• The height of the inferior tear meniscus was measured in 86 normal eyes. A value greater than 0.1 mm was obtained in 93% of the eyes that were studied. However, attempts to correlate meniscus height with subsequent Schirmer test results showed that these measurements varied randomly. Schirmer tests that were conducted on 265 eyes without instillation of 0.5% proparacaine hydrochloride and on 466 eyes with proparacaine showed that topical anesthesia reduced mean test values by 40%. When proparacaine was used prior to testing, no decrease in tear production with advancing age was demonstrated, nor were results significantly different in males and females. Schirmer test values, ranging from 0 to 3 mm, were obtained in 15% of the normal volunteers when the test was performed after instillation of topical anesthesia and after blotting of the tear lake from the inferior cul-de-sac.
Lamberts DW, Foster CS, Perry HD. Schirmer Test After Topical Anesthesia and the Tear Meniscus Height in Normal Eyes. Arch Ophthalmol. 1979;97(6):1082-1085. doi:10.1001/archopht.1979.01020010536004