Tear Osmolarity as a Sensitive Indicator of Environmental Changes: Investigation of the Effects of Environmental Factors on Dry Eye Disease

초록

Purpose : To investigate the effects of humidity, temperature, and air pollutants on dry eye disease (DED), including changes in tear osmolarity. Methods : A retrospective clinic-based cohort study was conducted on DED patients undergoing dry eye treatment. Symptoms and signs were evaluated by the Symptoms Assessment Questionnaire in Dry Eye (SANDE) score, tear secretion, tear film break-up time (TBUT), ocular staining score (OSS), and tear osmolarity at least three times during follow-up. Environmental factors included humidity, temperature, PM2.5, ozone, and nitrogen dioxide (NO2) concentrations. The mean values of outdoor environmental factors for one week before ocular examinations were used as the environmental exposure level. The relationships between environmental factors and DED clinical parameters were analyzed in single- and multi-environmental factor models. Results : The study included 53 patients with a mean age of 55.1 ± 12.0 years. SANDE score, OSS, and tear osmolarity were significantly lower in high temperature and high humidity conditions compared to low conditions (SANDE score and OSS: each P <0.05, tear osmolarity P ≤0.001). Additionally, tear osmolarity was significantly lower at low NO2 conditions compared to high conditions (P <0.01). In the multi-environmental factor model, SANDE score and tear osmolarity significantly increased as temperature decreased and air pollutant (PM2.5, ozone, and NO2) concentration increased (SANDE score: each P <0.05/ tear osmolarity: each P ≤0.02). Conclusions : Lower temperature and higher air pollutant exposure led to aggravated ocular symptoms and increased tear osmolarity. Tear osmolarity was the most sensitive indicator in changes of several climate and air pollution factors in DED patients.