Purpose To investigate the reliability of ocular aberration measurement in myopic children under scotopic conditions and to validate the mathematical Zernike pupil scaling-down technique. Methods Ocular aberrations of 45 myopic children were examined under scotopic conditions via iTrace aberrometer. The intra- and intersession repeatability was evaluated for both the measured values with the ...

PURPOSE Our aim was to obtain a complete description of the interactions of rigid gas permeable (RGP) contact lenses with the optics of normal eyes. METHODS We measured total and anterior-surface aberrations in four subjects, who were all long-term RGP contact lens wearers. The anterior-surface wave aberration was obtained from videokeratographic elevation maps, and ocular wave aberration was...

PURPOSE To compare the validity and effectiveness of 2 methods for expanding depth of focus to correct for presbyopia; that is, induction of spherical aberration and small-pupil apertures. SETTING University of California, Berkeley, California, USA. DESIGN Comparative case series. METHODS A random 4-alternative forced-choice acuity task was performed on 13 subjects. Visual performance and...

A comprehensive description of chromosome aberrations is introduced that is suitable for all cytogenetic protocols (e.g. solid staining, banding, FISH, mFISH, SKY, bar coding) and for mathematical analyses. "Aberration multigraphs" systematically characterize and interrelate three basic aberration elements: (1) the initial configuration of chromosome breaks; (2) the exchange process, whose cycl...

The wavelength dependence of the incoherent point spread function in a wide-field microscope was investigated experimentally. Dispersion in the sample and optics can lead to significant changes in the point spread function as wavelength is varied over the range commonly used in fluorescence microscopy. For a given sample, optical conditions can generally be optimized to produce a point spread f...

PURPOSE To evaluate the theoretical influence of the change in corneal asphericity (ΔQ) on the change in fourth-order Zernike spherical aberration coefficient (ΔC(4)0) with customized aspheric refractive correction of myopia and hyperopia. METHODS The initial anterior corneal surface profile was modeled as a conic section of apical radius of curvature R0 and asphericity Q₀. The postoperative ...

The attainable specimen resolution is determined by the instrumental resolution limit d(i) and by radiation damage. Solid objects such as metals are primarily damaged by atom displacement resulting from knock-on collisions of the incident electrons with the atomic nuclei. The instrumental resolution improves appreciably by means of aberration correction. To achieve atomic resolution at voltages...

BACKGROUND/PURPOSE We present a method for calibrating low-cost digital dermoscopes that corrects for color and inconsistent lighting and also corrects for chromatic aberration. Chromatic aberration is a form of radial distortion that often occurs in inexpensive digital dermoscopes and creates red and blue halo-like effects on edges. Being radial in nature, distortions due to chromatic aberrati...

This paper aims to clarify the role of aberration effects on the propagation and absorption of wave beams in inhomogeneous dispersive and dissipative media. We consider models in which aberration effects can be caused by the presence of either caustics or spatially dispersive absorption, with reference to the propagation near a cut-off or to the electron cyclotron (EC) resonance, respectively. ...

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