Clinical Optics

Clinical Optics

1st Edition - May 14, 1987

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  • Authors: Troy E. Fannin, Theodore Grosvenor
  • eBook ISBN: 9781483192598

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Description

Clinical Optics is intended primarily for use by optometry students, though it could also prove useful for the training of optometric technicians and dispensing opticians. This book is organized into thirteen chapters. These chapters cover most aspects of ophthalmic optics or clinical optics including the design and dispensing of eyewear, the types for lenses suitable for correcting high refractive errors, the optical principles governing low vision lenses and the importance of absorptive lenses and lens coatings for eye protection against radiation. This book will be of interest to optometry students and to those involved in the training of optometric technicians and dispensing opticians.

Table of Contents


  • Contents

    Preface

    Introduction. Sign Convention, Nomenclature, and Notation

    0.1 Sign Convention

    0.2 Nomenclature

    0.3 Notation

    Chapter One Ophthalmic Lens Materials

    Glass

    1.1 History of Glassmaking

    1.2 The Development of Optical Glass

    1.3 The Manufacture of Optical Glass

    1.4 Varieties of Optical Glass

    1.5 Desirable Characteristics and Defects of Optical Glass

    Plastic Materials

    1.6 Introduction

    1.7 Manufacturing Processes

    1.8 Development of Optical Plastics

    1.9 Manufacture of Plastic Lenses

    1.10 Optical and Physical Properties of Plastic Lenses

    The Strength of Lens Materials

    1.11 FDA Policies

    1.12 The Strength of Glass

    1.13 Methods of Tempering Glass Lenses

    1.14 Impact Resistance of Plastic Lenses

    1.15 Lenses for Occupational and Educational Use

    References

    Questions

    Chapter Two Characteristics of Ophthalmic Lenses

    Physical Characteristics

    2.1 Curvature

    2.2 Surfaces of Revolution

    2.3 Relationship between Curvature and Refracting Power of a Surface

    2.4 The Lens Measure

    2.5 Lens Form: Spherical Lenses

    2.6 Lens Form: Cylindrical and Toric Lenses

    2.7 Lens Blanks and Base Curves

    2.8 Specification of Cylinder Axes

    2.9 Prescription Writing and Transposition

    Optical Characteristics

    2.10 Basic Terminology

    2.11 Image Formation by a Spherical Lens

    2.12 Image Formation by Cylindrical and Toric Lenses

    2.13 Terminology and Basic Concepts Regarding Image Formation by a Lens

    2.14 Dimensional Aspects of the Conoid of Sturm

    2.15 Misconceptions Concerning Astigmatic Image Formation

    2.16 The Spherical Equivalent

    2.17 Power in an Oblique Meridian of a Cylindrical Lens

    2.18 Power in an Oblique Meridian of aToric Lens

    2.19 Obliquely Crossed Cylinders

    2.20 Astigmatism due to Lens Tilt

    2.21 The Maddox Rod

    References

    Questions

    Chapter Three. Power Specification and Measurement

    Power Specification

    3.1 Introduction

    3.2 Approximate Power

    3.3 Back Vertex Power

    3.4 Front Vertex Power, or Neutralizing Power

    3.5 Equivalent Power

    3.6 Effective Power

    Power measurement

    3.7 Hand Neutralization

    3.8 The Lensometer

    3.9 Lensometer Calibration, Alignment, and Measurement Errors

    3.10 Projection Lensometers

    3.11 Automatic Lensometers

    Relationships Between Lens Power and Lens Thickness

    3.12 The Sagitta Formula

    3.13 Formula Relating Power to Center Thickness and Edge Thickness

    3.14 Thickness Calculations for Cylindrical and Sphero-cylindrical Lenses

    Reference

    Questions

    Chapter Four

    Ophthalmic Prisms and Decentration

    4.1 Terminology

    4.2 Refracting Power of a Prism

    4.3 Specification of the Power of an Ophthalmic Prism

    4.4 Relationship between Refracting Angle and Angle of Deviation

    4.5 Effects of Prisms on Movements of the Eyes

    4.6 Prentice's Rule

    4.7 Oblique Prismatic Effects

    4.8 Obliquely Crossed Prisms

    4.9 Effective Power of a Prism in an Oblique Meridian

    4.10 Specification of Prismatic Effects: The Major Reference Point

    4.11 Specification of Lens and Frame Sizes

    4.12 Prismatic Power and Thickness

    4.13 Thickness of a Lens/Prism

    4.14 Prismatic Effects of Cylindrical Lenses

    4.15 Decentration

    4.16 Effects of Prisms on the Eyes

    4.17 Effectivity of a Prism

    4.18 Risley Prisms

    4.19 Fresnel Press-on Prisms

    References

    Questions

    Chapter Five. The Correction of Ametropia

    5.1 The Schematic Eye

    5.2 Emmetropia and Ametropia

    5.3 The Far and Near Points of Accommodation

    5.4 The Correction of Spherical Ametropia

    5.5 Range and Amplitude of Accommodation

    5.6 Spectacle Refraction versus Ocular Refraction

    5.7 Spectacle Accommodation versus Ocular Accommodation

    5.8 Accommodation and Effectivity in Anisometropia

    5.9 Accommodation and Effectivity in Astigmatism

    5.10 Retinal Image Size in Uncorrected Ametropia

    5.11 Retinal Image Size in Corrected Ametropia

    References

    Questions

    Chapter Six. Aberrations and Ophthalmic Lens Design

    Introduction

    6.1 Laws of Geometrical Optics

    Chromatic Aberration and Achromatic Lenses

    6.2 Chromatic Aberration

    6.3 Chromatic Dispersion

    6.4 Chromatic Aberration in Prisms

    6.5 Achromatic Prisms

    6.6 Chromatic Aberration in Lenses

    6.7 Achromatic Lenses

    The Monochromatic Aberrations

    6.8 Spherical Aberration

    6.9 Coma

    6.10 Oblique Astigmatism

    6.11 Curvature of Image

    6.12 Distortion

    Principles of Lens Design

    6.13 Introduction

    6.14 Lens Design Variables

    6.15 Design Assumptions

    6.16 The Base Curve of a Lens

    History and Evolution of Lens Design

    6.17 Spherical Lenses

    6.18 Sphero-Cylindrical Lens Design

    6.19 Negative versus Positive Toric Lenses

    6.20 Design of High Plus Lenses

    The Optometrists Role in Lens Design

    6.21 Changes in the Optical Industry and in ANSI Standards

    6.22 Base Curve Specification

    References

    Questions

    Chapter seven. Absorptive Lenses and Lens Coatings

    Effects of Radiation on the Eye

    7.1 The Nature of Light

    7.2 The Visible Spectrum

    7.3 Classification of Radiation Effects

    7.4 Concentration of Radiant Energy by the Eye

    7.5 Absorption of Radiation by the Ocular Tissues

    7.6 Effects of Ultraviolet Radiation

    7.7 Effects of Infrared Radiation

    7.8 The Effects of Visible Radiation

    7.9 Other Forms of Radiation

    7.10 Recommended Levels of Retinal Illumination

    Absorptive Lenses

    7.11 Reflection, Absorption, and Transmission

    7.12 Opacity

    7.13 Density

    7.14 Methods of Manufacturing Absorptive Lenses

    7.15 Categories of Absorptive Lenses and Specification of Transmission

    7.16 General-Wear Lenses Absorbing the Spectrum Evenly

    7.17 Lenses That Selectively Absorb Ultraviolet Radiation While Transmitting the Visible Spectrum in a

    Uniform Manner

    7.18 Lenses That Selectively Absorb Both Ultraviolet and Infrared Radiation While Absorbing a Substantial

    Amount of Visible Radiation in a Relatively Uniform Manner

    7.19 Lenses That Selectively Absorb Portions of the Visible Spectrum

    7.20 Absorptive Lenses Designed for Occupational Use

    7.21 Photochromic Lenses

    7.22 Lens Thickness and Transmission

    7.23 Prescribing Absorptive Lenses

    7.24 Miscellaneous Absorptive Lenses

    Lens Reflections and Coatings

    7.25 Refleaions from Spectacle Lens Surfaces

    7.26 Types of Surface Reflections

    7.27 Methods of Controlling Surface Reflections

    7.28 Antireflective Coatings

    7.29 Optical Principles of Antireflective Coatings

    7.30 Production of Antireflective Coatings

    7.31 Reflections Annoying to an Observer

    References

    Questions

    Chapter Eight. Multifocal Lenses

    Physical Characteristics

    8.1 History and Development of Multifocal Lenses

    8.2 Fused Bifocal Lenses

    8.3 One-Piece Bifocal Lenses

    8.4 Double-Segment Bifocals

    8.5 "Minus Add" Bifocal

    8.6 Trifocal Lenses

    8.7 Plastic Multifocal Lenses

    Multifocal Lens Manufacturing Processes

    8.8 Glass Multifocals

    8.9 Plastic Multifocals

    Optical Principles of Multifocal Lens Design

    8.10 Powers of the Distance and Reading Portions

    8.11 One-Piece Bifocals

    8.12 Fused Bifocals

    Performance Characteristics

    8.13 Vertical Placement of the Optical Center of the Segment

    8.14 Lateral Placement of the Optical Center of the Segment

    8.15 Differential Displacement (Image Jump)

    8.16 The Zone of Confusion

    8.17 Differential Displacement at the Reading Level

    8.18 Total Displacement at the Reading Level

    8.19 Transverse Chromatic Aberration

    Clinical Considerations

    8.20 Theories of Bifocal Selection

    8.21 Segment Size and Shape

    8.22 Horizontal Prismatic Effects

    8.23 Differential Vertical Prismatic Effects at the Reading Level

    8.24 Ordering and Dispensing Bifocals

    8.25 Verification of Bifocals

    8.26 Prescribing and Fitting Double-Segment Bifocals

    8.27 Prescribing and Fitting Trifocals

    Invisible bifocals and progressive addition Lenses

    8.28 Invisible Bifocals

    8.29 Blended Bifocals

    8.30 Progressive Addition Lenses

    8.31 Patient Selection and Dispensing Considerations

    References

    Questions

    Chapter Nine. Eyewear Design and Dispensing

    Spectacle Frames and Mountings

    9.1 Historical Introduction

    9.2 Modern Frames and Mountings

    9.3 Metal Frame and Mounting Materials

    9.4 Plastic Frame Materials

    9.5 Bridge and Temple Styles

    Frame Selection and Ordering Materials

    9.6 Measuring Interpupillary Distance

    9.7 Frame Selection

    9.8 Fitting Principles

    9.9 Frame Alignment

    9.10 Frame and Mounting Specifications

    9.11 Lateral Placement of Optical Centers

    9.12 Vertical Placement of Optical Centers

    9.13 Centering Problems and Solutions

    9.14 Bifocal Segment Inset

    9.15 Prescription Order Forms

    Verification and Dispensing

    9.16 Verification

    9.17 Dispensing and Adjusting

    References

    Questions

    Chapter Ten. Anisometropia and Aniseikonia

    Anisometropia

    10.1 Problems Resulting from Anisometropia

    10.2 Horizontal Prismatic Effects

    10.3 Differential Vertical Prismatic Effects at the Reading Level

    Aniseikonia

    10.4 Introduction

    10.5 Etiology of Aniseikonia

    10.6 Significance of Aniseikonia

    10.7 The Spectacle Magnification Formula

    10.8 Clinical Application of the Spectacle Magnification Formula

    10.9 Comparison of Spectacle and Contact Lens Magnification

    10.10 Spectacle Magnification in Astigmatism

    10.11 Relative Spectacle Magnification

    10.12 Relative Spectacle Magnification in Axial Ametropia

    10.13 Relative Spectacle Magnification in Refractive Ametropia

    10.14 Relative Spectacle Magnification in Astigmatism

    10.15 The Dilemma of Relative Spectacle Magnification

    10.16 Clinical Considerations in Anisometropia and Astigmatism

    Prescribing to Eliminate or Minimize Induced Aniseikonia

    10.17 Indications of the Presence of Aniseikonia

    10.18 Measurement of Image Size Differences

    10.19 Estimating the Amount of Aniseikonia

    10.20 Avoiding or Minimizing Induced Aniseikonia

    10.21 Prescribing and Lens Design

    10.22 The Use ofEikonic Lenses in Fit-Over Form

    10.23 Frame Selection for Eikonic Lenses

    10.24 Aniseikonia: Clinical Considerations in Anisometropia and Astigmatism

    References

    Questions

    Chapter Eleven. Lenses for High Refractive Errors

    Lenses for Aphakia and High Hyperopia

    11.1 Management of the Cataract Patient

    11.2 Optical Consequences of Cataract Surgery

    11.3 Predicting the Power of an Aphakic Lens

    11.4 Problems with Aphakic Spectacles

    11.5 Parameters of Aphakic Lenses

    11.6 Aphakic Lens Design

    11.7 Frames for Aphakic Lenses

    11.8 The Unilateral Aphakic

    11.9 Determining^the Final Aphakic Prescription

    11.10 The High Hyperope

    Lenses for High Myopia

    11.11 Problems Caused by High Minus Lenses

    11.12 Minimizing Edge Thickness

    11.13 Minimizing Edge Reflections

    11.14 Lenticular Lenses

    11.15 Fresnel Press-on Lenses

    References

    Questions

    Chapter Twelve. Optical Principles of Lenses for Low Vision

    12.1 Methods of Providing Magnification

    Optical Aids for Distance Vision

    12.2 Afocal Telescopes

    12.3 Headborne Telescopic Systems

    12.4 Nonprescription Telescopes

    Optical Aids for Near Vision

    12.5 Microscopic Lenses

    12.6 Telescopic Lenses for Near Vision

    12.7 Hand Magnifiers

    12.8 Stand Magnifiers

    12.9 The Paperweight Magnifier

    References

    Questions

    Chapter Thirteen. Optics of Contact Lenses

    Basic Contact Lens Optics

    13.1 The Contact Lens as a Thick Lens

    13.2 The Effective Power of a Contact Lens

    13.3 Calibration of the Keratometer

    The Contact Lens/Eye Optical System

    13.4 The Contact Lens on the Eye

    13.5 Over-refraction

    13.6 Contact Lenses and Corneal Astigmatism

    13.7 Fitting Steeper or Flatter Than the Cornea

    13.8 The Optics of Bifocal Contact Lenses

    13.9 Residual Astigmatism and Its Correction

    13.10 Magnification Effects of Contact Lenses

    Effects of Contact Lenses on Binocular Vision

    13.11 Accommodative Demand

    13.12 Accommodative Convergence

    13.13 Prismatic Effects

    13.14 Prescribing Prism in a Contact Lens

    Aberrations and Field of View

    13.15 Aberrations

    13.16 Field of View

    Aphakia

    13.17 Aphakic Contact Lenses

    Instrumentation

    13.18 The Radiuscope

    References

    Questions

    Answers to Questions

    Index


Product details

  • No. of pages: 480
  • Language: English
  • Copyright: © Butterworth-Heinemann 1987
  • Published: May 14, 1987
  • Imprint: Butterworth-Heinemann
  • eBook ISBN: 9781483192598

About the Authors

Troy E. Fannin

Theodore Grosvenor

Adjunct Professor, Pacific University College of Optometry, Forest Grove, OR; Professor Emeritus, Indiana University School of Optometry, Bloomington, IN; Professor Emeritus, University of Houston College of Optometry, Houston, TX

Affiliations and Expertise

Pacific University College of Optometry, Forest Grove, OR, USA

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