Fluorescein is a synthetic organic compound that emits bright green fluorescence when exposed to ultraviolet light. It is commonly used as a dye in various applications, including biological research, medical diagnostics, and environmental monitoring. In medicine, fluorescein is often used in eye examinations to detect corneal abrasions and other eye conditions. In addition to its medical uses, fluorescein is also employed in water tracing studies to track the movement of water in natural and engineered systems. Its ability to fluoresce makes it a valuable tool in both laboratory and field settings for visualizing and analyzing various processes.