Relative Humidity Affects Dry Eye Disease Prevalence

Relative humidity (<70%) may be associated with an increase in dry eye disease (DED) prevalence, according to a study published in Contact Lens and Anterior Eye. This finding suggests that climate databases should be included in DED research. 

Researchers enrolled 1033 individuals (mean age, 52.5 years; 60.8% women) in a cross-sectional, multi-center investigation and stratified study participants according to DED status (Ocular Surface Disease Index [OSDI]>22 vs OSDI ≤22) and the relative humidity of their place of residence (low humidity, <70% vs high humidity, ≥70%). 

Overall, 15.5% (95% CI 13.2%–17.6%) of participants had moderate or severe DED, according to the report. Individuals residing in lower humidity climates had a higher prevalence of DED (17.7%; 95% CI 14.5%–21.1%; P < .01) compared with individuals living in higher relative humidity conditions (13.6%; 95% CI 11.1%–16.7%). Although DED risk was slightly higher among individuals residing in conditions of lower humidity, this risk was not statistically significant (odds ratio [OR], 1.34; 95% CI, 0.96-1.89; P = 0.09). However, this risk was significant among individuals older than 50 years (OR, 1.51, 95% CI, 1.06-2.16; P =.02) and women (OR, 1.99; 95% CI, 1.36-2.90; P <.01) . 

Climate variables, which include mean wind gusts (P =.11), air temperature (P =.35), and atmospheric pressure (P =.85) did not significantly affect DED prevalence.

“[T]he results of this study could be of paramount relevance, suggesting that maintaining appropriate humidity and temperature in the ambient air, for example, at patients’ homes or workplaces, could be recommended for eye health, especially in patients who live in locations with low [relative humidity],” according to the researchers. “Additionally, these results will help practitioners to improve DED management in a comprehensive way, taking into account the impact of climate on patients’ symptomatology to manage early dry eye symptoms and avoid disease progression, including recommendations to use humidifiers in the treatment plan to reduce exposure to the adverse environment.”

Study limitations include a failure to obtain objective clinical measurements, the inclusion of participants with and without dry eye symptoms, and potential geographic bias.