142
Even though the pathogenesis of the PED is not com-
pletely understood, from these studies the CNVs’ forma-
tion seems to be a pivotal moment.
At fundus examination, a serous PED appears as a round
or oval, distinct dome-shaped area of regular detachment
of the RPE and the overlying neurosensory retina, yel-
low to orange color and smooth surfaced. Margins are
typically sharply demarcated; focal RPE atrophy and pig-
ment figures are frequently observed
(2,18)
. However, the
concurrent presence of a CNV can generate a variety of
associated ophthalmoscopic aspects, such as hemorrhagic
and exudative components, areas of irregular elevation of
the RPE and serous detachment of the surrounding neu-
roretina. A CNV located at the margin of the PED can
vary its shape, resulting in a reniform or notched aspect,
or a flat-sided RPE detachment
(19)
.
Serous PED imaging study includes fluorescein angiog-
raphy (FA), indocyanine green angiography (ICGA) and
optical coherence tomography (OCT). The diagnosis
of a serous PED is made with fluorescein angiography.
Examined by FA, a serous PED classically shows an early
uniform hyperfluorescence of the entire lesion, slightly
delayed compared to the background fluorescence, that
progressively increases in brightness as the examina-
tion progresses (pooling). Serous PED’s hyperfluores-
cence typically does not change in size or shape during
the angiographic phases. FA can also demonstrate the
presence of CNV, usually associated to a serous PED as
“occult CNV”, like areas of indistinct late subretinal
staining, more evident when located at the margin of
the RPE detachment or corresponding to the “notch”
(18)
.
The presence of a CNV can be also deducted by the pres-
ence of an hemorrhagic component of the PED, the
dark meniscus described by Gass
(19)
. However, a more
precise localization of the neovascular component can
be obtained with digital ICGA. Indocyanine green mol-
ecule has biophysical properties that, unlike fluorescein,
make it useful to enhance vessel’s anatomy through RPE,
blood and turbid exudation. In detail, ICGA enables to
better delineate the presence and the type of newves-
sels associated with a serous PED and for this reason is
considered a fundamental tool in the management of this
disease
(20,-22)
.
On ICGA, serous PED appears as an hypofluorescent
lesion, with sharply delineated margins, that remains
constantly hypofluorescent during all the phases of the
examination
(23)
.When the newvessels are not present, no
signs of localized hyperfluorescent areas are detectable;
the outline of the PED is sharply round and it’s there-
fore considered a pure serous PED. In AMD patients,
Yannuzzy found an incidence of 4% of non-vascularized
PED among serous PED
(22)
.
When the neovascular component is present, it has been
suggested the term vascularized PED
(22)
.
Its frequency
accounts for approximately 24% of newly diagnosed
exudative AMD
(24)
Newvessels associated with serous
PED are represented in different subtypes. High-speed
videoangiography with scanning laser ophthalmoscope
appears a precious tool that allows the ophthalmologist
to identify the newvessel pattern and their angiographic
behavior
(25)
.To recognize the different types of neovascular-
ization by distinguish angiographic findings is mandatory
for the distinct natural course, visual prognosis and specially
different response to the treatments of the three main kinds
of newvessels associated to serous PED in AMD.
Themore common type of newvessels associatedwith serous
PED are those of choroidal origin, or CNV
(22,24)
(Fig.1).
In the early phases, ICGA shows the CNV’s feeder
artery vessel that arises from the choroidal circulation,
and subsequently the draining venule. At the same time
the capillary network of the neovascular membrane
can be detected. Unlike fluorescein, indocyanine green
leaks slightly and the CNV’s hyperfluorescence is usu-
ally minimal, with the exception of some cases that
show an intense leakage, considered as very active CNV.
Frequently, in the late phases, a well-defined area of mild
hyperfluorescence corresponding to the CNV network
can be appreciable. The second type of newvessels that
complicate serous PED are the so-called retinal angioma-
tous proliferations (RAP) or more recently type 3 neo-
vascularization
(15,26-28)
. These vascular lesions, as reported
by various authors, are referred to invade the outer retina
and to involve the RPE, through a progression that,
to the best of our knowledge, has been hypothesized
to originate from either the retinal circulation or the
choroid. ICGA shows the presence of a “hot-spot”, due
to the early hyperfluorescence of the intraretinal neovas-
cular complex, that increases during the angiography,
with an intense leakage in the late phases. Its brightess
is enhanced by the surrounding hypofluorescence of the
underlying PED (Fig. 2).
Hallmark of the RAP, the neovascular complex is typi-
cally connected with one or more retinal vessels, tortu-
ous and dilated, that suddenly deepen toward the vas-
cular lesion
(15,26,29)
. Single or multiple, the RAPs origin
are classically extrafoveal, and an intraretinal hemorrhage
corresponding to the neovascular lesion is frequently
observed
(26)
.
The third type of newvessels associated with serous
PED in AMD is consistent with polypoidal choroidal
