Advanced Designs Of Progressive Lenses A Brief Overview
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Advanced Designs Of Progressive Lenses A Brief Overview
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Author : Debapriya Mukhopadhyay
language : en
Publisher: Debapriya Mukhopadhyay
Release Date : 2023-10-24
Advanced Designs Of Progressive Lenses A Brief Overview written by Debapriya Mukhopadhyay and has been published by Debapriya Mukhopadhyay this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-10-24 with Medical categories.
Progressive lenses are a type of multifocal lenses that provide a smooth transition from distance to near vision without visible segments or lines. They are designed to correct presbyopia, a condition that affects most people over 40 and causes difficulty focusing on close objects. Progressive lenses have become increasingly popular due to their aesthetic appeal and functional benefits. However, not all progressive lenses are created equal. There are different types of progressive lens designs, each with its own advantages and disadvantages. This book provides a brief overview of the main categories of progressive lens designs, such as conventional, free-form, personalised, digital, and AI-designed progressive lenses. It also explains the key factors that influence the performance and comfort of progressive lenses, such as the fitting parameters, the lens material, the coating, and the frame shape. The book aims to help optometrists, opticians, and eyewear consumers understand the basic principles and features of progressive lens designs and make informed choices when selecting or prescribing them.
Optimization Methods For The Design Of Progressive Lenses
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Author : Glòria Casanellas
language : en
Publisher:
Release Date : 2020
Optimization Methods For The Design Of Progressive Lenses written by Glòria Casanellas and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
This work is the result of an Industrial Doctorate developed through a partnership agreement between the Universitat Politècnica de Catalunya and the company Horizons Optical. This thesis solves the complex design of progressive lenses for eyeglasses, which is a real problem in the industry. The lens is the transparent part of the eye behind the pupil that helps humans to see clearly by focusing light onto the retina. Over time, the lens loses some of its elasticity and therefore can no longer accommodate clearly for near vision. This phenomenon is called presbyopia and explains why people need reading glasses as they become older. Progressive lenses correct presbyopia and have a complex design: they have an upper region for far vision, a low region for near vision (reading), and a corridor that connects these areas which allows clearly vision at an intermediate distance, for example, when looking at a computer screen. The surface of the progressive lens designed in this thesis is the surface that is farthest from the eye, thus the power in the near region is bigger than the power in the far region.In geometrical terms, power and astigmatism are calculated using the principal curvatures of the lens surface. When the power changes vertically, unwanted lateral astigmatism (aberrations) appear as a result of the Minkwitz theorem. The focus of this thesis is the use of optimization methods in order to design progressive lenses minimizing the lateral aberrations (astigmatism) and providing the power required in each zone.This thesis presents two different models for computing progressive lens. Both models are highly nonlinear, nonconvex and continuous and were solved using the AMPL modeling language and the interior point solvers IPOPT, LOQO and KNITRO. Both models have approximately 900 variables (the coefficients of a third-degree B-spline basis). The first model has about 7000 constraints, while the second model has about 15000 constraints. Each constraint corresponds to a property of power or astigmatism at a point on the grid that defines the lens surface. The first model uses Cartesian coordinates and is an improved version of a previous model by the same author, published in a master's thesis. The CPU time in the master thesis was between 10 and 33 minutes, and in this thesis it has been reduced to less than 3 minutes using the same machine and the LOQO solver. In this thesis, all of the proposed instances converged using the LOQO solver and the Cartesian coordinate model, which was not the case in the master's thesis. However, with other solvers some of the instances did not converge using the Cartesian coordinate model of this thesis.The second model uses spherical coordinates and exhibits better convexity properties than the previous one based on Cartesian coordinates. All of the problem instances converged using all the proposed solvers, and the quality of the solution was improved. CPU time for spherical coordinates increased in relation to the Cartesian coordinate model, due to large calculations involved, but the number of iterations needed to converge decreased considerably (for example, from a maximum of 192 iterations using the Cartesian coordinate model to a maximum of 84 iterations using the spherical coordinate model and the same LOQO solver).These models resulted in two publications. The first one is a patent for an invention that uses the Cartesian coordinate model and orients the astigmatism gradient, which is useful when personalizing progressive lenses for real users. The second publication is a scientific article published in Optimization and Engineering that proposes the spherical coordinate model.
Design Of Progressive Lenses Mathematical Analysis And Numerical Methods
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Author : Jing Wang
language : en
Publisher:
Release Date : 2002
Design Of Progressive Lenses Mathematical Analysis And Numerical Methods written by Jing Wang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with categories.
Optical And Statistical Analysis Of Progressive Addition Lenses
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Author : Raymond Fairbanks Hardy
language : en
Publisher:
Release Date : 2007
Optical And Statistical Analysis Of Progressive Addition Lenses written by Raymond Fairbanks Hardy and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with Eye categories.
Abstract: This study is a follow-up to a previous one in which the optics of several progressive addition lens (PALs) designs were measured and analyzed1. The objective is to provide information about various PAL designs to enable eye care practitioners to select designs based upon the particular viewing requirements of the patient. The optical properties of 12 lenses of the same power for each of 23 different PAL designs were measured with a Rotlex Class Plus lens analyzer. Lenses were ordered through optical laboratories and specified to be piano with +2.00 add. Measurements were normalized to piano at the manufacturer- assigned location for the distance power to eliminate laboratory tolerance errors. The magnitude of unwanted astigmatism and the widths and areas of the distance, intermediate, and near viewing zones were calculated from the measured data according to the same criteria used in a previous study. The optical characteristics of the different PAL designs are significantly different one from the other. The differences are significant in terms of the sizes and widths of the viewing zones, the amount of unwanted astigmatism, and the minimum fitting height. Ratings of the distance, intermediate and near viewing areas were calculated for each PAL design based upon the widths and sizes of those zones. Ratings for unwanted astigmatism and recommended minimum fitting heights were also determined. Ratings based upon combinations of viewing zone ratings are also reported. The ratings are intended to be used in order to select a PAL design that matches the particular visual needs of the patient and also to evaluate the success and performance of currently worn PALs. Reasoning and task analyses1 suggest that these differences can be used to select a PAL design to meet the individual visual needs of the patient; clinical trials studies are required to test this hypothesis.
Theory And Design Of Freeform Gradient Index Optics And Applications In Progressive Addition Lenses
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Author : Nicholas S. Kochan
language : en
Publisher:
Release Date : 2022
Theory And Design Of Freeform Gradient Index Optics And Applications In Progressive Addition Lenses written by Nicholas S. Kochan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with categories.
"The progressive addition lens (PAL) is an eyeglass which continuously changes optical power as the gaze of the wearer moves downwards through different viewing zones. The astigmatism must be corrected within viewing zones of the lens. Correction of this astigmatism with power addition defines the PAL design space and is limited for homogeneous PAL designs. The present work identifies the ways in which gradient index (GRIN) lenses can be implemented as PALs. It is shown that the design space for the GRIN PAL is at least as large as that for the homogeneous PAL. It is derived that the contributions to power and astigmatism come from local constant, linear, and quadratic terms of surface and GRIN parametrized in the moving frame of the ray. This behavior constitutes freeform GRIN generalized Coddington's equations (GCE) developed in this work. There are four types of contributions. The GCE are applied analytically to three test cases to demonstrate consistency of derived theory with known ray behavior for homogeneous and GRIN distributions. Because it may not always be possible to know the GRIN distribution in terms of the moving frame of the ray, the GCE are reparametrized from ray coordinates into global coordinates. The reparametrization is numerically analyzed for the four types of GCE contributions, and assumptions and evaluation residuals are deemed sufficient for the range of powers relevant to PAL design. The GCE in global coordinates enable the simultaneous optimization of freeform GRIN and freeform surface in a PAL. Zonal performance can be evaluated by GCE without raytracing, enabling analytical design. A design study is provided showing the convergence of optimization for freeform GRIN and freeform surface PAL designs. Raytrace performance analysis supplements developed theory and design methods in this work. The performance contributions due to zonal constant and second order terms of surface and GRIN are those which dominate the design result. This is apparent because the optimized PAL with freeform surface and freeform GRIN have surface and GRIN bearing the same form of profile. The analysis of the GCE terms shows that for a given effect on power or astigmatism, terms dependent on zonal linear profile contributions require larger sag and index variation than contributions from curvature. It is shown that the freeform GRIN PAL design space is at least as large as that of surface PALs. The optimization of a freeform GRIN PAL with a freeform surface shows contributions to optical performance are dominated by zonal quadratic term variation in practice. Equivalent zonal linear profile sag and index variation contributes smaller performance for given index and sag variation. When the linear term contribution is negligible, performance contribution to correction of power and astigmatism is the approximate linear combination of surface and GRIN contributions. For design optimization, the zonal quadratic and constant terms of surface and GRIN are those which dominate performance contribution on propagation through the lens. To complement analysis of optical performance, it is shown that an embedded optical surface can be converted to GRIN directly while maintaining input and output ray trajectory. This enables designing a GRIN by first designing a cemented surface homogeneous optic and applying the conversion method. Consistent with framework of GCE, freeform GRIN PAL and freeform homogeneous PAL are fabricated to the same performance prescription. A scanning Shack-Hartmann wavefront sensor is built to evaluate performance. The PAL is scanned and target performance is validated by polynomial fitting performance measurement. Oscillatory performance deviation is observed in the GRINPAL. Oscillatory variation and random variation in index of refraction are each observed as a deviation from design in the manufactured GRIN PAL. These are due to inkjet printing artifacts, and are further characterized by using phase-stepping interferometry and transmission deflectometry. Manufacturing artifacts significant for performance validation are 1.5-2mm mid-spatial frequency (MSF) vertical bands on the GRIN PAL and high-spatial freqency (HSF) fluctuation due to printing on the scale of 100-200 æm period. Both artifacts have amplitude on the scale of 1 - 2 × 104 index of refraction. Analysis is provided showing that MSF contribution to performance departure scales quadratically with spatial frequency, and that the oscillations measured are on a scale which contributes diopter-scale oscillatory performance departure. Performance errors from polynomial fit in homogeneous PAL are on the scale of desired 0.1-0.125 D performance tolerance, but are single diopter scale for the GRIN. Proper performance is evident in the GRIN PAL, but index fluctuation is approximately ten times too large. This thesis identifies the need to minimize this error"--Pages xi-xiii
Introduction To Lens Design
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Author : José Sasián
language : en
Publisher: Cambridge University Press
Release Date : 2019-09-26
Introduction To Lens Design written by José Sasián and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-09-26 with Medical categories.
A concise introduction to lens design, including the fundamental theory, concepts, methods and tools used in the field. Covering all the essential concepts and providing suggestions for further reading at the end of each chapter, this book is an essential resource for graduate students working in optics and photonics.
Progressive Addition Spectacle Lenses
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Author : Julie L. Preston
language : en
Publisher:
Release Date : 1998
Progressive Addition Spectacle Lenses written by Julie L. Preston and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with categories.
The lens design with the widest near zone was rated significantly lower than the other near zone width designs for nearly every question relating to vision , adaptation, and satisfaction. This lens was also least preferred of all the designs. Preferences for corridor length were evenly distributed among the three designs. Of patient characteristics, years of progressive addition lens wear and gender significantly affected design preference in this population. Initial impressions were not predictive of satisfaction after a week of wear. The rating instrument was judged to have low repeatability.
Lens Design Fundamentals
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Author : Rudolf Kingslake
language : en
Publisher: Society of Photo Optical
Release Date : 2010-01-01
Lens Design Fundamentals written by Rudolf Kingslake and has been published by Society of Photo Optical this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-01-01 with Science categories.
R. Barry Johnson is the 2012 winner of the Joseph W. Goodman Book Writing Award. Rudolf Kingslake (1903-2003) is widely considered to be the father of lens design in the United States. Now his student and friend, R. Barry Johnson, updates Kingslake's bestselling work for modern times, revising all chapters, including more examples and references, and augmenting all subject content to reflect the many changes in design that have occurred since the first edition was published in 1978. Changes include a new overview chapter on aberrations, a completely rewritten chapter on automatic lens design, and expansion of the chapter on mirrors and catadioptric systems to include a variety of newer systems with some having eccentric pupils. Published in cooperation with Academic Press.
Modern Ophthalmic Optics
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Author : José Alonso
language : en
Publisher: Cambridge University Press
Release Date : 2019-04-11
Modern Ophthalmic Optics written by José Alonso and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-04-11 with Medical categories.
Provides a comprehensive account of the most recent developments in modern ophthalmic optics, including free form technology.
Clinical Optics
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Author : Neal H. Atabara, M.d.
language : en
Publisher: Amer Academy of Ophthalmology
Release Date : 2012
Clinical Optics written by Neal H. Atabara, M.d. and has been published by Amer Academy of Ophthalmology this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Medical categories.
Continually updated by a faculty of leading opthalmologists in academia and practice, the titles in the 'Basic and Clinical Science Course' series provide a source of up-to-date clinical knowledge for practitioners.