1821
Determines whether the eye produces enough tears to keep it moist.
A negative test result is normal if there is more than 10 mm of moisture on filter paper in 5 minutes
Both eyes normally secrete the same amount of tears.
The test uses paper strips inserted into the eye for several minutes to measure tear production.
Both eyes are tested at the same time.
A small strip of filter paper is placed inside the lower eyelid and the eyes are closed for 5 minutes.
The paper is removed and the amount of moisture is measured.
A topical anesthetic may be placed into the eye before the filter paper to prevent tearing due to the irritation from the paper, ensuring that only basal tear secretion is being measured.
The Schirmer’s test measures basic tear function.
A normal young individual moistens 15 mm of each paper strip.
33% of normal elderly persons may wet only 10 mm in 5 minutes.
Persons with Sjogren’s syndrome moisten less than 5 mm in 5 minutes.
The Schirmer test has a sensitivity of 42% and a specificity of 76% for Sjogren syndrome.
Schirmer’s test analysis:
1. Normal which is 15 mm wetting of the paper after 5 minutes.
2. Mild which is 14-9 mm wetting of the paper after 5 minutes.
3. Moderate which is 8-4 mm wetting of the paper after 5 minutes.
4. Severe which is <4 mm wetting of the paper after 5 minutes.
Persons older than 40 years may moisten between 10 mm and 15 mm.
The test does not identify many patients with dry eyes, and better tests of tear production and function are available.
An iron-binding molecule lactoferrin is related to tear production so patients with low tear production and dry eyes have low levels of this molecule.
Tears may be examined for their content of lysozyme, an enzyme normally found in tears.
Fluorescein eye drops drain with tears through the lacrimal duct into the nose within 2 minutes and if patients do not have enough tears to flush the dye into the nose, this time will be longer.