AIM: To determine how green tea and catechins can affect intraocular pressure (IOP) changes. METHODS: Totally 43 young volunteers were included in the study. The experiment was held between noon and 2 p.m. Two extracts—green tea and epigallocatechin gallate (EGCG, 400 mg capsules) and placebo (400 mg capsules) were used in the study. Participants were divided into three groups. Green tea extract group (GT group) had 17 subjects, EGCG extract group 17 subjects, control (placebo) group 9 subjects. IOP was measured with the Icare tonometer before and 30min, 1, 1.5, 2h after the consumption of each extract and placebo. Results were analyzed using the IBM SPSS program. Statistical confidence level P<0.05. RESULTS: The most significant reduction of IOP from the beginning of the experiment was measured after 2h in GT group (left 2.18±3.19 mm Hg, P=0.012; right 2.59±1.97 mm Hg, P<0.000) and after 1h in EGCG extract group (left 2.41±2.98 mm Hg, P<0.004; right 1.94±1.98 mm Hg, P<0.001). In control group no significant changes were measured. CONCLUSION: People who have increased IOP or risk factors for glaucoma development, could benefit from drinking green tea or its concentrated extracts in moderate doses.