Ophthalmic Photography
What is an Angiogram?
The fluorescein angiogram (FA) is a study of the retinal blood circulation on the inside back of the eye. Since some eye diseases affect these retinal blood vessels, the dye helps us to diagnose vision loss that may be due to these irregularities. Dye is injected into a suitable vein in the arm. It travels to the eye in about 15 seconds, and photographs are taken about once a second, for about one minute, to document how this dye enters the different vessels. Usually, photographs are then taken about 10-15 minutes later, depending on the specific disease, in order to show staining that may indicate leaks or swelling on the retina.
The Indocyanine Green Angiogram (ICG-A) procedure is similar. Your eye condition may indicate the need for this additional procedure if the leakage is suspected to involve the choroid (the area behind the retina), or if the source of the leak is obscured by hemorrhage on the retina. The patient will receive both the fluorescein dyes and the ICG dyes in succession. Side effects from ICG are even more unlikely than fluorescein sodium; however, patients known to have an iodine or shellfish allergy, or those with a history of liver disease, should advise their doctor.
We use state-of-the-art digital cameras, and are able to provide instant results of your FA or ICG-A. If necessary, some digital techniques enable us to locate trouble spots more effectively than traditional film methods.
Side Effects:
The dye is a relatively simple solution, and rarely does it cause any side effects. About 5% of patients may feel some transient nausea for a few seconds during the initial phase. Less than 5% may have an allergic reaction which usually produces a slight skin rash. Most rashes clear up on their own within 10 minutes. Those few patients who continue with a more extensive rash can be treated effectively with diphenhydramine (Benadryl).
Other minor side effects are that the dye will usually discolor the skin and give it a "suntan" appearance for about 24 hours. Since the dye is processed through the kidneys, the patient's urine will also be a very bright yellow for 24 hours.
What to Expect:
The FA procedure takes about twenty minutes; the ICG-A procedure takes longer, about 45 minutes. Patients should wear loose fitting clothing to aid us in finding a suitable injection site in the arm. Depending on their condition, some patients are expected to wait for follow-up advice and/or procedures from their doctor. Some patients may leave directly afterwards, as sometimes follow-up treatment is more appropriate at a later date.
It is well-advised that patients plan to have someone else drive them home afterwards. These dye tests do not in themselves create a short-term visual problem; however, your eyes will probably be dilated for several hours after you leave, and will make driving difficult, if not dangerous, for most people.
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