نتایج جستجو برای: aberration

تعداد نتایج: 6840  

Journal: :Investigative ophthalmology & visual science 1983
J G Sivak A Dovrat

Split laser beams of varying separation were directed through the crystalline lenses of rats of young, old, and intermediate age. The variation in back vertex distance was determined from photographs of the focal effects of each lens. The results indicate that negative spherical aberration of the rat lens increases with age. In addition, local reversals in the slopes of the negative spherical a...

Journal: :Optics express 2013
Lucimara Cristina Nakata Scaduto Jose Sasian Mario Antonio Stefani Jarbas Caiado de Castro Neto

Misalignments always occur in real optical systems. These misalignments do not generate new aberration forms, but they change the aberration field dependence. Two-mirror telescopes have been used in several applications. We analyze a two-mirror telescope configuration that has negligible sensitivity to decenter misalignments. By applying the wave aberration theory for plane-symmetric optical sy...

Journal: :Investigative ophthalmology & visual science 1989
R P Hemenger A Tomlinson P J Caroline

A technique is described to determine the change in image contrast as a result of the spherical aberration induced by the radial keratotomy procedure. The hypothesis that the loss in contrast sensitivity of the RK eye is due to the change in spherical aberration postsurgically, is found to be acceptable for some patients. However, this is not a sufficient explanation in all cases. This conclusi...

Journal: :Optics letters 2000
R Navarro E Moreno-Barriuso S Bará T Mancebo

We present a method for manufacturing phase plates to compensate for the wave aberration in the human eye. The wave aberration of the eye is measured in vivo by a new laser ray-tracing method and then compensated for by a phase plate placed in front of the eye. This plate is made from a gray-level single-mask photosculpture in photoresist. Two experiments were carried out, first with an artific...

2009
Lei Sheng Shanjun Zhang Hongbing Zhu

In this paper, a simulation method for lens design is presented considering the aberration effect. Traditionally, most optical path calculation algorithms are based on aberration theory and result in approximation. For eliminating this problem and avoiding the limitations from aberration theory, this paper considers paraxial rays and others as the same to trace their paths. For checking out the...

Journal: :American journal of ophthalmology 2014
Eloy A Villegas Encarna Alcón Sandra Mirabet Inés Yago José María Marín Pablo Artal

PURPOSE To evaluate the quality of vision and depth of focus induced by controlled amounts of negative spherical aberration in patients implanted bilaterally with light-adjustable intraocular lenses. DESIGN Prospective, nonrandomized clinical trial. METHODS Seventeen patients were implanted and treated with appropriate spatial irradiance light profiles. One eye was set for emmetropia, and t...

2014
Hun Lee Kwanghyun Lee Ji Min Ahn Eung Kweon Kim Bradford Sgrignoli Tae-im Kim

PURPOSE We investigated the correlations between optical quality parameters obtained from the double-pass system and ocular aberrations obtained from the ray-tracing aberrometer in multifocal intraocular lens (IOL) implanted eyes. MATERIALS AND METHODS Twenty eyes from 20 patients were enrolled in this study. Modulation transfer function cutoff frequency, The Strehl ratio, objective scatter i...

Journal: :The Journal of the Acoustical Society of America 2004
Anthony Gerig James Zagzebski

Current ultrasonic scatterer size estimation methods assume that acoustic propagation is free of distortion due to large-scale variations in medium attenuation and sound speed. However, it has been demonstrated that under certain conditions in medical applications, medium inhomogeneities can cause significant field aberrations that lead to B-mode image artifacts. These same aberrations may be r...

Journal: :Investigative ophthalmology & visual science 2013
Alberto de Castro Judith Birkenfeld Bianca Maceo Fabrice Manns Esdras Arrieta Jean-Marie Parel Susana Marcos

PURPOSE To estimate changes in surface shape and gradient refractive index (GRIN) profile in primate lenses as a function of accommodation. To quantify the contribution of surface shape and GRIN to spherical aberration changes with accommodation. METHODS Crystalline lenses from 15 cynomolgus monkeys were studied in vitro under different levels of accommodation produced by a stretching system....

Journal: :Journal of microscopy 2002
L Sherman J Y Ye O Albert T B Norris

We demonstrate adaptive aberration correction for depth-induced spherical aberration in a multiphoton scanning microscope with a micromachined deformable mirror. Correction was made using a genetic learning algorithm with two-photon fluorescence intensity feedback to determine the desired shape for an adaptive mirror. For a 40x/0.6 NA long working distance objective, the axial scanning range wa...

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