Abstract
Purpose::
The aim was to determine correlations among upper and lower tear menisci, non-invasive tear break-up time and Schirmer’s test in normal people.
Methods::
Thirty-six healthy subjects (16 men and 20 women, mean ± SD age: 45 ± 15 years, ranged from 20 to 70 years) without previously diagnosed dry eye were recruited. A real-time corneal optical coherence tomography (OCT) was used to image upper and lower tear menisci immediately after blinks during normal and delayed blinking sessions. A video monitoring Keeler Tearscope was used to measure non-invasive tear break-up time (NITBUT). A routine Schirmer’s test with topical anaesthetic was also performed. One randomly selected eye of each subject was studied to avoid possible sympathetic reaction between eyes.
Results::
Compared to normal blinking, significant increases of the radius, height and cross-sectional area of upper and lower tear menisci were found during delayed blinking session when the subject was asked to hold the eye open as long as she/he could (ANOVA, P < 0.01, post hoc test, p < 0.01). NITBUT was significantly related to the height (r = 0.36, P = 0.03) and area (r = 0.37, P = 0.03) of lower tear meniscus measured during normal blinks. Schirmer’s test was significantly related to the age (r = -0.47, P = 0.004). The age also was significantly and negatively related to upper tear meniscus (r ranged from 0.36 to 0.37 for the radius, height and area, P < 0.05) measured during delayed blinking session.
Conclusions::
NITBUT appears to relate to lower tear meniscus measured at baseline and the invasive Schirmer’s test may not relate to both tear menisci measured non-invasively. This study was supported by research grants from NEI (R03 EY016420), Bausch & Lomb, Allergan and the Challenging grant from Research to Prevent Blindness (RPB).
Keywords: cornea: tears/tear film/dry eye