanotubes (SWNT). The individual aberrations are adjusted and set up manually using an imaging CS-corrector. We demonstrate how coma B2 can be recognized by an ex...
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