Low ambient temperature correlates with the severity of dry eye symptoms

PURPOSE: The symptoms of dry eye disease (DED) are influenced by environmental factors, but the effect of ambient temperature is less certain. Our purpose was to investigate the relationship between the severity of DED symptoms and the ambient temperature. MATERIALS AND METHODS: This retrospective study reviewed the symptom scores, including ocular surface disease index (OSDI) and standardized patient evaluation of eye dryness (SPEED), as well as tear film parameters of first-time DED patients between June 2018 and June 2019. The contribution of tear film parameters and environmental factors, including ambient temperature, humidity, wind speed, and the concentration of air pollutants, to the severity of dry eye symptoms was evaluated by univariate and multivariate linear regression analyses. RESULTS: There were 351 patients included aged 52.8 +/- 13.6 years, and 257 (73.2%) were female. The average tear film break-up time, Schirmer test value, and lipid layer thickness were 2.6 +/- 0.7 s, 5.5 +/- 4.3 mm, and 64.1 +/- 6.0 mu m, respectively. The average OSDI and SPEED were 41.8 +/- 19.8 and 12.1 +/- 5.1, respectively. In winter, the patients reported higher OSDI and SPEED. Both scores were significantly correlated with low ambient temperature. Regression analysis showed that low ambient temperature and Schirmer test value contributed to higher OSDI, while low ambient temperature and younger age contributed to higher SPEED. CONCLUSION: Low ambient temperature plays a significant role in DED symptom severity.