DOI: 10.1177/1934578x261463592 ISSN: 1934-578X

Short-Term Effects of a Single Dose of Black Tea on Tear Film Stability and Quality in Healthy Adults: An Interventional Study

Essam S. Almutleb, Meznah S. Almutairi, Abdulaziz A. Almajed, Gamal A. El-Hiti, Basal H. Altoaimi, Saud A. Alanazi, Ali M. Masmali
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Objective

Black tea contains caffeine and polyphenols, which affect the tear film. The impact of these substances on the tear film was evaluated using the standard patient evaluation of eye dryness (SPEED) questionnaire, as well as noninvasive tear breakup time (NITBUT), tear meniscus height (TMH), and tear ferning (TF) tests.

Methods

A total of 60 participants, free of any eye disease or disorder, were recruited. All participants consumed a single dose of Lipton Yellow Label black tea (100 × 2 g bags) steeped in hot water (200 mL). The SPEED questionnaire was completed first, followed by the NITBUT, TMH, and TF tests. After the first measurements were taken, the participants consumed the beverage. After 1 h of tea consumption, the second set of measurements was taken.

Results

Significant differences (Wilcoxon signed-rank test) were observed in the median SPEED ( P < 0.001), NITBUT ( P < 0.001), and TF ( P < 0.001) scores among the study participants before and after consuming the beverage. Conversely, no significant difference ( P = 0.070) was observed in median TMH scores before and after black tea consumption. The Spearman correlation coefficient ( r ) indicated a strong correlation between SPEED ( r = 0.874; P < 0.001) scores before and after tea consumption and between TMH ( r = 0.694; P < 0.001) scores before and after tea consumption. A medium correlation ( r = 0.363; P < 0.001) was found between the NITBUT scores before and after the consumption of the drink.

Conclusion

A single dose of black tea is associated with changes in tear film parameters, resulting in reduced comfort, stability, and quality. However, further research is required to validate and expand these findings.

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