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N. Yokoi, R. Sakai, S. Kinoshita, Y. Mizukusa, A. J. Bron, J. M. Tiffany, G. A. Georgiev; Possible Factors That Determine Precorneal Tear Film Stability. Invest. Ophthalmol. Vis. Sci. 2010;51(13):5201.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate possible factors that determine precorneal tear film stability.
This study involved one eye from each of 31 subjects (3 males and 28 females; mean age: 53.4 yrs) with different tear volumes [3 normal eyes, 17 symptomatic dry eyes, 2 epiphora eyes due to blockage of the lacrimal system, and 9 eyes with symptoms and a reduced BUT (breakup time) alone] and no meibomian gland dysfunction. Examinations were performed on study eyes in the order of least to most invasive, as follows 1) measurement of the radius (R) of the lower central tear meniscus by meniscometry, 2) measurement of the initial velocity of the tear film lipid layer (TFLL) spread [H’(0), mm/sec.] using a cross-correlation method and the rheological Voigt model, 3) measurement of the elapsed time until the appearance of tear film breakup, i.e., non-invasive BUT (NIBUT, in seconds) with a video-interferometer (DR-1TM; Kowa Co. Ltd., Japan), measurement of fluorescein BUT, 4) summed scores for punctate fluorescein staining of the cornea and conjunctiva [Scores: from 0 (none) to 9 (most severe)], and 5) the Schirmer 1 test. Spearman’s correlation coefficient value was used to find the relationship between each type of examination.
Statistically significant correlations were found in all comparisons [Coefficient values varied from 0.4568 (p=0.0098) on comparing R and H’(0)to 0.8913 (p<0.0001) on comparing NIBUT and H’(0)]. Multiple regression analysis using the Stepwise procedure has shown that NIBUT could be expressed significantly (p<0.0001) by H’(0) and the Scores [NIBUT=3.80 + 0.77 x H’(0) - 0.34 x Scores].
The findings of the present study revealed that precornealtear film stability can be determined by the velocity of TFLL spread and the degree of ocular surface damage.
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