Fluorescein angiography is a specialized medical imaging technique used primarily in ophthalmology to visualize the blood vessels in the retina and choroid. This procedure involves the intravenous injection of a fluorescent dye, fluorescein, which circulates through the bloodstream and illuminates the blood vessels in the eye when exposed to a specific wavelength of light. It is a critical tool for diagnosing and managing various retinal disorders such as diabetic retinopathy, macular degeneration, and retinal vein occlusion.