نتایج جستجو برای: aberration
تعداد نتایج: 6840 فیلتر نتایج به سال:
PURPOSE To analyze internal spherical aberration in pseudophakic eyes that underwent aspheric intraocular lens (IOL) implantation, and to investigate the relationships between biometric data and the effectiveness of aspheric IOL implantation. METHODS This retrospective study included 40 eyes of 40 patients who underwent implantation of an IOL having a negative spherical aberration of -0.20 μm...
The in vivo spherical aberration of the lenses of 26 subjects was estimated from the measured total aberration of the eye and that predicted from the measured shape of the anterior corneal surface. Since it was only possible to estimate the aberration contribution from the posterior corneal surface, its value led to an uncertainty in the final aberration level of the lens. For all the subjects ...
The ideal location for an aberration corrector in an electron-optical column is at the place where the aberration is introduced. In practice, this of course typically cannot be achieved. The resultant separation between where an aberration is introduced and where it is removed produces combination aberrations for all aberrations of higher than first order. In the case of third-order aberration ...
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 ideal location for an aberration corrector in an electron-optical column is exactly at the place where the aberration to be corrected is introduced. In practice, this of course cannot be achieved. The resultant separation between where an aberration is introduced and where it is removed produces combination aberrations for all aberrations of higher than first order. A case of particular imp...
purpose: to compare acrysof iq and akreos ao aspheric intraocular lenses (iols) in terms of spherical aberration and contrast sensitivity. methods: thirty-seven eyes of 37 patients undergoing phacoemulsification cataract surgery were randomized to implantation of acrysof iq or akreos ao iols. three months postoperatively, best-corrected visual acuity (bcva), spherical aberration (with 4 and 6 m...
PURPOSE Adaptive optics systems can be used to investigate the potential visual benefit associated with correcting ocular wave-front aberration. In this study, adaptive optics techniques were used to evaluate the potential advantages and disadvantages associated with intraocular lenses (IOLs) with modified spherical aberration profiles. METHODS An adaptive optics vision simulator was construc...
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...
Control of chromatic aberration through purely optical means is well known. We present a novel, to our knowledge, optical-digital method of controlling chromatic aberration. The optical-digital system, which incorporates a cubic phase-modulation (CPM) plate in the optical system and postprocessing of the detected image, effectively reduces a system's sensitivity to misfocus in general or axial ...
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