As part of the evaluation your retina, you may need a retinal angiography (often called a “dye test”) to study your eye’s blood vessels in microscopic detail. This test is often critical to guide our treatment decisions for many retinal disorders.
The test is most commonly performed by injecting fluorescein dye into a vein in your hand or arm. Fluorescein is an orange dye that glows when exposed to blue light. A few seconds after the injection, the dye travels to your eyes. Because the structures of the eye are transparent, a photographer can take pictures of the blood vessels with a camera. Unlike angiograms in other parts of the body, no X-rays are necessary. The dye may leak or stain areas of your retina in particular patterns. These patterns will help guide us in deciding on the best course of treatment. For example, if you have diabetes, the dye might show leaks in blood vessels that may need treatment with laser or steroids. If you have macular degeneration, blood vessels growing under the retina can be detected and a plan of treatment arranged.
Fluorescein is a safe dye that has been used in hundreds of thousands of tests over decades. However, like any drug, it has potential side effects. It will impart a yellow tinge to the skin for several hours, and, because it is eliminated by your kidneys, it will turn your urine a bright orange color for a day. About 1 in every 25 people will experience transient nausea. One in 100 patients will have a mild allergic reaction and develop some itching, or, in more severe cases, hives. Benadryl may be needed to control these symptoms. Dye that leaks out of the injection site can cause a temporary staining of the skin in that area for a few days, but usually goes away on its own. Very rarely, a serious allergic reaction called anaphylaxis, that can occur with any medication, occurs and requires emergency medical treatment.
For specialized situations, sometimes another dye is used called indocyanine green (ICG). ICG is another water-soluble dye with a long history of safe use in checking the blood flow in the retina with a low incidence of allergic reactions. Because ICG has different characteristics than fluorescein, it can be used to further help define and diagnose retinal disease, especially when the problems lie in the choroid, the layer of blood vessels under the retina.
On the whole, the retinal angiography is one of our most important tests, as it helps not only to diagnose retinal diseases, but also to monitor your response to treatment. This test can be performed at any of our office locations.