7 Quantitative Analysis of Retinal Layers’ Optical Intensities …
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less pronounced in photoreceptor layer. The negative correlation between age and
optical intensity from RNFL to OPL, except for ONL and photoreceptor layer, as
well as the positive correlation between age and RPE optical intensity, remained after
adjustment of other factors, such as image quality. The strongest association with
age was the optical intensity of RPE layer (had the highest standardized β values
0.456). No correlation was found, after adjustment, between retinal optical intensity
and sex, height, weight, SE, axial length, disc area and rim/disc area ratio.
7.4.5 Discussion
In this study, by analyzing three-dimensional OCT data with our automatic software,
the retinal optical intensity of adults in different age groups was described, and the
effects of various factors on this parameter was explored. The interoperator reproducibility of optical intensity measurement in healthy eyes was good. Mean optical
intensity was highest in RPE layer, photoreceptor layer and RNFL, and lowest in
ONL. Optical intensity was low in the central area of RNFL, GCL, IPL, INL, OPL
and photoreceptor layers, and high in the center of RPE layer. In RNFL and GCL,
mean optical intensity of the nasal sectors was greater than in the temporal sectors,
whereas the ONL, photoreceptor layer and RPE had the opposite distribution. The
results also demonstrated that retinal optical intensity of most retinal layers increased
with image quality, and decreased with age. There was no relationship between retinal optical intensity and sex, height, weight, SE, axial length, disc area or rim/disc
area ratio.
7.5 The Optical Intensity Distribution in Central Retinal
Artery Occlusion (CRAO)
7.5.1 Central Retinal Artery Occlusion
Central retinal artery occlusion (CRAO) is an ocular emergency that can lead to
severe ischemia of the retina and cause a sudden loss of vision [30]. In the acute
phase, whitish opacification of the retina is present at the posterior pole except fovea,
which does not have inner retinal layers. The opacification typically resolves spontaneously within a month [31]. On fundus fluorescein angiography, delay of arteriovenous transit time and retinal artery filling time is usually observed [32]. However,
fluorescein angiography is invasive, and subject to severe complications, including
a possibility of allergic shock. Furthermore, fluorescein angiography provides only
limited information about the severity of retinal damage [33].
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less pronounced in photoreceptor layer. The negative correlation between age and
optical intensity from RNFL to OPL, except for ONL and photoreceptor layer, as
well as the positive correlation between age and RPE optical intensity, remained after
adjustment of other factors, such as image quality. The strongest association with
age was the optical intensity of RPE layer (had the highest standardized β values
0.456). No correlation was found, after adjustment, between retinal optical intensity
and sex, height, weight, SE, axial length, disc area and rim/disc area ratio.
7.4.5 Discussion
In this study, by analyzing three-dimensional OCT data with our automatic software,
the retinal optical intensity of adults in different age groups was described, and the
effects of various factors on this parameter was explored. The interoperator reproducibility of optical intensity measurement in healthy eyes was good. Mean optical
intensity was highest in RPE layer, photoreceptor layer and RNFL, and lowest in
ONL. Optical intensity was low in the central area of RNFL, GCL, IPL, INL, OPL
and photoreceptor layers, and high in the center of RPE layer. In RNFL and GCL,
mean optical intensity of the nasal sectors was greater than in the temporal sectors,
whereas the ONL, photoreceptor layer and RPE had the opposite distribution. The
results also demonstrated that retinal optical intensity of most retinal layers increased
with image quality, and decreased with age. There was no relationship between retinal optical intensity and sex, height, weight, SE, axial length, disc area or rim/disc
area ratio.
7.5 The Optical Intensity Distribution in Central Retinal
Artery Occlusion (CRAO)
7.5.1 Central Retinal Artery Occlusion
Central retinal artery occlusion (CRAO) is an ocular emergency that can lead to
severe ischemia of the retina and cause a sudden loss of vision [30]. In the acute
phase, whitish opacification of the retina is present at the posterior pole except fovea,
which does not have inner retinal layers. The opacification typically resolves spontaneously within a month [31]. On fundus fluorescein angiography, delay of arteriovenous transit time and retinal artery filling time is usually observed [32]. However,
fluorescein angiography is invasive, and subject to severe complications, including
a possibility of allergic shock. Furthermore, fluorescein angiography provides only
limited information about the severity of retinal damage [33].