Which test measures tear flow?

The Schirmer test is specifically designed to measure tear production and evaluate the tear flow in the eyes. It involves placing a small strip of filter paper under the lower eyelid and measuring the amount of moisture that the paper absorbs over a specified period of time, typically five minutes. This test is crucial for diagnosing conditions related to dry eyes or other tear deficiency problems.

The other options pertain to different evaluations: the Schiotz tonometer is used for measuring intraocular pressure, the Streit test focuses on visual fields, and the Snellen chart is utilized for assessing visual acuity. None of these options are related to measuring tear production, making the Schirmer test the appropriate choice for this particular assessment.