|When interpreting fluorescein angiography,
the simultaneous use of colour picture fundal is recommended. If you
were in a viva, ask the examiner if you could see the colour fundal picture.
In the OSE, you are likely to be given an enlarged single frame showing
The fluorescein angiography may be given as a positive
or negative transparency (see picture below). As most fluorescein
angiographies encountered are on positive transparency, all the following
interpretations are based on the apparance on positive tranparency.
Positive fluorescein angiography
Negative fluorescein angiography
The fluorescein angiography is best viewed by placing
the transparency on a viewing box and examine the frames with a 20 D lens
(those used for indirect ophthalmoscopy). The frame also contains the time
lapsed from the moment of intravenous fluorescein sodium injection.
Fluorescein angiography can be analysed
in the following ways (which complements each other):
Sequential analysis -
it is examined frame by frames
in the order that it was photographed. The major vascular phases of the
angiogram is emphasized. This method is most useful in analysing vascular
disorders of the retinal and choroidal.
Anatomic analysis -
observes each of the major layers
of the posterior pose of the eye - the choroidal,
RPE and neurosensory retina.
Morphologic analysis -
considers overall patterns. In
an abnormal angiogram, some areas may be darker (hyperfluorescent) or lighter
(hypofluorescent) than usually in a given location.
In the viva, the examiner would expect you to use
the following term while describing the frames
(refer to principles of
fluorescein angiography for pictures):
red free: taken before the fluorescein injection