| Schirmer's test | |
| Purpose: | assess tear production |
Schirmer's test determines whether the eye produces enough tears to keep it moist. This test is used when a person experiences very dry eyes or excessive watering of the eyes. It can cause damage to the cornea.[1] A negative (more than 10 mm of moisture on the filter paper in 5 minutes) test result is normal. Both eyes normally secrete the same amount of tears.
It is named for Otto Schirmer.[2]
The test works by the principle of capillary action, which allows the water in tears to travel along the length of a paper test strip in an identical fashion as a horizontal capillary tube. The rate of travel along the test strip is proportional to the rate of tear production. The patient is instructed to look upward, and the patient’s eyelid is pulled down. The bent end of the test strip is placed in the eye such that it rests between the palpebral conjunctiva of the lower eyelid and the bulbar conjunctiva of the eye.Schirmer's test uses paper strips inserted into the eye for several minutes to measure the production of tears. Both eyes are tested at the same time. Most often, this test consists of placing a small strip of filter paper inside the lower eyelid (inferior fornix). The eyes are closed for 5 minutes. The paper is then removed and the amount of moisture is measured. After five minutes, the patient is asked to open both eyes and look upward so the test strips may be removed. The Schirmer test score is determined by the length of the moistened area of the strips (using the scale packaged with the strips) The use of the anesthetic ensures that only basal tear secretion is being measured.[3]
A young person normally moistens 15 mm of each paper strip. Because hypolacrimation occurs with aging, 33% of normal elderly persons may wet only 10 mm in 5 minutes. Persons with Sjögren's syndrome moisten less than 5 mm in 5 minutes.
How to read results of the Schirmer's test:
1. Normal which is ≥10 mm wetting of the paper after 5 minutes.[3]
2. Tear deficiency which is <5 mm wetting of the paper after 5 minutes.[3]
Even though this test has been available for over a century, several clinical studies have shown that it does not properly identify a large group of patients with dry eyes. Newer and better tests of tear production and function are now emerging.
Dry eyes can occur from conditions such as:[4]
The inability of tears to drain into the nose can occur with:
