Schirmer’s test is a diagnostic procedure used to evaluate the eyes’ ability to produce tears. Its primary function is to assess the rate of tear secretion, providing insights into the overall health of the tear film.
Purpose of the Test
Doctors often recommend Schirmer’s test when a patient experiences symptoms suggestive of insufficient tear production. It serves as a diagnostic tool for conditions like Dry Eye Syndrome, which occurs when tear glands do not produce enough tears to maintain eye moisture. The test also aids in identifying autoimmune disorders, such as Sjögren’s syndrome, where the body’s immune system mistakenly attacks moisture-producing glands, including those in the eyes. Patients might report common symptoms such as a gritty sensation, persistent itching, burning, stinging, or redness in the eyes.
The Test Procedure
Before the Schirmer’s test begins, individuals are typically advised to remove contact lenses if they wear them. The procedure involves placing a small, standardized strip of filter paper into each eye. The bent end of the strip is gently inserted into the lower eyelid, resting between the palpebral conjunctiva of the lower lid and the bulbar conjunctiva of the eye itself. Patients are then instructed to gently close their eyes for five minutes, avoiding any squeezing or rubbing that could influence the results.
Anesthetic eye drops may or may not be administered prior to the test, depending on what the doctor intends to measure. If no anesthetic is used, the test measures total tear secretion, which includes both basal (resting) and reflex (stimulated) tearing. Conversely, if an anesthetic is applied, only the basal tear secretion is measured, as the anesthetic numbs the eye and prevents reflex tearing caused by the paper strip’s presence. After five minutes, the strips are carefully removed.
Interpreting Test Results
After removal, the results of the Schirmer’s test are interpreted by measuring the length of the moistened area on each filter paper strip in millimeters (mm). A normal result typically indicates that more than 10 millimeters of the strip have become wet within the five-minute timeframe. Some practitioners consider more than 15 mm without anesthesia or about 10 mm with anesthesia as normal.
A measurement between 5 mm and 10 mm may suggest a mild or borderline case of dry eye, indicating some level of tear deficiency. Results showing less than 5 mm of moisture in five minutes are generally considered indicative of severe dry eye, pointing to significantly reduced tear production. The doctor will combine these findings with other clinical observations and the patient’s reported symptoms to arrive at a comprehensive diagnosis and determine appropriate next steps, which may include recommendations for managing dry eye symptoms.