Michael W. Belin – Elevation Based Corneal Tomography (Second Edition)

Автор: Michael W. Belin
Название книги: Elevation Based Corneal Tomography
Формат: PDF
Жанр: Оптическая когерентная томография
Качество: Изначально компьютерное, E-book

Chapter 1: Introduction and Overview
Chapter 2: Evolution of Topographic / Tomographic Imaging
Chapter 3: Understanding Elevation Based Topography: How Elevation Data is Displayed
Chapter 4: The Importance of Understanding the Reference Surface
Chapter 5: Suggested Set-up and Screening Guidelines
Chapter 6: Normative Data for the Oculus Pentacam
Chapter 7: Comprehensive Pachymetric Evaluation
Chapter 8: Keratoconus / Ectasia Detection with a Modified (Enhanced) Reference Surface – Belin / Ambrósio Enhanced Ectasia Display III
Chapter 9: Keratoconus & Ectasia Detection: Asymmetric Keratoconus & Post LASIK Ectasia Study
Chapter 10: Applications of Artificial Intelligence Techniques for Improving Tomographic Screening for Ectasia
Chapter 11: Elevation Topography Atlas
Chapter 12: Scheimpflug Images in Clinical Practice
Chapter 13: BESSt 2 Formula for IOL Calculation
Chapter 14: Evaluation of Corneal Optical Quality for Premium IOLs with Pentacam HR
Chapter 15: Scheimpflug Evaluation of Primary Angle Closure Glaucoma
Chapter 16: Other Displays
Chapter 17: The Use of Pentacam in a Cataract Practice
Chapter 18: Glossary

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.

Why a book on elevation topography, and now, why a second edition? While
curvature analysis is understood by most refractive surgeons, there are essential differences
between curvature analysis and elevation analysis. To properly utilize modern elevation based
systems it is essential to understand these differences. Often users of elevation systems rely
only on the curvature maps and as such are not making full use of the increased information
offered by elevation systems. It is the hope of the authors that this book will give the reader
a better understanding of the wealth of information available with optical cross sectioning
based topography. While the book will deal almost exclusively with the Oculus Pentacam
(OCULUS Optikgeräte GmbH, Wetzlar, Germany), the principles presented are applicable
to any elevation based topography system. (The samples used throughout this book are from
multiple sources and represent both the authors’ private practice and cases sent to the authors
for consultation. Because of the diverse source of the maps there is some inconsistency in the
location of the individual maps in the composite display.)
Topography/Tomography (Tomography refers to systems that can generate a threedimensional
reconstruction of the anterior segment using a series of optical cross-sections)
is considered an essential part of every refractive surgery evaluation. Original topography
systems were based on reflective technology and relied on the digitalization of a Placido image
and determined slope as the basic unit of measure. The topographic data was presented
as the first derivative of slope (curvature) which was initially more intuitive for the general
refractive surgeon. Those systems were relatively inexpensive, however, they had a number
of limitations.
Placido based systems rely on the analysis of a reflected image. This precludes
obtaining data from both the peripheral cornea and the posterior corneal surface. Additionally,
without information about the posterior corneal surface, complete pachymetric evaluation is
not possible. While ultrasonic pachymetry can give you central or isolated readings, a full
pachymetric map requires accurate data from both the anterior and posterior corneal surface
(pachymetric computations are based on the spatial difference between anterior and posterior
surfaces)