Miscellaneous diagnostic dyes 

Miscellaneous diagnostic dyes are administered to a patient to get a visualization of the organ or vessels being studied. The type of vessel or organ being observed determines which dye will be used and the visualization technique that will be employed.

The three dyes typically used in eye care are sodium (NaFl) fluorescein, lissamine green and rose bengal, with fluorescein being the most common. Sodium fluorescein is an orange, water-soluble dye that penetrates damaged corneal epithelial cells.

Various natural or synthetic dyes are used primarily to ensure the appearance and the ability to distinguish the individual drugs. These compounds have different chemical compositions and may interact in differ- ent ways with the human body.

Due to the use of dyes as biological stains, dye therapy was the initial basis for chemotherapy and many modern drugs have dye antecedents. Dyes used in the medical field today may certainly be found as drug colourants, in vital staining, tracing and histopathology, but some also remain as chemotherapeutics.