Effect of Caffeine on Ocular Circulation in High Myopes

Sponsor
The Hong Kong Polytechnic University (Other)
Overall Status
Completed
CT.gov ID
NCT03294967
Collaborator
(none)
18
1
2
28
0.6

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
  • Dietary Supplement: Caffeine
  • Dietary Supplement: Vitamin E
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

Study Type:
Interventional
Actual Enrollment :
18 participants
Allocation:
Randomized
Intervention Model:
Crossover Assignment
Intervention 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.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 (Participant)
Masking Description:
Participants will not see the label of the capsule.
Primary Purpose:
Diagnostic
Official Title:
Effect of Caffeine on Ocular Circulation in High Myopes
Actual Study Start Date :
Sep 1, 2017
Actual Primary Completion Date :
Dec 31, 2019
Actual Study Completion Date :
Dec 31, 2019

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

  1. Choroidal thickness [Within 4 hours]

    Choroidal thickness measured by the optical coherence tomography

Secondary Outcome Measures

  1. Retinal vessel density [Within 4 hours]

    Superficial retinal vessel density measured by OCTA

Eligibility Criteria

Criteria

Ages Eligible for Study:
20 Years to 49 Years
Sexes Eligible for Study:
All
Accepts Healthy Volunteers:
Yes
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.
Responsible Party:
Dr Andrew KC Lam, Associate Professor, The Hong Kong Polytechnic University
ClinicalTrials.gov Identifier:
NCT03294967
Other Study ID Numbers:
  • HSEARS20170613002
First Posted:
Sep 27, 2017
Last Update Posted:
Jul 29, 2020
Last Verified:
Jul 1, 2020
Individual Participant Data (IPD) Sharing Statement:
No
Plan to Share IPD:
No
Studies a U.S. FDA-regulated Drug Product:
No
Studies a U.S. FDA-regulated Device Product:
No
Keywords provided by Dr Andrew KC Lam, Associate Professor, The Hong Kong Polytechnic University
Additional relevant MeSH terms:

Study Results

No Results Posted as of Jul 29, 2020