Ординатура / Офтальмология / Английские материалы / Wavefront Analysis Aberrometers and Corneal Topography_Boyd_2003

Contents

CHAPTER 9

TOPOGRAPHIC AND PACHYMETRIC

CHANGES INDUCED BY

CONTACT LENSES

Jairo E. Hoyos, MD. ; Melania Cigales, MD

Jairo Hoyos-Chacón, MD.

CHAPTER 10

CORNEAL TOPOGRAPHY IN

CATARACT SURGERY

Samuel Boyd, M.D.

Virgilio Centurion, M.D.

CHAPTER 11

CORNEAL TOPOGRAPHY IN PHAKONIT WITH A 5 MM OPTIC ROLLABLE IOL

Amar Agarwal, MD, MS,FRCS, FRCOpth Soosan Jacob, MD, MS, DNB, FERC Athiya Agarwal, MD, FRSH, DO

Sunita Agarwal, MD, MS, FSVH,FRSH,DO

What is Wavefront Technology? Current Ocular Refraction Evaluation

Systems

Phoroptor and Autorefractors Corneal Topography

20/10 Perfect Vision Wavefront System Other Wavefront Sensing Devices How the Visx 20/10 Wavefront

System Works

How to Read a Wavefront Map

The Shortcomings of Shack-Hartmann Wavefront Analysis

Clinical Examples

CHAPTER 14

UNDERSTANDING OPTICAL ABERRATIONS OF THE EYE AND PRINCIPLES OF MEASUREMENT

L.A. Carvalho, MD.; J. C. Castro, MD. W. Chamon, MD.; P. Schor, MD.

L. A. V. de Carvalho, Ph.D.

History

Principles of Eye Aberration Measurements

with the Hartmann-Shack Sensor

CHAPTER 16

BAUSCH & LOMB ZYWAVE II

WAVEFRONT SYSTEM

Jaime R. Martiz, M.D.; Stephen G. Slade, M.D.

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CHAPTER 21

ABERROPIA: A NEW REFRACTIVE

ENTITY

Amar Agarwal, MD, MS,FRCS, FRCOpth

Nilesh Kanjiani DO, MD, FERC

Soosan Jacob, MD, MS, DNB, FERC

Athiya Agarwal, MD, FRSH, DO

Sunita Agarwal, MD, MS, FSVH,FRSH,DO Tahira Agarwal, MD, F.I.C.S., DO, F.O.R.C.E.,

CHAPTER 22

CORRECTION OF HIGHER-ORDER ABERRATIONS WITH VISX WAVEFRONT TECHNOLOGY

David R. Hardten, MD.;

Richard L. Lindstrom, MD.

CHAPTER 23

TECHNOLOGY REQUIREMENTS FOR CUSTOMIZED CORNEAL ABLATION

Ronald R. Krueger, M.D.

CHAPTER 24

ABERROMETRY IN IRREGULAR

ASTIGMATISM

Jorge L. Alió, MD, PhD

Robert Montés-Micó, OD, MPhil

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CHAPTER 28

THE FUTURE OF WAVEFRONT TECHNOLOGY AND CUSTOMIZED ABLATIONS

Renato Ambrósio Jr., MD.; Marcelo V. Netto, MD.

Steven E. Wilson, MD.

BACKGROUND

The eye manifests its refracting power via several curved surfaces, each separated by media with different indices of refraction. The cornea and the lens primarily serve the optical functions of the eye. The most significant refractive surfaces are the anterior and posterior surfaces of the cornea and crystaline lens, the aqueous and the vitreous play only a passive role.1This apparatus ensures a clear image formation on the retina.

In its path to the retina, light encounters various interfaces at which refraction of the light rays may occur. These include the anterior surface of the cornea, the substance of the cornea, the posterior surface of the cornea, the aqueous humor, the anterior surface of lens, substance of lens, posterior surface of lens and the vitreous humor.1

In the emmetropic eye (without any refractive error), the range of corneal refracting power is between 39 and 48 diopters, while the range of

refracting power of the crystalline lens is between 15 and 24 diopters. In the emmetropic eye, the axial length (from the posterior corneal surface to the retina) varies from 22 to 26 mm. The following are the clear ocular media and structures (through which light passes before it reaches the retina) and their respective indices of refraction: Precorneal Tear Film 1.33, Cornea 1.37, Aqueous Humor 1.33, Crystalline Lens 1.41, and Vitreous Humor 1.33. The features of importance, which determine their optical power, are the radius of curvature, the index of refraction and the distance between the various interfaces1.

It is important to understand the optical, refractive peculiarities as well as anatomico-physio- logical consideration of the refractive media of the eye, viz., cornea, aqueous and vitreous humor, and the crystalline lens (Figure 1). In this chapter we shall describe the various refractive properties of the different components of this optical apparatus of the eye and also emphasize the relevant anatomico-phys- iological details and their clinical application.