Fluorescein is widely used in ophthalmology as a diagnostic tool to detect eye injuries and abnormalities. It is applied as a dye to highlight corneal abrasions, ulcers, and foreign bodies, making them visible under a blue light. In angiography, it is injected intravenously to examine blood flow in the retina and choroid, aiding in the diagnosis of conditions like diabetic retinopathy and macular degeneration. Additionally, fluorescein is employed in environmental studies to trace water flow and detect leaks in plumbing systems due to its strong fluorescence under UV light. In forensic science, it is used to reveal latent bloodstains at crime scenes. Its versatility and vivid fluorescence make it a valuable compound across medical, environmental, and investigative fields.