Evaluation of tear volume is essential for diagnosing dry eye disease. At the clinical site, dedicated devices such as slit lamp microscopy or Schirmer’s strip have been used to quantify tear volume. However, these devices have access only in medical office and therefore have limited availability for the public. Tear volume changes with environmental, physical or psychological situation such as room temperature, mental stresses or biorhythm. For that reason, measurement of tear volume in the daily life can be beneficial for efficient treatment and prevention of dry eye. In this study, a tear volume measurement system based on the principle of meniscometry was developed and implemented on the smartphone. Then, diurnal tear volume variation during the daily life was measured by this system. The result showed that tear volume significantly decreased from morning to evening as in the previous study (p<.05). This suggests that the smartphone-based measurement system can be useful for measuring tear volume in the daily life.
