Abstract
Purpose:
To investigate whether pre-corneal tear film thinning rate is associated with tear film break up time, central corneal staining and osmolarity.
Methods:
Data for this analysis was taken from 363 postmenopausal women with mean age of 62 (± 9.6 yrs). Pre-corneal tear film thinning rate was examined using wavelength-dependent interference as described previously (King-Smith et al, 2000). Fluorescein Tear Break-up Time (TBUT) was measured three times and averaged. Central corneal staining was analyzed using NEI Dry Eye Workshop guidelines (Lemp, 1995) subjectively on a scale of 0 (none) to 3 (severe). Tear osmolarity was measured using Advanced Instruments Tear Osmometer 3100 (Norwood, MA). Pre-corneal tear film thinning rate was compared with tear film break up time, central corneal staining and osmolarity using Spearman’s correlation coefficient. Only right eye readings were used for comparison purposes.
Results:
The mean pre-corneal tear film thinning rate was 3.30 ± 3.96 µm/min, TBUT was 8.02 ± 5.97 seconds and osmolarity was 317.31 ± 21.93. The most frequent central corneal staining grade evaluated was 0. Pre-corneal tear film thinning rate was not significantly correlated with tear film break up time (r=-.078, p=0.14). A non-significant correlation was observed between tear film thinning rate and central corneal staining (r=-0.048, p=0.22), and tear film thinning rate and osmolarity (r=-0.08, p=0.09).
Conclusions:
Tear film thinning rate does not seem to be associated with tear film break up time, central corneal staining and osmolarity in postmenopausal women. This is similar to prior findings that show low correlations between clinical tests of tear physiology.