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Clinical Trial Details — Status: Completed

Administrative data

NCT number NCT03294967
Other study ID # HSEARS20170613002
Secondary ID
Status Completed
Phase N/A
First received
Last updated
Start date September 1, 2017
Est. completion date December 31, 2019

Study information

Verified date July 2020
Source The Hong Kong Polytechnic University
Contact n/a
Is FDA regulated No
Health authority
Study type Interventional

Clinical 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.


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.


Recruitment information / eligibility

Status Completed
Enrollment 18
Est. completion date December 31, 2019
Est. primary completion date December 31, 2019
Accepts healthy volunteers Accepts Healthy Volunteers
Gender All
Age group 20 Years to 49 Years
Eligibility 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

Study Design


Related Conditions & MeSH terms


Intervention

Dietary Supplement:
Caffeine
As in group descriptions
Vitamin E
As in group descriptions

Locations

Country Name City State
Hong Kong School of optometry Hong Kong

Sponsors (1)

Lead Sponsor Collaborator
The Hong Kong Polytechnic University

Country where clinical trial is conducted

Hong Kong, 

Outcome

Type Measure Description Time frame Safety issue
Primary Choroidal thickness Choroidal thickness measured by the optical coherence tomography Within 4 hours
Secondary Retinal vessel density Superficial retinal vessel density measured by OCTA Within 4 hours
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