Abstract
Purpose: :
To investigate the repeatability of tear meniscus measurements using anterior segment swept source optical coherence tomography (SS-OCT) and the relationship of tear meniscus measurements with tear breakup time (BUT), Schirmer’s test, and vital staining scores.
Methods: :
Thirty right eyes of 30 subjects were enrolled (20 males, 10 females; mean age 34.5±5.3years) in this study. Examinations were conducted in the following sequence; anterior segment vertical raster scans by SS-OCT, vital staining scores, BUT, and Schirmer’s test. Each subject underwent SS-OCT measurements twice on a different day by the same grader, and the central upper and lower tear menisci height (TMH), area (TMA), and the lower tear meniscus volume (TMV) were examined. Each OCT image was evaluated by two masked graders using the software calipers. On each image within the range of 3mm to 12mm, outlines of the lower tear meniscus area were plotted manually, and then TMV was automatically computed by integration analysis based on the computer program.
Results: :
The average upper TMH and lower TMH were 225.06±85.71µm and 253.77±57.49µm, respectively, and the average upper TMA and lower TMA were 17642±7904µm2 and 21144±7732µm2, respectively. The average TMV was 0.1338±0.052mm3. The between-image intraclass correlations (ICC) for all the parameters were over 98%, and the between-grader ICCs were over 95%. The between-visits coefficients of variation for upper TMH, lower TMH, upper TMA, lower TMA, and TMV were 9.87%, 6.26%, 15.98%, 15.79%, and 15.20%, respectively. A significant correlation between the OCT tear meniscus measurements and the Shirmer test was found (p<0.05, Spearman’s nonparametric correlation analysis). Vital staining scores were not significantly related to any parameters of the tear menisci (p>0.05).
Conclusions: :
SS-OCT demonstrated good between-grader and between-image repeatability in tear meniscus measurements. SS-OCT is a noninvasive and practical method for quantitative evaluation of tear fluid.
Keywords: cornea: tears/tear film/dry eye