Feasibility Study of Smartphone-Based Tear Volume Measurement System

Evaluation of tear volume is important for diagnosing dry eye disease. At the clinical site, dedicated devices such as slit lamp microscopy or Schirmer’s test strip have been used to quantify tear volume by ophthalmologist. 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. For that reason, measurement of tear volume regardless of location, time or circumstances can be beneficial. In this study, a tear volume measurement system based on the principle of meniscometry was developed and implemented on the smartphone, and its feasibility was evaluated. It was shown that tear meniscus radii of 22 human subjects were calculated to be mean 0.31 (SD 0.06) mm which was within the range of the previous study. The results suggested the feasibility of tear volume measurement system using the smartphone based on the principle of meniscometry as an IoT sensor.