The Eyes iii THE FACTS ON FILE ENCYCLOPEDIA OF HEALTH AND MEDICINE IN FOUR VOLUMES: VOLUME 4 An Amaranth Book iv The Eyes To your health! The information presented in The Facts On File Encyclopedia of Health and Medicine is provided for research purposes only and is not intended to replace consultation with or diagnosis and treatment by medical doctors or other qualified experts. Readers who may be experiencing a condition or disease described herein should seek medical attention and not rely on the information found here as medical advice. The Facts On File Encyclopedia of Health and Medicine in Four Volumes: Volume 4 Copyright © 2007 by Amaranth Illuminare All rights reserved. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher. For information contact: Facts On File, Inc. An imprint of Infobase Publishing 132 West 31st Street New York NY 10001 Produced by Amaranth Illuminare PO Box 573 Port Townsend WA 98368 Library of Congress Cataloging-in-Publication Data The Facts on File encyclopedia of health and medicine / Amaranth Illuminare and Deborah S. Romaine. p. ; cm. “An Amaranth book.” Includes index. ISBN 0-8160-6063-0 (hc : alk. paper) 1. Medicine—Encyclopedias. 2. Health—Encyclopedias. [DNLM: 1. Medicine—Encyclopedias—English. 2. Physiological Processes—Encyclopedias—English. WB 13 R842f 2006] I. Title: Encyclopedia of health and medicine. II. Romaine, Deborah S., 1956- III. Facts on File, Inc. IV. Title. R125.R68 2006 610.3—dc22 2005027679 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 design and typesetting by Rhea Braunstein, RB Design Cover design by Dorothy Preston Printed in the United States of America VB RB 10 9 8 7 6 5 4 3 2 1 This book is printed on acid-free paper. The Eyes v CONTENTS VOLUME 4 Foreword by Maureen Pelletier, M.D., C.C.N., F.A.C.O.G. vii How to Use The Facts On File Encyclopedia of Health and Medicine ix Preface to Volume 4 xiii Preventive Medicine 1 Alternative and Complementary Approaches 51 Genetics and Molecular Medicine 109 Drugs 145 Nutrition and Diet 174 Fitness: Exercise and Health 210 Human Relations 238 Surgery 257 Lifestyle Variables: Smoking and Obesity 282 Substance Abuse 311 Emergency and First Aid 355 Appendixes: I. Vital Signs 389 II. Advance Directives 390 v vi Contents III. Glossary of Medical Terms 391 IV. Abbreviations and Symbols 394 V. Medical Specialties and Allied Health Fields 398 VI. Resources 399 VII. Biographies of Notable Personalities 410 VIII. Diagnostic Imaging Procedures 417 IX. Family Medical Tree 420 X. Immunization and Routine Examination Schedules 422 XI. Modern Medicine Timeline 424 XII. Nobel Laureates in Physiology or Medicine 425 Selected Bibliography and Further Reading 433 Medical Advisory Review Panel 439 Cumulative Index to Volumes 1–4 443 FOREWORD A big part of my role as a physician is educating your body in isolation from other body structures my patients about their health. I take as much and functions. Your body attempts to compensate time as each person needs to explain prevention and adjust, often without your awareness, until it measures, test results, and treatment options. I can no longer accommodate the injury or illness. encourage questions. But in the moment, sitting The symptoms you bring to your doctor may there in my office, most people do not yet know reflect this compensation, for example frequent what to ask me. By the time questions flood headaches that point not to brain tumor (as many their thoughts, they may be back at work or at people fear but is very rare) but to eye strain or home. muscle tension or sometimes to hypertension Numerous events and circumstances can chal- (high blood pressure). lenge health, and we all need to know what In my medical practice I emphasize integrative actions we can take to keep ourselves healthy as health care, embracing the philosophy that health well as to obtain appropriate treatment for health exists as the intricate intertwining of the body’s conditions that do affect us. Knowledge empow- many systems, structures, and functions. So, too, ers all of us to make informed and appropriate does the care of health. I received my medical decisions about health care. Certainly there is no degree from Tufts University School of Medicine shortage of reference material. Yet there is so in Boston, an institution noted for remaining at much information available today! Even for the forefront of the medical profession. I also physicians, it is challenging to keep up. How can completed clinical programs in Mind-Body Medi- you get to the core of what you want to know, cine at Harvard University, Integrative Medicine at reliably and to the level of detail you need? the University of Arizona School of Medicine, and The Facts On File Encyclopedia of Health and Medi- Medical Acupuncture at the University of Califor- cine is a great resource for up-to-date health infor- nia-Los Angeles (UCLA). I am a board-certified mation presented in a manner that is both obstetrician-gynecologist, a board-certified clinical comprehensive and easy to understand no matter nutritionist, and a licensed acupuncturist. I see what your level of medical knowledge. The ency- patients in my practice in Cincinnati, Ohio; I clopedia organizes entries by body system. The teach, I lecture, and I frequently go on television progression of body systems—and entries— and radio to talk about health topics. In each of throughout the encyclopedia presents topics the these areas, I encourage people to think about way you think about them. their health and health concerns from an integra- Going beyond this basic structure, however, is tive perspective. When you understand your another layer of organization that particularly health from multiple dimensions, you can better appeals to me, which is a comprehensive structure understand what to do to keep yourself as healthy of cross references that integrates entries across as possible. body systems. After all, your body functions in an I wish you the best of health for all of a long, integrated way; so, too, should a reference series satisfying life. But when the time comes that you that discusses your body’s health. Not very much must make decisions about medical care, I want that happens with your health affects one part of you to have the knowledge to make informed vii viii Foreword choices that are right for you. Whether you start Encyclopedia of Health and Medicine to be a most here and move on to more specialized resources valuable reference resource. or locate all the information you need within —Maureen M. Pelletier, M.D., C.C.N., these four volumes, you will find The Facts On File F.A.C.O.G. HOW TO USE THE FACTS ON FILE ENCYCLOPEDIA OF HEALTH AND MEDICINE Welcome to The Facts On File Encyclopedia of Health with its surroundings and the external envi- and Medicine, a four-volume reference set. This ronment. comprehensive resource is an indispensable refer- • Volume 2 presents the cell- and fluid-based ence for students, allied health professionals, body systems that transport nutrients, remove physicians, caregivers, lay researchers, and people molecular wastes, and provide protection from seeking information about health circumstances infection. and conditions for themselves or others. Entries • Volume 3 presents the biochemical body sys- present the latest health concepts and medical tems that support cellular functions. knowledge in a clear, concise format. Readers may easily accumulate information and build a com- • Volume 4 presents topics that apply across plete medical profile on just about any health or body systems (such as “Fitness: Exercise and medical topic of interest or concern. Health”) or that address broad areas within health care (such as “Preventive Medicine”). A New Paradigm for the • The appendixes provide supportive or additional Health and Medical Encyclopedia reference information (such as “Appendix X: As the art and science of health and medicine con- Immunization and Routine Examination tinues to evolve, with complex and elegant discov- Schedules”). eries and new techniques, medications, and treatments emerging all the time, the need has Following Research Pathways arisen for a new paradigm for the encyclopedia of The Facts On File Encyclopedia of Health and Medi- health and medicine—a rethinking of the old, and cine’s organization and structure support the increasingly outmoded, presentations. Carefully reader’s and researcher’s ease of use. Many ency- researched and compiled, The Facts On File Encyclope- clopedia users will find all the information they dia of Health and Medicine offers many distinguishing desire within one volume. Others may use several features that present readers and researchers with or all four of the encyclopedia’s volumes to arrive an organization as up-to-date and compelling as the at a comprehensive, multifaceted, in-depth under- breakthrough information its entries contain. standing of related health and medical concepts Recognizing the current emphasis on present- and information. Researchers efficiently look up ing a truly integrative approach to both health information in The Facts On File Encyclopedia of and disease, The Facts On File Encyclopedia of Health Health and Medicine in several ways. and Medicine organizes content across volumes Each section’s entries appear in alphabetical within a distinctive format that groups related order (except the entries in Volume 4’s “Emer- entries by body system (for example, “The Cardio- gency and First Aid” section, which are grouped vascular System”) or by general health topic (for by type of emergency).