A fluorescein angiogram is a diagnostic test used to evaluate the health and blood flow of the retina. It can be a diagnostic tool and is used primarily by retinal specialists.
Inject Dye into the Arm
A small amount (3-5 cc) of fluorescein dye is injected into your arm. The dye will travel to your retina in about 12-15 seconds (depending upon your heart). A series of pictures are then taken as the dye travels through the retina.
Usually there are no side effects. Itching and nausea can occur, but passes quickly. As with peanuts or bee stings, severe allergy to the dye can occur.
The test may last for as long as 15 minutes depending on what we are studying.
The dye is cleared by the kidneys…your skin will have a yellowish tint and your urine will be colored for the next day!
Fluorescein is unique to ophthalmology, it is not related to other contrast dyes used in other fields such as urology, cardiology or radiology.
The test is great for evaluating macular degeneration. The retina is a laminated tissue (it has 3 layers) and abnormalities of all 3 layers can be detected. Macular degeneration is a disease of the middle layer of the retina called the retinal pigment epithelium (the RPE).
It’s a perfect way to diagnose cases of wet macular degeneration and to monitor patients receiving anti-VEGF treatments.
I use this test to differentiate patients with “normal” drusen from patients with drusen who have macular degeneration.
Diabetic retinopathy has characteristic changes of the normal vessels causing macular edema. Abnormal vessels can grow in various parts of the eye in patients with proliferative diabetic retinopathy.
The different manifestations of diabetic retinopathy can all be diagnosed with a fluorescein angiogram.
Other Eye Diseases
There are many other diseases, principally of the retina, where a fluorescein angiogram is helpful including; central serous retinopathy, macular edema, macular dystrophy (e.g. Stargardt’s disease), retinitis pigmentosa to name a few.
What Does This Mean?
Performing an angiogram is a team effort. While it is my practice to personally inject the dye into your arm, many other practices have taught their staff to perform the actual injections.
The most important person in this process is the photographer. There is a true art to taking ophthalmic pictures and, in fact, there is a certification available.
In most offices, only a few people have enough experience to run the camera and larger practices may even have a dedicated ophthalmic photographer!
Ophthalmic photography is a little known, but truly valuable, profession.