Article

Assessing Dry Age-Related Macular Degeneration in a Mexican Population with Fundus Autofluorescence and Spectral Domain Optical Coherence Tomography

Assessing Dry Age-Related Macular Degeneration in a Mexican
Population with Fundus Autofluorescence and Spectral Domain Optical
Coherence Tomography
Renata del Carmen García Franco, Marlon Rafael García Roa*, Veronica Romero Morales, Miguel Angel Vazquez Membrillo, Ximena Mira Lorenzo, Paulina
Ramirez Neria, Charles Van Lansingh and Ellery Lopez Star
Instituto Mexicano de Oftalmología, I.A.P. (Mexican Institute of Ophthalmology), Queretaro, Queretaro, Mexico
*Corresponding author: Dr. Marlon Rafael García Roa, Instituto Mexicano de Oftalmología, I. A. P, Circuito Exterior Estadio Estadio Corregidora S/N, Colinas Del
Cimatario, Queretaro, Queretaro, Mexico 76090, Tel: +52 4422290776; E-mail: drmgroa@hotmail.com
Received date: September 26, 2018; Accepted date: October 09, 2018; Published date: October 16, 2018
Copyright: ©2018 Franco RCG, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
Purpose: To evaluate early and intermediate dry age-related macular degeneration (AMD) in a Mexican
population using enhanced depth imaging spectral-domain optical coherence tomography (EDI SD-OCT) to
determine fundus autofluorescence (FAF) patterns, choroidal thickness, and their correlations.
Methods: This cross-sectional study evaluated patients aged >50 y with early and intermediate dry AMD.
Angiography and EDI SD-OCT were used to take digital retinal images, which were evaluated manually to determine
the FAF pattern (using the Possible correlations with age and visual acuity (Log MAR) were investigated.
Results: Fifty-eight patients (84 eyes) were enrolled (mean age: 77 y; SD: 9 y); 72.4% were women (n=42). The
mean visual acuity was 0.4 Log MAR (SD: 0.24). Reticular autofluorescence was the major pattern observed in
29.8% of eyes, followed by minimal change (23.8%), focal increased (19%), normal pattern (14.3%), linear (5.9%),
patchy (3.6%), speckled (2.4%), and lacelike (1.2%). There was a statistically significant correlation between
choroidal thickness (mean: 202.8 μm; SD: 69.8 μm) and 34 age (p<.01) and visual acuity (p=0.0243). The patchy
pattern had the most reduced choroidal thickness (mean: 184.3 μm; SD: 104.6 μm), and the increased focal pattern
had the lowest visual acuity (mean: 0.53 Log MAR: SD: 0.3 Log MAR).
Conclusions: Among a Hispanic population with early and intermediate dry AMD, the predominant
autofluorescence pattern was reticular, with few cases of lacelike pattern observed. There was a tendency for
choroidal thickness to decrease with age and visual acuity level.
Keywords: Early and intermediate dry age-related macular
degeneration; Fundus autouorescence (FAF) patterns; Choroidal
thickness; Dry age-related macular degeneration in a Mexican
population; Imaging spectral-domain optical coherence tomography
(EDI SD-OCT); Fundus autouorescence classication system
Introduction
Age-related macular degeneration (AMD) is the principal cause of
blindness in developed countries [1-6]. e global prevalence rate of
AMD is 8.7% and increasing with the aging population, with 196
million people projected to have AMD by 2020, which will potentially
increase to 288 million in 2040 without the development of an eective
treatment [1,7]. At least 1 in 10 Hispanics have AMD, which is slightly
higher than the global rate [1]. Moreover, given that these
epidemiological estimates were derived from historical AMD cases
identied using fundus photographs, the prevalence rates may be
underestimated, as the newer diagnostic modality of optical coherence
topography (OCT) is much more precise in detecting AMD [7].
OCT is a reproducible, noninvasive modality that produces a 3-
dimensional, cross-sectional, high-resolution image of the retina
in
vivo
[8]. OCT used with fundus autouorescence (FAF) is the current
standard diagnostic and monitoring modality to detect dry AMD and
follow up on its progression [9]. Enhanced depth imaging (EDI)
spectral-domain OCT (SD-OCT) examines the eye at a closer distance
to produce an inverted image of the retina, which provides an even
more detailed visualization of the choroid and the deeper layers of the
retina [8-13].
Impaired choroidal circulation is thought to have a role in the
development of AMD, by producing vascular endothelial growth factor
that causes the retinal pigment epithelium to become hypoxic and
ischemic, resulting in choroidal neovascularization [8,14-16].
Decreased blood volume and progressively impaired circulation have
been observed in eyes with dry AMD, as the disease progresses,
[8,14,17,18] and are thought to result from choroidal thinning, the
narrowing of the choriocapillaries lumen, and cellularity loss [8,14].
Given the diculty in measuring choroidal thickness and
circulation, their relationship with the development of AMD has not
been conrmed. However, the use of EDI SD-OCT allows for a more
accurate evaluation of the eect of choroidal thickness on the
development of dry AMD [10,19-21]. EDI SD-OCT has shown that the
choroidal thickness decreases with aging [11,19,22]. Studies have
observed increased choroidal thinning in eyes with early AMD [11,23]
and late AMD [24-26]. Eyes with dry AMD with reticular
pseudodrusen (RPD) have been reported to have signicantly reduced
choroidal thickness and vessel density [27]. Choroidal thickness has
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ISSN: 2155-9570
Journal of Clinical & Experimental
Ophthalmology Franco et al., J Clin Exp Opthalmol 2018, 9:5
DOI: 10.4172/2155-9570.1000754
Research Article Open Access
J Clin Exp Opthalmol, an open access journal
ISSN:2155-9570
Volume 9 • Issue 5 • 1000754
also been found to be inversely correlated with drusen load (r=-0.35,
p=0.04) [10] and related to the severity and progression of dry AMD
[28]. In both normal and unhealthy eyes, choroidal thickness has been
found to be associated with better visual acuity [29]. Choroidal
thickness also appears to be related to visual acuity in dry AMD
[10,28].
To the best of our knowledge, the relationship between choroidal
thickness and FAF alterations has not yet been examined. FAF maps
the density of lipofuscin, the excessive accumulation of which is known
to be a factor in the development of retina diseases [30-34]. Abnormal
FAF changes have been evaluated in AMD [30,35,36]. Eight
phenotypic patterns of FAF have been identied in early dry AMD:
normal, minimal change, focal increased, patchy, linear, lacelike,
reticular, and speckled [30].
e purpose of this study was to evaluate early and intermediate dry
AMD in a Mexican population using EDI SD-OCT to determine FAF
patterns, choroidal thickness, and their relationships with each other,
age, and visual acuity levels.
Methods
Study design and patient recruitment
is descriptive, observational, cross-sectional study was carried out
over a 19- month period at the Instituto Mexicano de Oalmología,
I.A.P. (IMO, Mexican Institute of Ophthalmology) among rst-time
patients aged 50 y or older attending the retina department, who
received a diagnosis of early and intermediate dry AMD determined
by 4 ophthalmologists training to be retinal specialists
via
a
comprehensive ophthalmic examination (done by biomicroscopy with
slit lamp and dilated fundus examination using slit lamp and indirect
ophthalmoscope). An experienced vitreoretinal specialist conrmed
the diagnosis.
Early dry AMD was dened as cases with less than 20 medium-
sized drusen (63-124 μm) or with pigmentary anomalies. Intermediate
dry AMD was dened as eyes presenting with geographic atrophy
(GA) that did not extend under the macula or those with large drusen
(at least 125 μm), or at least 20 medium-sized, irregular drusen, or at
least 65 medium-sized, dened drusen. ere was no dened sample
size calculated for this study, given the intent to capture the most rst-
time patients possible during the study period. Patients were excluded
from this study if they had:
Eye surgery performed within 2 months prior
A preexisting choroidal disease
• Glaucoma
Media opacities
Myopia greater than 6 diopters
Wet AMD in both eyes
Another macular disease dierent than dry AMD.
Patients, who met the above inclusion criteria, were willing to have
FAF and EDI-OCT performed, and who provided their signed
informed consent aer explanation of the nature and possible
consequences of the study were consecutively enrolled.
e study protocol adhered to the tenets of the Declaration of
Helsinki and was approved by the IMO Clinical Research Committee.
Study intervention
Participants had 1 study visit, during which the study
ophthalmologists measured their visual acuity using a Snellen chart,
which was later converted to logarithm of the minimal angle of
resolution (Log MAR) for statistical analysis. Patient age and sex were
also recorded. An OCT-certied technician examined each participant
3 times with the SD-OCT instrument (Spectralis®, Heidelberg
Engineering, Heidelberg, Germany) set to the EDI mode. A 488 nm
excitation wavelength and 500 nm barrier lter were used. ree retina
images per participant were also captured using the same instrument
set to the scanning laser fundus imaging modality (BluePeak-Blue
Laser).
Pattern Definition
Normal
· Homogeneous background
· Yellow macular pigment casts a masking effect that results in
a gradual decrease in the inner macula toward the foveola
· Soft or hard drusen may be present
· Abnormal alterations may be absent
Minimal
Change
· Minimally irregular decrease or increase of background FAF
· No obvious topography
Focal
Increased
· ≥ 1 area of <200 μm diameter present
· Markedly increased and brighter FAF, which may be
surrounded by a darker halo
· Well-defined borders, with no gradual decrease between the
areas with focal increased FAF and the background
· Areas may correspond to drusen or focal hyperpigmentation
Patchy
· ≥ 1 spot of >200 μm diameter present of increased, brighter
FAF
· Less defined borders with a gradual increase between the
FAF and the background
· Areas may correspond to hyperpigmentation or large, soft
drusen
Linear
· ≥ 1 area of increased FAF
· Well-defined borders
· No decrease between the background and linear structure of
FAF
· Linear structures usually correspond to hyperpigmentation
Lacelike
· Increased FAF forms multiple-branching linear structures
· Less defined borders
· Gradual decrease of FAF from the center of the linear areas
toward the background can be observed
· Areas may correspond to hyperpigmentation or no visible
change
Reticular
· >1 areas of <200 μm diameter of decreased FAF present
· Less defined borders with a decrease in FAF from the
center of the areas toward the background.
· Found in both macular and superotemporal areas
Citation: Franco RCG, García Roa MR, Morales VR, Membrillo MAV, Lorenzo XM, et al. (2018) Assessing Dry Age-Related Macular
Degeneration in a Mexican Population with Fundus Autofluorescence and Spectral Domain Optical Coherence Tomography. J Clin Exp
Opthalmol 9: 754. doi:10.4172/2155-9570.1000754
Page 2 of 7
J Clin Exp Opthalmol, an open access journal
ISSN:2155-9570
Volume 9 • Issue 5 • 1000754
· Areas may correspond to small, soft, hard, drusen, reticular
pseudodrosen, pigmentary alterations, or no visible changes
Speckled
· >1 small punctuate or linear areas of irregularly decreased
and increased FAF present beyond the macular area and
potentially covering the entire posterior fundus
· Visible alterations correspond to hyper- and
hypopigmentation and subconfluent and confluent drusen
Table 1: Fundus autouorescence (FAF) patterns, based on
descriptions dened by the International Fundus Autouorescence
Classication Group [30].
For each participant, the vitreoretinal specialist selected the FAF
image with the best quality and examined it to determine the patterns
based on those previously described by the International Fundus
Autouorescence Classication Group (Table 1) [30]. She also
manually measured the subfoveal choroidal thickness using the
guidelines of the International Nomenclature for Optical Coherence
Tomography Panel, which describes the structure of the retinal
pigment epithelium and choroidal-scleral interface [37].
Statistical analysis
e study ophthalmologists collected the study data and recorded
them in an Excel database. e Statistics Department at the IMO
analyzed the data using Stata 13 (StataCorp LLC, College Station, TX,
USA. e qualitative variables are shown as absolute and relative
frequencies, while the quantitative variables are shown as measures of
central tendency and dispersion according to the distribution of the
data, which was evaluated by the Shapiro-Wilk test. Descriptive
statistics were used to analyze patient clinical and demographics data.
To determine the correlation between visual acuity and subfoveal
choroidal thickness, the Spearman correlation coecient was used,
given the nonnormality of the variable visual acuity. e correlation
between the variables age and subfoveal choroidal thickness was
determined by the Pearson correlation coecient, given the normality
of both variables. In all cases a p-value less than 0.05 was considered
statistically signicant.
Results
is study took place from February 2016 through August 2017. e
ophthalmologists screened 256 patients with AMD; 161 patients were
excluded due to having wet AMD, 11 were excluded for having the
advanced atrophic stage, and 26 with early and intermediate dry AMD
were excluded due to also having cataracts (n=9), epiretinal membrane
(n=3), pterygium (n=2), glaucoma (n=8), proliferative diabetic
retinopathy (n=2), myopia greater than 6 diopters (n=1), and choroidal
melanoma (n=1). Fiy-eight patients were enrolled, 26 (44.8%) of
whom had dry AMD in both eyes; therefore, 84 eyes with early and
intermediate dry AMD were evaluated in this study. e majority of
participants were female (n=42; 72.4%). Among participants, the mean
age was 75 y (SD: 8.4 y), and the mean visual acuity level was 0.4 Log
MAR (SD: 0.24).
e most frequent FAF pattern found in study eyes was reticular
(n=25, 29.8%), followed by minimal change (n=20, 23.8%), focal
increased (n=16, 14.3%), normal (n=12, 14.3%), linear (n=5, 5.9%),
patchy (n=3, 3.6%), speckled (n=2, 2.4%, and lacelike (n=1, 1.2%).
Figures 1-3 show examples of the most frequent FAF patterns observed
in this study: reticular (Figure 1), minimal change (Figure 2), and focal
increased (Figure 3).
Figure 1: An example of the reticular pattern observed in an eye
aected with dry age-related macular degeneration using
autouorescence.
Figure 2: An example of the minimal change pattern observed in an
eye aected with dry age-related macular degeneration using
autouorescence.
Citation: Franco RCG, García Roa MR, Morales VR, Membrillo MAV, Lorenzo XM, et al. (2018) Assessing Dry Age-Related Macular
Degeneration in a Mexican Population with Fundus Autofluorescence and Spectral Domain Optical Coherence Tomography. J Clin Exp
Opthalmol 9: 754. doi:10.4172/2155-9570.1000754
Page 3 of 7
J Clin Exp Opthalmol, an open access journal
ISSN:2155-9570
Volume 9 • Issue 5 • 1000754
Figure 3: An example of the focal increased pattern observed in an
eye aected with dry age-related macular degeneration using
autouorescence.
Figure 4: A manual take of choroidal thickness, measuring at 201
μm.
An example of the choroidal thickness of an eye measured manually
at 201 μm is provided in Figure 4. e mean subfoveal choroidal
thickness was 209.7 μm (SD: 69.8 μm). ere was a weak, negative
Pearson correlation between visual acuity and subfoveal choroidal
thickness (r=-0.2457; Figure 5), which was statistically signicant
(p=0.0243).
ere was a moderate, negative Spearman’s rank correlation
between age and subfoveal choroidal thickness (r=-0.3560, Figure 6),
which was statistically signicant (p<0.01).
Figure 5: Pearson correlation of visual acuity with subfoveal
choroidal thickness in eyes with early and intermediate dry age-
related macular degeneration.
Figure 6: Spearman’s rank correlation of age with subfoveal
choroidal thickness in eyes with early and intermediate dry age-
related macular degeneration.
FAF Pattern
Mean
(μm)
Standard
Error (μm)
Median
(μm)
Minimum
(μm)
Maximum
(μm)
Normal 221.8 52.9 213.5 132 301
Minimal
Change 219 78.5 229.5 68 372
Linear 213 40.9 225 158 261
Reticular 199.3 62.4 201 119 343
Focal
Increased 208.6 90.2 220 69 368
Speckled 204.5 64.4 204.5 159 250
Lacelike 228 N/A 228 N/A N/A
Patchy 184.3 104.6 163 92 298
Table 2: Summarizes the choroidal thickness ndings for each FAF
pattern.
Citation: Franco RCG, García Roa MR, Morales VR, Membrillo MAV, Lorenzo XM, et al. (2018) Assessing Dry Age-Related Macular
Degeneration in a Mexican Population with Fundus Autofluorescence and Spectral Domain Optical Coherence Tomography. J Clin Exp
Opthalmol 9: 754. doi:10.4172/2155-9570.1000754
Page 4 of 7
J Clin Exp Opthalmol, an open access journal
ISSN:2155-9570
Volume 9 • Issue 5 • 1000754
Table 2 summarizes the choroidal thickness ndings for each FAF
pattern. e distribution of choroidal thickness among FAF patterns is
shown in Figure 7. Study eyes with the autouorescent patchy patterns
had the thinnest choroidal thickness (mean: 184.3 μm; SD: 104.6 μm),
while the eye with the lacelike pattern had the greatest choroidal
thickness at 228 μm.
Figure 7: Distribution of choroidal thickness among fundus
autouorescence patterns in eyes with early and intermediate dry
age-related macular degeneration.
Figure 8: Distribution of visual acuity levels among fundus
autouorescence patterns in eyes with early and intermediate dry
age-related macular degeneration.
Table 3 summarizes the visual acuity level ndings among FAF
patterns. Figure 8 shows the distribution of visual acuity levels among
FAF patterns. Study eyes with the focal increased pattern had the worst
visual acuity level, while the eye with the lacelike pattern had the best
visual acuity level at 0.1.
FAF Pattern
Mean
(μm)
Standard
Error (μm)
Median
(μm)
Minimum
(μm)
Maximum
(μm)
Normal 0.2 0.13 0.25 0 0.3
Minimal
Change 0.35 0.23 0.3 0 1
Linear 0.46 0.32 0.3 0.2 1
Reticular 0.38 0.14 0.4 0.1 0.6
Focal
Increased 0.53 0.36 0.4 0 1
Speckled 0.35 0.07 0.35 0.3 0.4
Lacelike 0.1 N/A 0.1 N/A N/A
Patchy 0.39 0.1 0.3 0.2 0.4
Table 3: Summarizes the visual acuity level ndings among FAF
patterns.
Discussion
In this study of FAF patterns in a Hispanic population with early
and intermediate dry AMD, the most frequent pattern observed was
the reticular pattern (29.8%). e least frequent pattern was lacelike
(1.2%). In a Turkish study of 178 eyes with dry AMD, the authors also
found that the most frequent pattern among 26% of eyes was reticular
[38]. e reticular pattern has a greater risk of developing
neovascularization at 30 months in 20% of cases [38]. From among 100
FAF images of eyes with early AMD, Bindewald et al. [30] found that
the speckled pattern was the most frequent (26%), which only
appeared in 2.4% of eyes in our study. However, the lacelike pattern
was also the least frequent in both studies, with Bindewald et al.
observing this pattern in 2% of eyes.
Structural and functional changes to the choroids are known to
occur during the aging process. SD-OCT has shown that the mean
subfoveal choroidal thickness in normal, healthy eyes is 278 μm, which
decreased 15.6 μm each decade in 30 patients with a mean age of 50.4
years [19]. Another study found that choroidal volume decreases by
0.54 mm3 every decade of life [21]. Choroidal thickness (mean=209.7
μm) had a moderate, negative correlation with age in our study
(r=-0.3560, p=0.009). Manjunath et al. found that the mean choroidal
thickness in eyes with dry AMD measured with SD-OCT was similar
to our study’s at 213.4 μm, but there was a stronger, statistically
signicant correlation with age (r=-0.703; P=0.002) [8]. Ko et al. did
not nd that the relationship between choroidal thickness and age was
statistically signicant [10]. It is not understood why choroidal
thickness is variable in eyes with AMD [8]. To the best of our
knowledge, our study was the rst to examine the relationship between
choroidal thickness and FAF patterns. e patchy pattern showed the
most reduced choroidal thickness at 184.3 μm.
e mean visual acuity in this study was 0.4 LogMAR, which tended
to be better with greater choroidal thickness. is relationship was
statistically signicant (r=-0.2457, p=0.0243), similar to ndings
previously reported [8]. Previous studies did not look at the
relationship between visual acuity and FAF patterns. We found that the
focal increased pattern had the worst visual acuity at 0.53 Log MAR.
Limitations
is study was limited by its single-center, cross-sectional design
with a small sample size. As also observed by Ko et al. [10] the small
sample size in this study resulted in greater bias with increased
standard error when analyzing the dierent variables. However,
obtaining a larger sample size was a challenge in this study, given the
low prevalence rate of the disease. A recent Mexican analysis of 39,280
Citation: Franco RCG, García Roa MR, Morales VR, Membrillo MAV, Lorenzo XM, et al. (2018) Assessing Dry Age-Related Macular
Degeneration in a Mexican Population with Fundus Autofluorescence and Spectral Domain Optical Coherence Tomography. J Clin Exp
Opthalmol 9: 754. doi:10.4172/2155-9570.1000754
Page 5 of 7
J Clin Exp Opthalmol, an open access journal
ISSN:2155-9570
Volume 9 • Issue 5 • 1000754
fundus images taken with a nonmydriatic camera of 16,939 eyes from
9,280 patients from 17 states in Mexico, including Queretaro, found
that 7% of eyes (n=1,189) had AMD [43]. It is not known how many
eyes had dry AMD, but we can assume that there were some cases.
Furthermore, the retina department of the IMO saw 9,523 patients of
the retina department at IMO in 2017, which includes both rst-time
and repeat patients for all retina diseases, which is why we chose not to
work with a predened sample size, with the hopes of recruiting the
greatest number of patients with dry AMD possible for this study.
e cross-sectional design and the fact that the duration of dry
AMD was unknown among the study participants, who were rst-time
patients at the IMO, also weakens our conclusions, as we do not know
if there were changes in choroidal thickness over time [8]. In our study,
only 1 assessor interpreted the FAF images, which also increases the
bias of our results. A nal limitation of this study was that Snellen
charts were used to collect visual acuity data [39-42], whereas Early
Treatment Diabetic Retinopathy Study charts are the preferred tool to
measure visual acuity in AMD trials, with better visual acuity
consistently reported [40,43].
Conclusion
e most frequently observed AF pattern in this study of early and
intermediate dry AMD in a Hispanic population was the reticular
pattern, while the lacelike pattern was only observed in 1 eye.
Choroidal thickness was weakly correlated with age and moderately
correlated with visual acuity. e patchy pattern had the most reduced
choroidal thickness, while the focal increased pattern had the worst
visual acuity level.
Funding
e Instituto Mexicano de Oalmología, I.A.P. funded this study.
Acknowledgements
e authors would like to thank Kristen Eckert, independent
consultant, (San Antonio Tlayacapan, Jalisco, Mexico) for her
assistance in writing, translating, and editing this manuscript.
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J Clin Exp Opthalmol, an open access journal
ISSN:2155-9570
Volume 9 • Issue 5 • 1000754
... AMD is characterized by progressive degeneration of the macula, causing central field vision loss. The global prevalence of AMD is 8.7% worldwide [1,2]. Importantly, at least 1 out of 10 Hispanics have AMD, which is slightly higher than the global rate [3]. ...
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Purpose: To compare macular choroidal thickness (MCT) in eyes with adult onset foveomacular vitelliform dystrophy (AOFVD) and eyes with AMD. Methods: Five groups of 38 eyes each were included in a prospective, observational, comparative study: AOFVD eyes with fluid accumulation; AOFVD fellow eyes without fluid (early stage); advanced exudative (wet) AMD; advanced dry AMD; and healthy normal eyes. All study eyes underwent a comprehensive ophthalmologic examination. Macular choroidal thickness was measured using enhanced depth imaging optical coherence tomography (EDI-OCT). Results: Subfoveal choroidal thickness (SFCT) in AOFVD with subretinal fluid (325.66 ± 85.98 μm) was significantly (P < 0.001) thicker compared with that in exudative AMD (158.55 ± 57.87 μm) and in dry AMD (157.53 ± 67.08 μm). Also, in AOFVD, the choroid was significantly (P = 0.001) thicker than that in the normal group (255.87 ± 87.46 μm). However, in AOFVD, there was no significant difference (P = 0.69) between the SFCT in the study eye and in the fellow eye (317.66 ± 90.04 μm). The choroidal thickness at each of the other 12 measured points showed similar results. Conclusions: This study demonstrates choroidal thickening in AOFVD in contrast with the choroidal thinning observed in advanced AMD. These findings suggest that the pathogenic mechanisms in AOFVD are different from those in exudative AMD. Choroidal thickness measurement could help differentiate the challenging diagnosis between exudative AMD and the advanced stage of AOFVD (with fluid accumulation but without choroidal neovascularization).
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Purpose: To examine the association between best corrected visual acuity (BCVA) and subfoveal choroidal thickness. Design: Population-based study. Methods: The Beijing Eye Study 2011 included 3468 subjects with ages of 50+ years. The participants underwent an ophthalmologic examination including spectral-domain optical coherence tomography with enhanced depth imaging for measurement of choroidal thickness. BCVA was measured as logarithm of the minimal angle of resolution. Results: Of the 3468 participants, choroidal measurements were available for 3233 (93.2%) subjects. In multivariate analysis, better BCVA was significantly associated with thicker subfoveal choroid (P < 0.001) in general and a subfoveal choroid thicker than 30 μm (P < 0.001) in particular, after adjusting for younger age (P < 0.001), higher level of education (P < 0.001), taller body stature (P < 0.001), higher body mass index (P = 0.005), absence of glaucoma (P = 0.001), absence of diabetic retinopathy (P < 0.001), absence of late-stage age-related macular degeneration (P < 0.001), and axial length shorter than 26.0 mm (P < 0.001) (correlation coefficient r:0.56). If eyes with glaucoma, diabetic retinopathy, late-stage age-related macular degeneration or myopic retinopathy were excluded, better BCVA was still significantly associated with thicker subfoveal choroid (P < 0.001) and subfoveal choroid thicker than 30 μm (P < 0.001) in multivariate analysis. In a reverse manner, thicker subfoveal choroid was associated with better BCVA (P < 0.001) after adjusting for younger age (P < 0.001), male gender (P < 0.001), longer axial length (P < 0.001), and higher corneal curvature radius (P < 0.001). Conclusions: Better visual acuity is strongly associated with thicker subfoveal choroid independent of additional factors, such as age, axial length, education level, and major ocular diseases.
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Purpose To develop a consensus nomenclature for the classification of retinal and choroidal layers and bands visible on spectral-domain optical coherence tomography (SD-OCT) images of a normal eye. Design An international panel with expertise in retinal imaging (International Nomenclature for Optical Coherence Tomography [IN•OCT] Panel) was assembled to define a consensus for OCT imaging terminology. Participants A panel of retina specialists. Methods A set of 3 B-scan images from a normal eye was circulated to the panel before the meeting for independent assignment of nomenclature to anatomic landmarks in the vitreous, retina, and choroid. The outputs were scrutinized, tabulated, and used as the starting point for discussions at a roundtable panel meeting. The history of anatomic landmark designations over time was reviewed for the various cellular layers of the ocular structures that are visible by SD-OCT. A process of open discussion and negotiation was undertaken until a unanimous consensus name was adopted for each feature. Main Outcome Measures Definitions of normal eye features showed by SD-OCT. Results Definitions for various layers changed frequently in the literature and were often inconsistent with retinal anatomy and histology. The panel introduced the term “zone” for OCT features that seem to localize to a particular anatomic region that lacks definitely proven evidence for a specific reflective structure. Such zones include the myoid, ellipsoid, and the interdigitation zones. Conclusions A nomenclature system for normal anatomic landmarks seen on SD-OCT outputs has been proposed and adopted by the IN•OCT Panel. The panel recommends this standardized nomenclature for use in future publications. The proposed harmonizing of terminology serves as a basis for future OCT research studies.
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Purpose: To investigate the correlation between subfoveal choroidal thickness (SFChT) and the severity or progression of nonexudative AMD. Methods: One hundred seventy-six eyes of 114 patients with nonexudative AMD were included in this study. These eyes were divided into stages I through IV, based on the Age-Related Eye Disease Study (AREDS) classification of fundus findings. Using enhanced depth imaging from spectralis domain optical coherence tomography (SD-OCT), the central retinal thickness (CRT), SFChT, and parafoveal choroidal thickness (PFChT) were measured. The area of geographic atrophy (GA) was measured from fundus autofluorescence (FAF) images, and the progression of GA was calculated using RegionFinder software. Results: The age-adjusted SFChT levels were lower at later stages of nonexudative AMD. These measurements were as follows: 266.68 ± 12.60 (stage I: 28 eyes), 263.34 ± 9.87 (stage II: 48 eyes), 200.55 ± 8.83 (stage III: 71 eyes), and 188.34 ± 13.72 (stage IV: 29 eyes) (P = 0.0028). The age-adjusted SFChT was also negatively correlated with the best corrected visual acuity (BCVA) (estimate, -0.001; P = 0.0006). Among 16 eyes with GA at baseline, SFChT showed a negative correlation with the baseline area of GA (r = 0.5521, P = 0.0133). In addition, GA progressed more rapidly during the mean follow up of 22.19 ± 9.08 months when the SFChT was lower at baseline (r = 0.5658, P = 0.0112). Conclusions: Subfoveal choroidal thickness is closely related to the BCVA, the severity of nonexudative AMD, as well as the rate of GA progression. Subfoveal choroidal thickness may be a predictor of disease progression in GA cases.