FLUORESCEIN SODIUM (OPHTHALMIC)

Indications/Pharmacology

Fluorescein sodium is a yellow water soluble dye. It is used mostcommonly to delineate full thickness loss of corneal epithelium. In this instance it will stain the cornealstroma. The epithelium is not stained because its outer lipid cell membrane repels the stain. Descemet'smembrane will not stain with fluorescein stain and this is used to indicate descemetocele formation, anocular emergency.
Fluorescein stain is applied to the precorneal tear film in dogs and cats and the break-up of this stainwith time, as observed through a slit lamp biomicroscope using a cobalt blue light source, is used todetermine the tear film break-up time (normal 19s), an indicator of tear film quality.
Fluorescein stain is applied to the tear film of dogs to determine patency of the nasolacrimal outflowsystem. The normal wait time is 2-5 minutes in dogs and up to 10 minutes in cats. A positive testindicates patency of the system. A negative test is not indicative of disease as the test is negative in alarge percentage of normal animals. Fluorescein stain, then, can be added to irrigating solution to flushthe nasolacrimal system, making detecting the irrigation solution at the nose more obvious duringflushing of the system.Suggested Dosages/Precautions/Adverse Effects - Fluorescein stain is applied by dropping a drop ofirrigating solution onto the sterile strip and then allowing the drop to fall on the eye. The strip should notcontact the cornea or it will cause false positive stain retention at the site of contact with the epithelialcells. After a few seconds, the excess fluorescein is irrigated from the eye, staining areas of full thicknessepithelial loss.
Conjunctival or corneal epithelial cells for fluorescent antibody testing should be collected prior toapplication of fluorescein stain, which can cause a false positive test for several days after application ofthe stain.
Fluorescein may rarely cause hypersensitivity reactions. Temporary staining of fur and skin may result.
Do not use during intraocular surgery.Dosage Forms/Preparations/FDA Approval Status - Veterinary-Approved Products: None
Human-Approved Products: Sterile strips of paper impregnated with fluorescein sodium are themost commonly used form in veterinary medicine. Solutions (2%) of fluorescein are available, however they are not popular following one study indicating that Pseudomonas is readily grown insuch solutions. Injectable products are also available (for ophthalmic angiography), but are notroutinely used in veterinary medicine.
Fluorescein Sodium Strips 0.6 mg Ful-Glo® (Barnes Hind); 1 mg Fluorets® (Akorn), Fluor-I-Strip®-A.T. (W-A); 9 mg Fluor-I-Strip® (W-A); All Rx.