Effects of Green Tea Consumption on Retinal Nerve Fiber Layer ( RNFL) and Intraocular Pressure ( IOP) in Patients With Primary Glaucoma

Glaucoma is a progressive optic neuropathy characterised by loss of retinal ganglion cells (RGCs) with corresponding visual field loss. The current established treatment of glaucoma is by reducing IOP, as one of neuroprotectant factor to prevent further loss RGCs. However, it is not always sufficient to fully prevent disease progression. Oxidative stress is one of biological insult contribute to etiology and progression of glaucoma. Antioxidants represent the first line of defence against oxidative stress and are obtained through the diet and produced internally has shown to be protective towards glaucoma. Green tea is one of the most antioxidant rich drink due to its high content of flavonoids commonly known as catechins.

The investigator would like to evaluate the effect of 6 months consumption of green tea on intraocular pressure (IOP) and retinal nerve fibre layer thickness (RNFL) in patients with primary glaucoma. This is a randomised controlled study involving primary glaucoma patients who are attending ophthalmology clinic at Hospital Universiti Sains Malaysia. Evaluation of study sample includes baseline ocular examination, IOP and Optical Coherence Tomography Retinal Nerve Fibre Layer (OCT RNFL). Subjects who fulfil the inclusion and exclusion criteria for the study will be selected.

Patients in Group A will consume two cups per day (250ml for each cup) of hot green tea, five days per week for 6 months while other Group B (control group) will not consume green tea. IOP and OCT RNFL measurement will be taken at baseline, first month, 3rd month and 6th month post recruitment of subjects. All patients will be given dietary diary to note down their daily drinks' consumption.