Handbook Of Vitreo-retinal Disorder Management: A Practical Reference Guide

A Practical Reference Guide

Susanna S Park

• Publisher: WSPC
• Year: 2015
• ISBN:
  9789814663311
• Topic: Ciencias biológicas
• Subtopic: Ciencias en general

This unique one-volume handbook provides a quick and concise reference guide for practising ophthalmologists, retinal specialists, vitreo-retinal fellows, ophthalmology residents and optometrists on the latest recommendations for managing common vitreo-retinal disorders seen in everyday retina practise.

It provides comprehensive and essential information on diagnosis and management in outline and table format for conciseness and quick access. Color illustrations of important clinical manifestations are provided in an appendix.

Dr Susanna Park is a Professor of ophthalmology and Director of Vitreo-retinal Fellowship and Ocular Oncology at the University of California Davis Eye Center. She has over 20 years clinical experience as a vitreo-retinal specialist and published over 100 journal papers and book chapters on the subject.

This unique one-volume handbook provides a quick and concise reference guide for practising ophthalmologists, retinal specialists, vitreo-retinal fellows, ophthalmology residents and optometrists on the latest recommendations for managing common vitreo-retinal disorders seen in everyday retina practise.

It provides comprehensive and essential information on diagnosis and management in outline and table format for conciseness and quick access. Color illustrations of important clinical manifestations are provided in an appendix.

Dr Susanna Park is a Professor of ophthalmology and Director of Vitreo-retinal Fellowship and Ocular Oncology at the University of California Davis Eye Center. She has over 20 years clinical experience as a vitreo-retinal specialist and published over 100 journal papers and book chapters on the subject.

Readership: Practicing opthalmologists, retinal specialists, vitreo-retinal fellows, ophthalmology residents and optometrists.
Key Features:

• The volume is compact and self-contained
• No competing titles to the best of author's knowledge
• Outline bullet format of presentation makes retrieval of information easier

SECTION 1:
DIAGNOSTIC TESTING

Chapter 1: Retinal Imaging

Amar Patel and Susanna S. Park

1. Optical Coherence Tomography (OCT)

a.Non-invasive real-time cross-sectional imaging

b.Specifications (see Table 1 for various types of OCT)

i.	Axial resolutions variable depending on type of OCT
ii.	Transverse resolution 10 to 20 μm
iii.	Macular scans are typically 6 mm × 6 mm

c.Normal macular morphology on OCT (Figure 1A)

i.	The interface between the posterior hyaloid and the internal limiting membrane is visualized when the hyaloid is separated from retina.
ii.	The fovea is thinned due to the absence of the inner retinal layers. The ellipsoid zone, also called the inner segment-outer segment junction (IS/OS), is elevated slightly due to the presence of densely packed cones in the foveal center

Table 1. Comparison of OCT modalities.

iii.	Reflectivity of retinal layers is based upon the arrangement of their structures as well as their biological densities and degree of pigmentation

1.High reflectivity: the nerve fiber layer (NFL), the inner plexiform layer (IPL), and outer plexiform layer (OPL) are highly reflective due to the horizontally oriented axonal structures. The retinal pigment epithelium (RPE) and choriocapillaris form the outermost highly reflective structure visible due to their high melanin and vascular content, respectively

2.Lower reflectivity: the ganglion cell layer (GCL), the inner nuclear layer (INL), and the outer nuclear layer (ONL) are less reflective due to the vertical orientation of their elements

Figure 1. Spectral-domain OCT.

(A) B-scan image of a normal macula showing the various retinal layers; nerve fiber layer (NFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), external limiting membrane (ELM), and retinal pigment epithelium (RPE). (B) A commercial spectral-domain OCT (Cirrus, Zeiss) showing diffuse macular thinning (yellow-red zones in the ETDRS thickness map and blue in the macular cube volume scan) in an eye with exudative macular degeneration following anti-VEGF therapy. No residual macular fluid is detected but a residual sub macular hyperreflective lesion is noted. The macular cube scan (right) shows the three-dimensional depiction of regional changes in the macula at various layers. Image signal strength is denoted at the top of the page.

d.Image orientation and quality

i.	Scanned images have a legend that indicates the directionality of the currently displayed scan. By convention, the right side of the image corresponds to the arrowhead
ii.	Signal-to-noise ratio is displayed and labeled as signal strength. (Figure 1B) A signal strength of 10 represents the highest quality imaging, whereas a signal strength of zero represents the lowest quality. Signal strength can be affected by media opacities. Adequate signal strength is ≥5
iii.	For macular thickness measurements, ILM and RPE borders are corrected by automated algorithm. However, manual correction option is available
iv.	Macula centered in the scan: The foveal depression should be in the center of the scan

e.Macular thickness map (Figure 1B)

i.	The macula is artificially divided into nine regions of the ETDRS macular thickness map and the average retinal thickness is calculated for each region. The inner circle of the map has a diameter of 1.0 mm and correlates roughly with the fovea. The middle circle has a diameter of 3.0 mm and the outer circle a diameter of 6.0 mm, which is the length of the axial scans. A color coding system is used to correlate the thickness to the normative values. Pink denotes >99% normal, green denotes 95% normal, and red denotes <1% normal
ii.	A color coded macular thickness map of the three-dimensional reconstruction of the entire macula image (macular cube) is also available along with a legend displayed to facilitate rapid interpretation of the numerical values. Greater retinal thickness is represented by the “hotter” colors such as red and white. Average retinal thickness is represented by green, thin and atrophic areas of retina are represented by the “cooler” colors such as blue or black
iii.	Central retinal or foveal thickness and total volume of the macula are displayed in numerical format

f.Choroidal imaging: the choriocapillaris and the deeper larger sized choroidal vessels cannot be seen well using conventional OCT due to the shadowing from the overlying RPE. The following modalities are useful for imaging the choroid

i.	Enhanced depth imaging (EDI)-OCT

1.Place the objective lens of the device closer to the eye so that an inverted image is obtained. This maneuver allows deeper structures to be placed closer to the zero delay, thereby allowing for better visualization of the choroid

ii.	Swept source

1....

Table of contents

• Cover
• Halftitle
• Title
• Copyright
• Preface
• Contributing Authors
• Contents
• Section 1: Diagnostic Testing
• Section 2: Acquired Macular Disorders
• Section 3: Retinal Vascular Disorder
• Section 4: Hereditary Retinal Degeneration
• Section 5: Posterior Uveitis
• Section 6: Trauma
• Section 7: Retinal Detachment
• Section 8: Oncology
• List of Abbreviations
• Index