Ординатура / Офтальмология / Английские материалы / Essentials in Ophthalmology Glaucoma_Grehn, Stamper_2006

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The series Essentials in Ophthalmology was initiated two years ago to expedite the timely transfer of new information in vision science and evidence-based medicine into clinical practice. We thought that this prospicient idea would be moved and guided by a resolute commitment to excellence. It is reasonable to now update our readers with what has been achieved.

The immediate goal was to transfer information through a high quality quarterly publication in which ophthalmology would be represented by eight subspecialties. In this regard, each issue has had a subspecialty theme and has been overseen by two internationally recognized volume editors, who in turn have invited a bevy of experts

to discuss clinically relevant and appropriate topics. Summaries of clinically relevant information have been provided throughout each chapter.

Each subspecialty area now has been covered once, and the response to the first eight volumes in the series has been enthusiastically positive. With the start of the second cycle of subspecialty coverage, the dissemination of practical information will be continued as we learn more about the emerging advances in various ophthalmic subspecialties that can be applied to obtain the best possible care of our patients. Moreover, we will continue to highlight clinically relevant information and maintain our commitment to excellence.

G. K. Krieglstein

R. N.Weinreb

Series Editors

This second volume in the series Essentials of Ophthalmology, as in the first, seeks to bring the ophthalmic practitioner up to date on the important new advances or changes in glaucoma diagnosis and management that has occurred in the last 10 years. The last decade has seen significant changes in our understanding of the pathophysiology of some glaucomas, both in our diagnostic approaches and in our management. Toward the goal of providing the most up-to-date information in a readable fashion, we have asked some of the world’s experts to discuss areas to which they have contributed in a way that will be useful for the practicing doctor.

For example, Dr. Johnstone, one pioneer in the study of trabecular meshwork, explains his new theories of how aqueous gets through the meshwork and Schlemm’s canal. He proposes that the trabecular drainage system is not just a passive screen as has been conceived for the past century but a much more dynamic system than has been heretofore acknowledged.

Electrophysiology has improved both our understanding of the processes of glaucoma damage but has also provided new diagnostic tools. Thanks to the completion of several randomized controlled trials, we are now able to actually calculate the risk of developing glaucoma in a patient who is a glaucoma suspect. Dr. Mansberger explains this new development.

Our understanding of the complicated issue of what factors drive our patients to follow our prescriptions or not has been given a boost by several studies in recent years. Dr. Schwartz describes some of the advances in our understanding of patient adherence and persistence.

Health economics, rarely discussed before in this kind of ophthalmic venue, has become more important as healthcare groups, health insurers and governments grapple with the problems of providing ophthalmic care with resources that are stressed by ever-increasing demands and options. This issue is addressed by Dr. Tuulonen, as is the problem of glaucoma in the developing world which, as difficult as it may be with firstrate resources, becomes even more daunting when the resources are severely limited.

Drs. Kaufman and Gabelt give us a look at the future of medical treatment. The use of new imaging techniques has given us new insights into the pathophysiology of filtering blebs.

Dr. Freedman updates our concepts of tubeshunt procedures and offers some practical advice on how to improve results. Many of the mechanisms discussed and illustrated in this volume have not appeared in textbook format before. We hope that all the topics and authors we have selected are helpful in improving the understanding of the many faces of glaucoma and will ultimately contribute to reduced visual loss and better care for our patients.

Franz Grehn

Robert L. Stamper

Basics and Diagnosis

Chapter 1

A New Model Describes an Aqueous

Outflow Pump and Explores Causes

of Pump Failure in Glaucoma

Murray A. Johnstone

1.1 Introduction . . . . . . . . . . . . . . . . 3

1.1.1 Overview . . . . . . . . . . . . . . . . . . . 3

1.1.2The Trabecular Meshwork

1.1.3The Aqueous Outflow System Is Part of a Vascular

Circulatory Loop . . . . . . . . . . . . 4

1.1.4Circulatory Loops Return Fluid to the Heart

by Pumping Mechanisms . . . 5

1.2Laboratory Evidence

of a Mechanical Aqueous

Outflow Pump . . . . . . . . . . . . . . 6

1.2.1Anatomic Relationships That

1.2.2IOP Transients Move Trabecular Tissues to Power

1.2.3IOP Decreases Cause Trabecular Tissue Recoil . . . . . 8

1.2.4Trabecular Tissues Respond

1.2.5Trabecular Tissues Move

1.3.1Appearance and

1.4.Trabecular Tissues and

Aqueous Valves Are the

Pump . . . . . . . . . . . . . . . . . . . . . 12

1.4.1Trabecular Tissues Distend

and Recoil with IOP

Changes . . . . . . . . . . . . . . . . . . 12

1.4.2Trabecular Tissue Movement

1.4.3IOP Transients Provide

Energy to Power the Pump 12

1.5Clinical Evidence of a Mechanical Aqueous

Outflow Pump . . . . . . . . . . . . . 12

1.5.1Clinical Evidence of Pulsatile

Aqueous Flow . . . . . . . . . . . . . 13

1.6Pump Regulation of

Pressure and Flow: Short

Term . . . . . . . . . . . . . . . . . . . . . . 14

1.6.1Length-to-Tension

Relationships Govern Stroke

Volume . . . . . . . . . . . . . . . . . . . 14

1.6.2Clinical Evidence of Pump-

Dependent Pressure

Regulation . . . . . . . . . . . . . . . . 15

1.7Pump Regulation

of Pressure and Flow:

Long Term . . . . . . . . . . . . . . . . . 16

1.7.1Trabecular Tissue

Information Networks . . . . . 16

1.7.2Trabecular Tissue Tethers

and Signaling Mechanisms 17

1.7.3Endothelial Cells Regulate

Trabecular Tissue

Composition . . . . . . . . . . . . . . 17

1.7.4Regulation of Trabecular

Tissue Composition Is Pump

Regulation . . . . . . . . . . . . . . . . 18

1.8The Pump Fails to Control

Pressure in Glaucoma . . . . . . 19

1.8.1Overview of the Failure

Mechanism . . . . . . . . . . . . . . . . 19

1.8.2Laboratory Evidence: Pump Failure Mechanisms

in Living Eyes . . . . . . . . . . . . . . 19

1.8.3Laboratory Evidence: Pump Failure Mechanisms

in Enucleated Eyes . . . . . . . . . 22

1.9Clinical Evidence of Pump

Failure Mechanisms

in Glaucoma . . . . . . . . . . . . . . . 28

1.9.1Pulsatile Aqueous Flow

Decreases in Glaucoma

Eyes . . . . . . . . . . . . . . . . . . . . . . . 28

1.9.2Pulsatile Aqueous Flow

Stops As IOP Increases

in Glaucoma Eyes . . . . . . . . . . 28

1.9.3Pulsatile Aqueous Flow Stops with Episcleral Venous

Pressure Increases . . . . . . . . . 29

1.9.4Pilocarpine: Pulsatile Aqueous Flow Increases

1.9.5SC Blood Reflux: Measure of Trabecular

Tissue Movement . . . . . . . . . . 29

1.10 Conclusion . . . . . . . . . . . . . . . . 32

References . . . . . . . . . . . . . . . . 32

Chapter 2

Risk Calculators: Evidence-Based

Care of Ocular Hypertension

and Glaucoma Patients

Steven L. Mansberger

and Emily L. Patterson

2.1 Introduction . . . . . . . . . . . . . . . 36

2.2Evidence from Recent

Randomized Clinical Trials . 36

2.2.1Preventing or Delaying Glaucoma: The Ocular

Hypertension Treatment

Study . . . . . . . . . . . . . . . . . . . . . 37

2.2.2Treating Newly Diagnosed Glaucoma: the Early Manifest Glaucoma Trial

and the Collaborative Initial

Glaucoma Treatment Study 37

2.2.3Treating Moderate to Advanced Normal

Tension Glaucoma: the

Collaborative Normal-

Tension Glaucoma Study . . . 37

2.2.4Treating Uncontrolled Glaucoma: the Advanced

Glaucoma Intervention

Study . . . . . . . . . . . . . . . . . . . . . 37

2.2.5Integrating Information

2.3How Do Clinicians Use This

Important Information

to Take Care of Patients? . . . 38

2.4Implementing Information

from Clinical Studies into Clinical Care of Patients . . . . 40

2.4.1A Current Risk Calculator:

The Devers Ocular

Hypertension to Glaucoma

Risk Calculator . . . . . . . . . . . . . 40

2.4.2Benefits to Eye Care

2.4.4Benefits to Society of a Risk

Calculator . . . . . . . . . . . . . . . . . 42

2.4.5Disadvantages of Risk

Calculators . . . . . . . . . . . . . . . . 42

2.4.6Future Risk Calculators . . . . . 43

2.4.7 Conclusion . . . . . . . . . . . . . . . . 44

References . . . . . . . . . . . . . . . . 44

Chapter 3

Dynamic Contour Tonometry

Evelin Schneider, Hartmut E. Kanngiesser,

Christoph Kniestedt

3.1.2Principles and Problems of

IOP Measurement Methods 48

3.1.3Comparison of Common

Tonometers . . . . . . . . . . . . . . . 49

3.2Dynamic Contour

Tonometry . . . . . . . . . . . . . . . . 50

3.2.1Physical Methodology . . . . . 50

3.2.2Measurement Procedure . . . 51

3.2.3Absolute and Relative

Accuracy . . . . . . . . . . . . . . . . . . 53

3.3Clinical Application

of Dynamic Contour

Tonometry . . . . . . . . . . . . . . . . 56

3.3.1Dynamic Contour Tonometry or Applanation

3.3.3DCT in Clinical Practice:

Experiences, Advantages,

and Disadvantages . . . . . . . . 58

References . . . . . . . . . . . . . . . . 61

Chapter 4

Effect of Corneal Thickness on Applanation Tonometry, Pneumotonometry,

and Tonopen Measurements

Lutz E. Pillunat, Markus Kohlhaas, Andreas G. Boehm, Eberhard Spoerl

4.1Influencing Factors in

Applanation Tonometry . . . 65

4.2Approach to a Clinical

4.4Results of a Clinical Study Pitfalls and Solutions for

Chapter 5

Electrophysiology

in the Diagnosis of Glaucoma

Thomas Meigen and Michael Bach

5.1 Introduction . . . . . . . . . . . . . . . 73

5.1.1Glaucomatous Damage

5.1.2The Importance of Early

Detection of Glaucoma . . . . 74

5.1.3Electrophysiological Procedures

in Ophthalmology . . . . . . . . . 75

5.2Early Detection of Glaucoma

5.3.1Conventional VEP

Recordings in Glaucoma . . . 83

5.3.2Multifocal VEP Recordings

in Glaucoma . . . . . . . . . . . . . . . 85

References . . . . . . . . . . . . . . . . 86

Chapter 6

Adherence and Persistence

in Glaucoma

Gail F. Schwartz

6.1 Introduction . . . . . . . . . . . . . . . 91

6.2 Adherence . . . . . . . . . . . . . . . . 92

6.3 Persistence . . . . . . . . . . . . . . . . 96

6.4Barriers to Adherence

and Persistence . . . . . . . . . . . . 99

6.4.1Patient Demographics . . . 100

6.4.2 Behavioral Factors . . . . . . . 100

6.4.3Treatment Regimen

6.5Improving Adherence

and Persistence . . . . . . . . . . 101

6.5.1Improve Motivation and Knowledge

by Reinforcing the Importance of Adherence

and Persistence . . . . . . . . . . 102

6.5.2Provide Literature to Read

at Home . . . . . . . . . . . . . . . . . 102

6.5.3Write Down All Drop

Directions; Consider

an Easy-to-Read Chart . . . 102

6.5.4Regularly Evaluate

the Treatment Regimen . . 102

6.5.5Improve Patient Skills

by Monitoring Drop

Instillation Techniques . . . 102

6.5.6Question Patients Concerning Adherence

and Persistence . . . . . . . . . . 102

6.5.7Help Patients Fit

the Treatment Regimen

6.5.8Consider Health System

Issues . . . . . . . . . . . . . . . . . . . 103

6.6 Conclusion . . . . . . . . . . . . . . 103

References . . . . . . . . . . . . . . 103