An observational study in Primary Angle-Closure Glaucoma, sponsored by Peking University People's Hospital. Recruiting at 1 site in China. Open to participants aged 30 Years to 79 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-04-13.
Sponsored by Peking University People's Hospital · Observational
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.
91 studies on the registry are indexed under Glaucoma, Angle-Closure; 17 are open to participants now.
This study's planned enrollment of 440 is above the median of 225 across 32 observational studies indexed under Glaucoma, Angle-Closure.
Browse Glaucoma, Angle-Closure studies →Peking University People's Hospital is the lead sponsor of 609 studies on the registry; 247 are open to participants now.
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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.
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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 .
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 . 4. Inability to undergo ultrasound biomicroscopy (UBM) examination due to inability to maintain supine position or other . 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.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Vitreous Zonule Visibility on Ultrasound Biomicroscopy
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.
Time frame: Baseline
Started Jan 2025 (actual). Primary completion is estimated for Jun 2027, 29 months after the start.
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