Study reveals link between ambient temperature and allergic
Using national health and weather datasets, researchers examined the relationship between meteorological conditions and the risk of a visit for allergic conjunctivitis (AC).

This retrospective, the case-crossover study included patient data from 74,951 individuals from a Veterans Affairs clinic and local climate data from the National Climatic Data Center. All patients were assigned a random control date prior to diagnosis and the daily time-lagged exposures were computed for 30-day lags. Investigators calculated associations between temperature, temperature variation, relative humidity, temperature-humidity interactions, and visit risk.

Prevalence of allergic conjunctivitis visits was highest in spring (more than 10% April–May) in the Northeast and Southeast, and lowest in winter (less than 6.1% December–February) in the Pacific Northwest. The risk of an allergic conjunctivitis visit was positively tied to temperatures, temperature variation, and temperature-relative humidity interaction and negatively linked with relative humidity.

The study was limited to a veteran population older than typical allergic conjunctivitis patients such as those undergoing cataracts or refractive surgery.

This is an interesting study that looked at clinical visits for allergic conjunctivitis among various regional populations. The authors used a very large dataset that could be mirrored in a younger population undergoing refractive surgery.