Effect of Caffeine on Ocular Circulation in High Myopes
Study Details
Study Description
Brief 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.
Condition or Disease | Intervention/Treatment | Phase |
---|---|---|
|
N/A |
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
Arms and Interventions
Arm | Intervention/Treatment |
---|---|
Active Comparator: Caffeine To determine the effect of caffeine on ocular circulation in high myopes by consuming 200 mg caffeine capsule |
Dietary Supplement: Caffeine
As in group descriptions
|
Placebo Comparator: Vitamin E To determine the effect of caffeine on ocular circulation in high myopes by consuming and 200 International Unit vitamin E control capsule, as control |
Dietary Supplement: Vitamin E
As in group descriptions
|
Outcome Measures
Primary Outcome Measures
- Choroidal thickness [Within 4 hours]
Choroidal thickness measured by the optical coherence tomography
Secondary Outcome Measures
- Retinal vessel density [Within 4 hours]
Superficial retinal vessel density measured by OCTA
Eligibility Criteria
Criteria
Inclusion Criteria:
-
Refractive error should be at least -6 Diopters or lower (spherical equivalent)
-
Best corrected visual acuity of at least 6/6
-
Non-smoker
Exclusion Criteria:
- Diagnosed with any ocular diseases and systemic diseases
Contacts and Locations
Locations
Site | City | State | Country | Postal Code | |
---|---|---|---|---|---|
1 | School of optometry | Hong Kong | Hong Kong |
Sponsors and Collaborators
- The Hong Kong Polytechnic University
Investigators
- Principal Investigator: Kwok Cheung Andrew Lam, PhD, The Hong Kong Polytechinc University
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- HSEARS20170613002