Minims® Fluorescein sodium contains a diagnostic agent. The active substance, fluorescein sodium, is a temporary dye used to help your doctor or eye specialist to examine your eye. Scratches on the conjunctiva (the lining of the inside of the eyelids and part of the eye) are stained yellow or orange by fluorescein. Damages to the cornea (the transparent membrane covering the surface of the eye) are stained green. Any foreign bodies which are stuck in your eye are surrounded by a green ring.