Fluorescein is used to help in the diagnosis of a number of eye problems. When applied as a drop or within a strip of paper to the surface of the eye, it is used to help detect eye injuries such as foreign bodies and corneal abrasions.
Tear film works to wash the dye across the animal's cornea. Any areas with corneal injuries will then glow with an easy-to-detect fluorescent green color.
For staining the anterior segment of the eye when fitting contact lenses, in disclosing corneal injury and in applanation tonometry.