OCT-A can differentiate and monitor various optic nerve head disorders by characterizing retinal vasculature. It provides quantitative assessment of microcirculation changes in the optic nerve head and peripapillary region. Normal eyes have higher vessel density and smaller vessel spacing compared to diseases like glaucoma where vessel density decreases with severity. OCT-A may help prognosticate diseases by monitoring progression of structural changes in the retinal and optic nerve vascular network.

1. Prognostic value
of multiple differential
diagnosis
for optic nerve head by
OCT Angio
Naglaa Hassan
MIOR

3. OCT A
Optical Coherence Tomography Angiography (OCT-A)
is an imaging modality that can be used to characterize
vasculature in various retinal layers, providing
quantitative assessment of the microcirculation in the
optic nerve head and peripapillary region

5. There are some vascular parameters:
vessel density en face
vessel density inside disc spacing between large vessels
spacing between small vessels outside the disc
Normal eyes have
a higher vessel density, higher vessel density inside disc,
lower spacing between large vessels and small vessels.

7.  NFLP = nerve fiber layer plexus GCLP = ganglion cell layer plexus;
ICP = intermediate capillary plexus; DCP = deep capillary plexus.
 The NFLP and GCLP can be combined superficial vascular
complex (SVC), which contain both large vessels and capillaries.
 The ICP and DCP can be combined into deep vascular complex

10. OCT-A can play a pivotal role in the detection,
differentiation and monitoring of a wide range of ONH
disorders.
OCT-A can provides valuable data about the
structural changes of the retinal and optic nerve
vascular network
It can be used for monitoring the disease
progression .

11. Color-coded peripapillary OCTA images with four different ONH diseases.
A) Compression due to optic nerve head drusen
B) Retinal vein occlusion earlier in life
C) Chronic non-arteritic anterior ischemic optic neuropathy,
D) Advanced glaucoma

12. OCTA in
ONH compressive disorders
(Drusen)

13. Reduced vascular density consistent with the blue areas on color
vascular density map in the both eyes
Optic disc Drusen

14. Optic disc drusen ( multi modal imaging )

15. SCP of optic disc (OCTA) with large vessel removal, annulus region of
interest, and demarcation of the four quadrants
vessel density heat map,
and vessel complexity heat map.
Vessel area density and vessel complexity index are calculated and
represent area occupied by vessel divided by total area and branching
complexity of the perfused vasculature, respectively .
For ease of comparison, these values are shown on a linear color scale

16. Optic disc drusen does not require treatment,
and patients generally have good visual
prognosis.
There is currently no effective treatment for
patients who have gradual loss of visual fields

17. OCTA in Retinal vein
occlusion

18. Inside disc Vessel Density (VD) (F), measured inside the optic
disc boundary and peripapillary VD, calculated for the region
of 750 μm-wide elliptical annulus extending from the optic
disc boundary.

19. Optic nerve vessel density changes before (A) and after 4-months
(D) from intravitreal anti-(VEGF) injection.
Inside disc and peripapillary VD OCTA showed increase in the
papillary area in patients affected by CRVO after anti-VEGF
therapy.
Follow-up OCT vertical scans show a reduction of macular edema
from baseline to 4-months (This area could represent a new region
of interest to study microvasculature changes concomitant with
severe macular edema.
Prognostic
value

20. OCTA in
Neurodegenerative diseases

21. Anterior Ischaemic Optic Neuropathy
Multimodal analysis of right eye in an AION The fundus
examination show a moderately pale optic disc .
OCTA scans a reduction of the OCTA whole perfusion density and
circumpapillary density (even considering the color-coded flow
density map) in the superior Hemifield topographically correlated
with the ONH and RNFL damage.

22. In NAION, it has been found that there is significant
sectorial capillary density reduction and subsequent
decrease in the blood flow to the corresponding region of
the optic nerve head.

23. 1st presentation, diffuse edema with normal vascular perfusion
was observed then A month later, optic disc atrophy was
established with Extensive areas of reduced perfusion are
observed in the peripapillary area.
Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION)

24. MS
Optic neuritis can be the initial symptom in approximately
25% of patients
up to 50% of MS patients will suffer from at least one episode
of optic neuritis during the course of their disease
OCT-A findings in MS include significant reduction of the blood
flow within the parafoveal region and the optic nerve head.
It is still not clear why the blood flow of the retina and optic
nerve is reduced in MS patients.

25. Disc OCT-A of a healthy control subject.
Right side: Disc OCT-A of an optic neuritis disc showing reduced
density of the optic nerve head blood vessel network.
This implies reduced blood flow on the optic nerve head.

26. OCTA in
Glaucoma

27. Among the glaucoma ,glaucomatous eyes, the spacing between
large vessels was significantly higher in moderate and severe
glaucoma grades than in early glaucoma

28. Vessel density of the optic disc, peripapillary Angio flow density
map (PAFD) displays loss of the retinal nerve fiber layer in a
patient diagnosed with glaucoma.

33.  OCT-A vessel density is lower in glaucoma patients compared
with healthy and glaucoma suspects
 The Diagnostic accuracy of OCT-A and the ability to
noninvasively evaluate the capillary networks shows promise for
prognostic value for characterizing glaucomatous retinal
vascular changes and may have a role in glaucoma management.
 Also determination whether a lower vessel density found in
glaucoma patients precedes or follows optic nerve damage and
whether this information can be used to improve glaucoma
management.

35. A) untreated eye with high intraocular pressure.
B) The same eye one month later under combined intraocular
pressure lowering medication and with more than 50%
intraocular pressure reduction
The peripapillary vessel density map shows a clear increase in
capillary perfusion
Prognostic
value

36. 1-OCT-A can play a pivotal role in differentiation and monitoring
of a wide range of ONH disorders.
2-OCTA can be used for the development of biomarkers to monitor
the disease progression .
3-Not only RNFL analysis. .O.N.H micro vasculature does matter as
the same important .
4-O.N.H and peri papillary area could represent a new region of
interest to study microvasculature changes.
Take home
message