A recent study described the distribution of tear fluid quantity by Schirmer test (ST) and found an association between ST measures and topical and systemic medication use among numerous other variables.

This prospective observational study assessed ST under topical anesthesia for five minutes (ST-5) and three minutes (ST-3) in a cohort of 1,999 participants. The team recorded various ocular metrics, plus history of systemic diseases and systemic or eye medication use, and analyzed their influence on ST measurements.

The researchers found the length of wetting of the Schirmer strips for ST-5 and ST-3 to be 23.2±9.31mm OD and 22.9±9.00mm OS and 20.0mm OD and 19.1mm OS, respectively. They noted that the clinical cutoff of 10.0mm for ST-5 corresponded with an 8.0mm cutoff for ST-3.

The investigators added that smaller ST-5 measures were associated with male sex, older age, socioeconomic status, season, prostaglandins, topical beta-blockers, oral NSAIDs, peptic ulcer disease drugs, gastroesophageal reflux disease drugs, thyroid hormones, progesterone and estrogen combination drugs, hypnotics and sedatives. They were not, however, linked to diabetes or smoking.