,3 Clinical Optics and
Vision Rehabilitation
Last major revision 2022–2023
2023–2024
BCSC
Basic and Clinical
Science Course™
Published after collaborative
review with the European Board
of Ophthalmology subcommittee
, The American Academy of Ophthalmology is accredited by the Accreditation Council for Con-
tinuing Medical Education (ACCME) to provide continuing medical education for physicians.
The American Academy of Ophthalmology designates this enduring material for a maximum of
™
15 AMA PRA Category 1 Credits . Physicians should claim only the credit commensurate with
the extent of their participation in the activity.
CME expiration date: June 1, 2025. AMA PRA Category 1 Credits
June 1, 2022, and the expiration date.
™ may be claimed only once between
®
BCSC volumes are designed to increase the physician’s ophthalmic knowledge through study and
review. Users of this activity are encouraged to read the text and then answer the study questions
provided at the back of the book.
™
To claim AMA PRA Category 1 Credits upon completion of this activity, learners must demon-
strate appropriate knowledge and participation in the activity by taking the posttest for Section 3
and achieving a score of 80% or higher. For further details, please see the instructions for requesting
CME credit at the back of the book.
The Academy provides this material for educational purposes only. It is not intended to represent the
only or best method or procedure in every case, nor to replace a physician’s own judgment or give
specific advice for case management. Including all indications, contraindications, side effects, and
alternative agents for each drug or treatment is beyond the scope of this material. All information and
recommendations should be verified, prior to use, with current information included in the manufac-
turers’ package inserts or other independent sources, and considered in light of the patient’s condition
and history. Reference to certain drugs, instruments, and other products in this course is made for
illustrative purposes only and is not intended to constitute an endorsement of such. Some material
may include information on applications that are not considered community standard, that reflect
indications not included in approved FDA labeling, or that are approved for use only in restricted
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Cover image: From BCSC Section 9, Uveitis and Ocular Inflammation. Image courtesy of Sam S.
Dahr, MD, MS.
Copyright © 2023 American Academy of Ophthalmology. All rights reserved. No part of
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,Basic and Clinical Science Course
Christopher J. Rapuano, MD, Philadelphia, Pennsylvania
Senior Secretary for Clinical Education
J. Timothy Stout, MD, PhD, MBA, Houston, Texas
Secretary for Lifelong Learning and Assessment
Colin A. McCannel, MD, Los Angeles, California
BCSC Course Chair
Section 3
Faculty for the Major Revision
Scott E. Brodie, MD, PhD
Thomas F. Mauger, MD
Chair
Morgantown, West Virginia
New York, New York
Marcus Ang, MBBS, PhD Tyler Oostra, MD
Singapore Columbus, Ohio
Kristina Irsch, PhD
Kamran M. Riaz, MD
Baltimore, Maryland
Oklahoma City, Oklahoma
and Paris, France
Mary Lou Jackson, MD Joshua A. Young, MD
Vancouver, Canada New York, New York
,The Academy wishes to acknowledge the following committees for review of this edition:
Committee on Aging: Daniel C. Tu, MD, PhD, Portland, Oregon
Vision Rehabilitation Committee: Mary Lou Jackson, MD, Vancouver, Canada
BCSC Resident/Fellow Reviewers: Sharon L. Jick, MD, Chair, St. Louis, Missouri; Jennifer
Lynne Barger, MD; Tamara Lee Lenis, MD, PhD; Kenneth W. Price, MD; Brittany Sim-
mons, MD; Heather Stiff, MD; Nandini Venkateswaran, MD; James T. Walsh, MD; Mad-
eline W. Yung, MD
Practicing Ophthalmologists Advisory Committee for Education: Bradley D. Fouraker,
MD, Primary Reviewer, Tampa, Florida; Cynthia S. Chiu, MD, Oakland, California;
George S. Ellis Jr, MD, New Orleans, Louisiana; Philip R. Rizzuto, MD, Providence, Rhode
Island; Gaurav K. Shah, MD, Town and Country, Missouri; Rosa A. Tang, MD, MPH,
MBA, Houston, Texas; Troy M. Tanji, MD, Waipahu, Hawaii; Michelle S. Ying, MD, Lad-
son, South Carolina
The Academy also wishes to acknowledge the following committee for assistance in devel-
oping Study Questions and Answers for this BCSC Section:
Resident Self-Assessment Committee: Evan L. Waxman, MD, PhD, Chair, Pittsburgh, Penn-
sylvania; Robert A. Beaulieu, MD, Southfield, Michigan; Benjamin W. Botsford, MD, New
York, New York; Olga M. Ceron, MD, Grafton, Massachusetts; Kevin Halenda, MD, Cleve-
land, Ohio; Amanda D. Henderson, MD, Baltimore, Maryland; Andrew M. Hendrick, MD,
Atlanta, Georgia; Joshua Hendrix, MD, Dalton, Georgia; Matthew B. Kaufman, MD, Port-
land, Oregon; Zachary A. Koretz, MD, MPH, Pittsburgh, Pennsylvania; Kevin E. Lai, MD,
Indianapolis, Indiana; Kenneth C. Lao, MD, Temple, Texas; Yasha S. Modi, MD, New York,
New York; Mark E. Robinson, MD, MPH, Columbia, South Carolina; Jamie B. Rosen-
berg, MD, New York, New York; Tahira M. Scholle, MD, Houston, Texas; Ann Shue, MD,
Sunnyvale, California; Jeong-Hyeon Sohn, MD, Shavano Park, Texas; Misha F. Syed, MD,
League City, Texas; Parisa Taravati, MD, Seattle, Washington; Sarah Van Tassel, MD, New
York, New York; Matthew S. Wieder, MD, Scarsdale, New York; Jules A. Winokur, MD,
Great Neck, New York
European Board of Ophthalmology: Lotte Welinder, MD, Liaison, Aalborg, Denmark;
Roger C. Humphry, MD, MBBS, Salisbury, England
Financial Disclosures
Academy staff members who contributed to the development of this product state that
within the 24 months prior to their contributions to this CME activity and for the dura-
tion of development, they have had no financial interest in or other relationship with any
entity that produces, markets, resells, or distributes health care goods or services con-
sumed by or used in patients.
,The authors and reviewers state that within the 24 months prior to their contributions
to this CME activity and for the duration of development, they have had the following
financial relationships:*
Dr Fouraker: Addition Technology (C, L), AJL Ophthalmic, S.A. (C, L), Alcon (C, L),
OASIS Medical (C, L)
Dr Jackson: Astellas Pharma (C)
Dr Lai: Twenty/Twenty Therapeutics (C)
Dr Modi: Alimera Science (C), Allergan (C), Carl Zeiss (C), Genentech (C), Novartis (C),
Théa Laboratories (C)
Dr Riaz: Bausch + Lomb (L), Beaver-Visitec International (C), CorneaGen (L), Impri-
misRx (S)
Dr Robinson: Horizon Therapeutics (O)
Dr Shah: Allergan (C, L, S); Bausch + Lomb (L); D.O.R.C. Dutch Ophthalmic Research
Center (International) B.V. (S); Regeneron Pharmaceuticals (C, L, S)
Dr Tang: EMD Serono (L); Horizon Therapeutics (C, S); Immunovant (S); Novartis (S);
Quark Pharmaceuticals (C, S); Regenera Pharma (S), Sanofi (L), ZEISS (L)
Dr Van Tassel: AbbVie (C), Aerie Pharmaceuticals (C), Allergan (C), Bausch + Lomb (C),
Carl Zeiss Meditec (C), Equinox (C), New World Medical (C, L)
Dr Young: Johnson & Johnson Vision (C)
All relevant financial relationships have been mitigated.
The other authors and reviewers state that within the 24 months prior to their contribu-
tions to this CME activity and for the duration of development, they have had no financial
interest in or other relationship with any entity that produces, markets, resells, or distrib-
utes health care goods or services consumed by or used in patients.
Recent Past Faculty
Pankaj C. Gupta, MD
Leon Strauss, MD, PhD
Edmond H. Thall, MD
In addition, the Academy gratefully acknowledges the contributions of numerous past
faculty and advisory committee members who have played an important role in the devel-
opment of previous editions of the Basic and Clinical Science Course.
* C = consultant fee, paid advisory boards, or fees for attending a meeting; E = employed by or received
a W2 from a commercial company; L = lecture fees or honoraria, travel fees or reimbursements when
speaking at the invitation of a commercial company; O = equity ownership/stock options in publicly or
privately traded firms, excluding mutual funds; P = patents and/or royalties for intellectual property; S =
grant support or other financial support to the investigator from all sources, including research support
from government agencies, foundations, device manufacturers, and/or pharmaceutical companies
,American Academy of Ophthalmology Staff
Dale E. Fajardo, EdD, MBA, Vice President, Education
Beth Wilson, Director, Continuing Professional Development
Denise Evenson, Director, Brand & Creative
Susan Malloy, Acquisitions and Development Manager
Stephanie Tanaka, Publications Manager
Jasmine Chen, Manager of E-Learning
Lana Ip, Senior Designer
Beth Collins, Medical Editor
Amanda Fernandez, Publications Editor
Sarah Page, Online Education and Licensing Manager
Rayna Ungersma, Manager, Curriculum Development
Eric Gerdes, Interactive Designer
Kenny Guay, Publications Specialist
Debra Marchi, Administrative Assistant
American Academy of Ophthalmology
655 Beach Street
Box 7424
San Francisco, CA 94120-7424
,Contents
Introduction to the BCSC . . . . . . . . . . . . . . . . . . . . . . xv
Introduction to Section 3 . . . . . . . . . . . . . . . . . . . . . . xvii
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Quick-Start Guide: Optics, Refraction, and Retinoscopy . 3
Part 1: Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
The Camera Obscura: Pinhole Imaging . . . . . . . . . . . . . . . 5
Convex Lenses . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Combining Lenses . . . . . . . . . . . . . . . . . . . . . . . . 8
Imaging Nearby Objects: Vergence and the Vergence
Equation . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Concave Lenses . . . . . . . . . . . . . . . . . . . . . . . . . 11
Summary Thus Far . . . . . . . . . . . . . . . . . . . . . . . 12
Images in Denser Media . . . . . . . . . . . . . . . . . . . . . 13
A Very Much Simplified Model Eye . . . . . . . . . . . . . . . . 13
Astigmatism . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Part 2: Refraction . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Overview of Clinical Refraction . . . . . . . . . . . . . . . . . . 22
Step 1. Perform the Preliminaries . . . . . . . . . . . . . . . . . 24
Step 2. Occlude 1 Eye . . . . . . . . . . . . . . . . . . . . . . . 27
Step 3. Obtain Initial Estimate of the Refractive Error . . . . . . . . . 28
Step 4. Refine Cylinder Axis and Power . . . . . . . . . . . . . . . 31
Step 5. Refine Sphere Power . . . . . . . . . . . . . . . . . . . . 34
Step 6. Occlude the Right Eye, Refract the Left Eye . . . . . . . . . . 34
Step 7. Accommodative Control and Binocular Balance . . . . . . . . 35
Step 8. Refract for Near Vision . . . . . . . . . . . . . . . . . . . 38
Final Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Part 3: Retinoscopy . . . . . . . . . . . . . . . . . . . . . . . . . 40
Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
The Role of Retinoscopy . . . . . . . . . . . . . . . . . . . . . 41
Types of Retinoscopes . . . . . . . . . . . . . . . . . . . . . . 41
Fundamental Concepts . . . . . . . . . . . . . . . . . . . . . . 42
Preliminaries for Retinoscopy . . . . . . . . . . . . . . . . . . . 43
Basic Retinoscope Operation . . . . . . . . . . . . . . . . . . . 44
vii
, viii ● Contents
Putting It All Together . . . . . . . . . . . . . . . . . . . . . . 49
Subjective Retinoscopy Findings . . . . . . . . . . . . . . . . . . 51
Final Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . 51
1 Geometric Optics . . . . . . . . . . . . . . . . . . . . . . . 53
Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Refractive Index . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Flat Refracting Surfaces: Snell’s Law . . . . . . . . . . . . . . . . . . 58
Prisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Prism Power . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Fresnel Prisms . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Reflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Critical Angle and Total Internal Reflection . . . . . . . . . . . . . 64
Refraction by a Single Curved Surface . . . . . . . . . . . . . . . . . 66
Two-Sided Lenses . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Principal Planes and Ray Tracing . . . . . . . . . . . . . . . . . 71
Depth of Focus and Depth of Field . . . . . . . . . . . . . . . . . 73
General Refracting Systems . . . . . . . . . . . . . . . . . . . . . . 76
Characteristics of Objects and Images: Real and Virtual . . . . . . . . 79
Transverse Magnification . . . . . . . . . . . . . . . . . . . . . 80
Axial (Longitudinal) Magnification . . . . . . . . . . . . . . . . 82
Conjugate Points . . . . . . . . . . . . . . . . . . . . . . . . 83
Nodal Points . . . . . . . . . . . . . . . . . . . . . . . . . . 83
The Reduced, or Equivalent, Optical System . . . . . . . . . . . . . 84
Aberrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Point Spread Function . . . . . . . . . . . . . . . . . . . . . . 86
Wavefront Theory . . . . . . . . . . . . . . . . . . . . . . . . 87
Chromatic Aberration . . . . . . . . . . . . . . . . . . . . . . 92
Astigmatism . . . . . . . . . . . . . . . . . . . . . . . . . . 92
The Conoid of Sturm . . . . . . . . . . . . . . . . . . . . . . . 93
The Spherical Equivalent . . . . . . . . . . . . . . . . . . . . . 94
The Power Cross . . . . . . . . . . . . . . . . . . . . . . . . 95
Power-Versus-Meridian Graph . . . . . . . . . . . . . . . . . . 97
Jackson Cross Cylinder . . . . . . . . . . . . . . . . . . . . . . 97
Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Telescopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Appendix 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Derivation of the Vergence Equation and the Lensmaker’s Equation
From Snell’s Law . . . . . . . . . . . . . . . . . . . . . . . 103
Appendix 1-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Fermat’s Principle . . . . . . . . . . . . . . . . . . . . . . . 105
Appendix 1-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Derivation of the Vergence Equation for Mirrors . . . . . . . . . . 107
Appendix 1-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
1 short Dynamic Ray Tracing . . . . . . . . . . . . . . . . . . . . . . 108
even
1 long
, Contents ● ix
2 Physical Optics . . . . . . . . . . . . . . . . . . . . . . . . 109
Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
What Is Light? . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Visible Light . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Wave or Particle? . . . . . . . . . . . . . . . . . . . . . . . . 112
Quantum Electrodynamics: Unifying Theory of Light . . . . . . . . . 114
Refraction and Reflection . . . . . . . . . . . . . . . . . . . . 114
Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Phenomena of Light . . . . . . . . . . . . . . . . . . . . . . . . 116
Polarization . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Interference and Coherence . . . . . . . . . . . . . . . . . . . 117
Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Measures of Light . . . . . . . . . . . . . . . . . . . . . . . . . 127
Radiometry . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Photometry . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Conversion Between Radiometric and Photometric Outputs . . . . . 129
Light Sources: Lasers . . . . . . . . . . . . . . . . . . . . . . . . 130
Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . 130
Therapeutic Laser–Tissue Interactions . . . . . . . . . . . . . . 132
Light Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Appendix 2-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Reconciliation of Geometric Optics and Physical Optics . . . . . . . 139
Chapter Exercises . . . . . . . . . . . . . . . . . . . . . . . . . 140
Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
3 Optics of the H
uman Eye . . . . . . . . . . . . . . . . . . 143
Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Schematic Eyes . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Important Axes of the Eye . . . . . . . . . . . . . . . . . . . . . 148
Pupil Size and Its Effect on Visual Resolution . . . . . . . . . . . . . 149
Visual Acuity . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Contrast Sensitivity and the Contrast Sensitivity Function . . . . . . . . 154
Refractive States of the Eyes . . . . . . . . . . . . . . . . . . . . . 157
Binocular States of the Eyes . . . . . . . . . . . . . . . . . . . . . 160
Accommodation and Presbyopia . . . . . . . . . . . . . . . . . . . 161
Eye Growth and Refractive Errors . . . . . . . . . . . . . . . . . . 161
Developmental Myopia . . . . . . . . . . . . . . . . . . . . . . . 162
Prevention of Myopia Progression . . . . . . . . . . . . . . . . . . 163
Developmental Hyperopia . . . . . . . . . . . . . . . . . . . . . 164
Appendix 3-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 164
Explanation of the ETDRS Visual Acuity Chart . . . . . . . . . . . 164 1 short
even
1 long
