What is the duration of the Schirmer's test for measuring tear production?

The Schirmer's test is a diagnostic procedure used to evaluate tear production by measuring the wetting of a standardized strip of filter paper placed in the lower conjunctival sac. The correct duration for this test is 5 minutes. This time allows for an adequate measurement of the amount of tear fluid produced under normal or stimulated conditions. During this 5-minute interval, clinicians are able to assess the patient's tear production capacity effectively.

Shorter durations might not provide enough data to accurately reflect tear production levels, while longer durations could lead to unnecessary discomfort for the patient and do not contribute significant additional information. Thus, 5 minutes is the established standard duration for the Schirmer's test.