What test measures tear flow?

The Schirmer test is specifically designed to measure tear flow and assess the production of tears. It involves placing a small strip of filter paper inside the lower eyelid to capture the amount of tears produced over a specific period, usually five minutes. By quantifying the tear production, healthcare providers can diagnose conditions such as dry eye syndrome or other tear film abnormalities. This test is valuable because it directly correlates with the functionality of the lacrimal glands, which are responsible for tear secretion.

In contrast, the other tests mentioned serve different purposes. The fluorescein test involves the use of a dye to assess the integrity of the corneal epithelium and to detect any corneal abrasions or foreign bodies. Contrast sensitivity testing evaluates a person’s ability to distinguish between different levels of contrast, which is crucial for overall visual function but does not measure tear production. Visually evoked potential testing measures the electrical activity of the brain in response to visual stimuli, providing insights into the visual pathways but again not related to tear flow or production.