Special Skills and Techniques

The Basic Bookshelf for Eyecare Professionals is a series that provides fundamental and advanced material with a clinical approach to clinicians and students. A special effort was made to include information needed for the certification exams in ophthalmic and optometric assisting, as well as for surgical assistants, opticians, plus low vision, and contact lens examiners.

This book moves beyond basic exam skills into the arena of more advanced diagnostic testing. Topics include biometry and echography, electrophysiology, psychophysical testing, and microbiology. Special tests such as exophthalmometry, pachymetry, and ophthalmoscopy are also covered. This is the ultimate how-to book for those performing detailed patient exams.

Contents

Dedication
Acknowledgements
About the Author
Introduction
The Study Icons

Part I. Advanced Tests and Techniques

Chapter 1. Diagnostic Testing
Exophthalmometry
Pachymetry
The Photokeratoscope
Corneal Topography
Pupillometry
Pupillography
Ophthalmoscopy

Chapter 2. Psychophysical Testing
Overview of Psychophysical Testing
Advanced Color Vision Testing
Dark Adaptometry Testing
The Macular Photostress Test
The Potential Acuity Meter
The Glare Test and the Brightness Acuity Test
Contrast Sensitivity

Chapter 3. Microbiology
Overview
Ocular Microbiology
Identification of the Infectious Antigen
The Immune System

Part II. Biometry and Echography

Chapter 4. Axial Eye Length A-Scans and Intraocular Lens Calculations
Axial Eye Length
Techniques of Axial Eye Length A-Scans
Brief Review
Probe Placement
Calculating Axial Eye Lengths with the A-scan Echo Patterns
Conducting an Axial Eye Length Examination
IOL Power Calculations

Chapter 5. Diagnostic A- and B- Scan Ultrasonography
Basic Principles
Standardized Echography Examination Techniques
B-Scan Examination
A- and B- Scan Used Together
Indications

Part III. Electrophysiology Testing

Chapter 6. Electroretinography
Introduction to the Electroretinogram
The Full-Field ERG
Materials Needed for Recording the ERG
Recording a Full-Field ERG According to International Standards
Recording a Dark-Adapted ERG
Recording a Light-Adapted ERG
Concluding the ERG Testing Session
Results of ERG Testing
The Clinical Usefulness of the ERG
Case Histories - Basic Waveform Abnormalities
Case Histories - Disorders Suggesting Cone Photoreceptor Cell Abnormality
Case Histories - Disorders Suggesting Rod Photoreceptor Cell Abnormality
Case Histories - The ERG in Unexplained Vision Loss

Chapter 7. Electro-Oculography
Introduction to the Electro-Oculogram
Preparing the Patient for an EOG
Recording the EOG
Evaluating the EOG
Clinical Usefulness of the EOG
Case Histories

Chapter 8. Visual Evoked Response
Introduction to the Visual Evoked Response
Stimuli
Averaging
VER Testing
Evaluating Test Results
The Clinical Usefulness of Flash and Pattern VER Testing
Case Histories

Appendix A. Disability Determination: Who Qualifies and Who Doesn't
Impairment and Disability
Definitions of Vision Loss
Importance of Determining Level of Impairment and Disability
Assessing and Documenting Vision Loss
Other Visual System Abnormalities Affecting Disability Determination

Appendix B. Universal Precautions
Protecting Patients from Exposure
Protecting Staff and Physicians from Exposure
Exposure

Index

About the Author

Gretchen Beal Van Boemel, PhD, COMT

Gretchen Beal Van Boemel, PhD, COMT, has worked in the field of ophthalmology since 1982. She received her undergraduate defree from California State University, Long Beach in the field of research psychology. After 1 year of working as a research assistant in the Department of Cardiology at the University of Southern California, Gretchen started working for the Doheny Eye Institute. She started out as a trainee in electrophysiology under the direction of Thomas E. Ogden, MD, PhD. Within several years, she was teaching electrophysiology courses to University of Southern California medical students and ophthalmology residents. She taught her first JCAHPO course on electrophysiology in 1985, and has taught various courses to ophthalmic technicians and registered nurses since that time. After 5 years she began teaching the practical aspects of ocular electrophysiology and psychophysiology to ophthalmology and psychology fellows (including foreign fellows).

After several years of working at Doheny, she found that she was fascinated by the other facets of the field of ophthalmology. She first studied for her COT, and received it in 1985. Later she went on for her COMT certification, which she received in 1991. While at the Doheny Eye Institute, Gretchen also conducted original research in the areas of the usefulness of electrophysiology in the evaluation of the traumatized eye, and VER testing for unexplained vision loss. While conducting the later study, she became intrigued with what appeared to be psychogenic blindness in certain refugee women. With the assistance of a colleague specializing in psychology, Gretchen embarked on a research agenda that included investigating the consequences of severe trauma as the likely cause of psychogenic blindness in a group of older Cambodian women. That work resulted in national and international attention with appearances on ABC's 20/20 news program, and CNN evening news segment, British and German equivalents of 20/20, as well as being featured in numerous newspaper articles, including a feature story in the New York Times Magazine.

As a result, Gretchen felt it necessary to continue her education, and she went back to graduate school while maintaining a full-time position as director of the electrophysiology and psychophysiology department at Doheny. She received her doctorate in Social Ecology with an emphasis in Health Psychology from the University of California, Irvine, in 1995.

Since receiving her doctorate, Gretchen has continued to work as director of the electrophysiology and psychophysiology department, but has taken on new responsibilities, as well. She was asked to create a multidisciplinary low vision rehabilitation program that she currently heads. She is also the director of the Continuing Medical Education program at the Doheny Eye Institute. She has coordinated a grant on why preventable blindness occurs in diabetes and is currently investigating barriers to low vision care. Additionally, she has been a principal investigator on a Social Security Administration project aimed at assisting low income blind and visually impaired individuals in receiving appropriate benefits. She continues teaching JCAHPO courses, as well as courses at USA and California State University, Long Beach in the Health Science Department.

Gretchen truly loves the field of ophthalmology. It is her sincere hope that many of you will develop a greater appreciation of the field after reading this book. The areas covered are often considered tedious to get through, she hopes that the care examples she has provided with allow these subjects to "come alive."