The Schirmer test is a well-established clinical procedure performed to help diagnose chronic dry eye disorders, such as Sjogren's syndrome. The test involves inserting a strip of filter paper between the eyeball and the lower eyelid for several minutes to collect natural tears. Based on the amount of moisture absorbed, a doctor can determine the severity of dryness. The procedure usually takes about ten minutes to complete and can be performed in an optometrist's office, an ophthalmology center, a hospital, or a specialty lab.
A patient who is scheduled for a Schirmer test is usually instructed to avoid using eye drops and wearing contact lenses on the day of the exam to make sure that findings will be accurate. During the procedure, a small, thin strip of sterile filter paper is inserted in the lower eyelid. The patient is then instructed to gently keep his or her eyes closed for at least five minutes. Anesthetic eye drops may be applied if the test causes discomfort or irritation. The paper is removed after the allotted time so the eye doctor can evaluate how much moisture was collected.
Assessing the results of a Schirmer test is not an exact science, but most doctors agree that if the moist spot is less than about 0.4 inches (about 1 centimeter) in diameter, there is reason to conclude that a dry eye condition may exist. If the spot is larger, tear secretion is considered normal and other causes of a patient's symptoms must be considered. Not all clinics and optometrists agree on the threshold between normal and abnormal readings, so a person may be declared healthy even if the Schirmer test shows a smaller than average moisture spread. In addition, value ranges may be adjusted according to a patient's age. People over the age of 60, for instance, generally have less tear production than younger people without reason for concern.
By itself, a Schirmer test is not sufficient to make a clinical diagnosis. Dry eye symptoms can be caused by a number of different factors, and the test simply indicates whether further investigation is necessary. Before performing the test, a doctor usually asks about medication use, any known allergies, familial history of dry eye, and the length of time a patient has been experiencing symptoms. If a Schirmer test suggests the possibility of Sjogren's syndrome, a tissue sample may need to be collected from the tear duct and analyzed to confirm the diagnosis.