Repeatability of keratometry depending on tear film osmolarity.

PURPOSE: To determine the repeatability of keratometry and astigmatism measurements of patients depending on the tear film osmolarity using three different devices.

METHODS

In this study, 97 eyes of 97 patients with a mean age of 64.92 ± 12.07 years received three repeated measurements with the IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany), Pentacam AXL (Oculus Optikgeräte GmbH, Wetzlar, Germany) and Galilei G6 (Ziemer Ophthalmic Systems, Port, Switzerland). After that, tear film osmolarity was obtained with the TearLab Osmolarity System (TearLab Corporation, San Diego, CA, USA) for quantification of dry eye disease. Four groups were formed depending on tear film osmolarity: group 1 (<300 mOsm/L), group 2 (300-310 mOsm/L), group 3 (311-320 mOsm/L) and group 4 (>320 mOsm/L). Intraclass correlation coefficient (ICC) and vector analysis were calculated to assess the repeatability of keratometry and astigmatism measurements.

RESULTS

ICC values for keratometry were 0.957 or higher in all osmolarity groups. Highest ICC values for astigmatism were in group 1 with the Pentacam (0.986) and in group 2 (0.979), group 3 (0.951) and group 4 (0.950) with the IOL-Master 700 respectively. Highest astigmatism ICC value for the Galilei G6 was 0.884 in group 4 and the lowest in group 3 (0.405). Vector analysis of astigmatism showed no statistically significant difference between the osmolarity groups and IOL-Master 700 (p = 0.947), Pentacam (p = 0.353) and Galilei G6 (p = 0.660).

CONCLUSION

Tear film osmolarity showed no consistent association with the repeatability of keratometry or astigmatism measurements for the IOLMaster 700 and Pentacam AXL whereas the Galilei G6 demonstrated lower repeatability overall.