LASEK, PRK, AND EXCIMER LASER STROMAL SURFACE ABLATION

REFRACTIVE SURGERY

Series Editors

Dimitri T.Azar, M.D.

Massachusetts Eye and Ear Infirmary

Schepens Eye Research Institute

and Harvard Medical School

Boston, Massachusetts

Douglas D.Koch, M.D.

Cullen Eye Institute

Baylor College of Medicine

Houston, Texas

1.LASIK: Fundamentals, Surgical Techniques, and Complications, edited by Dimitri T.Azar and Douglas D.Koch

2.Hyperopia and Presbyopia, edited by Kazuo Tsubota, Brian S.Boxer Wachler, Dimitri T.Azar, and Douglas D.Koch

3.LASEK, PRK, and Excimer Laser Stromal Surface Ablation, edited by Dimitri T.Azar, Massimo Camellin, Richard W.Yee

ADDITIONAL VOLUMES IN PREPARATION

Phakic and Accomodating IOLs, edited by Steve Lane and Jose Guell

LASEK, PRK, AND EXCIMER LASER STROMAL SURFACE ABLATION

edited by

Dimitri T.Azar

Massachusetts Eye and Ear Infirmary

Schepens Eye Research Institute

and Harvard Medical School

Boston, Massachusetts, U.S.A.

Massimo Camellin

SEKAL Rovigo Micro Surgery

Rovigo, Italy

Richard W.Yee

Hermann Eye Center

and University of Texas Health Science Center

Houston, Texas, U.S.A.

Associate Editors

Robert T.Ang, MD,Sandeep Jain, MD,TakujiKato, MD, PhD Jae-Bum Lee, MD, PhD,Ronald R.Krueger, MD

Series Editors

Dimitri T.Azar, MD,Douglas D.Koch, MD

MARCEL DEKKER

NEW YORK

This edition published in the Taylor & Francis e-Library, 2005.

“To purchase your own copy of this or any of Taylor & Francis or Routledge’s collection of thousands of eBooks please go to http://www.ebookstore.tandf.co.uk/.”

Although great care has been taken to provide accurate and current information, neither the author(s) nor the publisher, nor anyone else associated with this publication, shall be liable for any loss, damage, or liability directly or indirectly caused or alleged to be caused by this book. The material contained herein is not intended to provide specific advice or recommendations for any specific situation.

Trademark notice: Product or corporate names may be trademarks or registered trademarks and are used only for identification and explanation without intent to infringe.

Library of Congress Cataloging-in-Publication Data A catalog record for this book is available from the Library of Congress.

ISBN 0-203-02591-1 Master e-book ISBN

ISBN: 0-8247-5434-4 (Print Edition)

Headquarters Marcel Dekker, 270 Madison Avenue, New York, NY 10016, U.S.A. tel: 212– 696–9000; fax: 212–685–4540

Distribution and Customer Service Marcel Dekker, Cimarron Road, Monticello, New York 12701, U.S.A. tel: 800–228–1160; fax: 845–796–1772

World Wide Web http://www.dekker.com/

The publisher offers discounts on this book when ordered in bulk quantities. For more information, write to Special Sales/Professional Marketing at the headquarters address above.

Copyright © 2005 by Marcel Dekker.

All Rights Reserved. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without permission in writing from the publisher.

Preface

Ignotum per ignotius

[(To explain) the unknown by the more unknown]

How important are the subtle technical details in improving the clinical outcomes of LASEK surgery? Is the reduction of wavefront error greater in LASEK and Epi-LASIK than in LASIK? Does alcohol kill the corneal epithelial cells or does it allow epithelial cell proliferation to occur divorced from the unwanted process of epithelial cell migration over a denuded stroma? These questions, and many others, have fueled the debate regarding LASEK and Epi-LASIK vs. PRK and LASIK.

LASEK and Epi-LASIK are not universally employed refractive surgical procedures. They have several advantages over LASIK in patients with relatively thin pachymetry and in patients with borderline corneal topographical changes. However, the advantages of these techniques over PRK are yet to be established. Despite numerous anecdotal reports, clinical observations, and variations of surgical techniques suggesting certain advantages of LASEK and Epi-LASIK over PRK, other studies suggest possible advantages for PRK, at least in the early postoperative period. Clearly, large prospective randomized multi-center studies, carried out by experienced LASEK surgeons, are lacking. New techniques of LASEK also hold great promise to overcome some of its current limitations.

Despite the apparent and sometimes unavoidable bias toward LASEK and surface ablation in many chapters of this book, the aim is not to present an argument favoring these techniques, but rather to present a panoramic view of various aspects of these techniques. We focus on the indications, contraindications, and surgical techniques of stromal surface ablation and discuss the postoperative care, wound healing, clinical outcomes, and complications. Also included are several basic chapters discussing wavefront analysis, optical aberration changes after LASEK, the effect of alcohol on corneal cell-cell and cell-matrix interactions, and the pathogenesis and treatment options for postoperative stromal haze.

Inclusion of this book in our “Refractive Surgery Series” was initiated with the help of several of the associate editors, who had been postgraduate fellows at the Corneal and Refractive Surgery Service of the Massachusetts Eye and Ear Infirmary. Progress of this project was hindered by the lack of definitive answers to our questions in the peerreviewed literature. Completion of the first draft of the book would not have been possible without the efforts of Drs. Suphi Taneri and Puwat Charukamnoetkanok. Additional manuscripts from Drs. Massimo Camellin, Richard Yee, Ronald Krueger, and several other experienced LASEK surgeons provided more comprehensive coverage of the topic.

We acknowledge the support of Dr. Geoff Greenwood and Rosemary Doherty of Taylor and Francis, Inc. and their commitment to this series dedicated to Refractive Surgery. We also thank Leona Greenhill for editorial assistance. Special thanks go to

Rhonda Harris, who has managed this project with utmost dedication, care, and attention to detail.

We also thank the contributors for presenting the results of their investigations. Their work will not only help answer many important questions about LASEK and surface ablation, but also underscore the fact that many answers remain unknown. Yes, the field still suffers from explanations of the unknown by even more unknowns, but the observations (and opinions) of the contributors mark a step forward in the path of discovery in this important field. They pave the way for future scientific investigations, which will undoubtedly increase our understanding of LASEK and surface ablation and improve the visual outcomes of future patients undergoing conventional and customized keratorefractive surgery.

Dimitri T.Azar

Douglas D.Koch

Contents