scholarly journals Wavefront optics and retinal image quality

2013 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Cristina M. Oliveira ◽  
Sandra Franco
Keyword(s):  
Vision Research ◽  
Optical Quality ◽  
Wavefront Sensing ◽  
Zernike Polynomials ◽  
Secondary Effect ◽  
General Description ◽  
Wave Optics ◽  
Optical Aberrations ◽  
Optical Components ◽  
Optical Structure

With the increasing importance of optical aberrations in both vision research and clinical practice, it becomes necessary for vision scientists to have a thorough understanding of the concepts behind wavefront optics. Therefore, in this review, we provide some basic wave optics concepts useful to understand wavefront analysis, and describe the application of Zernike polynomials in the decomposition of aberrations. A general description of the human eye optical structure is given, followed by a more detailed analysis of the optical components of the eye and optical aberrations, and their secondary effect on overall optical quality. We further provide an overview of the current corneal and ocular wavefront sensing methods.

On the circle polynomials of Zernike and related orthogonal sets

1954 ◽  
Vol 50 (1) ◽  
pp. 40-48 ◽  
Author(s):  
A. B. Bhatia ◽  
E. Wolf
Keyword(s):  
Unit Circle ◽  
Generating Functions ◽  
Legendre Polynomials ◽  
Phase Contrast ◽  
Diffraction Theory ◽  
Zernike Polynomials ◽  
Optical Aberrations ◽  
Orthogonal Set ◽  
Complete Orthogonal Set ◽  
Explicit Expressions

ABSTRACTThe paper is concerned with the construction of polynomials in two variables, which form a complete orthogonal set for the interior of the unit circle and which are ‘invariant in form’ with respect to rotations of axes about the origin of coordinates. It is found that though there exist an infinity of such sets there is only one set which in addition has certain simple properties strictly analogous to that of Legendre polynomials. This set is found to be identical with the set of the circle polynomials of Zernike which play an important part in the theory of phase contrast and in the Nijboer-Zernike diffraction theory of optical aberrations.The results make it possible to derive explicit expressions for the Zernike polynomials in a simple, systematic manner. The method employed may also be used to derive other orthogonal sets. One new set is investigated, and the generating functions for this set and for the Zernike polynomials are also given.

scholarly journals On the Relationship between Corneal Biomechanics, Macrostructure and Optical Properties

2021 ◽  
Author(s):  
Francisco J. Ávila ◽  
Laura Remón ◽  
Maria Concepción Marcellán
Keyword(s):  
Optical Properties ◽  
Biomechanical Properties ◽  
Optical Quality ◽  
Optical Transparency ◽  
Optical Aberrations ◽  
Corneal Aberrations ◽  
Scheimpflug Imaging ◽  
The Hierarchical Structure ◽  
The Relationship

Optical properties of the cornea are responsible for correct vision, ultrastructure allows optical transparency and biomechanical properties governs the shape, elasticity or stiffness of the cor-nea affecting ocular integrity and intraocular pressure. Therefore, optical aberrations, corneal transparency, structure and biomechanics play a fundamental role in the optical quality of hu-man vision, ocular health and refractive surgery outcomes. However, the convergence of those properties is not yet reported at macroscopic scale within the hierarchical structure of the cornea. This work explores the relationships between biomechanics, structure and optical properties (corneal aberrations and optical density) at macrostructural level of the cornea through dual Placido-Scheimpflug imaging and air-puff tonometry systems in a healthy young adult popula-tion. Results showed convergence between optical transparency, corneal macrostructure and biomechanics.

Beam forming optic aberrations’ impact on maximum range of semiconductor laser based rangefinders

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
J. Wojtanowski ◽  
M. Zygmunt ◽  
M. Traczyk ◽  
Z. Mierczyk ◽  
M. Jakubaszek
Keyword(s):  
Semiconductor Laser ◽  
Signal To Noise Ratio ◽  
Beam Forming ◽  
Substantial Part ◽  
Optical Fabrication ◽  
Optical Aberrations ◽  
Optical Components ◽  
Current Trends ◽  
Maximum Range ◽  
Measurable Range

AbstractMiniature rangefinding modules based on pulsed semiconductor laser technology are becoming more and more popular components of a variety of modern optoelectronics devices where precise, fast and eye-safe range estimation is needed. Current trends associated with minimization of both physical dimensions and cost of such modules lead to the design approach relying on exact meeting the requirements of a given application, concerning the spatial resolution and especially the maximum range. Optical components of a rangefinder cover a substantial part of its cost and determine its overall dimensions, but primarily — the indigenous parameters of the transmitter and receiver trains are crucial for the maximum measurable range. The quantitative analysis of transmitter optics aberrational characteristics impact on signal-to-noise ratio range dependence and thus the maximum range of a laser rangefinder is presented in the paper. Modern optical fabrication technology offers a huge range of solutions, changing in imaging/projecting characteristics which implies the price level as well. Rangefinder optics has a very specific task which sometimes makes it unreasonable to fight for the diffraction limited performance. The article provides the approach how to determine the acceptable level of optical aberrations which still does not degrade the measurable range significantly.

scholarly journals X-ray optics and beam characterization using random modulation: experiments

2020 ◽  
Vol 27 (2) ◽  
pp. 293-304 ◽  
Author(s):  
Sebastien Berujon ◽  
Ruxandra Cojocaru ◽  
Pierre Piault ◽  
Rafael Celestre ◽  
Thomas Roth ◽  
...  
Keyword(s):  
Online Optimization ◽  
Minimum Amount ◽  
Wavefront Sensing ◽  
Optical Components ◽  
Ray Optics ◽  
Active Optics ◽  
X Ray ◽  
Wavefront Distortion ◽  
Random Modulation ◽  
Beam Characterization

A parallel paper [Berujon, Cojocaru, Piault, Celestre, Roth, Barrett & Ziegler (2020), J. Synchrotron Rad. 27, 284–292] reviewed theoretically some of the available processing schemes for X-ray wavefront sensing based on random modulation. Shown here are experimental applications of the technique for characterizing both refractive and reflective optical components. These fast and accurate X-ray at-wavelength metrology methods can assist the manufacture of X-ray optics that transport X-ray beams with a minimum amount of wavefront distortion. It is also recalled how such methods can facilitate online optimization of active optics.

KDP Crystals Grown in Defined Crystallographic Direction

2014 ◽  
Vol 1004-1005 ◽  
pp. 321-324
Author(s):  
Ji Long Wen ◽  
Bing Teng ◽  
De Gao Zhong ◽  
Jian Geng ◽  
Qing Sun
Keyword(s):  
High Resolution ◽  
Chemical Etching ◽  
Optical Quality ◽  
Crystallographic Direction ◽  
X Ray Diffraction ◽  
Labor Costs ◽  
Optical Components ◽  
X Ray ◽  
Characterization Studies ◽  
Kdp Crystals

KDP crystals are restrained to grow along (100) direction by a new designed platform. Compared to conventional method, it enables us to grow KDP crystals with higher optical utilization and less labor costs in fabrication process of optical components. The size of the grown crystals is 20×20×10mm3. Its quality has been analyzed by UV-vis spectral, chemical etching and high resolution X-ray diffraction. The FWHM of diffraction curves is 32 and 36 arc s. The transparency measured by UV-vis spectrometer is up to 80%. The results from various characterization studies indicate that the optical quality is almost as same as the conventionally grown crystals.

Ontogenetic and Phylogenetic Variation of Form and Function of the Ocular Lens

1989 ◽  
Vol 174 ◽  
Author(s):  
J. G. Sivak
Keyword(s):  
Refractive Index ◽  
Life Histories ◽  
Spherical Aberration ◽  
Focal Length ◽  
Relative Size ◽  
Crystalline Lens ◽  
Optical Quality ◽  
Form And Function ◽  
And Function ◽  
Optical Structure

AbstractThe crystalline lens of the eye is a unique optical structure that continues to develop within the eye throughout life. This process of development results in the formation of a lens with a gradient refractive index that has important optical consequences, particularly in the control of spherical aberration. The optical characteristics of the vertebrate crystalline lens are reviewed in terms of environmental concerns and spherical aberration. Lens shape and relative size are determined by such factors as whether the eye is to be used in air or water and whether it is to be used under scotopic or photopic conditions. The continued growth of the lens through life can be related to whether the lens exhibits positive or negative spherical aberration. In general, spherical aberration, as measured using a split laser beam method with excised lenses, is minimized in species with life histories indicating superior resolution ability. In addition, lens optical quality, as indicated by zonular differences in focal length, deteriorates with lens age. While the embryonic and post-embryonic lens undergoes significant change in size, shape and refractive index distribution, it appears that focal constancy is maintained, at least in certain species. This finding may indicate a means of simplifying the process of emmetropization.

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