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Study shows caffeine stimulates tear secretion
Schirmer’s test scores increased after caffeine intake in a study of non-dry eye subjects reported in Optometry & Vision Science.
Osei and colleagues sought to determine 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, according to the study abstract.
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 that 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.