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EW RETINA
October 2015
Contact information
Huang: huangd@ohsu.edu
acceptable amount of risk to broadly
screen everyone, Dr. Huang said.
The research also indicated that
it was possible to detect retinal neo-
vascularization by showing vessels
in the vitreous above the inner lim-
iting membrane of the retina. This
may not be intuitive to those who
are looking for blood vessel leakage
at first. It's just a question of chang-
ing the way that you are thinking,
Dr. Huang said. "On OCT angio-
grams you detect neovascularization
by the fact that they're in the wrong
layer," he said. "You should not have
blood vessels in the vitreous; if they
are there, it is neovascularization."
The fact is that a lot of things,
such as microaneurysms, can also
leak and may be mistaken for neo-
vascularization with fluorescein an-
giography, Dr. Huang said. By find-
ing blood vessels where they should
not be with OCT angiography,
investigators are beginning to come
up with new theories on neovascu-
larization. "On OCT angiography
we're seeing small tufts of neovascu-
larization in the vitreous that look
like microaneurysms on fluorescein
angiography," he said. "I think
that might explain why sometimes
physicians see no neovascularization
and somehow the diabetic patient
has vitreous hemorrhage." It is likely
that neovascularization is present
but the older technology did not
pick this up before, he explained.
Because the new technology is
three-dimensional it is possible to
clearly separate the different layers
seen. "In geographic atrophy and in
choroideremia, we can see the atro-
phy of the choriocapillaries, which
are normally nearly confluent and
have very different patterns from
the outer choroidal vessels, which
are sparse and larger," he said.
While OCT angiography
officially entered the market
internationally in late 2014 with
the AngioVue Imaging System
(Optovue, Fremont, Calif.), three
other companies, Carl Zeiss Meditec
(Jena, Germany), Heidelberg Engi-
neering (Heidelberg, Germany), and
Topcon (Oakland, N.J.), now have
prototypes in the wings, Dr. Huang
said. Carl Zeiss Meditec recently
received FDA 510K approval for
its OCT angiography software. Dr.
Huang is confident that in the near
future, American physicians will
be able to use OCT angiography
for more than just investigational
purposes. EW
Editors' note: Dr. Huang has financial
interests with Optovue and Carl Zeiss
Meditec.
