Table 1.

Clinical trials showing beneficial effects of GT and its ingredients on ocular diseases.

ophthalmic disease	number of participants	intervention	final effect	reference
retinal microvasculature	60	black tea (2 mg/250 mL water)	Black tea consumption did not have any immediate effect on macular microcirculation in healthy individuals.	[51]
glaucoma	43	GTE and EGCG extract (capsule 400 mg)	Individuals with elevated intraocular pressure or risk factors for glaucoma development may benefit from moderate consumption of GT or its concentrated extracts.	[52]
dry eye and meibomian gland dysfunction (MGD)	60	topical GTE (1 mg/5 mL distilled water)	Topical application of GTE is a safe, effective, and well-tolerated treatment option for mild to moderate evaporative dry eyes and meibomian gland dysfunction.	[53]
diabetic retinopathy	200	Chinese GT (regularly drink every week for at least one year)	Regular consumption of Chinese GT for at least one year may decrease the risk of diabetic retinopathy by about 50% compared to those who do not consume it. This suggests that regular consumption of Chinese GT may be a new approach to prevent diabetic retinopathy.	[54]
ocular hypertension (OHT) and open-angle glaucoma (OAG)	18 OHT patients and 18 OAG patients	EGCG oral treatment (200 mg/day)	Although this study did not provide evidence for the long-term benefits of EGCG supplementation in open-angle glaucoma, and the observed effect is small, the results suggest that EGCG may have a positive impact on inner retinal function in eyes with early to moderately advanced glaucomatous damage.	[55]

EGCG: epigallocatechin-3-gallate.