Other forms of uveitis may be of autoimmune nature which the underlying infectious trigger could not be identified. Though the precise pathogenesis is complicated and still unclear, accumulating evidence has demonstrated that some uveitis sub-types are caused by infectious agents and could be rehabilitated by specific antimicrobial therapies with or without corticosteroids ( 8). Uveitis can be limited to the eye or associated with systemic syndromes, such as ankylosing spondylitis, Behçet disease, and Vogt–Koyanagi–Harada disease ( 7). The prevalence and characteristics of various uveitis subtypes depend on age, gender, genetic background and geographic distribution ( 5, 6). Based on inflammatory involvement of the anatomic framework, the International Uveitis Study Group (IUSG) classified uveitis into anterior, intermediate, posterior, or pan-uveitis ( 4) ( Figure 1). Uveitis represents any intraocular inflammation from the uvea which comprises the iris, ciliary body, and choroid as well as the vitreous, retina, and even a part of optic nerve ( 3). Uveitis is also a potentially blinding disease, which causes ~10-15% of visual impairment worldwide and 25% of legal blindness in developed countries ( 1, 2). One major entity of ocular inflammation appears in uvea, which leads to uveitis, a complex group of manifestations of intraocular inflammation with variable consequences ranging from persistent irritations, pain, and vision impairment. Multiple eye tissues, from ocular surface to intraocular tissues, could be targeted by inflammation. We discuss the insights and perspectives of these experimental results, which would be useful for future development of novel therapeutics in human.

We also review the pharmacokinetics of GTE constituents and safety of green tea consumption. Here we review the experimental investigations on the effects of GTE and catechins on various ocular inflammation related diseases including glaucoma, age-related macular degeneration, uveitis and ocular surface inflammation. Research on the ocular inflammation in animal models has made significant progress in the past decades and several key disease mechanisms have been identified. In in vitro and in vivo studies, GTE and catechins present inhibition of inflammatory responses in the development of ocular inflammation including infectious, non-infectious or autoimmune, and oxidative-induced complications. Catechins are the biologically active constituents of GTE. One of the proven health benefits of consuming green tea extract (GTE) is anti-inflammation.

Green tea is a popular beverage throughout the world. Ocular inflammation is a common complication of various eye diseases with wide consequences from irritations to potentially sight-threatening complications.

4Hong Kong Eye Hospital, Hong Kong, Hong Kong SAR, China.

3Bachelor of Medicine and Bachelor of Surgery Programme, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China.

2Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China.

1Department of Ophthalmology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China.

Jian Li 1,2 †, Lin Du 2 †, Jing Na He 2, Kai On Chu 2, Cosmos Liutao Guo 3, Mandy Oi Man Wong 2,4, Chi Pui Pang 2 and Wai Kit Chu 2 *

Annan retina eye center