ELEVATION BASED CORNEAL TOMOGRAPHY

263 Pages·2012·17.418 MB·English

by  MICHAEL W. BELIN STEPHEN KHACHIKIAN RENATO AMBROSIO JR.

Elevation Based
Corneal Tomography
Second Edition
Editors:
Michael W. Belin, MD, FACS
Stephen S. Khachikian, MD
Renato Ambrósio Jr., MD, PhD
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© Copyright, English Edition, 2012 for Jaypee - Highlights Medical Publishers, Inc.
All rights reserved and protected by Copyright. No part of this publication may be reproduced, stored in retrieval
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Due to the fact that this book will reach ophthalmologists from different countries with different training,
cultures and backgrounds, the procedures and practices described in this book should be implemented in a
manner consistent with the professional standards set for the circumstances that apply in each specific situation.
Every effort has been made to confirm the accuracy of the information presented and to correctly relate generally
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the publisher.
Belin, Michael W., MD, FACS; Khachikian, Stephen S., MD; Ambrosio Jr., Renato, MD, PhD
“ELEVATION BASED CORNEAL TOMOGRAPHY”
Second Edition
ISBN: 978-9962-678-53-3
Published for: Jaypee - Highlights Medical Publishers, Inc.
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Editors
Michael W. Belin, MD., FACS
Professor of Ophthalmology & Vision Science
University of Arizona &
Southern Arizona Veterans Administration
Health Care System
Tucson, Arizona (USA)
Stephen S. Khachikian, MD
Black Hills Regional Eye Institute
Rapid City, South Dakota (USA)
Renato Ambrósio Jr., MD, PhD
Instituto de Olhos Renato Ambrósio
Rio de Janeiro Corneal Tomography
and Biomechanics Study Group
Assistant Professor of Ophthalmology
Federal University of São Paulo
Brazil
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Contributing Authors
Renato Ambrósio Jr., MD, PhD Frederico P. Guerra, MD
Instituto de Olhos Renato Ambrósio Brazilian Study Group of Artificial Intelligence
Rio de Janeiro Corneal Tomography and Corneal Analysis (BrAIn), Brazil
and Biomechanics Study Group Instituto de Olhos Renato Ambrósio &
Assistant Professor of Ophthalmology Rio de Janeiro Corneal Tomography and
Federal University of São Paulo, Brazil Biomechanics Study Group,
Rio de Janeiro, Brazil
Luana P. N. Araújo, MD
Brazilian Study Group of Artificial Intelligence Stephen S. Khachikian, MD
and Corneal Analysis (BrAIn), Brazil Black Hills Regional Eye Institute
Universidade Federal de Alagoas, Rapid City, South Dakota (USA)
Maceió, Brazil
Michael W. Belin, MD., FACS Joerg Iwanczuk, Dipl Ing (FH)
Professor of Ophthalmology & Vision Science Product Manager
University of Arizona & OCULUS Optikgeräte, GmbH
Southern Arizona Veterans Administration Wetzlar, Germany
Health Care System
Tucson, Arizona (USA)
Shuning Li, MD, PhD
Beijing Ophthalmology &
Edmondo Borasio, MedC, BQ, FEBO Visual Science Key Lab,
Consultant Ophthalmic Surgeon Beijing Tongren Eye Center,
Moorfields Eye Hospital, Dubai Beijing Tongren Hospital,
Capital Medical University, Beijing, China
Isaac Carvalho de Oliveira Ramos, MD
Anterior Segment Fellow at
Hospital Nossa Senhora da Saúde Allan Luz, MD, PhD
(Gamboa), Rio de Janeiro, Brazil Doctorate Fellow at
Federal University of São Paulo
Cornea Department of
Dilraj Grewal, MD Hospital de Olhos de Sergipe
Department of Ophthalmology São Paulo, Brazil
Northwestern University
Chicago, Illinois, (USA)
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João Marcelo Lyra, MD, PhD Guilherme Ribeiro, MD
Professor of Post-Graduation in Brazilian Study Group of Artificial Intelligence
Artificial Intelligence and Ophthalmology and Corneal Analysis (BrAIn), Brazil
Alagoas Federal University Universidade Federal de Alagoas,
Member of Brazilian Study Group of Maceió, Brazil
Artificial Intelligence and Corneal Analysis
(BrAIn), Maceió, Brazil
Marcella Salomão, MD
Clinical Director of Femtolaser-RIO
Aydano P. Machado, MSc, PhD Rio de Janeiro, Brazil
Brazilian Study Group of Artificial Intelligence
and Corneal Analysis (BrAIn), Brazil
Universidade Federal de Alagoas, Satinder Pal Singh Grewal, MD
Maceió, Brazil Grewal Eye Institute
Chandigarh, India
Naoyuki Maeda, MD
Department of Ophthalmology Bruna V. Ventura, MD
Osaka University Brazilian Study Group of Artificial Intelligence
Graduate School of Medicine and Corneal Analysis (BrAIn), Brazil
Yamadaoka, Japan Universidade Federal de Alagoas,
Maceió, Brazil
Leonardo N. Pimentel, MD
Cornea Department of Federal University of
Rio Grande do Norte
Natal, Rio Grande do Norte, Brazil
Isaac Ramos, MD
Brazilian Study Group of Artificial Intelligence
and Corneal Analysis (BrAIn), Brazil
Instituto de Olhos Renato Ambrósio & Rio de
Janeiro Corneal Tomography and Biomechanics
Study Group, Rio de Janeiro, Brazil
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Preface
PREFACE TO THE SECOND EDITION (2012)
by Michael W. Belin, MD
Tucson, Arizona (USA)
It’s been over three years since the first edition went to press. In the intervening period
the technology has improved and numerous maps/displays have been added. In the second
edition every chapter has been updated and new chapters have been added to reflect the
expanded clinical use of Scheimpflug imaging. As in the first edition, we have attempted to
keep the reading easy and hopefully, for some, enjoyable.
PREFACE TO FIRST EDITION (2008)
by Michael W. Belin, MD
Albany, New York (USA)
The last thing I wanted to do is write a book. There is a saying “Those who can…
Do .. and Those who can’t … Teach.” I feel about the same about writing text books. It
is a thankless job that usually means you have too much free time or nothing better to do. I
wish that was the case. Constant nagging by my current research and clinical fellow (Stephen
S. Khachikian, MD) about the need for a book on elevation topography and promises that it
would not be that much work eventually wore me down. Well, in hindsight, he was half right.
Elevation based topography (or Tomography) is a new and comprehensive way of
looking at the cornea, its structure, shape and performance. For many practitioners used to
relying on anterior curvature analysis it may initially appear foreign. It is the authors’ belief,
however, that cross-sectional Scheimpflug analysis offers significant advantages in treatment,
diagnosis and patient safety.
We tried to make the book easy to read and comprehend and filled it with numerous
color figures. Each chapter was designed to stand on its own, though for those with time and
inclination the chapters are arranged in an orderly progression. We hope we have met our
goal.

The book was made possible in part by an unrestricted educational and research grant from the
Sight Society of Northeastern New York, Inc and the Lions Eye Bank at Albany (New York). The authors are
indebted to their continued support.
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Contents
CHAPTER 1
Introduction and Overview.............................................................................. 1
Michael W. Belin, MD, FACS; Stephen S. Khachikian, MD
CHAPTER 2
Evolution of Topographic / Tomographic Imaging........................................... 15
Stephen S. Khachikian, MD; Michael W. Belin, MD, FACS; Renato Ambrósio Jr., MD, PhD
CHAPTER 3
Understanding Elevation Based Topography: How Elevation Data is Displayed....... 25
Michael W. Belin, MD, FACS; Stephen S. Khachikian, MD; Renato Ambrósio Jr., MD, PhD
CHAPTER 4
The Importance of Understanding the Reference Surface............................... 47
Michael W. Belin, MD, FACS; Stephen S. Khachikian, MD; Renato Ambrósio Jr., MD, PhD
CHAPTER 5
Suggested Set-up and Screening Guidelines..................................................... 57
Michael W. Belin, MD, FACS; Stephen S. Khachikian, MD; Renato Ambrósio Jr., MD, PhD
CHAPTER 6
Normative Data for the Oculus Pentacam.......................................................... 71
Stephen S. Khachikian, MD; Michael W. Belin, MD, FACS; Renato Ambrósio Jr., MD, PhD
CHAPTER 7
Comprehensive Pachymetric Evaluation............................................................ 81
Renato Ambrósio Jr., MD, PhD; Isaac Carvalho de Oliveira Ramos, MD; Allan Luz, MD;
Frederico Guerra, MD; Marcella Salomão, MD ; Michael W. Belin, MD, FACS
CHAPTER 8
Keratoconus / Ectasia Detection with a
Modified (Enhanced) Reference Surface
Belin / Ambrósio Enhanced Ectasia Display III............................................................. 93
Michael W. Belin, MD, FACS; Renato Ambrósio Jr., MD, PhD; Stephen S. Khachikian, MD
viii
CONTENTS
CHAPTER 9
Keratoconus & Ectasia Detection:
Asymmetric Keratoconus & Post LASIK Ectasia Study..................................... 105
Marcella Salomão, MD; Isaac Carvalho de Oliveira Ramos, MD; Allan Luz, MD;
Frederico Guerra, MD; Leonardo N. Pimentel, MD; Renato Ambrósio Jr., MD, PhD
CHAPTER 10
Applications of Artificial Intelligence Techniques for
Improving Tomographic Screening for Ectasia................................................ 123
João Marcelo Lyra, MD, PhD; Aydano P. Machado, MSc, PhD; Bruna V. Ventura, MD;
Guilherme Ribeiro, MD; Luana P. N. Araújo, MD; Isaac Ramos, MD;
Frederico P. Guerra, MD; Renato Ambrósio Jr, MD, PhD
CHAPTER 11
Elevation Topography Atlas............................................................................ 137
Stephen S. Khachikian, MD; Michael W. Belin, MD, FACS; Renato Ambrósio Jr., MD, PhD
CHAPTER 12
Scheimpflug Images in Clinical Practice...................................................... 167
Michael W. Belin, MD, FACS; Renato Ambrósio Jr., MD, PhD; Stephen S. Khachikian, MD
CHAPTER 13
BESSt 2 Formula for IOL Calculation........................................................ 185
Edmondo Borasio, MedC, BQ, FEBO
CHAPTER 14
Evaluation of Corneal Optical Quality for Premium IOLs with Pentacam HR... 197
Naoyuki Maeda, MD
CHAPTER 15
Scheimpflug Evaluation of Primary Angle Closure Glaucoma...................... 205
Shuning Li, MD
CHAPTER 16
Other Displays................................................................................................ 211
Joerg Iwanczuk, Dipl Ing (FH); Michael W. Belin, MD, FACS
CHAPTER 17
The Use of Pentacam in a Cataract Practice............................................... 229
Dilraj Grewal, MD; Satinder Pal Singh Grewal, MD
CHAPTER 18
Glossary........................................................................................................... 247
Stephen S. Khachikian, MD; Michael W. Belin, MD, FACS; Renato Ambrósio Jr., MD, PhD
ix