Results 261 to 270 of about 9,035 (308)

A discussion of two wavefront aberration correction procedures

Ultrasonic Imaging, 1992
This review paper discusses the basic properties of two adaptive signal processing procedures for dealing with weak scattering in a phased array transducer system. A fundamental improvement in the lateral resolution of ultrasonic echo scanners will result if the weight vector of a large phased array transducer can be modified to account for distortion ...
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Higher‐Order Wavefront Aberrations in Retinitis Pigmentosa

Optometry and Vision Science, 2005
ABSTRACT: Purpose. The purpose of this study was to characterize higher‐order wavefront aberrations associated with posterior subcapsular (PSC) cataracts in patients with retinitis pigmentosa (RP). Methods.
Aruna S, Rajagopalan, Mahnaz, Shahidi, Kenneth R, Alexander, Gerald A, Fishman, Ruth, Zelkha   +4 more
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Objective Measurement of Wavefront Aberrations With and Without Accommodation

Journal of Refractive Surgery, 2001
ABSTRACT PURPOSE: The measurement of the refractive error profile is more useful than corneal topography in understanding the complexities of refractive surgery. We report on experimental studies of the spatially resolved refractometer Tracey-1, developed in Ukraine by IBME in medical cooperation with VEIC, Greece. METHODS: Ten eyes
L G, Pallikaris, S I, Panagopoulou, C S, Siganos, V V, Molebny   +3 more
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Optical Wavefronts and Their Aberrations

2013
The position and the size of the Gaussian image of an object formed by an optical imaging system is determined by using its Gaussian imaging equations. We have stated in Chapter 1 that the quality of the diffraction image depends on the aberrations of the system. A spherical wave originating at a point object is incident on the system. The image formed
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Changes in Wavefront Aberration With Pharmaceutical Dilating Agents

Journal of Refractive Surgery, 2005
ABSTRACT PURPOSE: Finding the best way to capture the wavefronts of small pupils for refractive surgery has become a more pressing issue as the general population ages. This study explores whether pharmaceutical dilation impacts wavefront measurement and pupil centroid.
K Ashley, Tuan, Seema, Somani, Dimitri A, Chernyak   +2 more
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Analysis of higher order aberrations in recently developed wavefront-shaped IOLs

Graefe's Archive for Clinical and Experimental Ophthalmology, 2021
R. Schmid, A. Borkenstein
semanticscholar   +1 more source

The Calculation of the Wavefront Aberration Polynomial

Optica Acta: International Journal of Optics, 1980
This paper presents a method of generating the wavefront polynomial using a set of orthogonal polynomials that are particularly relevant to the ray fans used in optical design and evaluation. This method avoids the unsatisfactory aspects of conventional curve-fitting techniques that use collocation, osculation or least-squares to establish a polynomial
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MEASUREMENT OF THE AXIAL WAVEFRONT ABERRATION OF THE HUMAN EYE

Ophthalmic and Physiological Optics, 1985
Abstract— An objective variation of Howland and Howland's subjective crossed‐cylinder aberroscope method of estimating ocular aberration is described. An ophthalmoscopic arrangement allows the distorted retinal image of the aberroscope grid to be directly photographed for later analysis.
G, Walsh, W N, Charman
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Evaluation of the Wavefront Aberration in Holography

Optica Acta: International Journal of Optics, 1973
A method is described, using exact ray-tracing, for calculating the wavefront aberration which arises from a change in geometry or wavelength between the recording and reconstructing processes, of a holographic image point, in the case of a plane hologram.
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Wavefront aberrations variations with accommodation

Acta Ophthalmologica, 2009
Abstract Purpose To study the effects of phenylephrine 5% topical administration on accommodative response and wavefront aberrations variation. Methods The research followed the tenets of the Declaration of Helsinki . 28 eyes from 14 volunteers with spherical equivalent defocus error between –2D and +1D, no eye disease history and between 20 to 25 ...
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