Pigment epithelial detachment (PED) occurs when the retinal pigment epithelium separates from the underlying Bruch's membrane, usually due to fluid accumulation. There are several types of PED including drusenoid, serous, and vascularized PEDs. PEDs can be caused by conditions like age-related macular degeneration and central serous choroidopathy. Optical coherence tomography is used to characterize the type and contents of the PED. Treatment depends on the specific cause and characteristics of the PED.

1. Pigment epithelial
detachment (PED)
Mohammad Riyaj Ali
MSc Optometry

2. PED
• Retinal pigment epithelial detachments (PEDs) are
structural splitting within the inner aspect of Bruch’s
membrane separating the RPE from the remaining
Bruch’s membrane
• It means that there is fluid beneath the retinal
pigment epithelium (RPE) which is the layer of cells
beneath the retina. PED has many causes but the
most common are age-related macular degeneration
and central serous choroidopathy

3. • PED can occur associated with multiple ocular
and infrequently also primarily non-ocular
pathologies. They can be sub-divided into
drusenoid, serous, serous-vascularized and
fibrovascular PED. Most commonly PED is
found in age-related macular degeneration.
• The space created by this separation is
occupied by blood, serous exudate, drusenoid
material, fibrovascular tissue or a combination

4. What causes pigment epithelial detachment?
• Pigment epithelial detachment (PED) is a
pathological process in which the
retinal pigment epithelium separates from the
underlying Bruch's membrane due to the
presence of blood, serous exudate, drusen, or
a neovascular membrane

5. Here are the different types of PED:
•with CSCR (not ARMD)
•serous (avascular) PED, not CSR (dry ARMD)
•drusenoid PED (a dry ARMD, Adult Bests)
•vascularised PED ( type 1 of wet ARMD)
•haemorrhagic PED (a type of wet ARMD,)
•PED as part of PCV (a type of wet ARMD)

9. • Serous PED is defined as an area of sharply
demarcated, dome-shaped serouselevation of
the retinal pigment epithelium (RPE). The
histopathology of serous PED is consistent with
the detachment of the RPE basement
membrane, along with the overlying RPE from
the remaining Bruch's membrane due to
accumulation of fluid(1).

10. The PED is a dome of fluid under the
pigment layer of the retina. there is a
'PED' only, no leak
'PED', with a leak under the retina
(shown here) or in the retina

11. • Drusenoid PED was defined as ½ disc diameter
(DD) of confluent soft drusen under the centre
of the macula. All patients underwent visual
acuity measurement, biomicroscopic fundus
examination, stereoscopic colour photograph,
and fluorescein and indocyanine green
angiography.

12. • The classification of PEDs in AMD can be
divided based on their contents. Categories
include drusenoid, serous, vascularized, or
mixed components. Drusenoid PEDs are seen
mostly in nonneovascular or dry AMD. Serous
PEDs are typically associated with the
neovascular or wet form of AMD, but their
natural history is relatively more favorable.
Vascularized PEDs associated with Type 1 (sub-
RPE) neovascularization and wet AMD, in
contrast, have a greater risk of vision loss. In
eyes with AMD, it is not uncommon to see
more than one type of PED.

13. • PEDs are present in several chorioretinal
diseases including Vogt-Koyanagi-Harada (VKH)
Syndrome, Idiopathic Central Serous
Chorioretinopathy (CSC) small multifocal
idiopathic PEDs, Polypoidal Choroidal
Vasculopathy (PCV), and Exudative/Non-
Exudative Age-Related Macular Degeneration
(AMD).

14. • Pathophysiology
• The retinal pigment epithelium (RPE) monolayer, extending from the
optic disk margin uninterrupted through to the ciliary body epithelium,
is bounded by the apical surface of the retina and on its basal surface by
the collagenous layer of Bruch’s membrane.
• The forces maintaining normal adhesion between the RPE and Bruch’s
membrane are not well understood. Under normal conditions, there
exists a net bulk flow of fluid towards the choroid from the vitreous,
with its generation dependent upon hydrostatic and osmotic forces
within the two bodies. Both the RPE and the retina produce resistance
to this fluid flow. The RPE has greater resistance due to its limited
hydraulic conductivity, subsequently, a vector force is generated
pushing it against Bruch’s membrane. The attachment of the RPE
basement membrane to Bruch’s membrane is possibly supplemented
by regions of hemidesmosomes containing fine filaments of laminin,
proteoglycans and collagen types IV and V.
• Age-related deposition of lipids, such as cholesterol esters, triglycerides,
and fatty acids in Bruch's membrane may change its permeability
altering retinochoroidal flow.Fluid may accumulate in the sub- RPE
space, unable to pass through Bruch membrane, resulting in RPE
elevation.

15. Clinical Exam
• Often PEDs will transilluminate if they are filled predominantly with serous fluid when
observed at the slit lamp. Pigment figures can also indicate chronicity of disease.
Examination reveals a reticulated pattern of increased pigmentation extending radially
over the PED, likely due to migration of RPE cells into the outer retinal space however it
is unclear whether these carry a prognostic significance.
• Drusenoid PED: Drusenoid PEDs appear as well-circumscribed yellow or yellow–white
elevations of the RPE that are usually found within the macula. They may have
scalloped borders and a slightly irregular surface. It is not uncommon to observe a
speckled or stellate pattern of brown or gray pigmentation on their surface.
• Serous PED: Serous PED appears as a distinct circular or oval-like detachment of the
RPE. Clear or yellowish–orange in color, this dome-shaped elevation of the RPE has a
sharply demarcated border.
• Vascular PED: Gass reported that a flattened or notched border of the PED is a frequent
and important sign of hidden associated CNV.[7] Other biomicroscopic findings
suggestive of possible occult CNV association include yellow subretinal and intraretinal
exudates that occur typically at the PED margins, subretinal hemorrhages at PED
margins, sub-RPE blood which appears darker than subretinal blood with a fluid-level
sign, irregular elevation of the PED because of organization in the lesser elevated area,
and radial chorioretinal folds surrounding the PED caused by the contraction of Bruch
membrane and the CNV.[

16. Optical coherence tomography
• Drusenoid PED: Drusenoid PEDs usually show a smooth contour of
the detached hyperreflective RPE band that may demonstrate an
undulating appearance. The material beneath the RPE band typically
exhibits a dense homogeneous appearance with moderate or high
hyperreflectivity. Drusenoid PEDs are typically not associated with
overlying subretinal or intraretinal fluid.
• Serous PED: On OCT, serous PEDs appear as well-demarcated, abrupt
elevations of the RPE with a homogenously hyporeflective sub-RPE
space. Enhanced depth imaging (EDI) OCT is useful to determine
whether serous PED is caused by AMD (normal subfoveal choroidal
thickness) or by CSC (increased subfoveal choroidal thickness). [10]
• Vascular PED: Optical coherence tomography allows better
visualization of the exact relationship between neovascular
membranes and PEDs. Enhanced depth imaging OCT enables better
visualization of the contents of PEDs. Untreated PEDs demonstrate
evidence of fibrovascular proliferation, often coursing along the back
surface of the detached RPE.

18. Fundus autofluorescence imaging
Drusenoid PED: Drusenoid PEDs may exhibit decreased FAF but typically they are
isofluorescent or hyperautofluorescent.Drusenoid PEDs often show an evenly
distributed, modest increase in the FAF signal surrounded by a well defined,
hypoautofluorescent halo delineating the entire border of the lesion.
Serous PED: Serous PEDs most often have an even distribution of
hyperautofluorescence corresponding to the detachment and are surrounded by
a hypoautofluorescent border.
Vascular PED: Fundus autofluorescence imaging of vascularized PEDs has not
been evaluated systematically in large series of patients. More work needs to be
done to correlate the FAF pattern of PEDs and any associated CNV with findings
obtained with FA and SD-OCT.

19. Fluorescein angiography
Drusenoid PED: Drusenoid PEDs demonstrate faint hyperfluorescence in the early
phase that increases throughout the transit stage of the study without late
leakage. The correlation of FA findings with SD-OCT and occasionally ICGA may
help differentiate drusenoid from vascularized PEDs.
Serous PED: Serous PEDs demonstrate intense early hyperfluorescence and brisk,
progressive pooling within the PED in a homogeneous and well-demarcated
manner. Late staining of serous PEDs is typical and may make it difficult to
differentiate these PEDs from those that are vascularized based on FA alone. In
cases where there is suspicion of associated CNV, ICGA is a useful imaging
modality.
Vascular PED: From the analysis of fundus photographs of the macula and FA, the
Macular Photocoagulation Study identified two main patterns of CNV: classic and
occult. Classic CNV is characterized by a well-defined area of early typically lacy
hyperfluorescence with progressive leakage in the late stages of the study. An
additional fluorescein angiographic pattern of vascularized PEDs is a serous PED
with a notch (e.g., kidney bean–shaped PED) or hot spot that may be referred to
as a vascularized serous PED.

20. Indocyanine green angiography
Drusenoid PED: Using a confocal scanning laser ophthalmoscope (SLO) system and
ICGA, the content of the drusenoid PED will block the fluorescence emitted from the
underlying choroidal vasculature and, therefore, the PED will appear as a
homogeneous hypofluorescent lesion during the early phase and remain
hypofluorescent throughout the transit.
Serous PED: With an infrared fundus camera, the ICGA reveals only variable, minimal
blockage of normal choroidal vessels by the serous PEDs in the late phase. Using a
confocal SLO system, the ICGA reveals hypofluorescence in both the early and the late
phases of the ICGA study with complete blockage of the normal choroidal vasculature.
Vascular PED:Vascularized PEDs may demonstrate either of two major findings with
ICGA analysis. A focal bright area of well-defined hyperfluorescence less than 1 disk
diameter in size referred to as a hot spot or focal CNV.

26. Absent reflectivity of underlying choroid green band due
to shadowing effect of the blood beneath the RPE

28. PEDs appear as broad elevations
of the RPE band relative to Bruch’s
membrane . Fibrovascular PEDs
may be accompanied by variable
quantities of serous exudation
and/or hemorrhage, with the
slope of the PED varying according
to fluid content (A, B). Using
spectral domain OCT, many
fibrovascular PEDs appear to be
filled with solid layers of material
of medium reflectivity, separated
by hyporeflective clefts (B). Serous
PEDs are seen on OCT as areas of
smooth, sharply demarcated,
domeshaped RPE elevation,
typically overlying a
homogenously hyporeflective
space. Bruch’s membrane is often
visible as a thin hyperreflective
line at the outer aspect of the PED
(C).

29. A: On optical coherence tomography (OCT) (Cirrus seen as dome-shaped elevations of
the retinal pigment epith separating the RPE from the underlying Bruch’s membrane. (B
be seen as discrete foci of hyperreflectivity with underlying s attached to areas of
elevated RPE overlying drusen. Epir hyperreflective bands anterior to the inner retinal
surface, wi

30. On OCT, fibrovascular tissue in the subretinal space often appears as an amorphous lesion of
mediumto high- reflectivity above the RPE (A); with increased scarring, it may be seen as a
more well-demarcated, highly hyperreflective lesion (B). Invasion of fibrovascular tissue is
often accompanied by profuse leakage from its immature blood vessels that appears on OCT
images as areas of hyporeflective space between the neurosensory retina and the RPE
(Spectralis; Heidelberg Engineering)

31. On OCT, vitreomacular traction may be seen when a thickened, taut, posterior hyaloid causes
deformation of the inner retinal surface, occasionally leading to formation of a full-thickness
macular hole (A, B). Epiretinal membranes are often seen on OCT as hyperreflective bands
anterior to the inner retinal surface, with distortion of the underlying anatomy (C) and
pseudohole formation (D)

32. ears in the retinal
pigment
epithelium (RPE)
are a well-
described
complication of
neovascular AMD
(A, B). On OCT, RPE
tears are typically
seen as an area of
discontinuity in a
large pigment
epithelium
detachment (PED)
(Spectralis;
Heidelberg
Engineering) (C,
D); with time, a
disciform scar may
form (E, F ).

33. Polypoidal choroidal vasculopathy (PCV) is associated with a branching vascular network and
polypoidal lesions (A). On optical coherence tomography (OCT), branching vascular networks are
associated with shallow elevations of the retinal pigment epithelium (RPE), while polypoidal
lesions appear as sharper protuberances (Cirrus HD-OCT; Carl Zeiss Meditec) (B, C). As the
exudative complications of these lesions evolve, large serosanguineous pigment epithelium
detachments (PEDs) develop adjacent to the polypoidal bulges, creating a tomographic notch.
With continued exudation, these polypoidal lesions remain adherent to the RPE and are lifted
away from Bruch’s membrane (B).

34. OCT showing multiple PEDs as dome
shaped elevations of the RPE with few
intervening drusens seen as hyper
reflective elevations.

36. Massive PED
occupying the right
macula (a) and two
small PEDs in the left
eye (b). Fluorescein
angiography (c and d)
show pooling with
hypofluorescent
streaks
corresponding to
altered pigmentation
on the PED surface in
the right eye (c).
Spectral domain
optical coherence
tomography
demonstrates serous
PEDs (e and f); PED in
the right eye had
subretinal fluid at its
apex with retinal
pigment epithelium
hyperplasia (arrow).

37. Treatment depends on the location, size and cause of
the PED. Some PEDs can resolve spontaneously, but
treatment may include drugs and/or laser.