Choroidal and Retinal Features in PACD and POAG on OCT and OCTA

May 6, 2026 updated by: Zhongshan Ophthalmic Center, Sun Yat-sen University
Glaucoma is a group of irreversible, progressive optic neuropathies that can lead to severe visual field defects and even blindness, affecting nearly 95 million people worldwide. Based on anterior chamber angle structure, glaucoma is classified into primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG). Although POAG is more common, PACG is more severe and more likely to cause blindness if not managed appropriately. Globally, PACG accounts for approximately 25% of all glaucoma cases but is responsible for roughly 50% of glaucoma-related blindness. Generally, the term "glaucoma" implies optic nerve damage; however, glaucomatous optic neuropathy may be absent in subacute and acute angle-closure glaucoma. Therefore, according to international consensus, primary angle-closure disease is categorized as PACD-encompassing primary angle-closure suspect (PACS), primary angle closure (PAC), and PACG-based on the extent of angle closure, intraocular pressure elevation, and optic nerve damage. With advances in ophthalmic imaging, an increasing array of diagnostic modalities has been applied to glaucoma diagnosis. Optical coherence tomography (OCT), which utilizes low-coherence light to display cross-sectional images of the retina in vivo, represents a rapid, non-invasive, and continuously evolving imaging method. Building upon OCT, OCTA has emerged as a novel imaging technique that allows non-invasive visualization and assessment of blood flow in individual retinal layers [5]. Existing OCT and OCTA research on glaucoma primarily focuses on the optic disc and macula of glaucoma patients, providing evidence of changes in the retinal nerve fiber layer, macular ganglion cell thickness, optic nerve head structure, and peripapillary and macular vasculature. Other studies have examined choroidal vascular architecture and thickness in glaucoma; previous findings from our research group also indicate that choroidal vascular density is significantly lower in eyes with POAG and PACG compared to normal eyes, while choroidal stromal area is significantly greater in PACG than in POAG eyes and normal controls. Further investigation into choroidal and retinal alterations in glaucoma is warranted. Consequently, the OCT and OCTA fundus characteristics of patients with PACD and POAG remain an area with unexplored unknowns. This study utilizes OCT and OCTA to observe the choroidal and retinal tissue structure and vascular hemodynamics in patients with PACD and POAG, aiming to comprehensively investigate structural changes in the glaucomatous fundus, broaden new research directions, and explore and supplement the understanding of glaucoma pathogenesis.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
132

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
    • Guangdong
      • Guangzhou, Guangdong, China, 510060
        • Recruiting
        • Zhongshan Ophthalmic Center, Sun Yat-sen University
        • Contact:

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

This study includes an observation cohort of adults diagnosed with POAG or PACD and a control cohort of healthy adults without glaucoma. Eligible participants range in age from 18 to 90 years and have no history of confounding retinal or neurological diseases that would interfere with OCT/OCTA imaging assessment.

Description

Inclusion Criteria:

  • Control group: Healthy individuals with no history of ocular surgery, IOP < 21 mmHg, and CDR < 0.5 bilaterally without asymmetry
  • Observation group: Glaucoma specialist-confirmed diagnosis of POAG or PACD (per ISGEO staging: PACS/PAC/PACG)

Exclusion Criteria:

  • History of retinal or macular disease (e.g., AMD, DR, RVO, ERM)
  • Non-glaucomatous optic neuropathy (e.g., MS, NMO)
  • Poor OCT/OCTA image quality
  • Refusal to sign informed consent

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Control Group

Inclusion Criteria:

  1. Individuals undergoing routine physical examination, generally in good health, with no history of prior surgery.
  2. No use of glaucoma medications, no evidence of elevated intraocular pressure (IOP < 21 mmHg), no significant optic nerve head (ONH) asymmetry (cup-to-disc ratio difference < 0.2), and cup-to-disc ratio (CDR) < 0.5 in both eyes.
  3. Age between 18 and 90 years, inclusive; any gender.

Exclusion Criteria:

  1. Known history of retinal disease, including any condition involving macular degeneration (e.g., age-related macular degeneration, diabetic retinopathy, retinal vein occlusion, viral retinitis, or epiretinal membrane).
  2. Optic nerve abnormalities other than glaucoma, such as those associated with neurological complications (e.g., Multiple Sclerosis, Neuromyelitis Optica).
  3. Poor quality of OCT or OCTA images obtained post-examination.
  4. Refusal to sign the informed consent form.
Observation Group

Inclusion Criteria:

  1. Confirmed diagnosis of Primary Open-Angle Glaucoma (POAG) or Primary Angle-Closure Disease (PACD) by a glaucoma specialist. The diagnosis of POAG is based on standard clinical criteria, specifically: presence of an open angle, glaucomatous optic neuropathy, current or past elevation of intraocular pressure, and visual field defects [10]. PACD cases are diagnosed and enrolled according to the clinical staging system of PACS, PAC, and PACG as established by the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) .
  2. Age between 18 and 90 years, inclusive; any gender.

Exclusion Criteria:

  1. Known history of retinal disease, including any condition involving macular degeneration (e.g., age-related macular degeneration, diabetic retinopathy, retinal vein occlusion, viral retinitis, or epiretinal membrane).
  2. Optic nerve abnormalities other than glaucoma, such as those observed in patients with neurological com

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Subfoveal choroidal thickness (μm)
Time Frame: Day 1
Subfoveal choroidal thickness (SFCT) is defined as the vertical distance between the outer border of the retinal pigment epithelium (RPE)/Bruch's membrane complex and the choroid-scleral junction directly beneath the fovea centralis. This measurement is obtained using a widefield swept-source OCT device, which enables enhanced depth imaging and high-resolution visualization of the choroid.The assessment is subsequently conducted by a masked, experienced grader using the integrated caliper tool. SFCT serves as a quantitative biomarker for choroidal structural changes associated with primary angle-closure disease (PACD) and primary open-angle glaucoma (POAG).
Day 1
Deviation of the horizontal watershed zone
Time Frame: Day 1
The deviation of the horizontal watershed zone (HWZ) is assessed by determining whether the HWZ is displaced superiorly or inferiorly relative to the fovea centralis. This evaluation is performed using 24 × 20 mm en face OCTA images acquired with a widefield swept-source OCTA device. All measurements are carried out with the device's built-in caliper tool by a masked, experienced grader. The HWZ deviation serves as a quantitative indicator reflecting alterations in choroidal venous outflow patterns.
Day 1

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Choroidal vascularity index (%)
Time Frame: Day 1
Choroidal vascularity index (CVI) is defined as the ratio of choroidal vascular volume to total choroidal volume within a designated region, expressed as a percentage, with higher values indicating greater vascular density. The measurement was performed on images acquired with a widefield swept-source OCTA deviceand assessed by a masked, experienced grader.
Day 1

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Zhongshan Ophthalmic Center, Sun Yat-sen 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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 16, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 20, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 20, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 16, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 6, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 12, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 6, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2024KYPJ067

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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