Vitreous Zonule in Primary Angle-Closure Glaucoma

April 5, 2026 updated by: Wu Huijuan, Peking University People's Hospital

A Cross-Sectional, Prospective Observational Study on the Role of the Vitreous Zonule in the Pathogenesis of Primary Angle-Closure Glaucoma

This study aims to investigate the role of the vitreous zonule (VZ) in the pathogenesis of primary angle-closure glaucoma (PACG) and to explore the feasibility of three-dimensional ultrasound biomicroscopy (3D-UBM) for imaging the circumferential VZ.

This prospective, observational study will enroll patients with primary angle-closure disease (PACD), including primary angle-closure suspect (PACS), primary angle-closure (PAC), and PACG, as well as healthy controls. All participants will undergo comprehensive ophthalmic examinations, including gonioscopy, biometric measurements using IOLMaster, and UBM imaging. The study consists of three main components: (1) analysis of VZ morphology, location, number of visible quadrants, and anterior segment parameters across different age groups and axial length groups in healthy individuals, with comparisons to age-matched PACD patients; (2) development and validation of a 3D-UBM imaging system using a rotational scanning approach to reconstruct the spatial structure of the VZ; and (3) characterization of VZ features, including density and morphology, in normal eyes versus PACD eyes using 3D-UBM.

The primary outcomes include the presence, quadrant count, and morphological characteristics (vitreous zonule-pars plana angle and maximum distance) of the VZ, as well as anterior segment parameters such as lens vault, anterior chamber depth, trabecular-iris angle, and angle opening distance. By elucidating age-related and axial length-related changes in the VZ and establishing 3D-UBM as a novel imaging modality for the posterior zonular apparatus, this study seeks to provide new evidence for the mechanistic role of the VZ in angle-closure glaucoma and to identify potential imaging biomarkers for early diagnosis and risk stratification.

Study Overview

Status

Recruiting

Conditions

Study Type

Observational

Enrollment (Estimated)

440

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 Locations

  • China
      • Beijing, China, 100044
        • Recruiting
        • Peking University People's Hospital
        • 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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

The study population will be recruited from the Department of Ophthalmology at Peking University People's Hospital, a tertiary referral center in Beijing, China. Participants will include patients diagnosed with primary angle-closure disease (PACS, PAC, and PACG) and healthy controls with open angles. Patients will be identified from outpatient clinics and through routine ophthalmic examinations. Healthy controls will be recruited from volunteers undergoing routine eye examinations, as well as from hospital staff and community members. All participants will be recruited prospectively and consecutively to minimize selection bias.

Description

Inclusion Criteria:

1. Age between 30 and 80 years, inclusive. 2. Diagnosis of primary angle-closure disease (PACS, PAC, or PACG) according to standardized gonioscopic criteria; or healthy controls with open angles. 3. Lens opacity graded < 2 for cortical and nuclear opacities according to the Lens Opacities Classification System III (LOCS III). 4. Ability and willingness to provide written informed consent.

Exclusion Criteria:

1. Any intraocular disease affecting the anterior or posterior segment, including but not limited to corneal disease, iris abnormalities, lens disorders other than age-related cataract, vitreous disorders, uveoretinal diseases, or optic neuropathies. 2. Prior intraocular surgery or laser treatment, including cataract surgery, trabeculectomy, laser trabeculoplasty, laser peripheral iridotomy, laser iridoplasty, or vitreoretinal surgery. 3. Systemic diseases that may affect ocular examination or confound measurements, such as end-stage cardiac disease, renal disease, pulmonary disease, or advanced malignancy. 4. Inability to undergo ultrasound biomicroscopy (UBM) examination due to inability to maintain supine position or other contraindications. 5. Pregnancy or lactation. 6. Any condition that, in the opinion of the investigator, would compromise the participant's ability to comply with study procedures or affect the validity of the study results.

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 1 Healthy Controls
Group 2 Primary Angle-Closure Suspects (PACS）
Group 3 Primary Angle Closure
Group 4 Primary Angle Closure Glaucoma

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Vitreous Zonule Visibility on Ultrasound Biomicroscopy
Time Frame: Baseline
Presence and quadrant count of the VZ assessed by ultrasound biomicroscopy (UBM). VZ is defined as fibrous bands extending from the pars plana to the posterior lens equator or ciliary processes. Presence is defined as VZ visible in at least one quadrant; quadrant count ranges from 0 to 4.
Baseline

Collaborators and Investigators

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

Sponsor

Peking University People's Hospital

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)

January 1, 2025

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

April 5, 2026

First Submitted That Met QC Criteria

April 5, 2026

First Posted (Actual)

April 13, 2026

Study Record Updates

Last Update Posted (Actual)

April 13, 2026

Last Update Submitted That Met QC Criteria

April 5, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PekingUPHOphthalmology003

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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