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CompletedNCT03675412Updated Oct 13, 2026

Caffeine Consumption in Glaucoma Patients and Healthy Subjects

An interventional study of Caffeine tablet in Glaucoma, Primary Open Angle, sponsored by Wills Eye. Completed at 1 site in United States. Open to participants aged 18 Years to 90 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-13.

Sponsored by Wills Eye · Not applicable, Interventional, and Diagnostic

Updated Oct 13, 2026Now CompletedPrimary completion moved+2 moreGo to Updates ↓
Phase
Not applicable
Study type
Interventional
Enrollment
18
Allocation
Non-randomized
Ages
18 Years to 90 Years
Sex
All
01

Study summary

Caffeine is the most widely consumed drinking nutrient in the world. Caffeine effects various organs and the vascular system. It decreases ocular blood flow due to vasoconstriction.

Read the detailed description

Ingestion of caffeine in glaucoma patients and healthy subjects may decrease peripapillary and macular blood flow in the back of the eye.

The primary objective of this study is to assess the acute changes in peripapillary and macular blood flow before and after an intake of oral caffeine (200 milligram tablet) in glaucoma patients and healthy subjects by using optical coherence tomography angiography (OCTA) scans. This novel imaging tool creates three-dimensional angiograms to assesses signal changes caused by flowing blood cells in a non-invasive angiogram scan. Blood flow is shown as vessel density measured in percentage.

02

Conditions studied

  • Glaucoma, Primary Open Angle

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Keywords

  • Primary Open Angle Glaucoma (POAG)
  • Optical Coherence Tomography Angiography (OCTA)
  • Caffeine
  • Macular Blood Flow
  • Peripapillary Blood Flow
03

In context

Glaucoma, Open-Angle

924 studies on the registry are indexed under Glaucoma, Open-Angle; 117 are open to participants now.

This study's enrollment of 18 is below the median of 80 across 692 interventional studies indexed under Glaucoma, Open-Angle.

Browse Glaucoma, Open-Angle studies →

Lead sponsor

Wills Eye is the lead sponsor of 77 studies on the registry; 2 are open to participants now.

Of its 12 completed or terminated interventional studies of FDA-regulated products, 10 (83%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 90 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • age 18 to 90 years
  • diagnosis of primary open angle glaucoma (Mild, Moderate and Advanced)
  • healthy subjects with no eye disease

Exclusion criteria

Exclusion Criteria:

  • Diseases, ophthalmic or systemic, that are likely to affect OCTA results
  • greater than moderate cataract
  • nystagmus
  • inability to look at target
  • macular degeneration other than mild drusen or pigmentary changes
  • diabetic retinopathy
  • neovascular glaucoma or non-glaucoma optic neuropathies
  • current macular edema, prior laser to retina, inflammatory retinopathy or choroidopathy
  • keratoconus, corneal ectasia, central corneal scarring
  • rheumatologic diseases or Raynaud's phenomena
  • pregnant and lactating women
  • mental illness or alcohol addiction
  • pre-existing bladder symptoms, cardiac disease or sleep disorder
  • refractive spherical diopter greater than 5 or cylinder greater than 3
  • possible tolerance to caffeine (drinking more than 1 cup coffee per day).
05

Study design

Phase
Not applicable
Primary purpose
Diagnostic
Allocation
Non-randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
18 participants (actual)

Study arms

  • Active comparator
    Glaucoma Patients

    Eligible participants include patients with mild, moderate or advanced primary open angle glaucoma (POAG) or primary angle closure glaucoma (PACG). Each participant will complete baseline study tasks. Each participant will then receive one 200 mg caffeine tablet to ingest. Study tasks will be performed 1 hour and 2 hours after caffeine ingestion.

    Dietary Supplement: Caffeine tablet

  • Active comparator
    Healthy controls

    Eligible participants include healthy subjects with no eye diseases. Each participant will complete baseline study tasks. Each participant will then receive one 200 mg caffeine tablet to ingest. Study tasks will be performed 1 hour and 2 hours after caffeine ingestion.

    Dietary Supplement: Caffeine tablet

Interventions

  • Dietary supplementCaffeine tablet

    Each eligible participant will receive one 200 mg caffeine tablet to ingest after completing all baseline study tasks.

06

What researchers measure

Primary outcomes

  1. Blood flow change in back of eye before and after caffeine

    Optical Coherence Tomography Angiography (OCTA) will be obtained using the Avanti AngioVue High Definition (HD) OCTA by Optovue. Images will include standard 4.5mm HD disc scan, 6mm HD retina scan, regular optic nerve head (ONH) structural scan, 3D-disc baseline scan and a regular ganglion cell complex analysis (GCCA) structural scan. This will measure blood flow changes in the back of the eye by imaging vessel density in percentage before then 1 and 2 hours after caffeine.

    Time frame: Baseline, Hour 1, Hour 2

07

Study locations

1 site
  • Wills Eye Glaucoma Service
    Philadelphia, Pennsylvania 19107, United States
08

References and documents

Study documents

PDFs hosted by the registry, ClinicalTrials.gov.

Individual participant data

Plan to share: No

09

Timeline

1 registry update since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedDate before it movedWhere the date was before it movedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Dec 2018 to primary completion in Feb 2024, 61 months.

Of 100 non-industry interventional studies with no phase under Glaucoma, Open-Angle, half reached primary completion within 35 months of starting (the median), counting those still running; a quarter within 16 and three quarters within 57. This study's 61 months is above that.

Counting every sponsor, half of 170 studies reached it within 35 months; a quarter within 19 and three quarters within 61.

Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 13, 2026: primary completion Apr 2027 → Feb 2024 and completion Jun 2027 → Feb 2024.

Earlier changes are on the record history on ClinicalTrials.gov ↗

How these figures are worked out, and which studies are left out of them.

Registered
Sep 5, 2018
First posted
Sep 18, 2018
StartActual
Dec 30, 2018
Primary completionActual
Feb 16, 2024was Apr 2027
CompletionActual
Feb 16, 2024was Jun 2027
Last update
Oct 13, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
Status
Recruiting→Completed
changed Oct 13, 2026
Primary completion
Apr 30, 2027→Feb 16, 2024 (actual)
Oct 13, 2026
Study completion
Jun 30, 2027→Feb 16, 2024 (actual)
Oct 13, 2026
Enrollment
80 (estimated)→18 (actual)
Oct 13, 2026
Show all 1 update
  1. Oct 13, 2026
    Recruiting→Completed
    Primary completion Apr 30, 2027→Feb 16, 2024 (now actual)
    Study completion Jun 30, 2027→Feb 16, 2024 (now actual)
    Enrollment 80 (estimated)→18 (actual)
    + 3 other changes: verification date, contact details and site details

From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗

10

Registry details

Key details

Study ID
NCT03675412
Lead sponsor
Wills Eye
Responsible party
M. Reza Razeghinejad MD (Principal Investigator, Wills Eye) — Principal investigator
First posted
Sep 18, 2018
Start date
Dec 30, 2018
Primary completion
Feb 16, 2024
Completion
Feb 16, 2024
Last update
Oct 13, 2026

Study contacts

M. Reza Razeghinejad, MD
principal investigator · Wills Eye Hospital

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.

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Studies of the drug tested here: Caffeine

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