THE ENCYCLOPEDIA OF BLINDNESS AND VISION IMPAIRMENT Second Edition THE ENCYCLOPEDIA OF BLINDNESS AND VISION IMPAIRMENT Second Edition Jill Sardegna; Susan Shelly; Allan Richard Rutzen, M.D.; Scott M. Steidl, M.D., D.M.A. The Encyclopedia of Blindness and Vision Impairment, Second Edition Copyright © 2002 by Jill Sardegna All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, elec- tronic or mechanical, including photocopying, recording, or by any information storage or retrieval sys- tems, without permission in writing from the publisher. For information contact: Facts On File, Inc. 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data The encyclopedia of blindness and vision impairment / Jill Sardegna . [et al.].—2nd ed. p. cm. — (The Facts on File library of health and living) First ed. cataloged under the m.e.: Sardegna, Jill according to AACR2. Includes bibliographical references and index. ISBN 0-8160-4280-2 (hardcover : alk. paper) 1. Blindness—Dictionaries. 2. Blind, Apparatus for the—Dictionaries. 3. Vision disorders—Dictionaries. 4. Visually handicapped—Dictionaries. I. Sardegna, Jill. II. Series. [DNLM: 1. Vision Disorders—encyclopedias.] RE91 .S27 2002 362.4’1’03—dc21 2001055653 Facts On File books are available at special discounts when purchased in bulk quantities for businesses, associations, institutions, or sales promotions. Please call our Special Sales Department in New York at (212) 967-8800 or (800) 322-8755. You can find Facts On File on the World Wide Web at http://www.factsonfile.com Text and cover design by Cathy Rincon Printed in the United States of America VB FOF 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. For Emily and Jack and Mary and Julius h To Ann, For the flowers in my life CONTENTS Preface to the First Edition ix Preface to the Second Edition xi Acknowledgments xiii Entries A–Z 1 Appendixes 271 Bibliography 311 Index 325 PREFACE TO THE FIRST EDITION he Encyclopedia of Blindness and Vision Impairment is however, will prove useful as a basic guide and can Tthe first A-to-Z compendium on the subject of serve as a reference to other sources of informa- blindness and its inherent issues and topics. In more tion. This volume includes a brief list of references than 500 entries, the volume encompasses all aspects at the end of each main article and a substantial of blindness, including health issues, surgery and bibliography. medications, social issues, myths and misconceptions, In an effort to maximize limited space, we have economic issues, education, adaptive aids, and organi- occasionally attempted to save words by using the zations. phrase “the blind” rather than more ideal alterna- The encyclopedia can be of use to both the pro- tives such as “blind individuals” or “people who are fessional and lay person. For the lay person, we blind.” In a similar manner, the pronoun “he” have tried to cover the issue with a minimum of appears in place of “he or she.” technical jargon while accurately presenting the We have taken care to avoid significant errors of facts. Though not intended as a diagnostic tool, the fact or interpretation. We accept, however, that in text provides basic information to enable the user a volume of this scope and length, minor errors to make informed decisions with the help of his may have inadvertently been included. Changing physician. statistics and daily medical breakthroughs may ren- For the professional we have been thorough and der the described current treatments and tech- avoided the simplistic, providing a handy guide niques outdated. We intend to remain current in covering aspects of vision impairment that may fall the field and update the information in future edi- outside the particular individual’s expertise. tions. We understand that a volume of this limited size may not meet every need of all who use it. Because —Jill Sardegna of the concise format, we may have failed to San Jose, California include entries needed by some individuals or —T. Otis Paul, M.D. given other entries limited treatment. The book, San Francisco, California ix PREFACE TO THE SECOND EDITION ight is one of human beings’ most precious and yet that have been significantly revised and updated. Smost taken-for-granted gifts. Most of us routinely Among the new topics covered are increasingly go about our daily business, relying on our sight to get common technologies and treatments such as ker- around, complete our work, recognize friends and atotomy, LASIK surgery, and progressive addition family, read, and generally make our lives easier and lenses; newly recognized potential causes of vision more enjoyable. Too often, only when we develop damage, such as automobile air bags and shaken problems with our eyes or eyesight do we appreciate baby syndrome; and new options for the blind, what a miracle the sense of sight is—or was. such as Braille music, the Employment Assistance The Encyclopedia of Blindness and Vision Impair- Referral Network, and guide horses. Also included ment, Second Edition, is an A–Z compendium on the are such recent milestones as the World Blind Sail- subject of blindness and issues and topics that ing Championship and the Mount Everest expedi- relate to blindness. It addresses topics as far-rang- tion of Eric Weihenmayer, who became the first ing as the mechanics of the eye to traditional biases blind person to climb the legendary peak. and prejudices against blind people. It seeks to help More than 100 entries have been updated to readers achieve a better understanding of how the reflect new developments and information, partic- eyes work and of the problems that can occur with ularly medical breakthroughs and current the eyes and with vision. It also addresses laws research, improvements and advances in existing affecting blind or visually impaired individuals, devices and technology to aid the blind and vision- procedures and medicines used to treat vision impaired, and changes to laws and government problems, and diseases and disorders that can affect programs. Eleven appendixes have been com- the eyes and their sight. pletely redone to provide accurate information The encyclopedia is designed to be a functional about various schools, organizations, associations, tool for a consumer or patient looking for informa- and publications of interest to the blind and vision tion relating to the eyes, as well as for the profes- impaired. All information included in this book is sional who is looking for information outside of his as current as possible. However, with rapidly or her area of expertise. While the book is not occurring medical advances and constantly chang- intended to be used as a diagnostic tool, it should ing statistics, some of the information may be out- be useful in providing readers with information dated, and minor errors may have inadvertently that can be used to make informed decisions in been included in this work. conjunction with their doctors. —Susan Shelly A great deal has changed regarding blindness Shillington, Pennsylvania and vision problems since the publication of the previous edition more than 10 years ago. This new —Allan Rutzen, M.D., and Scott Steidl, M.D. edition features many new entries, as well as many University of Maryland School of Medicine xi ACKNOWLEDGMENTS rofessional people working with all aspects of Foundation Fighting Blindness, Tom Moore, Eye Pblindness and vision impairment generously Bank Association of America, Mary Ellen Mulhol- gave of their time and talents to advise, counsel and land and Dr. Sandra Timmerman, American Foun- inform us. We would like to acknowledge their con- dation for the Blind, Dr. Harry Murphy and Neil tributions and offer our appreciation to Roger R. Scott, California State University, Northridge, Diane Cackler, County of Santa Clara Social Services, Dr. B. Piastro, Carol Ranalli, James C. Riley, California Peter D’Alena, Richard E. Dietl, The President’s State Department of Rehabilitation, Arnay Rosen- Committee on Employment of People with Disabil- blat, National Multiple Sclerosis Society, Victoria ities, Juliet Esterly, Council of Rehabilitation Spe- Sheffield, Helen Keller International, Sandy Smith cialists, Dr. Deborah Gilden, Smith-Kettlewell and Kenneth Stuckey, Perkins School for the Blind, Institute of Visual Sciences, Jessie A. Goehner, Michael A. Thoennes, Foundation for the Junior National Industries for the Blind, Joseph J. Hen- Blind, Todd Turiff, National Society to Prevent nessey, Western Blind Rehabilitation Center, E.K. Blindness, Heidi Williams, Vivian Younger, our Hudson, National Association for Parents of the friends at ABLEDATA, M.C. Migel Memorial Library Visually Impaired, Michelle Laboda, American and Information Center and National Rehabilitation Academy of Ophthalmology, Diane Lipton and Pam Information Center. Our special thanks to our edi- Stenberg, Disability Rights, Education, and Defense tors, Nicholas Bakalar and Kate Kelly. Fund, Joe Jackson, Media Access Office, Michael Thanks also to Allan Rutzen, M.D., F.A.C.S., and Larsen and Elizabeth Pomada, Sally Mangold, Cali- Scott Steidl, M.D., of the University of Maryland fornia State University, San Francisco, Marc Mauer, School of Medicine; the Wyomissing Optometric National Federation of the Blind, George McNally, Center in Wyomissing, Pennsylvania; and to Bert United Cerebral Palsy, Michaelann R. Meehan, RP Holtje and Gene Brissie of James Peter Associates. xiii ENTRIES A–Z A abacus The abacus is used to teach mathematics Contact: skills to blind and visually impaired students. The ABLEDATA Cranmer abacus is an adaptive device that has a 8401 Colesville Road, Suite 200 backing behind the beads to prevent accidental Silver Spring, MD 20910 movement or sliding. 800-227-0216 (ph) It is used to add, subtract, multiply, and divide 301-608-8958 (fax) whole numbers and decimals. Calculations can be done faster on a talking computer or a calculator, but the Cranmer abacus is considered to be faster Access-Able Travel Source An online service that provides access information about travel to and easier to use than a BRAILLE WRITER, TAYLOR disabled persons, including those who are blind or SLATE, or PEGBOARD.