Effects of Green Tea Consumption on Primary Glaucoma (GTG)

May 7, 2024 updated by: Siti Sarah Binti Shokri, Universiti Sains Malaysia

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

The goal of this randomised control trial is to learn about the effect of green tea consumption on patients with primary glaucoma.

The main questions to answer are:

  1. Is there any difference of intraocular pressure (IOP) in patient with primary glaucoma after 1 month, 3 months and 6 months who is consuming green tea compared to patient not consuming green tea?
  2. Is there any difference of retina nerve fibre layer in patient with primary glaucoma after 1 month, 3months and 6 months who is consuming green tea compared to patient not consuming green tea?

Researchers will compare patients with primary glaucoma who are consuming green tea and normal daily drinking to see if any affect to intraocular pressure and retina nerve fibre layer.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Estimated)

100

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Mr. Mohd Bazlan Hafidz Mukrim
  • Phone Number: 09-767 2354 / 09-767 2362
  • Email: bazlan@usm.my

Study Locations

  • Malaysia
    • Kelantan
      • Kubang Kerian, Kelantan, Malaysia, 16150
        • Recruiting
        • Hospital Universiti Sains Malaysia
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patient with confirmed diagnosis of primary glaucoma (POAG/PACG/NTG) that achieve target IOP with medical therapy at least for 6 months.
  • Never consume green tea as daily drinks.

Exclusion Criteria:

  • Dense cataract with Lens Opacity Classification Sytem (LOCS II) of more than grade 2
  • Any other ocular media opacity that may interfere with OCT imaging ( eg: cornea scar/vitreous haemorrhage)
  • Any history of optic neuropathy
  • History of glaucoma or retinal surgery
  • Macular degeneration and retinal disorder
  • Patient with caffein sensitive that causes unpleasant reaction (eg: palpitation, insomnia, nausea, constipation)
  • Allergic to green tea

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Green tea group
Patients in Group A will have to consume two cup (250ml for each cup) of hot green tea, five days per week for 6 months. A tea bag is brewed in 250ml hot water for 3 minutes.
Dietary supplement: Green tean group
Patients in Group A will have to consume two cups (250ml for each cup) of hot green tea, five days per week for 6 months. A tea bag is brewed in 250ml hot water for 3 minutes. They are only allowed to consume as hot drink, not for iced tea. Any sweetener or sugar is not allowed to mix in the drink. The green tea bag will be distributed to patient at beginning of research and at every visit. Patient will be reminded weekly using text messages or phone call by a research assistant for green tea consumption.
Experimental: Control Group
Patients in Group B will not consume green tea for 6 months during study period.
Dietary supplement: Control group
Patients in Group B will not be consuming green tea during 6 months of study period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Effect of green tea consumption on intraocular pressure in patient with primary glaucoma
Time Frame: IOP measurement will be taken at baseline, first, and 6th-month post recruitment for group A and B.
IOP measurement will be done using Goldmann Applanation Tonometer (GAT) for group A and Group B
IOP measurement will be taken at baseline, first, and 6th-month post recruitment for group A and B.
Effect of green tea consumption on retinal nerve fiber layer thickness ( RNFL) in patient with primary glaucoma
Time Frame: OCT RNFL will be conducted at baseline, 1 month, 3 month and 6 month post recruitment for group A and B.
Spectral domain Heidelberg Spectralis OCT will be used to measure RNFL thickness
OCT RNFL will be conducted at baseline, 1 month, 3 month and 6 month post recruitment for group A and B.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Universiti Sains Malaysia

Collaborators

Hospital Universiti Sains Malaysia

Investigators

  • Principal Investigator: Dr. Siti Sarah Shokri, Universiti Sains Malaysia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 1, 2024

Primary Completion (Estimated)

December 1, 2024

Study Completion (Estimated)

June 1, 2025

Study Registration Dates

First Submitted

October 6, 2023

First Submitted That Met QC Criteria

January 29, 2024

First Posted (Actual)

February 1, 2024

Study Record Updates

Last Update Posted (Actual)

May 8, 2024

Last Update Submitted That Met QC Criteria

May 7, 2024

Last Verified

May 1, 2024

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RSCH ID-23-03868-NIT

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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