<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT03294967</url>
  </required_header>
  <id_info>
    <org_study_id>HSEARS20170613002</org_study_id>
    <nct_id>NCT03294967</nct_id>
  </id_info>
  <brief_title>Effect of Caffeine on Ocular Circulation in High Myopes</brief_title>
  <official_title>Effect of Caffeine on Ocular Circulation in High Myopes</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>The Hong Kong Polytechnic University</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
  </sponsors>
  <source>The Hong Kong Polytechnic University</source>
  <oversight_info>
    <has_dmc>Yes</has_dmc>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      To investigate the effect of caffeine on ocular circulation by using Optical Coherence&#xD;
      Tomography and Optical Coherence Tomography Angiography. This study will evaluate blood&#xD;
      supply to the inner and outer retina after consumption of 200mg caffeine capsule, in&#xD;
      particular its effect in high myopes.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Caffeine could cause vasoconstriction. Previous studies revealed a reduction of retinal blood&#xD;
      vessels diameter, a decrease in macular blood flow, and a decrease in blood velocity of optic&#xD;
      nerve. Research devices, such as laser speckle tissue circulation analyzer and blue field&#xD;
      simulation technique, were used in previous studies.&#xD;
&#xD;
      With an advancement of technology such as optical coherence tomography (OCT), choroidal&#xD;
      thickness can be measured, which indicates blood supply to outer retina. In addition,&#xD;
      superficial retinal vasculature can be measured using optical coherence tomography&#xD;
      angiography (OCTA).&#xD;
&#xD;
      Previous studies found that subfoveal choroidal thickness declined with increase in myopia. A&#xD;
      negative association between subfoveal choroidal thickness and axial length was also found. A&#xD;
      recent study found a negative association between retinal vessel density with axial length in&#xD;
      Chinese myopes using OCTA. Therefore, caffeine consumption may further make high myopes prone&#xD;
      to ocular diseases development due to poor ocular circulation.&#xD;
&#xD;
      The current study will use OCTA to measure the superficial retinal vasculature and OCT to&#xD;
      measure choroidal thickness and choroidal volume of high myopes after consumption of caffeine&#xD;
      capsule.&#xD;
&#xD;
      Statistical analysis&#xD;
&#xD;
      Normality of data will be assessed. The effect of caffeine on choroidal thickness, choroidal&#xD;
      volume, vessel density, and perfusion density of superficial retinal layers will be analysed&#xD;
      using repeated-measures ANOVA (co-variates) to compare baseline data and that after caffeine&#xD;
      consumption at various time points. If significant difference is obtained, post hoc tests&#xD;
      will be conducted to compare results from various time points with the baseline data.&#xD;
      Difference between different age groups will be compared using unpaired t-test or Mann&#xD;
      Whitney test, as appropriate.&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Completed</overall_status>
  <start_date type="Actual">September 1, 2017</start_date>
  <completion_date type="Actual">December 31, 2019</completion_date>
  <primary_completion_date type="Actual">December 31, 2019</primary_completion_date>
  <phase>N/A</phase>
  <study_type>Interventional</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <allocation>Randomized</allocation>
    <intervention_model>Crossover Assignment</intervention_model>
    <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.</intervention_model_description>
    <primary_purpose>Diagnostic</primary_purpose>
    <masking>Single (Participant)</masking>
    <masking_description>Participants will not see the label of the capsule.</masking_description>
  </study_design_info>
  <primary_outcome>
    <measure>Choroidal thickness</measure>
    <time_frame>Within 4 hours</time_frame>
    <description>Choroidal thickness measured by the optical coherence tomography</description>
  </primary_outcome>
  <secondary_outcome>
    <measure>Retinal vessel density</measure>
    <time_frame>Within 4 hours</time_frame>
    <description>Superficial retinal vessel density measured by OCTA</description>
  </secondary_outcome>
  <number_of_arms>2</number_of_arms>
  <enrollment type="Actual">18</enrollment>
  <condition>High Myopia</condition>
  <condition>Choroid</condition>
  <arm_group>
    <arm_group_label>Caffeine</arm_group_label>
    <arm_group_type>Active Comparator</arm_group_type>
    <description>To determine the effect of caffeine on ocular circulation in high myopes by consuming 200 mg caffeine capsule</description>
  </arm_group>
  <arm_group>
    <arm_group_label>Vitamin E</arm_group_label>
    <arm_group_type>Placebo Comparator</arm_group_type>
    <description>To determine the effect of caffeine on ocular circulation in high myopes by consuming and 200 International Unit vitamin E control capsule, as control</description>
  </arm_group>
  <intervention>
    <intervention_type>Dietary Supplement</intervention_type>
    <intervention_name>Caffeine</intervention_name>
    <description>As in group descriptions</description>
    <arm_group_label>Caffeine</arm_group_label>
  </intervention>
  <intervention>
    <intervention_type>Dietary Supplement</intervention_type>
    <intervention_name>Vitamin E</intervention_name>
    <description>As in group descriptions</description>
    <arm_group_label>Vitamin E</arm_group_label>
  </intervention>
  <eligibility>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Refractive error should be at least -6 Diopters or lower (spherical equivalent)&#xD;
&#xD;
          -  Best corrected visual acuity of at least 6/6&#xD;
&#xD;
          -  Non-smoker&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
        - Diagnosed with any ocular diseases and systemic diseases&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>20 Years</minimum_age>
    <maximum_age>49 Years</maximum_age>
    <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
  </eligibility>
  <overall_official>
    <last_name>Kwok Cheung Andrew Lam, PhD</last_name>
    <role>Principal Investigator</role>
    <affiliation>The Hong Kong Polytechinc University</affiliation>
  </overall_official>
  <location>
    <facility>
      <name>School of optometry</name>
      <address>
        <city>Hong Kong</city>
        <country>Hong Kong</country>
      </address>
    </facility>
  </location>
  <location_countries>
    <country>Hong Kong</country>
  </location_countries>
  <verification_date>July 2020</verification_date>
  <study_first_submitted>September 20, 2017</study_first_submitted>
  <study_first_submitted_qc>September 22, 2017</study_first_submitted_qc>
  <study_first_posted type="Actual">September 27, 2017</study_first_posted>
  <last_update_submitted>July 27, 2020</last_update_submitted>
  <last_update_submitted_qc>July 27, 2020</last_update_submitted_qc>
  <last_update_posted type="Actual">July 29, 2020</last_update_posted>
  <responsible_party>
    <responsible_party_type>Principal Investigator</responsible_party_type>
    <investigator_affiliation>The Hong Kong Polytechnic University</investigator_affiliation>
    <investigator_full_name>Dr Andrew KC Lam</investigator_full_name>
    <investigator_title>Associate Professor</investigator_title>
  </responsible_party>
  <keyword>High Myopia</keyword>
  <keyword>Caffeine</keyword>
  <keyword>Choroidal Thickness</keyword>
  <keyword>Choroidal Volume</keyword>
  <keyword>Optical Coherence Tomography</keyword>
  <keyword>Optical Coherence Tomography Angiography</keyword>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Myopia</mesh_term>
  </condition_browse>
  <intervention_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Vitamin E</mesh_term>
    <mesh_term>Caffeine</mesh_term>
  </intervention_browse>
  <patient_data>
    <sharing_ipd>No</sharing_ipd>
  </patient_data>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT03294967
org study id: HSEARS20170613002
nct id: NCT03294967
lead sponsor: 
has dmc: Yes
is fda regulated drug: No
is fda regulated device: No
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.
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.
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.
primary purpose: Diagnostic
masking: Single (Participant)
masking description: Participants will not see the label of the capsule.
measure: Choroidal thickness
time frame: Within 4 hours
description: Choroidal thickness measured by the optical coherence tomography
measure: Retinal vessel density
time frame: Within 4 hours
description: Superficial retinal vessel density measured by OCTA
arm group label: Caffeine
arm group type: Active Comparator
description: To determine the effect of caffeine on ocular circulation in high myopes by consuming 200 mg caffeine capsule
arm group label: Vitamin E
arm group type: Placebo Comparator
description: To determine the effect of caffeine on ocular circulation in high myopes by consuming and 200 International Unit vitamin E control capsule, as control
intervention type: Dietary Supplement
intervention name: Caffeine
description: As in group descriptions
arm group label: Caffeine
intervention type: Dietary Supplement
intervention name: Vitamin E
description: As in group descriptions
arm group label: Vitamin E
criteria: 
gender: All
minimum age: 20 Years
maximum age: 49 Years
healthy volunteers: Accepts Healthy Volunteers
last name: Kwok Cheung Andrew Lam, PhD
role: Principal Investigator
affiliation: The Hong Kong Polytechinc University
facility: 
country: Hong Kong
responsible party type: Principal Investigator
investigator affiliation: The Hong Kong Polytechnic University
investigator full name: Dr Andrew KC Lam
investigator title: Associate Professor
mesh term: Myopia
mesh term: Vitamin E
mesh term: Caffeine
sharing ipd: No