Preface
Page: ii-iii (2)
Author: Miguel A. Quiroz-Reyes and Virgilio Lima-Gomez
DOI: 10.2174/9789815124095123010002
Principles of Optical Coherence Tomography Angiography in Ophthalmology
Page: 1-22 (22)
Author: Selma Alin Somilleda-Ventura DSc*
DOI: 10.2174/9789815124095123010004
PDF Price: $15
Abstract
Optical coherence tomography (OCT) has proven to be an effective
diagnostic technique for evaluating ocular structures, particularly for studying retinal
layers and other areas of the posterior segment of the eye. The incorporation of
strategies and algorithms that allow the observation of the retinal microvasculature and
the flow of red blood cells currently represents important advances in the diagnosis and
treatment of inflammatory, neural, and vascular retinal diseases. The advantage is that
OCT is a non-invasive method that does not require the use of contrast dyes. For this
reason, OCT combined with angiography (OCTA) is one of the most important
techniques for the study of vitreoretinal disorders. Its optical principle, which is based
on the Doppler technique, allows us to understand how OCTA equipment acquires and
processes images to facilitate visualization and interpretation through their two- and
three-dimensional reconstructions. In addition, OCTA allows the identification of
signal alterations that could appear as artifacts on each tomography or angiographic
scan. This chapter aims to explore the characteristics and further applications of OCTA
in addition to its relevance in ophthalmological clinical practice.
Contributions of Optical Coherence Tomography Angiography to the Current Study and Treatment of Eye Diseases
Page: 23-56 (34)
Author: Jesus H. Gonzalez-Cortes*, Alan B. Trevino-Herrera, Alper Bilgic, Sergio E. Hernandez Da Mota, Jesus E. Gonzalez-Cantu, Akin Akyurt and Renata García Franco
DOI: 10.2174/9789815124095123010005
PDF Price: $15
Abstract
Optical coherence tomography angiography (OCT-A) is an advanced
noninvasive retinal blood flow imaging technique. It uses motion-contrast imaging to
obtain high-resolution volumetric blood flow information to enhance the study of
retinal and choroidal vascular pathologies. OCT-A can obtain detailed images of the
radial peripapillary network, the deep capillary plexus (DCP), the superficial capillary
plexus (SCP) and the choriocapillaris. In addition, compared to fluorescein
angiography (FA), this technique does not require the use of injected dye. This chapter
aims to present OCT-A technology and clarify its terminology and limitations. The
discussion summarizes the potential application of the technology in different retinal
and choroidal diseases.
Optical Coherence Tomography vs Optical Coherence Tomography Angiography in the Differential Diagnosis of Choroidal and Vitreoretinal Diseases
Page: 57-72 (16)
Author: Martin Flores-Aguilar MD and MsSc*
DOI: 10.2174/9789815124095123010006
PDF Price: $15
Abstract
Optical coherence tomography (OCT) is a practical and common imaging
method for the study of diseases of the retina, choroid, and vitreoretinal interface.
Software and technological advances have allowed us to observe changes in the retinal
at resolutions less than 5 µm; the development of angiography with OCT (OCTA)
allows us to three-dimensionally evaluate the existing perfusion in the analyzed retina
and choroid non-invasively and without a specific dye, such as fluorescein or
indocyanine green angiography. We can detect important clinical differences between
OCT and OCTA, although these approaches are complementary. Diabetic retinopathy,
vascular occlusions, and choroidal neo-vascularization secondary to age-related
macular degeneration and other causes are among the conditions whose diagnosis,
treatment, and follow-up benefit from applying these techniques. Leak quantification in
cases of macular edema is a good candidate for future objective evaluation; currently,
its existence is only demonstrable in structural OCT, although it can be indirectly
inferred in OCTA by observing vascular displacements and deformity of the capillary
walls. Using OCTA, it is possible to detect intravascular flow even in fibrous tissue,
thereby allowing the evaluation of neo-vascular activity in vasoproliferative diseases.
Nomenclature and Current Indications of Optical Coherence Tomography Angiography in Diseases of the Choroid and Retina
Page: 73-113 (41)
Author: Sergio E. Hernandez Da Mota MD*, Jesus H. Gonzalez-Cortes and Renata Garcia-Franco
DOI: 10.2174/9789815124095123010007
PDF Price: $15
Abstract
One of the most significant developments in ocular imaging in the last
century was optical coherence tomography (OCT). OCT angiography (OCT-A), an
extension of OCT technology, offers depth-resolved images of the blood flow in the
choroid-retina that are much more detailed than those produced by earlier imaging
techniques such as fluorescein angiography (FA). Due to its requirements of novel
tools and processing methods, the prevailing imaging constraints, the rapid
improvements in imaging technology, and our knowledge of the imaging and relevant
pathology of the retina and choroid, this novel modality has been challenging to
implement in daily clinical practice. Even those familiar with dye-based ocular
angiography will find that mastering OCT-A technology requires a steep learning curve
due to these issues. Potential applications of OCT-A include almost all diseases of the
choroid and retina, as well as anterior segment diseases. Currently, the most common
indications are age-related macular degeneration and ischemic retinopathies, including
diabetic retinopathy and retinal occlusive vascular disorders. Incorporating OCT-A into
multimodal imaging for the comprehensive assessment of retinal pathology is a fast-growing area, and it has expanded our knowledge of these complex diseases in terms of
diagnosis and treatment. This review describes the current main indications of OCT-A
in retinal and choroidal diseases.
Normative Perfusion Indices in the Emmetropic Nondiabetic and Healthy Highly Myopic Adult Population
Page: 114-133 (20)
Author: Virgilio Lima-Gómez MD* and Miguel A. Quiroz-Reyes MD
DOI: 10.2174/9789815124095123010008
PDF Price: $15
Abstract
Reference values of optical coherence tomography angiography metrics vary
according to the device used to measure them and even based on the software on the
same device. There might exist measurement differences between different maps
within the same device: Variables such as age, gender, and signal strength might induce
changes in the measurement outputs.
This chapter deals with the values of vessel length and vessel area densities, and foveal
avascular zone values of healthy emmetropic people via the 3 × 3 mm map used in the
most common equipment that are available commercially. The text includes metrics of
the parafovea and fovea at the superficial, intermediate, and deep capillary plexuses.
These measurements corresponded to the adult non-diabetic population and were
distributed as center (foveal), inner (parafoveal) and full (whole map) densities,
depending on the evaluated region, according to densities in the foveal, parafoveal, and
whole map measurements. Metrics of the parafovea by subfield were also included. We
also report current cut-off values that have been proposed as normality references in
some variables. Values for the remaining metrics and devices can later be proposed.
We dedicate a special section to non-diabetic patients with high myopia without
pathology, which includes the same metrics as in emmetropic patients. The evaluation
of perfusion indices benefits from the simultaneous measurement of metrics as well as
regional evaluation. The signal strength is a key variable to consider.
Normative Perfusion Indices in the Diabetic Population
Page: 134-144 (11)
Author: Virgilio Lima-Gómez MD* and Miguel A. Quiroz-Reyes MD
DOI: 10.2174/9789815124095123010009
PDF Price: $15
Abstract
Diabetes damages retinal capillaries before clinical changes appear. Optical
coherence tomography can quantify changes in vessel length density and vessel area
density in diabetics without retinopathy and can lead to a reduction of these metrics in
different capillary plexuses. The mean values of vessel densities vary according to the
device used. Here, we review the values of vessel length density, vessel area density,
and foveal avascular zone metrics in diabetics without retinopathy in a 3 x 3 mm map
of the most used commercially available devices. We included measurements for the
superficial, intermediate, and deep capillary plexuses in the parafoveal region. The
information refers to adult type 2 diabetic people according to densities in the foveal,
parafoveal, and whole map measurements. We also included parafoveal distribution by
field as well. There are references to the foveal avascular zone—a common variable
measured to detect ischemia in patients with diabetic retinopathy—and we report them
for both superficial and deep capillary plexuses. We also include the proposed cut-off
values for normality for metrics of the superficial capillary plexus and propose an
explanation for the differences that exist between measurements with the same device
as related to diabetes duration.
Correlation of the Structural and Perfusion Findings in Patients with Surgically Resolved Myopic Foveoretinal Detachment
Page: 145-170 (26)
Author: Miguel A. Quiroz-Reyes MD*, Erick A. Quiroz-Gonzalez, Jorge Morales-Navarro, Miguel A. Quiroz-Gonzalez, Ana L. Diazceballos-Garcia, Sanjay Marasini, Mario Carranza-Casas and Virgilio Lima-Gomez
DOI: 10.2174/9789815124095123010010
PDF Price: $15
Abstract
Myopia is a global public health problem leading to visual impairment and
blinding complications. Myopic foveoschisis (MF)/foveoretinal detachment (FRD)
might be responsible for progressive visual loss in eyes with macular traction
maculopathy (MTM). An assessment of the macular microcirculation might identify
defects that are potentially implicated in subsequent pathological changes. In the
present chapter, macular perfusion in normal eyes was compared with that in highly
myopic eyes with MF/FRD. Vessel density (VD) differed between the groups, and the
superficial area of the foveal avascular zone (FAZ) was significantly larger in the
control groups. Better final visual acuity results were significantly correlated with
fewer structural findings and greater VD (p < 0.05). The central subfoveal thickness
was significantly larger in the control groups and significantly smaller in the surgery
group. These findings suggested a higher incidence of macular perfusional VD
deficiencies and abnormalities in the FAZ area in the highly myopic eyes.
Postoperative Macular Perfusion Evaluation in Eyes with Noncomplicated Retinal Detachment and Macular Involvement Surgically Managed with Primary Vitrectomy
Page: 171-176 (6)
Author: José Dalma-Weiszhausz*
DOI: 10.2174/9789815124095123010011
PDF Price: $15
Abstract
Rhegmatogenous retinal detachment (RRD) is fairly common and one of
the main causes of blindness if left untreated. In spite of the high anatomical success
rate for retinal detachment, visual recovery is lagging. Microvascular changes in the
macular area might play a role in determining poor visual outcomes. Methods: Optical
coherence tomography (OCT) and OCT angiography (OCT-A) technologies have been
used to determine the relationship between microvascular macular changes and visual
acuity. Results: RRD seems to alter microcirculatory anatomy in the macular area by
increasing the foveal avascular zone (FAZ) and diminishing the vascular density (VD)
of the superficial, deep and choroidal capillary plexuses. More so if the macula is
detached, these changes appear to recover with time and might be correlated with
postoperative visual acuity, but apparently do not entirely explain the sometimes-unexpected poor visual results.
Postoperative Analysis of Macular Perfusional Status in Giant Retinal Tear-Related Retinal Detachments
Page: 177-205 (29)
Author: Miguel A. Quiroz-Reyes MD*, Erick A. Quiroz-Gonzalez, Miguel A. Quiroz-Gonzalez, Ahmad R. Alsaber, Sanjay Marasini and Virgilio Lima-Gomez
DOI: 10.2174/9789815124095123010012
PDF Price: $15
Abstract
Rhegmatogenous retinal detachment (RRD) associated with giant retinal
tears (GRTs) can cause significant visual impairment due to structural or perfusional
macular sequelae. This condition is an acute-onset incident that leads to a full-thickness
circumferential retinal tear of at least 90°. Limited data are available concerning the
patients´ long-term perfusional status after successful surgery for GRTs with maculaoff RRD. This chapter examines the long-term outcomes of eyes treated with varying
degrees of GRT-associated RRD extensions and compares them with those of two
control groups. The surgical group was subdivided according to GRT-associated RRD
extension as follows: eyes with extension of <180° and eyes with extension > of >180°.
The eyes were further classified according to whether complementary 360° scleral
buckle (SB) placement was required. Postoperative optical coherence tomography
(OCT) demonstrated that 33.3% of the eyes had abnormal foveal contours, 39.4% had
ellipsoid zone (EZ) disruption, 2 had dissociated optic nerve fiber layer (DONFL)
defects, and 45.4% had external limiting membrane (ELM) line discontinuities. OCT
angiography (OCT-A) revealed abnormal perfusion indices in surgically treated eyes
(p<0.0001). Postsurgical best-corrected visual acuity (BCVA) was negatively
correlated with the superficial foveal avascular zone area, superficial parafoveal vessel density, and central subfoveal thickness but positively correlated with the
choriocapillaris flow area (CFA). Moreover, eyes treated surgically for GRT-associated
RRD had multiple structural alterations reflected by spectral-domain OCT biomarkers
and OCT-A perfusional findings correlated with visual outcomes. Despite successful
retinal reattachment without proliferation, management of GRT-associated RRD
remains challenging.
Macular Perfusion in Clinically Significant Diabetic Macular Edema and in Different Stages of Diabetic Retinopathy
Page: 206-219 (14)
Author: Virgilio Lima-Gómez MD* and Miguel A. Quiroz-Reyes MD
DOI: 10.2174/9789815124095123010013
PDF Price: $15
Abstract
Diabetic macular edema uses structural features as biomarkers and
predictors of treatment response. Optical coherence tomography angiography (OCTA)
metrics found a correlation between many structural biomarkers and reduced vessel
density. We present recent references of vessel length density, vessel area density, and
foveal avascular zone metrics in eyes with diabetic macular edema and comment on the
associations found between them and structural biomarkers. Diabetic macular edema
can change the level at which the capillary plexuses are located, with retinal cysts
altering the strength signal. Though image evaluation requires adjustment, intra-subject
comparison before and after treatment can be a useful tool to note changes in vessel
perfusion, combined with structural changes, to assess treatment outcomes. Macular
ischemia is a variable that can be identified reliably with OCTA and can be detected in
different capillary plexuses. For eyes with retinal thickening, OCTA evaluation
requires consistency to avoid inter-device variability. It is recommended to use the
same device, the same scanning protocol, and preferably the same software, to obtain
more reproducible measurements.
Evaluation of Macular Perfusion in Successfully Reattached Macula-off Diabetic Tractional Retinal Detachment
Page: 220-253 (34)
Author: Miguel A. Quiroz-Reyes MD*, Erick A. Quiroz-Gonzalez, Jorge Morales-Navarro, Miguel A. Quiroz-Gonzalez, Margarita Montano, Felipe Esparza-Correa, Jennifer H. Kim-Lee, Boris Moreno-Andrade, Alejandra Nieto-Jordan, Ahmad R. Alsaber and Virgilio Lima-Gomez
DOI: 10.2174/9789815124095123010014
PDF Price: $15
Abstract
Current imaging techniques based on optical coherence tomography (OCT)
angiography are useful for observing different retinal microcirculation patterns. The
primary purpose of this chapter was to describe the functional, structural, and serial
perfusion postoperative outcomes of successfully reattached macula-off tractional
retinal detachment (TRD). Patients who underwent a successful diabetic vitrectomy
were analyzed. The mean differences between the preoperative best-corrected visual
acuity (BCVA), 3-month BCVA, and final postoperative BCVA were statistically
significant (p < 0.05). The duration of vision loss before surgery was 11.6 ± 2.3 weeks
(mean ± standard deviation (SD)).
The mean duration (± SD) of the resolution of macular detachment was 3.6 ± 1.7 weeks
in the pure macular TRD group and 1.8 ± 0.8 weeks in the combined tractional and
rhegmatogenous macular detachment (p < 0.05) group. The mean follow-up duration of
all patients was 11.4 ± 5.7 months (mean ± SD). Longitudinal multimodal imaging tests
revealed abnormal superficial and deep microcirculation patterns with multiple
microabnormalities in the foveal avascular zone and different but distinct areas of the
non-perfused macula in different OCT angiography slabs. Additionally, disorganization of the retinal inner layers and chronic ischemic macular edema were observed in 82%
of eyes examined using the spectral domain (SD) OCT. Therefore, these data suggest
that despite the successful anatomical reattachment of the macula, long-term
postoperative microcirculatory abnormalities were detected in both groups; however,
these abnormalities were predominantly accompanied by severe persistent ischemia in
the recurrent TRD group due to the presence of multiple microcirculatory defects.
Subject Index
Page: 254-260 (7)
Author: Miguel A. Quiroz-Reyes and Virgilio Lima-Gomez
DOI: 10.2174/9789815124095123010015
Introduction
This handbook covers Optical Coherence Tomography Angiography (OCT-A) with a specific focus on choroidal and vitreoretinal disorders. It serves as an invaluable resource for teaching and aiding daily clinical decision-making in the field. Book chapters dissect the fundamentals of angiography through OCT, offering guidance on OCT-A and insights into macular perfusional findings across various vitreoretinal and choroidal pathologies. From diabetic retinopathy to autoimmune diseases and neovascularization, the book addresses prevalent vascular entities encountered in routine practice. Furthermore, it explores innovative approaches, including antivascular endothelial growth factor molecules and extended-release delivery devices, contributing significantly to the diagnostic and decision-making processes in clinical and surgical retina care. Each chapter is contributed by experts in the relevant subspecialty. Key Features: Practical, patient-centered guide emphasizing a clinical approach. Demonstrative clinical cases for enhanced understanding. Evaluation of perfusional indices using noninvasive and noncontact imaging techniques. High histopathological correlation of structural tissue characterization with microvascular evaluation. Exploration of new perfusion concepts and their role in disease pathogenesis. Part 1 of the book focuses on OCT-A principles and applications in ophthalmology. It covers the basics of OCT-A, its contributions to eye disease study and treatment, and a comparative analysis with OCT for choroidal and vitreoretinal diseases. Additional information on nomenclature, normative datasets, and data analysis, presenting indices in different eye conditions is also presented. The emphasis is on macular perfusion in surgically resolved myopic foveoretinal detachment, postoperative evaluation in retinal detachment, and long-term analysis in diabetic retinopathy.