A fluorescein dye disappearance test is used in children and adults to find out whether tears are draining normally from the eyes into the nose. Before the test, the eye is numbed with a medicine (topical anesthetic).

• One drop of a special dye (fluorescein) or a paper strip containing the dye is placed between the eyelid and the eye.
• After 10 to 15 minutes, the doctor looks in your eye using a blue light. The light can detect very small amounts of fluorescent dye. The doctor may also use the light to look in your throat and inside your nose.

Normally, tears sweep the dye out of the eye and into the tear ducts. If dye stays in the eye, the tear duct may be blocked.

Both eyes are usually tested and compared during this test, which is done after other exams have not clearly shown that the duct is blocked.

A baby may fuss and cry during this test. Parents are often asked to hold and soothe their child while he or she is being tested.