Effect of Caffeine on Ocular Circulation in High Myopes

July 27, 2020 updated by: Dr Andrew KC Lam, The Hong Kong Polytechnic University
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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

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 Type

Interventional

Enrollment (Actual)

18

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 Locations

  • Hong Kong
      • Hong Kong, Hong Kong
        • School of Optometry

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

20 years to 49 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

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 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: DIAGNOSTIC
  • Allocation: RANDOMIZED
  • Interventional Model: CROSSOVER
  • Masking: SINGLE

Arms and Interventions

Participant Group / 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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Choroidal thickness
Time Frame: Within 4 hours
Choroidal thickness measured by the optical coherence tomography
Within 4 hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Retinal vessel density
Time Frame: Within 4 hours
Superficial retinal vessel density measured by OCTA
Within 4 hours

Collaborators and Investigators

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

Sponsor

The Hong Kong Polytechnic University

Investigators

  • Principal Investigator: Kwok Cheung Andrew Lam, PhD, The Hong Kong Polytechinc University

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)

September 1, 2017

Primary Completion (ACTUAL)

December 31, 2019

Study Completion (ACTUAL)

December 31, 2019

Study Registration Dates

First Submitted

September 20, 2017

First Submitted That Met QC Criteria

September 22, 2017

First Posted (ACTUAL)

September 27, 2017

Study Record Updates

Last Update Posted (ACTUAL)

July 29, 2020

Last Update Submitted That Met QC Criteria

July 27, 2020

Last Verified

July 1, 2020

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HSEARS20170613002

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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