Objective: To investigate the effects of high caffeine intake in a short period on tear film dynamics in healthy adults. Methods: The participants were 12 healthy adults (20–30 years old) with no history of ocular surface disease. Participants were given 5.0 mg/kg caffeine (preset the coffee powder according to the concentration)under constant routine conditions. Tear film parameters were assessed and tear collection was performed 2 h before and after caffeine intake. The tear meniscus height, non-invasive tear break-up time, Schirmer I test, intraocular pressure and average lipid layer thickness were all measured after a large amount of caffeine intake. Results: The tear meniscus height, non-invasive tear break-up time and intraocular pressure were significantly increased after caffeine intake, while the average lipid layer thickness was significantly lower than that before caffeine intake. The amount of tear fluid collected by Schirmer’s I test paper was not statistically significant, and there was no gender difference in the effects of caffeine on tear secretion. Conclusion: After high caffeine intake, ocular tear dynamics are significantly altered and caffeine can stimulate tear secretion in healthy, non-dry-eyed subjects.