What’s that yellow stuff you’re putting in my eye…

What’s that yellow stuff you’re putting in my eye…

sodium fluorecein staining

The “yellow stuff” is called sodium fluorescein and is used to evaluate the cornea.  I often use sodium fluorescein during an eye exam, most commonly to check for dry eyes or corneal abrasions.  Patients are usually curious why making their tears look yellow and shining a blue light into their eyes helps me assess their eye health.

Sodium fluorescein is a water soluble dye that appears yellow once applied in the eye.  The dye usually comes on a sterile strip of blotting paper, but can also be found in the form of a drop.  The sodium fluorescein “fluoresces” or “glows” and appears green under cobalt blue illumination.  The dye stains damaged cells on the cornea, highlighting the problem areas.  The yellow dye will eventually get washed out by your own natural tears, or your eye doctor may choose to rinse it out of your eyes, especially if you will be wearing contacts shortly afterwards.

A normal result is if the dye remains on the tear film without ‘staining’ the corneal epithelium.  Abnormal results will be interpreted by your eye doctor.  This test can detect corneal abrasions, foreign bodies, injuries/trauma, infection, poorly fit hard contact lenses… to name a few.


Dr. Jessica Chang, OD


Vancouver Kerrisdale Optometrist

Contact Avenue Eyecare to book your appointment today.