Flourescein is a dye that is injected into a vein in the arm. This dye travels to the blood vessels in the eye allowing Dr. Campbell to study the blood vessels behind the eye. A special digital camera with filters highlight the dye and a series of photos are taken as the flourescein works through the blood vessels. The dye highlights abnormal blood vessel formation, any areas of ischemia, swelling, or leakage. This makes it very easy to diagnose and treat retinal disease.