Modeling of evaporation and accumulation of tears for predicting sensation of dryness at eyes

Abstract

In order to clarify the lower limit of humidity for human environment, it is necessary to find the relationship between moisture content at the human body surface and sensation of dryness. In this paper, for the purpose of explain the trend of the vote of sensation of dryness obtained in the experiment under the exposure to low humidity, the numerical model of tear volume was developed based on moisture evaporation model already proposed by the authors. Firstly, the measured values of the ocular surface temperature under low humidity conditions were compared with calculated values, and it was shown that consideration of the fluctuation in the physiological elements such as stability of oil layer of tear during exposure to low humidity was necessary in order to reproduce the measured values. Secondly, the calculated tear volume based on the current model did not show sufficient agreement with the trend of the sensation of dryness at the eye during the exposure to low humidity.