Caffeine intake significantly stimulates tear secretion in people who do not have dry eye, according to a small study published in Optometry & Vision Sciences.
The researchers measured the effect of oral caffeine ingestion in 41 healthy subjects 20 to 26 years old. Subjects drank either 5.0 mg/kg of caffeine dissolved in 200 mL of water or 200 mL of water on the first visit. On the second visit, they ingested the other treatment. Schirmer’s scores were measured at baseline and 45, 90, 135 and 180 minutes after treatment. The scores increased after caffeine intake – to a statistically significant degree at 45 and 90 minutes.
The authors reported that age, body mass and blood pressure had no correlation with the Schirmer’s scores, and gender had no influence on tear secretion.
“From our study, orally ingested caffeine appears to stimulate tear secretion in healthy non-dry eye subjects,” the authors concluded.
