نتایج جستجو برای: corneal wavefront aberration

تعداد نتایج: 38950  

Journal: :Vision Research 1999
Susana Marcos Stephen A. Burns Esther Moreno-Barriusop Rafael Navarro

We measured the ocular wavefront aberration at six different visible wavelengths (between 450 and 650 nm) in three subjects, using a spatially resolved refractometer. In this technique, the angular deviation of light rays entering the pupil at different locations is measured with respect to a target viewed through a centered pupil. Fits of the data at each wavelength to Zernike polynomials were...

Journal: :Vision Research 2000
J. C He S. A Burns S Marcos

The wave-front aberration of the human eye was measured for eight subjects using a spatially resolved refractometer (a psychophysical ray-tracing test). The eyes were undilated and presented with accommodative stimuli varying from 0 to -6 diopters. Monochromatic wave-front aberrations tend to increase with increasing levels of accommodation, although there are substantial individual variations ...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2003
Sergio Barbero Susana Marcos Ignacio Jiménez-Alfaro

Corneal and ocular aberrations were measured in a group of eyes before and after cataract surgery with spherical intraocular lens (IOL) implantation by use of well-tested techniques developed in our laboratory. By subtraction of corneal from total aberration maps, we also estimated the optical quality of the intraocular lens in vivo. We found that aberrations in pseudophakic eyes are not signif...

Journal: :Journal of cataract and refractive surgery 2004
Lisa A Ostrin Sanjeev Kasthurirangan Adrian Glasser

PURPOSE To measure accommodation subjectively and objectively in a satisfied bilateral scleral expansion band patient. SETTING University of Houston, College of Optometry, Houston, Texas, USA. METHODS One bilateral scleral expansion patient (age 50 years), 9 age-matched normal presbyopic control subjects (age range 48 to 52 years), and 1 normal control subject (age 27 years) participated. T...

Journal: :Investigative ophthalmology & visual science 2003
Michael K Smolek Stephen D Klyce

PURPOSE It is assumed that wavefront error data arising from aberrometry are adequately described by a Zernike polynomial function, although this assumption has not been extensively tested. Inaccuracies in wavefront error may compromise clinical testing and refractive correction procedures. The current retrospective study correlates visual acuity with corneal wavefront error and with the residu...

Journal: :Vision Research 2006
J. S. McLellan P. M. Prieto S. Marcos S. A. Burns

Wave aberrations degrade the optical quality of the eye relative to the diffraction limit, but there are situations in which having slightly aberrated optics can provide some relative visual benefits. This fact led us to consider whether interactions among aberrations in the eye's wavefront produce an advantage for image quality relative to wavefronts with randomized combinations of aberrations...

2018
M. Teich J. W. Czarske

Background: Optical distortions can significantly deteriorate the measurement accuracy in particle image velocimetry systems. Such distortions can occur at fluctuating phase boundaries during flow measurement and result from the accompanied refractive index changes. The usage of a wavefront sensor can be hindered by disturbing light reflexes or scattering. Methods: A combination of sharpness me...

2004
Brian Jeffrey Bauman

Designing an adaptive optics (AO) system for extremely large telescopes (ELT’s) will present new optical engineering challenges. Several of these challenges are addressed in this work, including first-order design of multi-conjugate adaptive optics (MCAO) systems, pyramid wavefront sensors (PWFS’s), and laser guide star (LGS) spot elongation. MCAO systems need to be designed in consideration of...

Journal: :Journal of cataract and refractive surgery 2010
Izzet Can Tamer Takmaz Hasan Ali Bayhan Başak Bostancı Ceran

PURPOSE To evaluate the efficacy and reliability of a microincision intraocular lens (IOL) and its use in biaxial microincision cataract surgery (MICS). SETTING Atatürk Training and Research Hospital, Ankara, Turkey. DESIGN Prospective clinical study. METHODS A microincision IOL (Akreos MI60) was implanted after cataract extraction by the biaxial MICS technique. Over a postoperative follo...

Journal: :Journal of biomedical optics 2010
Jae Won Cha Jerome Ballesta Peter T C So

The imaging depth of two-photon excitation fluorescence microscopy is partly limited by the inhomogeneity of the refractive index in biological specimens. This inhomogeneity results in a distortion of the wavefront of the excitation light. This wavefront distortion results in image resolution degradation and lower signal level. Using an adaptive optics system consisting of a Shack-Hartmann wave...

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