Schirmer's test determines whether the eye produces enough tears to keep it moist.

The health care provider will place paper strips under the eyelid, usually the bottom one. Both eyes are tested at the same time. Before the test, you may be given numbing eye drops to prevent your eyes from tearing due to irritation from the paper.

The exact procedure may vary somewhat. Most often, the eyes are closed for about 5 minutes. Close the eyes gently. Tight closing of the eyes or rubbing the eyes during the test can cause abnormal test results.

After 5 minutes, the doctor removes the paper and measures how moist it is.

Remove contact lenses before the test.

Some people find that holding the paper against the eye is irritating or mildly uncomfortable.

This test is used when a person experiences very dry eyes or excessive watering of the eyes.

More than 10 mm of moisture on the filter paper in 5 minutes is normal. Both eyes normally secrete the same amount of tears.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Dry eyes may result from:

• Aging
• Climate changes
• Corneal ulcers and infections
• Eye infections (for example, conjunctivitis)
• Previous eyelid or facial surgery
• Sjogren syndrome
• Tearing problems due to disorders such as lymphoma, leukemia, and rheumatoid arthritis
• Vitamin A deficiency

The inability of tears to drain into the nose can occur with:

• Blockage of the tear duct
• Some eye infections

There are no risks with this test.

Do not rub the eyes for at least 30 minutes after the test. Contact lenses should be left out for at least 2 hours after the test.

Even though Schirmer's test has been available for more than 100 years, several studies show that it does not properly identify a large group of patients with dry eyes. Newer and better tests are being developed. One test measures a molecule called lactoferrin. Patients with low tear production and dry eyes have low levels of this molecule.

Another test involves fluorescein eye drops, which contain a dye that is placed in the eye. Tears should flush the dye into the nose within 2 minutes. It will take longer in people with dry eyes.

Foulks GN. Treatment of dry eye disease by the non-Ophthalmologist. Rheum Dis Clin N Am. 2008;34:987-1000.

Dobie RA. Tests of facial nerve function. In: Cummings CW, Flint PW, Haughey BH, Robbins KT, Thomas JR, eds. Otolaryngology: Head & Neck Surgery. 4th ed. Philadelphia, Pa: Mosby Elsevier; 2005: chap 146.

Hurwitz JJ. The lacrimal drainage system. In: Yanoff M, Duker JS, Augsburger JJ, Azar DT, eds. Ophthalmology. 2nd ed. Philadelphia, Pa: Mosby Elsevier; 2004: chap 98.