Effect of Caffeine on Ocular Circulation in High Myopes

High Myopia Clinical Trial

Official title:

Effect of Caffeine on Ocular Circulation in High Myopes

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03294967
• Other study ID #: HSEARS20170613002
• Status: Completed
• Phase: N/A
• 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
• 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

Related Conditions & MeSH terms

• Choroid
• High Myopia
• Myopia

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