Low ambient temperature correlates with the severity of dry eye symptoms

A Comprehensive Analysis of the Influence of Temperature and Humidity on Dry Eye Disease

PURPOSE

To investigate the effects of humidity and temperature on dry eye disease (DED).

METHODS

A retrospective, clinic-based study was conducted on DED patients undergoing dry eye treatment. Patients were followed up at least twice, and symptoms and signs were evaluated using the Symptoms Assessment Questionnaire in Dry Eye (SANDE) score, tear secretion, tear film breakup time (TBUT), ocular staining score, and tear osmolarity. Mean humidity and temperature values for 1 week before ocular examinations were used as the environmental exposure level. The relationship between humidity and temperature, with DED clinical parameters was analyzed in single- and multi-environmental factor models.

RESULTS

The study included 33 patients with a mean age of 53.9 ± 12.2 years. The low humidity group showed significantly higher SANDE scores (p = 0.023) and tear osmolarity (p = 0.008), and the low temperature group had higher SANDE scores (p = 0.004), ocular staining scores (p = 0.036), and tear osmolarity (p < 0.001). In the linear mixed model, single factor analysis showed that an increase in humidity resulted in decreased SANDE scores (p = 0.043), and an increase in temperature led to a decrease in SANDE score (p = 0.007), ocular staining score (p = 0.007), and tear osmolarity (p = 0.012). In the multifactor analysis, changes in humidity had no significant effect on dry eye parameters, but an increase in temperature was significantly correlated with decreased SANDE score (p = 0.026), ocular staining score (p = 0.024), and tear osmolarity (p = 0.002).

CONCLUSIONS

Lower temperature led to aggravated symptoms and signs of DED and the effect of temperature on DED was more pronounced than humidity. Tear osmolarity was the most sensitive clinical parameter to be affected by climate factors in DED patients.

Short-term effect of meteorological factors and extreme weather events on daily outpatient visits for dry eye disease between 2013 and 2020: a time-series study in Urumqi, China

Dry eye disease (DED) is a common disorder of tear secretion on the ocular surface caused by multiple factors with dry eyes as the main symptom, but until now studies focusing on relationship between local meteorological factors and ocular surface diseases in Urumqi are very limited. Besides, the effects of long-term and extreme meteorological factors on DED and the lag effect have not been fully evaluated. Electronic case information of 9970 DED outpatients from the Ophthalmology Department of the First Affiliated Hospital of Xinjiang Medical University (Urumqi, Xinjiang, China) between January 1, 2013, and December 31, 2020, was screened and analyzed. We used a time-series analysis design and a quasi-Poisson generalized linear regression model combined with a distributed lagged nonlinear model (DLNM) to fit the effects of exposure to different meteorological factors and extreme weather on DED outpatient visits. Subgroup analyses were further performed for gender, age, and season. The results showed that exposure to extremely low mean temperature (P1:RR = 1.18), atmospheric pressure (P1:RR = 1.11), and extremely high relative humidity (P99:RR = 1.35) were the risk factors, while extremely high atmospheric pressure (P90:RR = 0.883) and extremely low humidity (P10:RR = 0.856) appeared to have a positive effect on reduced risk of DED. Relative humidity exhibited a 1-day lag effect (RR = 1.06). Increased mean temperature positively affected female DED patients (RR = 0.761) with similar effects in the cold season (RR = 0.926). However, elevated relative humidity had a negative effect on female patients (RR = 1.14). We conducted the first large sample size time-series analysis study in this major city at the farthest distance from the ocean in the world and in northwest China, confirming the association of DED outpatient visits with the remaining three meteorological factors except wind speed in Urumqi, and a larger sample size multi-center epidemiological study with a longer duration is still needed.

The environment and dry eye-manifestations, mechanisms, and more

Dry eye disease (DED) is a multifactorial condition that often presents with chronic symptoms of pain (that can be characterized as "dryness," "burning," and "irritation," to name a few) and/or fluctuating or poor-quality vision. Given its multifactorial nature, several pathophysiologic mechanisms have been identified that can underlie symptoms, including tear film, ocular surface, and/or corneal somatosensory nerve abnormalities. Research has focused on understanding how environmental exposures can increase the risk for DED flares and negatively impact the tear film, the ocular surface, and/or nerve health. Given that DED is a common condition that negatively impacts physical and mental functioning, managing DED requires multiple strategies. These can include both medical approaches and modulating adverse environmental conditions, the latter of which may be a cost-effective way to avoid DED flares. Thus, an understanding of how environmental exposures relate to disease is important. This Review summarizes research on the relationships between environmental exposures and DED, in the hope that this information will engage healthcare professionals and patients to consider environmental manipulations in their management of DED.