Fundus fluorescein angiography (FFA)
Fundus fluorescein angiography (FFA) is the study of retinal blood circulation and integrity of blood retinal barriers. In this investigation Sodium Fluorescein, a dark yellow colored dye, with property to absorb blue light and emits yellow green light, is injected in ante cubital vein and the serial photograph of retina is taken with time upto 10-15 minutes. If there is breach in blood retinal barrier there is leakage of dye which reflects as Hyperfluorescence. Hypofluorescence occurs when either there is blockade of normal fluorescence by something like pigment, blood, or there is obstruction in retinal circulation the dye does not pass into the circulation.
Eligibility criteria of patients for FFA: Although FFA is safe but patients should have normal kidney function test & cardiac status before the test. So, normal Serum Creatinine and ECG reports are necessary. Some patients may feel nausea during the test, so pre-test fasting of 4 hours is required.
Side effects & contraindications: These tests are considered safe for most patients, although it is possible to have a reaction to the dye and develop itching, nausea and a rash. These symptoms can usually be managed through oral medication if severe. Severe allergic reaction may lead to hypotension, shock or anaphylaxis. In addition, patients who receive fluorescein injections can expect that their urine will appear bright yellow-orange for the first twenty four hours after the test.