نتایج جستجو برای: aberrations
تعداد نتایج: 17220 فیلتر نتایج به سال:
An achromatic element eliminating only longitudinal chromatic aberration (LCA) while maintaining transverse chromatic aberration (TCA) is established for the eye model, which involves the angle formed by the visual and optical axis. To investigate the impacts of higher-order aberrations on vision, the actual data of higher-order aberrations of human eyes with three typical levels are introduced...
In an attempt to quantify the nonrandomness of primary neoplasia-associated acquired chromosomal aberrations in humans, we have retrieved information from a computerized data base on the chromosomal abnormalities of 9069 human neoplasms. By restricting the survey to the 1985 cases with a solitary structural rearrangement, we attempted to limit the analysis to only those aberrations that were mo...
In an attempt to quantify the nonrandomness of primary neoplasiaassociated acquired chromosomal aberrations in humans, we have re trieved information from a computerized data base on the chromosomal abnormalities of 9069 human neoplasms. By restricting the survey to the 1985 cases with a solitary structural rearrangement, we attempted to limit the analysis to only those aberrations that were mo...
Total ocular higher order aberrations and corneal topography of myopic, emmetropic and hyperopic eyes of 675 adolescents (16.9 ± 0.7 years) were measured after cycloplegia using COAS aberrometer and Medmont videokeratoscope. Corneal higher order aberrations were computed from the corneal topography maps and lenticular (internal) higher order aberrations derived by subtraction of corneal aberrat...
While correcting the aberrations of the eye produces large increases in retinal image contrast, the corresponding improvement factors in the contrast sensitivity function have been little explored and results are controversial. We measured the CSF of 4 subjects with and without correcting monochromatic aberrations. Monochromatic CSF measurements were performed at four orientations (0, 45, 90, a...
Introduction Former experiments have shown an increase in number of unstable chromosomal aberrations in normal human fibroblast strains with ongoing culturing time of the populations [1, 2]. These de novo formed unstable aberrations are an indicator of genomic instability which is considered to be one important step towards carcinogenesis. In the same experiments we observed the accumulation of...
Monochromatic aberrations that exist in the human eye will cause differences in the appearance of the point-spread function (PSF) depending on whether there is positive or negative defocus. We establish whether it is possible to use these differences in the PSF to distinguish the direction of defocus. The monochromatic aberrations of eight subjects were measured with a Hartmann-Shack wave-front...
PURPOSE Customized laser surgery attempts to correct higher order aberrations, as well as defocus and astigmatism. The success of such a procedure depends on using a laser beam that is small enough to produce fine ablation profiles needed to correct higher order aberrations. METHODS Wave aberrations were obtained from a population of 109 normal eyes and 4 keratoconic eyes using a Shack-Hartma...
OBJECTIVE Chromosomal aberrations are common causes of multiple anomaly syndromes. Recurrent chromosomal aberrations have been identified by conventional cytogenetic methods used widely as one of the most important clinical diagnostic techniques. MATERIALS AND METHODS In this retrospective study, the incidences of chromosomal aberrations were evaluated in a six year period from 2005 to 2011 i...
PURPOSE To determine the predictability, efficacy, safety, and stability of LASIK using custom ablation with the NIDEK Advanced Vision Excimer Laser System (NAVEX). METHODS One hundred twenty eyes underwent LASIK for myopia using the OPDCAT algorithm. Refractive outcomes and the change in higher order aberrations, coma, and spherical aberrations were analyzed. Postoperative follow-up ranged f...
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