Reliability of the drop test for the lacrimal drainage function.

PURPOSE

The purpose of this study was to investigate the reliability of the drop test.

METHODS

The repeatability of the test was studied with the same and three different examiners. The influence of the blink rate was investigated by recording the blink frequency in 63 subjects. The degree of reflex lacrimation during the test was assessed in ten patients. The effect of different test solutions was investigated in ten test subjects.

RESULTS

There was no significant difference when the test was repeated either by the same or different examiners. The reflex lacrimation during the drop test was not significant. There was no correlation between drop test result and blink rate. A moderate increase in the viscosity of the test solution affected the lacrimal drainage.

CONCLUSION

The drop test is a reliable test for the lacrimal drainage function.