High MyopiaNCT03294967
Effect of Caffeine on Ocular Circulation in High Myopes
A study testing Caffeine and Vitamin E in people with High Myopia and Choroid, run by The Hong Kong Polytechnic University at 1 site in Hong Kong.
Trial summary
To investigate the effect of caffeine on ocular circulation by using Optical Coherence Tomography and Optical Coherence Tomography Angiography. This study will evaluate blood supply to the inner and outer retina after consumption of 200mg caffeine capsule, in particular its effect in high myopes. Read more about this study
- Who is it for?
- Ages 20 to 49 yearsHealthy volunteers can take part
- Conditions the study is for
- High Myopia, Choroid
- What is being tested?
- Caffeine and Vitamin E
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 18 participants
- Where
- 1 siteHong Kong
- Study dates
- 1 Sep 2017to 31 Dec 2019
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 49 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Refractive error should be at least -6 Diopters or lower (spherical equivalent)
- Best corrected visual acuity of at least 6/6
- Non-smoker
Who cannot join
- Diagnosed with any ocular diseases and systemic diseases
Trial locations and contacts
1 site in 1 country.
About this study
To investigate the effect of caffeine on ocular circulation by using Optical Coherence Tomography and Optical Coherence Tomography Angiography. This study will evaluate blood supply to the inner and outer retina after consumption of 200mg caffeine capsule, in particular its effect in high myopes.
Read the detailed description
Caffeine could cause vasoconstriction. Previous studies revealed a reduction of retinal blood vessels diameter, a decrease in macular blood flow, and a decrease in blood velocity of optic nerve. Research devices, such as laser speckle tissue circulation analyzer and blue field simulation technique, were used in previous studies.
With an advancement of technology such as optical coherence tomography (OCT), choroidal thickness can be measured, which indicates blood supply to outer retina. In addition, superficial retinal vasculature can be measured using optical coherence tomography angiography (OCTA).
Previous studies found that subfoveal choroidal thickness declined with increase in myopia. A negative association between subfoveal choroidal thickness and axial length was also found. A recent study found a negative association between retinal vessel density with axial length in Chinese myopes using OCTA. Therefore, caffeine consumption may further make high myopes prone to ocular diseases development due to poor ocular circulation.
The current study will use OCTA to measure the superficial retinal vasculature and OCT to measure choroidal thickness and choroidal volume of high myopes after consumption of caffeine capsule.
Statistical analysis
Normality of data will be assessed. The effect of caffeine on choroidal thickness, choroidal volume, vessel density, and perfusion density of superficial retinal layers will be analysed using repeated-measures ANOVA (co-variates) to compare baseline data and that after caffeine consumption at various time points. If significant difference is obtained, post hoc tests will be conducted to compare results from various time points with the baseline data. Difference between different age groups will be compared using unpaired t-test or Mann Whitney test, as appropriate.
- Conditions
- High Myopia, Choroid
- Being tested
- Caffeine, Vitamin E
- Keywords
- High Myopia, Caffeine, Choroidal Thickness, Choroidal Volume, Optical Coherence Tomography, Optical Coherence Tomography Angiography
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
CaffeineDietary supplement
As in group descriptions
Vitamin EDietary supplement
As in group descriptions
| Study group | Role | What they receive |
|---|---|---|
| Caffeine | Active comparator | To determine the effect of caffeine on ocular circulation in high myopes by consuming 200 mg caffeine capsule Receives: Dietary Supplement: Caffeine |
| Vitamin E | Placebo comparator | To determine the effect of caffeine on ocular circulation in high myopes by consuming and 200 International Unit vitamin E control capsule, as control Receives: Dietary Supplement: Vitamin E |
What is being measured
The primary outcome is the main question the study is designed to answer.
Choroidal thickness
Choroidal thickness measured by the optical coherence tomography
Measured: Within 4 hours
Secondary outcomes (1)
Retinal vessel density
Superficial retinal vessel density measured by OCTA
Measured: Within 4 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Sep 2017
- Study start1 Sep 2017
- Primary completion31 Dec 2019
- Study completion31 Dec 2019
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for High MyopiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- This will be a crossover study. Each subject is required to consume 200mg caffeine capsule and 200IU vitamin E control capsule, as control, in two different visits. The two visits will be randomized, with a washout period of at least one week.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 18 participants (actual)
Sponsor and investigators
- Lead sponsor
- The Hong Kong Polytechnic University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Dr Andrew KC Lam, The Hong Kong Polytechnic University
- Investigators
- Kwok Cheung Andrew Lam, PhD, Principal investigator, The Hong Kong Polytechinc University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03294967
- Sponsor's protocol ID
- HSEARS20170613002
- Status last verified
- Jul 2020
- First submitted
- 20 Sep 2017
- Last updated
- 29 Jul 2020
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Jul 2020. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Caffeine on Ocular Circulation in High Myopes
- ClinicalTrials.gov ID
- NCT03294967
- Acronym / sponsor ID
- HSEARS20170613002
- Conditions
- High Myopia, Choroid
- Keywords
- High Myopia, Caffeine, Choroidal Thickness, Choroidal Volume, Optical Coherence Tomography, Optical Coherence Tomography Angiography
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- The Hong Kong Polytechnic UniversityUniversity, hospital or other
- Study start
- 1 Sep 2017 (actual)
- Primary completion
- 31 Dec 2019 (actual)
- Study completion
- 31 Dec 2019 (actual)
- First posted
- 27 Sep 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
To investigate the effect of caffeine on ocular circulation by using Optical Coherence Tomography and Optical Coherence Tomography Angiography. This study will evaluate blood supply to the inner and outer retina after consumption of 200mg caffeine capsule, in particular its effect in high myopes.
Detailed description
Caffeine could cause vasoconstriction. Previous studies revealed a reduction of retinal blood vessels diameter, a decrease in macular blood flow, and a decrease in blood velocity of optic nerve. Research devices, such as laser speckle tissue circulation analyzer and blue field simulation technique, were used in previous studies.
With an advancement of technology such as optical coherence tomography (OCT), choroidal thickness can be measured, which indicates blood supply to outer retina. In addition, superficial retinal vasculature can be measured using optical coherence tomography angiography (OCTA).
Previous studies found that subfoveal choroidal thickness declined with increase in myopia. A negative association between subfoveal choroidal thickness and axial length was also found. A recent study found a negative association between retinal vessel density with axial length in Chinese myopes using OCTA. Therefore, caffeine consumption may further make high myopes prone to ocular diseases development due to poor ocular circulation.
The current study will use OCTA to measure the superficial retinal vasculature and OCT to measure choroidal thickness and choroidal volume of high myopes after consumption of caffeine capsule.
Statistical analysis
Normality of data will be assessed. The effect of caffeine on choroidal thickness, choroidal volume, vessel density, and perfusion density of superficial retinal layers will be analysed using repeated-measures ANOVA (co-variates) to compare baseline data and that after caffeine consumption at various time points. If significant difference is obtained, post hoc tests will be conducted to compare results from various time points with the baseline data. Difference between different age groups will be compared using unpaired t-test or Mann Whitney test, as appropriate.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- This will be a crossover study. Each subject is required to consume 200mg caffeine capsule and 200IU vitamin E control capsule, as control, in two different visits. The two visits will be randomized, with a washout period of at least one week.
| Arm | Type | Receives |
|---|---|---|
| Caffeine | Active comparator | Dietary Supplement: CaffeineTo determine the effect of caffeine on ocular circulation in high myopes by consuming 200 mg caffeine capsule |
| Vitamin E | Placebo comparator | Dietary Supplement: Vitamin ETo determine the effect of caffeine on ocular circulation in high myopes by consuming and 200 International Unit vitamin E control capsule, as control |
Who may qualify
- Ages
- 20 to 49 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Refractive error should be at least -6 Diopters or lower (spherical equivalent)
- Best corrected visual acuity of at least 6/6
- Non-smoker
Key exclusion criteria (1 listed)
- Diagnosed with any ocular diseases and systemic diseases
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| CaffeineAs in group descriptions | Dietary supplement | Caffeine |
| Vitamin EAs in group descriptions | Dietary supplement | Vitamin E |
Primary outcome
Choroidal thickness
Time frame: Within 4 hours
Choroidal thickness measured by the optical coherence tomography
1 secondary outcome
Retinal vessel density
Time frame: Within 4 hours
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jul 2020.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Kwok Cheung Andrew Lam, PhD principal investigator
The Hong Kong Polytechinc University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Caffeine and Vitamin E in people with High Myopia and Choroid, run by The Hong Kong Polytechnic University at 1 site in Hong Kong.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 Jul 2020. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Hong Kong. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Choroidal thickness (time frame: Within 4 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Jul 2020.