Widely used in medical diagnostics, especially in ophthalmology for fluorescein angiography to visualize blood flow in the retina and detect abnormalities such as macular degeneration or diabetic retinopathy. Commonly employed in flow visualization and leak detection in industrial systems due to its bright fluorescence under UV or blue light, making it easy to trace fluid movement in pipelines or cooling systems. Used in environmental studies to track water movement, study groundwater flow, and detect surface water contamination or seepage in rivers and lakes. Applied in biological research as a fluorescent tracer to monitor cell permeability, label biomolecules, and perform viability assays. Found in some cosmetic products and tattoo inks for its vivid color, though limited due to potential sensitivity in some individuals.