Effects of Green Tea Consumption on Retinal Nerve Fiber Layer ( RNFL) and Intraocular Pressure ( IOP) in Patients With Primary Glaucoma
Phase: NA
Conditions: Primary Glaucoma
Sponsor: Universiti Sains Malaysia

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DISSERTATION PROTOCOL 
Effects of Green Tea Consumption on Retinal Nerve 
Fibre Layer Thickness and Intraocular Pressure in 
Patients with Primary Glaucoma 
RSCH ID-23-03868-NIT, Version 1.0 dated 1/07/2023 
DR SITI SARAH BINTI SHOKRI 
Department of Ophthalmology and Visual Science  
School of Medical Sciences  
Universiti Sains Malaysia 
 
SUPERVISOR 
Prof. Dr. Liza Sharmini Ahmad Tajudin 
Medical Lecturer and Senior Consultant Ophthalmologist (Glaucoma) 
Department Of Ophthalmology 
School Of Medical Sciences 
Universiti Sains Malaysia 
 
CO-SUPERVISOR 
Assoc. Prof. Dr. Rohana Abdul Jalil  
Lecturer Department of Community Medicine 
School of Medical Sciences  
Universiti Sains Malaysia 
 
Dr. Juanarita Jaafar 
Ophthalmologist Hospital Sultanah Bahiyah 
 
STUDY SITES 
Hospital Sultanah Bahiyah  
Hospital Raja Perempuan Zainab II 
Hospital Universiti Sains Malaysia  

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Table of Contents 
1. 
INTRODUCTION ......................................................................................................................... 4 
2. 
LITERATURE REVIEW............................................................................................................. 5 
2.1. Management of glaucoma ............................................................................................................ 5 
2.2. Role of oxidative stress in glaucoma ............................................................................................ 6 
2.3. Nutrients and antioxidant content of green tea .......................................................................... 7 
3. 
RATIONAL OF STUDY .............................................................................................................. 8 
4. 
OBJECTIVE ................................................................................................................................. 8 
4.1. General Objective ......................................................................................................................... 8 
4.2. Specific Objective .......................................................................................................................... 8 
4.3. Research Questions ....................................................................................................................... 9 
5. 
METHODOLOGY ....................................................................................................................... 9 
5.1. Research Design ............................................................................................................................ 9 
5.2. Study Location .............................................................................................................................. 9 
5.3. Study Duration .............................................................................................................................. 9 
5.4. Study Reference ............................................................................................................................ 9 
5.5. Study Source Population .............................................................................................................. 9 
5.6. Sampling Frame ............................................................................................................................ 9 
5.7. Sampling Method .......................................................................................................................... 9 
5.8. Study Participants ....................................................................................................................... 10 
5.9. Selection Criteria ........................................................................................................................ 10 
5.10. 
Randomisation ..................................................................................................................... 10 
5.11. 
Blinding ................................................................................................................................ 10 
5.12. 
Sample Size .......................................................................................................................... 11 
5.13. 
Definition of Terms ............................................................................................................. 11 
5.14. 
Withdrawal Criteria ........................................................................................................... 12 
5.15. 
Research Tools .................................................................................................................... 12 
5.16. 
Data Collection .................................................................................................................... 13 
5.17. 
Data Entry and Statistical Analysis ................................................................................... 14 
5.18. 
Plans for Minimizing Study Errors ................................................................................... 14 
6. 
ETHICAL CONSIDERATION ................................................................................................. 15 
6.1. Handling Privacy and Data Confidentiality ............................................................................. 15 
6.2. Potential Risk to Subjects ........................................................................................................... 15 
6.3. Direct and Indirect Benefits to Subjects ................................................................................... 16 
6.4. Incentive, Compensation and/or Reimbursement .................................................................... 16 
6.5. Declaration of Conflict of Interest ............................................................................................. 16 
6.6. Collaborative Study Term of Reference ................................................................................... 16 

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7. 
FLOW CHART OF STUDY ...................................................................................................... 17 
8. 
EXPECTED RESULT ................................................................................................................ 18 
8.1. Objective 1: .................................................................................................................................. 18 
8.2. Objective 2: .................................................................................................................................. 18 
9. 
GANNT CHART ......................................................................................................................... 19 
10. KEY MILESTONES .................................................................................................................. 20 
11. REFERRENCES ......................................................................................................................... 21 
ATTACHMENT A: Dietary Diet ...................................................................................................... 24 
ATTACHMENT B: Data Collection Form ...................................................................................... 25 
 
 
 
 

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1. INTRODUCTION 
 
Glaucoma is a progressive optic neuropathy characterised by excavated appearance of 
optic disc and loss of retinal ganglion cells (RGCs) with corresponding visual field loss 
(AAO, 2023). It affects more than 70 million people worldwide, making it one of the leading 
causes of irreversible blindness. Patients suffer from a centripetal loss of visual field 
associated with an increasing optic disc cupping while remaining asymptomatic until 
reaching advanced stages. Due to the lack of symptoms in the early stages, detection and 
treatment may be delayed until advanced stages of disease (Cohen et al, 2014).  It is 
estimated that half of patients with glaucoma are unaware of their diagnosis (Vajarant et al, 
2016). 
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 (Tezel et al, 2006). 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 (Braakhuis et al, 2017).  
Several studies reported glaucoma patients with younger age and more highly educated 
tend to use complementary and alternative medication in belief that can control their disease 
(Wan et al, 2012). Study by wan et al reported 34% of patients consumed herbal medication 
and 22% had dietary modification. There is no adequate clinical evidence to encourage 
patients to have certain dietary modification to support glaucoma management. Thus, we 
would like to study the effect of high antioxidant drink which is green tea on the glaucoma. 
High antioxidant drink can be more cost effective and safer to be promising potential as 
primary prevention for glaucoma. 
 
 

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2. LITERATURE REVIEW 
2.1. Management of glaucoma 
 
The current treatment of glaucoma is by reducing intraocular pressure (IOP) toward a 
target pressure through medication, laser, or surgery (AAO) to preserve visual function by 
lowering intraocular pressure (IOP) (AAO, 2023). In The Advanced Glaucoma Intervention 
Study (AGIS), reported lower IOP was associated with less visual field progression. In 
Collaborative Normal- Tension Glaucoma Study (CNTGS), IOP lowering by at least 30% 
reduced the 5- year risk of visual field progression from 35% to 12%. 
Target pressure is a therapeutic IOP upper range in which visual field loss is unlikely to 
significantly reduce a patient’s quality of life over his or her lifetime. In general, the initial 
target aims for about 20% to 50% reduction in pressure (AAO, 2023). Target pressure should 
be individualized for each eye initially based on the IOP level and the severity of glaucoma 
damage. Other several factors to consider including the observed rate of progression; life 
expectancy of the patient; history of disc hemorrhages, corneal thickness, or a family history 
of severe vision loss in the setting of glaucoma (AAO, 2023). 
The clinician must decide whether to achieve target pressure goal medically or surgically 
after discussing with patient the benefits and justify the risks of the opted treatment 
modalities. Laser trabeculoplasty is relatively safe outpatient procedure and effective in 
reducing IOP by increasing trabecular outflow. However, it does not replace medical as 
primary treatment in view of gradual diminishes effect over time (Juzych et al, 2004).  
Surgical trabeculectomy is indicated when maximally tolerated medical therapy and laser 
treatments fail to prevent progressive damage in view of its known complication including 
hypotony, malignant glaucoma and bleb fibrosis. In Collaborative Initial Glaucoma 
Treatment Study (CIGTS), reported patient with newly diagnosed open angle glaucoma 
showed greater IOP reduction in immediate trabeculectomy group compared to initial 
medical therapy. However, it does not show greater visual field preservation in the 
trabeculectomy group.  
Other surgical options of glaucoma treatment are plate- based tube implants to shunt 
aqueous from the anterior chamber to subconjunctival space (AAO, 2023). These implants 
usually reserved in eyes that had failed multiple prior trabeculectomies, active inflammation 
or neovascularization, or severe conjunctival scarring. In landmark study of The Tube Versus 
Trabeculectomy Study reported high success rates with tube shunt surgery in eyes with 
previous cataract surgery or trabeculectomy. Common complications are corneal endothelial 
loss and cornea decompensation.  
 

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2.2. Role of oxidative stress in glaucoma  
 
Current evidence suggests that oxidative stress has been implicated in a wide variety of 
neurodegenerative diseases (Juzych et al, 2004), including glaucoma (Tezel et al, 2006). 
Reactive oxygen species (ROS), including superoxide anion, hydrogen peroxide (H2O2), 
hydroxyl radical, and singlet oxygen, are generated intracellularly through many processes. 
For examples as by-products of aerobic metabolism and as second messengers in various 
signal transduction pathway. ROS can also be derived from exogenous sources including by 
exposure to various natural and synthetic toxicants and ultraviolet/ionizing radiation (Chen et 
al, 2003).  
An imbalance between ROS and antioxidants can result in excessive generation of ROS. 
Studies have observed diminished total antioxidant capacity in plasma or serum of glaucoma 
(Sorkhabi et al, 2011) (Mousa et al, 2015). These excessive ROS may cause damage to 
cellular nucleic acids, structural proteins, and lipids, and organelles including mitochondria, 
and also may promote cell death via apoptosis (Pinazo et al, 2015).  
Following acute elevation of IOP, oxidative stress may exert damage to retinal ganglion 
cells (Quan et al, 2007). An animal study has shown that chronic IOP elevation induced by 
weekly injections of hyaluronic acid into the anterior chambers of rat eyes reduced anti-
oxidant levels of superoxide dismutase (SOD), catalase, and glutathione associated with 
significant increased retinal lipid peroxidation (Moreno et al, 2004).  
Oxidative stress may also cause degeneration of the trabecular meshwork leading to 
interference with normal drainage of aqueous humour, and an increase in IOP thus priming 
the glaucoma pathogenetic cascade. There is evidence that cells within the trabecular 
meshwork of glaucoma cases have higher levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), 
a marker of oxidative damage to the DNA and its level correlate with visual field damage and 
IOP (Sacca et al, 2005).  
Unstable ocular perfusion especially when IOP or blood pressure fluctuates leads to a 
repeated reperfusion and thereby ROS formation contributing to glaucomatous damage 
(Mozaffarieh et al, 2008). Vascular diseases, including stroke, cardiovascular disease, 
migraine, and hypertension, are associated with increased risk for glaucoma, strongly 
suggesting that vascular abnormalities and impaired blood flow to the retina may play a role 
in development of the disease. 
   
 
 

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2.3. Nutrients and antioxidant content of green tea 
 
Tea is one of the most popular beverages consumed worldwide (Neves et al, 2011), which 
is made up from leaf of the plant Camellia sinensis. Depending on the manufacturing process, 
teas are classified into three major types which are ‘non-fermented’ green tea, ‘semi-
fermented’ oolong tea and ‘fermented’ black and red. Non fermented green tea is produced 
by drying and steaming the fresh leaves to impede oxidation by polyphenol oxidase. These 
processes preserve natural polyphenols contributing to the health-promoting properties 
(Naghma et al, 2007). For this reason, it is one of the most antioxidant rich drink due to its 
high content of flavonoids commonly known as catechins (flavan-3-ols).  
The most abundant and the most active catechins are epigallocatechin-3-gallate (EGCG), 
that represents approximately 59% of the total of catechins followed by approximately 19% 
of epigallocatechin (EGC); approximately 13.6% of epicatechin-3-gallate (ECG); and 
approximately 6.4% of epicatechin (EC) (Henning et al, 2003). Henning et al also reported 
Lipton Green Tea has the 2nd highest catechin level of EGCG followed by Cellestial 
Seasoning Green Tea.  
The calorie in green tea without added sugar is insignificant about 1-2kcal. The caffeine 
content is lower than in coffee, black tea, or cola soft-drinks. In addition to phytochemical 
substances, it also contains vitamins such as vitamin C, vitamin B, and minerals such as Mn, 
Cr, Se, Zn (Nutrient Data Laboratory, 2013). In this study, it is safe for subject to consume 
green tea with amount of 2 cup per day in 5 days per week. According to ‘National Center for 
Complementary and Intergrative Health (NCCIH),’ it is safe to consume green tea up to 8 
cups per day.  
In vitro study has shown that catechins found in green tea can penetrate the tissue of the 
rat eye after oral administration (Chu et al, 2010). Another study by Yang et al evidenced 
green tea extract acts as a neuroprotectant to rat RGCs after exposed to an oxidative stress 
induced by ischemia-reperfusion injury (Yang et al, 2019). Thus it can be speculated that 
green tea may have potential to act as antioxidant to human RGCs specifically for patients 
with glaucoma.  
In the Nurses’ Health Study (NHS) and Health Professionals Follow-up Study (HPFS), 
which included 116,484 participants ≥40 years of age, reported tea has been be possibly 
protective against developing glaucoma or its progression. Consuming 2 cups daily or median 
of 13.1 cups/week was associated with a significant 18% lower glaucoma risk (Kang et al, 
2018). In clinical study of 43 healthy subjects demonstrates that green tea extracts can also 
decrease IOP, however its clinically significant in patient with glaucoma is not known 
(Gasiunas et al, 2022). Another clinical study reported significant effect on inner retinal 
function as evaluated by PERG after taking EGCG supplement in patient with early to 
moderate open angle glaucoma (Falsini et al, 2009).  
 
 

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3. RATIONAL OF STUDY 
 
The current established treatment of glaucoma is by lowering of intraocular pressure 
(IOP) using medications, laser treatment, or surgery. However, these interventions are not 
always sufficient. Some patients continue to show disease progression causing severe vision 
loss despite achieving therapeutic IOP level. The identification of other options of modifiable 
risk factors can give significant implications for glaucoma prevention and perhaps can 
include in future treatment modalities. Many evidences showed an association between 
pathophysiology of oxidative stress and risk for glaucoma which suggesting that consumption 
of dietary antioxidants may be a factor capable of modifying disease risk.  
Hence in this study, green tea is chosen as it is among the highest antioxidant drink 
attribute to its flavonoid based catechin content. Green tea is considerable cheap, safe drink, 
easily prepared and easily available worldwide. Although green tea extract has higher content 
of polyphenol especially EGCG compared to green tea, green tea is chosen as it is more 
beneficial and safer. Green tea extract form in large bolus dose has been linked to liver 
problems, but not when consumed as brewed tea (Hu et al, 2018).  
In this study we would like to evaluate the effect of green tea consumption in patient with 
primary glaucoma. In view of its high antioxidant property, it may have potential as a 
complementary treatment to prevent or slow down progression of glaucoma. The simple 
modification of dietary drink is cheap, easy, and safe option to be taken as complementary 
management.  
 
4. OBJECTIVE 
 
4.1. General Objective 
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. 
4.2. Specific Objective  
4.2.1. To compare the IOP measurement at baseline, after 1 month, 3 months and 6 
months, between patients with primary glaucoma that consume green tea and not 
consume green tea. 
4.2.2. To compare the retinal nerve fibre layer thickness at baseline, after 1 month, 3 
months and 6 months, between patients with primary glaucoma that consuming 
green tea and not consuming green tea. 
 

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4.3. Research Questions 
4.3.1. Is there any difference of 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? 
4.3.2. 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?  
 
5. METHODOLOGY 
 
5.1. Research Design  
This is a randomized controlled trial study. 
 
5.2. Study Location  
1.1.1. Department of Ophthalmology, Hospital Sultanah Bahiyah (HSB), Kedah 
1.1.2. Department of Ophthalmology, Hospital Universiti Sains Malaysia (HUSM), 
Kelantan 
1.1.3. Department of Hospital Raja Perempuan Zainab (HRPZ), Kelantan 
 
5.3. Study Duration  
June 2023- June 2025 
 
5.4. Study Reference  
Population of primary glaucoma patients. 
 
5.5. Study Source Population  
Primary glaucoma patients attending eye clinic in Hospital Sultanah Bahiyah, 
Hospital Universiti Sains Malaysia and Hospital Raja Perempuan Zainab, Kelantan 
 
 
5.6. Sampling Frame  
All primary glaucoma patients attending ophthalmology clinic HSB, HUSM and 
HRPZ during study duration and fulfil selective criteria  
 
5.7. Sampling Method  
Block sample randomisation will be applied. 
 

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5.8. Study Participants  
Primary glaucoma patients who attended eye clinic HSB, HUSM and HRPZ selected 
according to inclusion and exclusion criteria 
 
 
5.9. Selection Criteria  
5.9.1. Inclusion Criteria 
5.9.1.1. 
Patient with confirmed diagnosis of primary glaucoma 
(POAG/PACG/NTG) that achieve target IOP with medical therapy at least 
for 6 months.  
5.9.1.2. 
Never consume green tea as daily drinks. 
 
5.9.2. Exclusion Criteria 
5.9.2.1. 
Dense cataract with Lens Opacity Classification Sytem (LOCS II) of   
more than grade 2  
5.9.2.2. 
Any other ocular media opacity that may interfere with OCT imaging ( 
eg: cornea scar/vitreous haemorrhage)  
5.9.2.3. 
Any history of optic neuropathy 
5.9.2.4. 
History of glaucoma or retinal surgery 
5.9.2.5. 
Macular degeneration and retinal disorder 
5.9.2.6. 
Patient with caffein sensitive that causes unpleasant reaction (eg: 
palpitation, insomnia, nausea, constipation)  
5.9.2.7. 
Allergic to green tea  
 
5.10. 
Randomisation 
Block randomization method using ‘Sealed Envelope’ website.  
 
5.11. 
Blinding 
Single blinded study where OCT operator and personnel taking IOP 
measurement will be blinded 
 

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5.12. 
Sample Size 
 
Sample size determination for IOP and RNFL thickness are done using sample 
size calculator by Wan Nor Ariffin. 
 
  
 
The final total sample size is 100 patients including 30% dropout with 50 patients in 
group A (interventional) and 50 patients in group B (non-interventional) 
 
5.13. 
Definition of Terms 
 
5.13.1. Primary Glaucoma  
 
Progressive optic neuropathy characterised by excavated appearance of optic 
disc and loss of retinal ganglion cells with corresponding visual field loss with 
no identifiable cause (AAO 2022-2023).  
 
5.13.2. Intraocular Pressure  
 
The IOP of the eye is determined by the balance between the amount of aqueous 
humor production and aqueous humor outflow. The parameters that contribute to 
intraocular pressure (IOP) are modeled by the modified Goldmann equation 
include outflow facility, aqueous humor production rate, episcleral venous 
pressure, and uveoscleral outflow rate. (AAO, 2022-2023) 
 
 

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5.13.3. RNFL Thickness  
 
The RNFL is formed by the expansion of the fibers of the optic nerve. RNFL 
thickness can be measured by optical coherence tomography (OCT) which can 
discriminate glaucomatous eyes from healthy eyes and to monitor the progress 
of disease. OCT RNFL thickness measurements are usually acquired in the 
peripapillary 3.45mm around the ONH. OCT reports global average 
peripapillary RNFL thickness and average RNFL thickness in quadrants or in 
small clock- hour sectors. RNFL thickness measurements are generally lower in 
glaucomatous eyes compared with those in non-glaucomatous eyes. (AAO, 
2022-2023). 
5.14. 
Withdrawal Criteria  
 
Withdrawal of subjects from study are considered when:  
i) Subject is unable to comply with the protocol.  
ii) If the subject in group A consumes green tea more than 2 cups or less per day 
iii) Subject in group A and B consumes antioxidant supplement during study period.  
iv) If the study subject developed gastrointestinal discomfort upon consumption of 
green tea. 
Subjects can choose to withdraw at any time. Subjects may be withdrawn if the 
investigator deems that it is detrimental or risky for the subject to continue. 
Withdrawn subjects will not be replaced. 
5.15. 
Research Tools  
 
5.15.1. Instruments 
i) Snellen Visual Acuity Chart for distance (Reichert, NY, USA)  
ii) Pinhole occluder 
iii) Slit lamp biomicroscopy (HAAG-STREIT International, UK) 
iv) Goldmann applanation tonometer (GAT) AT-900 (HAAG-STREIT 
International, UK)  
v) Condensing lens of 90D and 78D lenses (VOLK, USA)  
vi) Optical Coherence Tomography (Heidelberg Spectralis OCT, USA)  
vii) Dietary Diary 
 
5.15.2. Medication/Reagent  
5.15.2.1. Tropicamide 1% eye drop (mydriatic agent) 
5.15.2.2. Proparacaine Hydrochloride (Alcaine) 0.5% eye drop (topical local 
anesthesia)  
5.15.2.3. Phenylephrine Hydrochloride (Mydfrin) 2.5% eye drop (mydriatic 
agent)  
 
 

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5.16. 
Data Collection  
 
This study will be conducted after obtaining approval from the Universiti Sains 
Malaysia Ethical Committee (JPeM) and Medical Research and Ethics Committee, 
Ministry of Health, Malaysia and will be conducted in accordance to World Medical 
Association Declaration of Helsinki ethical principles for medical research involving 
human subjects. 
 
5.16.1. Patient Recruitment  
 
Primary glaucoma patients who attending ophthalmology clinic at HSB, HUSM and 
HRPZ during study duration June 2023–June 2025. Evaluation of study sample 
including systemic and ocular history, baseline ocular examination, IOP and OCT 
RNFL. Subjects who fulfil the inclusion and exclusion criteria for the study will be 
selected. An informed and written consent will be taken and information form given 
to patients. The selected patients will be randomized into 2 groups (A and B) using 
block sample randomisation. Group A patient will be consuming green tea drink and 
group B patient will not consume green tea drink. A data collection sheet will be 
used to gather all the data from the subjects. 
 
5.16.2. Informed Consent Process  
Patients shall be informed of the study during their usual clinic visits. They will be 
requested to contact investigators if they are interested. An appointment will be made 
where the patient information sheet will be provided and explained to them. If they 
are willing to participate, the consent forms will be signed and dated. If they need to, 
they are allowed to take the information sheet home to consult with their family 
members, and another day for getting consent arranged.  
 
5.16.3. Interventional Protocol 
 
50 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.  
 
50 patients in Group B will not be consuming green tea during 6 months of study 
period.  
 

14 
 
Patients in group A and group B will be given a dietary diary throughout the study 
period, where the patient will mark the intake of other drinks. The purpose of the 
diary is also to monitor patient intake of green tea and other drinks as well. 
 
5.16.4. IOP measurement  
 
IOP measurement will be done using Goldmann Applanation Tonometer (GAT) in 
sitting position by the primary investigator who will be blinded. GAT will be 
calibrated daily before used to measure the IOP. In order to prevent diurnal variation 
of IOP, measurement done in morning around 8am – 10am. Only one eye will be 
measured. If both eyes are eligible, only right eye will be selected regardless of 
severity of glaucoma. Three readings of IOP will be measured and the mean reading 
will be taken as result. IOP measurement will be taken at baseline, first, and 6th-
month post recruitment for group A and B. 
 
5.16.5. OCT evaluation on RNFL thickness  
Spectral domain Heidelberg Spectralis OCT will be used to measure RNFL thickness 
by trained personnel who is blinded. Patient is instructed to sit in front of machine, 
place his/her chin on the chinrest, lean forehead against the forehead rest, and then to 
look at target pointer inside the machine. The OCT will then scan patient’s eye 
without any direct eye contact. Good quality image included well centred optic nerve 
head and homogenous signal of overall image will be choosen. Poor image with 
artifacts, or with segmentation errors will be repeated. If there is unsatisfactory 
measurement after 3 attempts, the patient will be excluded from the study. In patient 
without media opacities but with poor signal strength the eye will be dilated first and 
if after dilation still unable to get satisfactory reading after 3 attempts, the patient will 
be excluded from the study. OCT will be conducted at baseline, 1 month, 3 month and 
6 month post recruitment for group A and B. 
 
5.17. 
Data Entry and Statistical Analysis 
 
Data entry and analysis will be performed by using the IBM Statistical Package 
for the Social Sciences (SPSS) licensed to USM. Paired t-test will be used to 
compare numerical data and chi-square test for categorical data between the two 
groups.  
 
5.18. 
Plans for Minimizing Study Errors 
 
These steps will be taken to minimize the errors while conducting the study:  
i. 
The same instruments and equipment will be used for repeated measurement in 
this study.  
ii. 
The measurements of IOP will be done by same person.  

15 
 
iii. 
The measurement of IOP will be done at the same time (8am-10am) in a day for 
all patients to prevent diurnal variation.  
iv. 
OCT measurements will be performed by qualified and trained personnel only. 
 
6. ETHICAL CONSIDERATION 
 
This study will be submitted to the Universiti Sains Malaysia Ethical Committee (JPeM) 
and Medical Research Ethics Committee (MREC), Ministry of Health of Malaysia and 
will be conducted in accordance to World Medical Association Declaration of Helsinki 
ethical principles for medical research involving human subjects. The information form 
will be given to all participants and an informed and written consent will be taken prior to 
data collection. 
6.1. Handling Privacy and Data Confidentiality 
 
6.1.1. Confidentiality  
All the information obtained in this study will be kept and handled in a confidential 
manner, in accordance with applicable laws and/or regulations. The confidentiality of 
the data will be strictly maintained, whereby only the author, supervisor and 
cosupervisor could access the data. Personal information and data will not be 
disclosed. The data collection sheets will have serial numbers instead of the names of 
the subjects to prevent recognition. Subjects are not given access to the personal 
information and study date. Subjects can write to the investigators to request access to 
study findings. 
 
6.1.2. Data Storage  
Research records will be stored securely in a locked cabinet and study data will be 
stored in a password-protected thumb drive. Medical information will be held and 
processed on a computer and will be entered using unique numbers into Microsoft 
Excel before analysis process using SPSS. Duration of storage and archival of 
medical records and study data will take about 3 years after completion of study. All 
digital data will be deleted permanently and all data collection sheets which contain 
the data will be disposed after the period of storage. The participants’ name will not 
appear on the materials published and the medical information of each subject will 
keep confidential unless disclosure is required by law. Participants will be offered to 
read the manuscripts and to see all publish materials in which they are included. 
6.2. Potential Risk to Subjects 
 
It is safe for subject to consume green tea with amount of 2 cup per day in 5 days per 
week. According to ‘National Center for Complementary and Intergrative Health 
(NCCIH),’ it is safe to consume green tea up to 8 cups per day. There are no serious 
side effects known to be caused by the investigational product.  

16 
 
The study procedures are all routine procedures for the disease/condition studied.   
However, the participants will be monitored by the researcher until confirmed not to 
have any side effect of the investigational product. If any side effects medical 
treatment will be given as necessary. However, if there are any important new 
information found during this study that may affect the decision in being part of the 
study, participants will be told about it right away. 
6.3. Direct and Indirect Benefits to Subjects  
 
Study drug and study procedures will be provided at no cost to all participants. 
Participants may receive information about their health from any physical 
examination and investigation tests to be done in this study. This intervention would 
increase the participant’s knowledge regarding dietary modification specifically high 
antioxidant drinks that may help towards successful treatment outcome in primary 
glaucoma.  
 
6.4. Incentive, Compensation and/or Reimbursement  
There is no any incentive, compensation and/or reimbursement given to all 
participants.  
 
6.5. Declaration of Conflict of Interest  
No conflict of interest is present. 
 
6.6. Collaborative Study Term of Reference  
There is no collaboration between researchers and other institute or ministry in this 
study.  
 
 
 
 
 
 
 
 
 
 

17 
 
7. FLOW CHART OF STUDY 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Asess for eligibility  
Eligible (n = 100) 
Randomised (n=100) 
Allocation 
Follow Up 
Analysis 
Enrolment  
Excluded (n= ) 
• 
Not meeting inclusion criteria 
(n= ) 
• 
Declined to participate (n= ) 
• 
Other reasons (n= ) 
Baseline evaluation of study sample 
(n = 100) 
• 
Complete history and ocular 
examination  
• 
IOP (Goldmann tonometer) 
Group A ( n=100)  
• 
Interventional  
• 
Consume 2 cups of green tea per 
day for 5 days per week  
Group A ( n=100)  
• 
Non-interventional  
• 
Normal drinks 
IOP and OCT at 1st, 3rd, and 6th month 
after consuming green tea  
Analysed ( n= ) 
Excluded from analysis ( give reasons) ( n= ) 
Data analysis using SPSS   
 IOP and OCT at 1st, 3rd, and 6th month 
of study period 
Analysed ( n= ) 
Excluded from analysis ( give reasons) ( n= ) 
Data analysis using SPSS   
Loss to follow up 
Discontinues 
intervention 
Loss to follow up 

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8. EXPECTED RESULT 
 
8.1. Objective 1:  
 
Table 1: Mean of IOP in green tea group and control group for 6 months 
IOP (mmHg) 
Time (month)  
Group A  
Group B 
P value  
Mean, SD 
Baseline 
 
 
 
1 
 
 
 
3 
 
 
 
6 
 
 
 
Statistical analyses will be performed with the Paired T test. P < 0.05 is significant. 
 
Table 2:  Changes of IOP at every visit from the baseline IOP in green tea group and control 
group  
Duration 
of study 
(Month) 
Group A 
Group B 
Mean of 
IOP 
differences 
95% CI of the 
difference 
P-
value 
Mean of 
IOP 
differences 
95% CI of the 
difference 
P-
value 
Upper 
border 
Lower 
border 
Upper 
border 
Lower 
border 
V0-V1 
 
 
 
 
 
 
 
 
V0-V3 
 
 
 
 
 
 
 
 
V0-V6 
 
 
 
 
 
 
 
 
V0: baseline reading, V1: visit at 1 month, V3: visit at 3month, V6: visit at 6 month  
Statistical analyses will be performed with one-way repeated measures analysis of variance 
(RM ANOVA). P < 0.05 is significant. 
8.2. Objective 2:  
Table 3: Mean of RNFL thickness observed in green tea group and control group  
RNFL 
thickness 
Group A 
Group B 
P 
value 
Baseline 
1 
month 
3 
months 
6 
months 
Baseline 
1 
month 
3 
months 
6 
months 
 
Average 
 
 
 
 
 
 
 
 
 
Superior 
 
 
 
 
 
 
 
 
 
Inferior 
 
 
 
 
 
 
 
 
 
Nasal  
 
 
 
 
 
 
 
 
 
Temporal  
 
 
 
 
 
 
 
 
Statistical analyses will be performed with the Paired t-test. P < 0.05 is significant. 
 
 

19 
 
 
 
 
Table 4: Changes of RNFL thickness at every visit from the baseline IOP in green tea group 
and control group 
Duration 
of study 
(Month) 
Group A 
Group B 
Mean of 
RNFL 
differences 
95% CI of the 
difference 
P-
value 
Mean of 
IOP 
differences 
95% CI of the 
difference 
P-
value 
Upper 
border 
Lower 
border 
Upper 
border 
Lower 
border 
V0-V1 
 
 
 
 
 
 
 
 
V0-V3 
 
 
 
 
 
 
 
 
V0-V6 
 
 
 
 
 
 
 
 
V0: baseline reading, V1: visit at 1 month, V3: visit at 3month, V6: visit at 6 month  
Statistical analyses will be performed with one-way repeated measures analysis of variance 
(RM ANOVA). P < 0.05 is significant. 
 
9. GANNT CHART 
 
 
2023 
2024 
2025 
 
J F M 
A M 
J J A S O N D J F M A M J J A S O N D J F M A M J 
Proposal 
Presentation 
and Ethics  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Data 
Collection 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Data 
Analysis  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Report 
Writing 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Submission 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

20 
 
 
10. KEY MILESTONES 
 
Month  
Expected Achievement 
June 2023 
• 
proposal preparation done 
• 
obtained ethical approval  
Dec 2023 
• 
40% data collection 
July 2024 
• 
100% data collection 
Dec 2024 
• 
100% data analysis 
May 2025 
June 2025 
• 
Complete report writing 
• 
submission final report 
 
 
 

21 
 
 
11. REFERRENCES 
 
American Academy of Ophthalmology. Basic and Clinical Science Course Section 10: 
Glaucoma . Singapore: American Academy of Ophthalmology, 2008 
 
American Glaucoma Society Annual Meeting, Fort Lauderdale, FL, USA, 3–6 March 2016 
Andersen, J.K., 2004. Oxidative stress in neurodegeneration: cause or consequence? Nat. 
Med. 10 (Suppl.), S18–S25 
 
Bernatoniene J, Kopustinskiene DM. The Role of Catechins in Cellular Responses to 
Oxidative Stress. Molecules. 2018 Apr 20;23(4):965. doi: 10.3390/molecules23040965. 
PMID: 29677167; PMCID: PMC6017297 
Braakhuis, Andrea J. et al. “The Association between Dietary Intake of Antioxidants and 
Ocular Disease.” Diseases 5 (2017) 
 
Chen, J.Z., Kadlubar, F.F., 2003. A new clue to glaucoma pathogenesis. Am. J. Med. 114, 
697–698 
 
Chu KO, Chan KP, Wang CC, Chu CY, Li WY, Choy KW, Rogers MS, Pang CP. Green tea 
catechins and their oxidative protection in the rat eye. J Agric Food Chem 2010;58(3):1523-
1534 
 
Cohen, L.P.; Pasquale, L.R. Clinical characteristics and current treatment of glaucoma. Cold 
Spring Harb. Perspect. Med. 2014,  
 
Falsini B, Marangoni D, Salgarello T, Stifano G, Montrone L, Di Landro S, Guccione L, 
Balestrazzi E, Colotto A. Effect of epigallocatechin-gallate on inner retinal function in ocular 
hypertension and glaucoma: a short-term study by pattern electroretinogram. Graefes Arch 
Clin Exp Ophthalmol. 2009 Sep;247(9):1223-33. doi: 10.1007/s00417-009-1064-z. Epub 
2009 Mar 17. PMID: 19290537. 
 
Gasiunas K, Galgauskas S. Green tea-a new perspective of glaucoma prevention. Int J 
Ophthalmol. 2022 May 18;15(5):747-752. doi: 10.18240/ijo.2022.05.09. PMID: 35601179; 
PMCID: PMC9091885. 
 
Henning SM, Fajardo-Lira C, Lee HW, Youssefian AA, Go VL, Heber D. Catechin content 
of 18 teas and a green tea extract supplement correlates with the antioxidant capacity. Nutr 
Cancer. 2003;45(2):226-35. 
 
Hu J, Webster D, Cao J, Shao A. The safety of green tea and green tea extract consumption in 
adults - Results of a systematic review. Regul Toxicol Pharmacol. 2018 Jun;95:412-433. doi: 
10.1016/j.yrtph.2018.03.019. Epub 2018 Mar 24. PMID: 29580974. 
Juzych MS, Chopra V, Banitt MR, Hughes BA, Kim C, Goulas MT, Shin DH. Comparison 
of long-term outcomes of selective laser trabeculoplasty versus argon laser trabeculoplasty in 

22 
 
open-angle glaucoma. Ophthalmology. 2004 Oct;111(10):1853-9. doi: 
10.1016/j.ophtha.2004.04.030. PMID: 15465546. 
 
Kang JH, Ivey KL, Boumenna T, Rosner B, Wiggs JL, Pasquale LR. Prospective study of 
flavonoid intake and risk of primary open-angle glaucoma. Acta Ophthalmol. 2018 
Sep;96(6):e692-e700. doi: 10.1111/aos.13705. Epub 2018 Mar 14. PMID: 29536641; 
PMCID: PMC6138582.  
 
Moreno, M.C.; Campanelli, J.; Sande, P.; Sanez, D.A.; Keller Sarmiento, M.I.; Rosenstein, 
R.E. Retinal oxidative stress induced by high intraocular pressure. Free Radic. Biol. 
Med. 2004, 37, 803–812. 
 
Mousa, A.; Kondkar, A.A.; Al-Obeidan, S.A.; Azad, T.A.; Sultan, T.; Osman, E.; Abu-Amero, 
K.K. Association of total antioxidants level with glaucoma type and severity. Saudi Med. 
J. 2015, 36, 671–677.  
 
Mozaffarieh M, Grieshaber MC, Flammer J. Oxygen and blood flow: players in the 
pathogenesis of glaucoma. Mol Vis. 2008 Jan 31;14:224-33. PMID: 18334938; PMCID: 
PMC2267728. 
 
Naghma K, Hasan M: Tea polyphenols for health promotion. Life Sciences 2007, 81:519-
533. 
 
Neves, M. F., Trombin, V. G., Lopes, F. F., Kalaki, R., & Milan, P. (2011). World 
consumption of beverages. The Orange Juice Business, 118–118. doi:10.3920/978-90-8686-
739-4_31  
 
Nutrient Data Laboratory, ARS, USDA National Food and Nutrient Analysis Program Wave 
17d , 2013  Beltsville MD  
 
Pinazo-Duran, M.D.; Zanon-Moreno, V.; Gallego-Pinazo, R.; Garcia-Medina, J.J. Oxidative 
stress and mitochondrial failure in the pathogenesis of glaucoma neurodegeneration. Prog. 
Brain Res. 2015, 220, 127–153.  
 
Quan Liu, Won-Kyu Ju, Jonathan G. Crowston, Fang Xie, George Perry, Mark A. 
Smith, James D. Lindsey, Robert N. Weinreb; Oxidative Stress Is an Early Event in 
Hydrostatic Pressure–Induced Retinal Ganglion Cell Damage. Invest. Ophthalmol. Vis. 
Sci. 2007;48(10):4580-4589. 
 
Saccà SC, Pascotto A, Camicione P, Capris P, Izzotti A. Oxidative DNA Damage in the 
Human Trabecular Meshwork: Clinical Correlation in Patients With Primary Open-Angle 
Glaucoma. Arch Ophthalmol. 2005;123(4):458–463.  
 
Sorkhabi R, Ghorbanihaghjo A, Javadzadeh A, Rashtchizadeh N, Moharrery M. Oxidative 
DNA damage and total antioxidant status in glaucoma patients. Mol Vis. 2011 Jan 7;17:41-6. 
PMID: 21245957; PMCID: PMC3021573. 
 
Tezel G. Oxidative stress in glaucomatous neurodegeneration: mechanisms and 
consequences. Prog Retin Eye Res. 2006 Sep;25(5):490-513. doi: 

23 
 
10.1016/j.preteyeres.2006.07.003. Epub 2006 Sep 7. PMID: 16962364; PMCID: 
PMC1820838. 
 
Vajaranant, T.; Maki, P.; Pasquale, L.; Khan, F.; Mares, J.; Meyer, K.; Haan, M. The 
accuracy of self-reported glaucoma in the Women’s Health Initiative. In Proceedings of the  
 
Wan MJ, Daniel S, Kassam F, Mutti G, Butty Z, Kasner O, Trope GE, Buys YM. Survey of 
complementary and alternative medicine use in glaucoma patients. J Glaucoma. 2012 
Feb;21(2):79-82. doi: 10.1097/IJG.0b013e3182027c0c. PMID: 21173701. 
 
Yang YP, Xu CY, Chen YH, Liang JJ, Xu YX, Chen SL, Huang SF, Yang QC, Cen LP, Pang 
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degeneration in rats. Oxid Med Cell Longev 2019;2019:8407206. 
 

24 
 
 
 
ATTACHMENT A: Dietary Diet 
 
  
 
 
 
 
Diari Amalan Minuman  
 
Bulan: ____________ 
Minggu: __________  
 
Sila catatkan jumlah pengambilan minuman harian dalam kuantiti cawan atau gelas. 
 
 
  
 
 
 
 
 
Bil. Minuman  
Jumlah Pengambilan  
( Nyatakan cawan atau gelas) 
Jumlah 
Pengambilan 
Seminggu  
Kenyataan 
Lain 
AHAD ISNIN SELASA RABU KHAMIS JUMAAT SABTU  
 
1.  Teh Hijau 
 
 
 
 
 
 
 
 
 
 
2.  Kopi  
 
 
 
 
 
 
 
 
 
 
3.  Nescafe  
 
 
 
 
 
 
 
 
 
 
4.  Milo 
 
 
 
 
 
 
 
 
 
 
5.  Vico 
 
 
 
 
 
 
 
 
 
 
6.  Air Coklat 
 
 
 
 
 
 
 
 
 
 
7.  Jus Buah 
  
 
 
 
 
 
 
 
 
 
8.  Lain-lain 
teh 
(nyatakan) 
  
 
 
 
 
 
 
 
 
 

25 
 
 
ATTACHMENT B: Data Collection Form   
 
Data Collection Form  
Research Title: Effects of Green Tea Consumption on Retinal Nerve Fiber Layer 
Thickness and Intraocular Pressure in Patients with Primary Glaucoma.  
 
Subject No: __________                                                                         Date of examination: ________  
 
A) Demographic Data  
Name:__________________________________________  
Registration No: _________________________________  
Age:____________  
Gender:_________  
Contact No: __________________   
Smoking/Not smoking  
Family History of glaucoma: NO/YES  
 
B) Comorbid:  
 
DM       
HPT 
HPL  
IHD  
CKD 
  
Others :__________________ 
 
C) Examination  
 
VA  
Baseline  
1 month  
3 month 
6 month  
RE 
 
 
 
 
LE 
 
 
 
 
IOP 
 
 
 
 
RE 
 
 
 
 
LE  
 
 
 
 
 
 
 
 
 

26 
 
 
 
 
D) Investigations  
 
OCT RNFL 
Baseline 
1 month 
3 month 
6 month  
Average  
 
 
 
 
Superior  
 
 
 
 
Inferior 
 
 
 
 
Nasal  
 
 
 
 
Temporal  
 
 
 
 
 
 
E) Treatment  
I. 
Topical antiglaucoma: Timolol / Xalatan / Travatan / Trusopt / Alphagan/ 
Lumigan  
 Other: ____________________ 
II. 
History of glaucoma laser treatment: NO/YES 
If YES, type of laser: __________________ 
 
 
F) Ocular characteristic  
Lens status: __________________  
Diagnosis: ___________________  
Duration of diagnosis: __________ 
Stage of glaucoma:_____________