Intravenous fluorescein angiography (IVFA)
is an important examination technique commonly used by ophthalmologists
to evaluate the status of the eyes’ internal blood circulation.
Where medically indicated, IVFA is essential for the accurate
diagnosis and effective treatment of several potentially vision-threatening
retinal and retina-vascular diseases. The most common conditions
requiring IVFA are certain cases of diabetic retinopathy and
age-related macular degeneration. Others include inflammatory
disease and hemorrhages or swelling of the retina, investigation
of suspected retinal tumors, and some cases of unexplained
vision loss.
The IVFA procedure itself involves the injection sodium fluorescein
into a vein of the forearm. The intravenous dye then enters
the blood circulation, a portion of which arrives in the retinal
blood vessels after several seconds. Using a specially designed
“fundus” camera focused through the widely dilated
pupil, a rapid sequence of flash photographs are taken of
the retinal vascular circulation before, during, and after
the appearance of dye in these vessels. The photoflash excites
the dye, which glows brightly against a darker background.
The resulting photographic record is called a fluorescein
angiogram, which can then be studied following conclusion
of the procedure. The IVFA itself takes about thirty minutes
to perform and 1 hour to process the film during a typical
office visit of two to three hours.
The IVFA is a safe test, but not without some risk. Adverse
reactions, usually self-limited, can and do occur shortly
after injection. Injection of the dye can be associated with
a brief warm, flushed sensation or, in some, momentary nausea.
Localized inflammation at the injection site, varying in severity,
occurs occasionally. Less common is a hypersensitivity to
the dye causing itching, skin rash or hives, and, most rarely,
anaphylactic shock. During the next two days following IVFA,
the yellow-green fluorescein normally causes temporary discoloration
of the skin as well as a distinct orange to yellow-green discoloration
of the urine. Any other reaction occurring after leaving the
office should be reported promptly. When the diagnostic benefits
of IVFA are felt to outweigh the potential risks of the procedure,
it is medically appropriate and advisable that the IVFA study
be conducted.
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