Ординатура / Офтальмология / Английские материалы / Quick Reference Dictionary of Eyecare Terminology 4th edition_Ledford, Hoffman_2005

x Acknowledgments

knowledge is helpful but whose support is essential. And thanks to Collin, our 19 year old, who knows exactly how to fix my computer complaints and enjoys spending his percentage. To Munchkin, Boonie, Angel, Josey Dee, and Nadia, a heartfelt meow and a promise of catnip.

Jan Ledford, COMT

October, 2004

Franklin, NC

ACKNOWLEDGMENTS, THIRD EDITION

Taking on the third and subsequent editions of this book meant that I will forever build on the work of Joe Hoffman. I thank him for establishing the foundation. Thank you to SLACK Incorporated employees Amy McShane, Debra Toulson, and John Bond for handing me this project. Others who helped are Tiffany K. Spooner, Paraoptometric Section of the AOA, for providing updated information on paraoptometric assistants; Art Giebel, MD, Loma Linda University Medical Center, a contact of Joe's, for providing abbreviations; Bernie Calaway for proofreading assistance and general encouragement; Jim Ledford, my husband, who understands; and Collin Ledford, our teenaged son, who also understands and even does some writing of his own.

—Jan Ledford, COMT

ABOUT THE AUTHORS

For over 20 years now, Jan Ledford has been using her skills both in the ophthalmic exam room and on the printed page. While she is probably best known for her certification review books and editorship of The Basic Bookshelf for Eyecare Professionals, she is also a published novelist. She combined her talent for medical research with that of story telling to produce The Cloning, a novel about human cloning, which is available at book stores everywhere as well as online. In spite of branching out, she has no intentions of leaving the field of eyecare, where, she says, she has found a permanent and happy home.

Joseph Hoffman has worked in medical publishing since 1985 and was the editor-in-chief of the Ocular Surgery News publication group from 1996 to 2001. He has won writing awards from the American Society of Business Publication Editors and Apex. He is currently the proprietor of Hoffman Health Care Communications.

PREFACE

I am way past grammar school, believe me, but the words “Go look it up” still strike terror in my heart. Not because I do not like to look up new terms—far from it. The problem is that I cannot look up just one! I get sidetracked right away by intriguing entries that I just might want to use someday. In the interest of expediency, it is much easier to have someone tell me the meaning.

Medicine has its own unique breed of terms, founded from Greek, Latin, and who knows where else. The current Stedman’s Medical Dictionary is a two-volume set… a place where I could easily get lost and spend many happy hours, if I just had the time.

Many of you in eyecare share my delight; others do not. Here is a single volume containing all things optic (well, lots anyway) plus a smattering of general medical terms to get you by. If you are new to the field, there’s a lot to learn. If you’re an old-timer (might we coin a new term here: presbytech?), there is something new right around every optic, ophthalmic, and optometric corner.

The task of taking on SLACK Incorporated’s ophthalmic dictionary, like most projects, turned out to be bigger than I thought. Not the least of these is a simple difference of opinion on some of the words themselves: Is it Grave disease, Graves disease, or Grave’s disease? I found references that confirmed each and every one, and doubtless some of you won’t agree with the spelling I selected. Then there are your personal pet obscure terms that I left in (spiral of Tillaux is one of mine, so it got in) and obsolete words that made the cut (such as squint). Others might argue that the inclusion of some general medical terms takes the book needlessly beyond the realm of eyecare.

In the final analysis, all I can offer is one of my favorite (and original) axioms regarding publishing: There is no such thing as a perfect book.

xiv Preface

Regardless, a lot of people worked really hard to make this one come as close as possible. Meanwhile, I’m starting on the fifth edition, and I’d appreciate your input. Please email me at bookspublishing@slackinc.com to share your ideas on what terms should be added and deleted, what new appendices would be most helpful, those definitions that need improvement, alternate spellings, typos—whatever! Together, we’ll continue to make The Quick Reference Dictionary of Eyecare Terminology the most turned-to word reference book in the field.

—Jan Ledford, COMT July 15, 2004

HOW TO USE THIS BOOK

As a general rule, the most commonly encountered form of the word (for example, cystoid macular edema) is given as the main entry (rather than edema, cystoid macular). Some groups of related terms, however, have been gathered under a unifying concept (for example, laser or nystagmus).

In addition to regular entries, some of the more important combining forms for ophthalmologic terms (such as phac- and kerat-) have been included.

Cross referencing directs the reader by the word see, to synonyms by Another term for, to antonyms with the word compare, and to related terms with the phrase see also.

The third and fourth editions have added some general medical terms appropriate to the field. A good medical dictionary such as Stedman's Medical Dictionary, 27th edition (Lippincott Williams & Wilkins) will fill in any gaps.

A

A-constant: 1. Number assigned to an intraocular lens (IOL) by the manufacturer based on the lens design; used in formulas for calculating power of IOL needed in a given patient; 2. number derived from actual visual results of IOL implantation by a particular surgeon; used as part of subsequent IOL power calculations to “personalize” the formula and better reflect the influence of surgeon technique.

“A” measurement: The horizontal eye size of a pair of spectacles, measured in millimeters from one side of the eyewire to the other; see also boxing system.

A pattern: See esotropia and exotropia.

A-scan: As used in ophthalmology, an ultrasound examination to determine the axial length of the eye (distance from the front of the cornea to the back surface of the retina at the macula) and possibly the depth of various intraocular structures; most commonly used in calculating the power of intraocular lenses; also called biometry; the “A” stands for amplitude, as the echoes are judged by their relative height; diagnostic A. ultrasound used to differentiate tissue (eg, melanoma versus hemangioma); also called standardized A-scan.

A-V crossing: Situation in which the retinal arterioles press down on underlying veins that they cross over, reducing blood flow and causing A-V nicking; also called crossing changes.

A-V nicking: Situation in which the retinal arterioles and veins exhibit areas of compression, giving the appearance that a “nick” has been taken out of them; associated with hypertension.

2 a-wave/aberrometer

a-wave: In electroretinography, the first part of the waveform, generated by the retinal photoreceptor cells; see also b-wave, c-wave.

ab externo: General medical term meaning from the outside; in ophthalmic usage, describing surgical procedures in which the approach to an anatomic structure is made from outside the globe.

Abbe value: A rating (from 1 to 100) that indicates the amount of chromatic aberration present in a lens material; a higher number indicates less likelihood of aberration; also called Nu value.

abducens nerve: Sixth cranial nerve; supplies the lateral rectus muscle.

abduct: General medical term for inducing motion away from the center of the body; in ophthalmic usage, muscles that move an eye toward the temple are called abductors; compare adduct.

aberration: Uneven refraction by an optical system of the wavefront of transmitted light, resulting in distortion of the image; see also chromatic aberration and spherical aberration; aberrations can be chromatic (affecting the colors of the image) or monochromatic (affecting only the focus of the image); in refractive surgery, monochromatic aberrations are usually divided into the lower-order aberrations (astigmatism and defocus, which includes myopia and hyperopia) and high- er-order aberrations (coma, spherical aberration, quadrafoil, secondary astigmatism, trefoil, etc.); see also wavefront, Zernike polynomials.

aberrometer: In ophthalmic usage, device that measures the optical aberrations of the eye; growing in use among refractive surgeons to create "customized" or "wavefront-guided" correction patterns for the excimer laser to apply to the cornea; see also wave- front-guided ablation; also called wavefront analyzer.

aberrometry/Acanthomoeba 3

aberrometry: In ophthalmic usage, process of measuring the optical aberrations of the eye and representing them numerically or graphically; also called wavefront analysis; see also Shack-Hartmann a., Tscherning a.

ablation: General medical term for destruction of tissue, usually as part of a surgical procedure; in refractive surgery, removal of corneal tissue by a laser (usually the ArFl excimer laser) to reshape the eye to correct ametropia; see also customized ablation, photoablation.

abnormal retinal correspondence (ARC): Another term for anomalous retinal correspondence.

abrasion: General medical term for wound in which layers of tissue are scraped away; in ophthalmic usage, often used as a synonym for corneal abrasion.

Acanthomoeba: Protozoan known for contaminating homemade saline and hot tubs, and thus a problem to some contact lens wearers; can cause severe corneal infection.