Measurement of Precorneal Tear Film Using Scheimpflug Camera and Relationship with Parameters for Dry Eye

ABSTRACT

PURPOSE: To compare the anterior segment parameters including precorneal tear film thickness (PTFT) using Pentacam(R) (Oculus, Wetzlar, Germany) between normal control and dry eye groups and to examine the relationships between the PTFT and other parameters for dry eye. METHODS: The present study included 23 normal controls (31 eyes) and 25 patients with dry eyes (31 eyes). We compared measurements including PTFT, corneal thickness and astigmatism using Pentacam(R) and analyzed the correlations among the PTFT and fluorescein tear break-up time (FBUT), Schirmer I test (without anesthesia), and ocular surface disease index (OSDI). RESULTS: The mean PTFT in dry eyes (21.1 +/- 2.0 microm) was significantly thinner than in normal eyes (37.6 +/- 2.0 microm; p < 0.01). In the dry eye group, the corneal thickness was thicker than in the normal eye group but there were no clinically significant differences. The dry eye group experienced more frequent and severe corneal astigmatism compared with the normal group. OSDI scores showed a weak negative correlation with objective clinical measures of dry eye (FBUT, Schirmer I test) but was not statistically significant. However, OSDI was statistically significantly negatively correlated with PTFT (r = -0.46, p < 0.01). The PTFT showed a weak positive correlation with FBUT and Schirmer I test without statistical significance. CONCLUSIONS: The mean PTFT using Pentacam(R) in the dry eye group was thinner than in the normal group. Additionally, the PTFT was correlated with subjective symptoms. Therefore, the PTFT measurement using Pentacam(R) could be considered a useful method for diagnosis and treatment of dry eye.