The Immediate Effects of Different Types of Tea Consumption on Ocular Biometric and Specular Microscopic Parameters in Healthy Subjects.

Background: Tea ranks among the most popular beverages globally. In this study, we assessed the short-term changes in ocular biometric and specular microscopic parameters in healthy subjects following the consumption of different types of tea. Methods: A total of 144 subjects were randomly assigned to 3 groups (black, green, and white tea groups) in this study. Ocular parameters, including axial length (AL), aqueous depth (AD), lens thickness (LT), and central corneal thickness (CCT), were measured using optic biometry. Endothelial cell density (ECD), coefficient of variation (CV), number of hexagonal cells (A6A), and average cell area (AVG) were evaluated using non-contact specular microscopy before, as well as 1 hour and 4 hours after, consuming a cup of tea (containing 60 mg of caffeine per 100 mL). Results: The average age of the subjects was 32.9 ± 5.9 years. A significant increase in AD values was observed specifically at the 1st hour following the consumption of black, green, or white tea in healthy subjects. Additionally, black and white tea significantly reduced LT in the 1st hour of the study. The differences in AL and CCT values, as well as in specular microscopy parameters, were not significant among all participants after consuming different types of tea. Conclusion: Black, green, and white tea induce a significant increase in AD, particularly observed 1 hour after oral intake. Furthermore, a reduction in LT parameters was observed in the black and white tea groups, respectively.