Ophthalmological Imaging and Applications

519 Pages·2014·60.98 MB·English

by  Y K Eddie Ng

BIOMEDICAL ENGINEERING Ng
• OPHTHALMOLOGICAL
OPHTHALMOLOGICAL IMAGING APPLICATIONS Acharya
AND
•
Edited by and featuring contributions from world-class researchers, Ophthalmological Imaging and Applica- Rangayyan IMAGING
AND
tions offers a unified work of the latest human eye imaging and modeling techniques that have been proposed and •
applied to the diagnosis of ophthalmologic problems, including inflammation, cataracts, diabetic retinopathy,
Suri
and glaucoma. With a focus on theory, basic principles, and results derived from research, the book:
APPLICATIONS
• Explores various morphological, textural, higher-order spectral, and wavelet transformation techniques
used to extract salient features from images of the human eye
• Examines 2D and 3D finite element and boundary element models of the human eye developed
to simulate thermal steady-state conditions O
• Addresses the difficult task of benchmarking the validity of human eye imaging techniques
P
and computer-simulated results with experimental measurements
H
Intended to be a companion to Image Analysis and Modeling in Ophthalmology, this volume covers several aspects
T
of multimodal ophthalmological imaging and applications, presenting information in an accessible manner to ap-
peal to a wide audience of students, researchers, and practitioners. Ophthalmological Imaging and Applications con- H
siders promising simulations that pave the way for new possibilities in computational methods for eye health care.
A
A
N
L
E. Y. K. Ng, PhD, earned his PhD from Cambridge University, UK and is an associate profes- D
sor at Nanyang Technological University, Singapore. He serves as editor for six international M
A
journals and as editor-in-chief for two SCIE indexed journals. His research interests are in
thermal imaging, biomedical engineering, breast cancer detection, and computational fluid P O
dynamics and heat transfer.
P
L
L O
I
U. Rajendra Acharya, PhD, DEng, is a visiting faculty in Ngee Ann Polytechnic, Singapore C G
and adjunct professor in University of Malaya, Malaysia. He received his PhD from the Na-
tional Institute of Technology Karnataka, Surathkal, India and DEngg from Chiba University, A I
C
Japan. He has published more than 285 papers in refereed international SCI-IF journals (178), T
international conference proceedings (48), textbook chapters (62), books (15 including in
A
I
press) with an h-index of 24. 
O
L
N
Rangaraj M. Rangayyan, PhD, DEng, is a professor with the University of Calgary, Canada. I
M
His research areas are digital signal and image processing, biomedical signal and image analysis, S
and computer-aided diagnosis. He is a Fellow of the IEEE, the Engineering Institute of
Canada, the American Institute for Medical and Biological Engineering, SPIE, the Society for A
Imaging Informatics in Medicine, the Canadian Medical and Biological Engineering Society, G
Edited by
and the Canadian Academy of Engineering, and was recognized with the 2013 Outstanding
Engineer Medal by IEEE Canada. I
N
E. Y. K. Ng
Jasjit S. Suri, PhD, MBA, Fellow AIMBE, is an innovator, scientist, and an internationally
G
known world leader and has spent over 20 years in the field of biomedical engineering/sciences
U. Rajendra Acharya
and its management. Suri was crowned with the President’s Gold medal in 1980 and named

a Fellow of American Institute of Medical and Biological Engineering for his outstanding
Rangaraj M. Rangayyan
contributions.
K15530
Jasjit S. Suri
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OPHTHALMOLOGICAL
IMAGING
AND
APPLICATIONS
Edited by
E. Y. K. Ng
U. Rajendra Acharya
Rangaraj M. Rangayyan
Jasjit S. Suri
Boca Raton London New York
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
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Contents
Preface ...............................................................................................................................................v
Editors ..............................................................................................................................................ix
Contributors ....................................................................................................................................xi
1. Retinal Vascular Imaging in Clinical Research ...............................................................1
Mohammad Kamran Ikram, Shaun Sim, Yi Ting Ong, Carol Y. Cheung, and Tien Yin Wong
2. Detection, Modeling, and Analysis of the Major Temporal Arcade
in Fundus Images of the Retina .........................................................................................21
Faraz Oloumi, Rangaraj M. Rangayyan, and Anna L. Ells
3. Application of Higher-Order Spectra Cumulants for Diabetic Retinopathy
Detection Using Digital Fundus Images .........................................................................53
Roshan Joy Martis, Karthikeyan Ganesan, U. Rajendra Acharya, Chua Kuang Chua,
Lim Choo Min, E.Y.K. Ng, Augustinus Laude, and Jasjit S. Suri
4. Quality Measures for Retinal Images ..............................................................................69
S.R. Nirmala, S. Dandapat, and P.K. Bora
5. Graph Search Retinal Vessel Tracking ............................................................................97
Enea Poletti and Alfredo Ruggeri
6. Fundus Autofluorescence Imaging: Fundamentals and Clinical Relevance ..........117
Yasir J. Sepah, Abeer Akhtar, Yamama Hafeez, Humzah Nasir, Brian Perez,
Narissa Mawji, Mohammad Ali Sadiq, Diana J. Dean, Daniel Araújo Ferraz,
and Quan Dong Nguyen
7. Needs/Requirements and Design of Retinal Imaging and Image
Processing Methods for Diabetic Retinopathy in the Indian Context ....................127
Sudipta Mukhopadhyay, Amod Gupta, and Reema Bansal
8. Application of Ocular Fundus Photography and Angiography ...............................135
Caroline Ka Lin Chee, Patrick A. Santiago, Gopal Lingam, Mandeep S. Singh,
Thet Naing, Aria E. Mangunkusumo, and Mohamed Naeem Naser
9. Optic Nerve Analysis and Imaging in Relation to Glaucoma ..................................157
Seng Chee Loon, Victor Koh, and Rosalynn Grace Siantar
10. Imaging of the Eye after Glaucoma Surgery.................................................................179
Mandeep S. Singh, Maria Cecilia D. Aquino, and Paul Tec Kuan Chew
11. Confocal Microscopy of Cornea ......................................................................................195
Manotosh Ray, Anna W.T. Tan, Aria E. Mangunkusumo, and Dawn K.A. Lim
iii
iv Contents
12. Corneal Topography and Tomography: The Orbscan II ............................................215
Anna W.T. Tan, Manotosh Ray, and Dawn K.A. Lim
13. Automatic Analysis of Scanning Laser Ophthalmoscope Sequences
for Arteriovenous Passage Time Measurement ...........................................................221
C. Marino, Marcos Ortega, J. Novo, Beatriz Remeseiro, Alba Fernandez, and F. Gomez-Ulla
14. Optical Coherence Tomography ......................................................................................237
Mohamed A. Ibrahim, Yasir J. Sepah, Millena G. Bittencourt, Hongting Liu, Mostafa
Hanout, Daniel Araújo Ferraz, Diana V. Do, and Quan Dong Nguyen
15. Role of Optical Coherence Tomography in Anterior Segment Imaging .................271
Tin Aung Tun, Sze-Yee Lee, Rachel Nge, and Louis Tong
16. Anterior Segment Imaging with Anterior Segment Optical
Coherence Tomography .....................................................................................................299
Zheng Ce and Paul Tec Kuan Chew
17. Cyst Detection in OCT Images for Pathology Characterization ..............................315
Ana González, Beatriz Remeseiro, Marcos Ortega, Manuel G. Penedo, and Pablo Charlón
18. Scanning Laser Ophthalmoscope Fundus Perimetry: The Microperimetry .........333
Millena G. Bittencourt, Daniel Araújo Ferraz, Hongting Liu, Mostafa Hanout,
Yasir J. Sepah, Diana V. Do, and Quan Dong Nguyen
19. In Vivo Confocal Microscopy: Imaging of the Ocular Surface ................................355
Sze-Yee Lee, Shakil Rehman, and Louis Tong
20. Biomechanical Modeling of Blood Vessels for Interpretation
of Tortuosity Estimates ......................................................................................................395
Martynas Patašius, Vaidotas Marozas, Darius Jegelevičius, Arūnas Lukoševičius,
Irmantas Kupčiūnas, and Audris Kopustinskas
21. Hybrid Finite Element Simulation for Bioheat Transfer in the Human Eye ..........409
Hui Wang, Qing-Hua Qin, and Ming-Yue Han
22. Effects of Electromagnetic Fields on Specific Absorption Rate
and Heat Transfer in the Human Eye .............................................................................427
Teerapot Wessapan and Phadungsak Rattanadecho
23. Dry Eye Characterization by Analyzing Tear Film Images .......................................449
Beatriz Remeseiro, Manuel G. Penedo, Carlos García-Resúa, Eva Yebra-Pimentel, and
Antonio Mosquera
24. Thermography and the Eye: A Look at Ocular Surface Temperature ......................477
Dawn K.A. Lim, Caroline Ka Lin Chee, and Thet Naing
Preface
The human eye is one of the most important organs and works like a camera. It is tedious
and time consuming to decipher minute changes in the anatomy of the eye caused by the
progression of abnormalities. The growth in image processing, artificial intelligence, high-
performance computing, and modeling techniques has had a significant impact on the
detection and treatment of eye diseases. Optical, digital fundus, infrared, optical coher-
ence tomography (OCT), and Heidelberg retina tomograph images have been widely used
to diagnose eye abnormalities.
This book covers wide-ranging topics such as computer-aided diagnosis of diabetic
retinopathy (DR), maculopathy, glaucoma, dry eyes, cysts, imaging of the eye after glau-
coma surgery, optic nerve analysis, anterior segment imaging of the eye, infrared imag-
ing of the eye, confocal microscopy of the cornea, OCT, scanning laser ophthalmoscopy
(SLO), fundus perimetry, fundus autofluorescence (FAF) imaging, in vivo confocal micros-
copy, hybrid finite element simulation of bioheat transfer in the human eye, and effects of
electromagnetic (EM) fields on specific absorption rates. FAF is a relatively new, noninva-
sive imaging modality that has been developed over the past decade.
The retina provides an ideal opportunity to explore the role of microvascular pathol-
ogy in the pathophysiology of cardiovascular diseases. Over the last decade, advances
in retinal vascular imaging allowed the development of accurate and reliable quantita-
tive parameters such as retinal vascular calibers. Using these parameters, several large
population-based studies have shown that retinal vascular calibers are related to cardio-
vascular diseases.
Chapter 1 presents the clinical application of retinal vascular imaging and its limitation.
Changes in the vascular structure of the retina can indicate the presence of several types
of pathology, such as hypertension, arteriosclerosis, proliferative diabetic retinopathy,
myopia, and retinopathy of prematurity.
Chapter 2 proposes parabolic modeling methods using the generalized Hough trans-
form to detect, measure, and parameterize the architecture of the major temporal arcade
in retinal fundus images.
An automated diagnosis system to diagnose DR using higher order spectra (HOS)
cumulants with digital fundus images is proposed in Chapter 3. HOS cumulants coupled
with a support vector machine yielded an accuracy rate of 97.06% in classifying normal
and DR images.
Chapter 4 presents new wavelet weighted distortion measures to quantify information
loss in retinal features. These measures are defined after carrying out analysis of reti-
nal image information in different wavelet subbands. It was shown that significant infor-
mation of a retinal feature was captured only in a few subbands. The analysis of retinal
fundus images is an important noninvasive procedure that allows early diagnosis and
effective monitoring of the response to retinopathy therapy. In order to derive a quantita-
tive evaluation of clinical features, an accurate identification of the vessel network has to
be provided.
A system for automatic extraction of the retinal vasculature based on a multidirectional
graph search approach is proposed and discussed in Chapter 5.
Chapter 6 presents the usefulness of FAF in understanding the pathophysiological
mechanisms, diagnostics, and identification of predictive markers for disease progression
v
vi Preface
and for monitoring novel therapies. At present, DR screening in India is undertaken in
various ways such as in eye camps, evaluation of the fundus of all diabetics attending
eye care facilities for any ocular problem, and through telemedicine, where digital retinal
images are analyzed by remotely placed experts.
Chapter 7 proposes an efficient imaging system that can be installed not only at a
national-level hospital but at the grass-root level as well, such as at primary health-care
units, so as to be able to image a layperson unaware of the problems related to diabetes
and DR. The fundus of the eye is situated at the back of the interior of the eyeball, which
can be viewed through the pupil using an ophthalmoscope.
Chapter 8 presents imaging of the ocular fundus with color photography, photography
with filters, and fluorescence angiography. The diagnosis of glaucoma and monitoring
its progression are challenging and difficult to the general ophthalmologist. In a setting
where there is lack of glaucoma expertise, instruments that quantify reproducible param-
eters and are easy to interpret could improve diagnostic accuracy.
Chapter 9 presents a discussion on the strengths and weaknesses of each imaging modal-
ity which resulted in accelerated modifications to improve its efficacy. The advent of newer
imaging technologies has enabled more detailed and comprehensive imaging than previ-
ously possible.
Chapter 10 provides an analysis on how morphological data provided by bleb imag-
ing may assist in the clinical management of glaucoma patients after filtration surgery.
In addition, bleb imaging may have a role in investigating novel surgical approaches. The
confocal microscope is one of the wonderful innovations in recent times; it is becoming
more popular every day and its indications are expanding.
Chapter 11 describes the usefulness of the confocal microscope for clinical diagnosis,
follow-up, and analysis of corneal lesions. Corneal analysis has evolved with recent soft-
ware technologies since the advent of the Placido’s disk.
Chapter 12 describes how advancing technologies have evolved patient care to its cur-
rent stage where analysis of corneal topography is part of the standard care in the present-
day practice of the cornea and refractive surgeon. Retinal microcirculation can vary in the
presence of retinopathies. One of the most widely used techniques for analyzing these
variations is fluorescein angiography. SLO sequences are obtained of a patient in whom a
fluorescent dye is injected. SLO techniques are useful for measuring biomedical metrics
such as the arteriovenous passage time.
Chapter 13 deals with the application and validation of the registration approach by
automatically estimating the dye dilution curves and computing arteriovenous passage
time in fundus images.
OCT is widely used in imaging biological tissues such as eye, skin, and most recently
blood vessels. Chapter 14 provides a brief history of OCT and its development, especially
in recent years. It focuses on the applications of OCT in the ophthalmological field, newer
developments in OCT technologies with a focus on research topics, and future directions
of use in ocular diseases.
Chapter 15 introduces clinical and research applications of OCT to understand the ana-
tomical structures and functions of the anterior segment of the eye. It covers the usage
of anterior segment OCT (AS-OCT) in corneal and glaucoma imaging by explaining the
pathophysiology of the diseases or conditions and the usefulness of AS-OCT in these con-
ditions. AS-OCT is applicable to assess a wide variety of anterior segment conditions. As
a noncontact method, AS-OCT is likely to become an essential tool for screening eye dis-
eases like primary angle closure, corneal lesions, and lens opacity.
Preface vii
Information obtained via OCT could be used in the assessment of the guidelines for
medical or surgical treatment and are discussed in Chapter 16. One of the retinal altera-
tions that is present in a wide number of pathologies is cystoid macular edema. It can
be easily detected using OCT, and its presence significantly affects visual function and
guides the therapeutic approach to follow in the case of pathologies with intraretinal
cysts.
Chapter 17 deals with the detection of cysts and their monitoring using OCT. SLO-
automated fundus perimetry, also known as microperimetry, is a relatively new imag-
ing modality bound to the study of the macular function. SLO fundus perimetry
provides a quantitative assessment of the retina’s sensitivity to light within the central
posterior pole.
Chapter 18 focuses on the evolution of fundus perimetry technology. It also describes
the features of different SLO fundus perimeters and their limitations and applicability to
specific diseases. A major advantage of confocal images is providing histological informa-
tion without prior staining and excising of the tissue, giving clinicians more control over
diagnosis. The slit scanning in vivo confocal microscope (IVCM) is used in ophthalmology
for obtaining useful information about the structure and function of the cornea and other
ocular surface structures, along with quantitative diagnosis of cell morphology, cell count,
and infections.
Chapter 19 provides a discussion on applications of IVCM in both the clinical setting
and research. There are many tortuosity estimates that can be correlated with blood pres-
sure. Their behavior in simplified conditions is worthy of investigation.
The finite element method was used to model blood vessels and validated experi-
mentally in the work presented in Chapter 20. Numerical simulation of bioheat transfer
in a two-dimensional human eye model including multiple material domains is per-
formed using the newly developed fundamental solution-based hybrid finite element
formulation.
In the absence of blood perfusion in the eyeball, Chapter 21 presents a method that is
verified by comparing with the results of numerical methods. Consequently, the effect of
the blood perfusion rate in the sclera on temperature change is investigated to study bio-
heat transfer behavior caused by interior heat energy exchange from the blood vessels in
the sclera region into the eyeball. A two-dimensional eye model is used to simulate tissue-
specific absorption rate and temperature distributions. EM wave propagation in the eye is
investigated using Maxwell’s equations.
An analysis of heat transfer in the eye exposed to a transverse magnetic mode of EM
fields is investigated using a heat transfer model in Chapter 22. Dry eye diagnosis is diffi-
cult to perform, especially because of its multifactorial nature. Thus, there are several clini-
cal tests to measure tear quality and quantity. Some tests assess the tear film by evaluating
the interference lipid pattern.
Chapter 23 describes an automatic image-processing methodology to perform the analy-
sis of the interference lipid pattern using Tearscope plus and Doane’s interferometer as
instruments to acquire tear film images. Infrared cameras are nowadays increasingly
applied in medical settings, with high sensitivity and reliability, the results of which can
be appreciated in a color-coded display.
Chapter 24 presents the application of infrared images to detect OST and the ocular fac-
tors influencing OST, as well as the limitations and possibilities of ocular thermography.
Many esteemed authors have contributed generously and made this book possible by
their diligent hard work and valuable time. We thank them wholeheartedly for their
viii Preface
significant contributions. The authors and their affiliations are listed in the following
Contributors section.
This book covers several aspects of multimodality imaging in ophthalmology and appli-
cations. It focuses on methods and techniques for imaging and their applications in eye
care. The chapters in the book cover theories and principles of imaging and present results
of practical applications. They are written in simple language for easy readability and
understanding.
The main purpose of this book is to present a unified work on eye imaging and modeling
techniques that have been proposed and applied to ophthalmologic problems. It represents
a novel and well-timed effort and is a substantial addition to literature in the field. The
book also represents various applications in this area. It is unique in its focus and is of
interest to researchers, students, and practitioners.
This book is intended for individuals engaged in research or in industry who are devel-
oping software incorporating elements of image processing and machine vision. It is also
suitable for a graduate course on image processing and machine vision, including ele-
ments of algorithm design and performance evaluation.
E.Y.K. Ng
U. Rajendra Acharya
Rangaraj M. Rangayyan
Jasjit S. Suri
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