A simple approach to the repeatability of the Schirmer test without anesthesia: eyes open or closed?

Purpose: To compare the repeatability of the Schirmer test (ST) administered with the eyes open (STo) with the repeatability of the ST administered with the eyes closed (STc).

Methods: STo and STc without anesthesia were alternately applied with 1-day intervals for a total of 6 times on 28 eyes of 14 healthy volunteers. The intraclass correlation coefficients (ICCs) and their 95% confidence intervals (CIs) were calculated to assess test-retest reliability of the STo and STc.

Results: STc scores were found to be statistically lower than the STo scores in general (right eyes: t = 2.033, P = 0.048; left eyes: t = 3.474, P = 0.004). The ICC was 0.632 (right eyes) and 0.618 (left eyes) for STo and 0.943 (right eyes) and 0.933 (left eyes) for STc.

Conclusions: Our study suggests that administering the ST with the patient's eyes closed produces less variable results and more repeatability than STo in normal subjects. Although our results may not extend to dry eye patient populations, we propose that STc without anesthesia can be considered by those ophthalmologists who frequently use the ST as an adjunct to the differential diagnosis of dry eye in patients presenting with ocular discomfort, making ST a more reliable test in everyday practice.