Predicting the Risk of Partial Ciliary Block After Cataract and Goniosynechialysis Surgery in Primary Angle-Closure Disease (PCB-Risk)

Risk Prediction of Partial Ciliary Block After Phacoemulsification Combined With Goniosynechialysis in Primary Angle-Closure Disease: A Prospective Multicenter Study

Primary angle-closure disease (PACD) is a major cause of vision loss, often treated with a combined surgery that removes the eye's natural lens (cataract surgery) and physically opens the eye's drainage system (goniosynechialysis). While effective, this surgery carries a small risk of a severe complication called ciliary block (or aqueous misdirection), where fluid builds up in the wrong part of the eye, pushing structures forward and causing high eye pressure. Recently, doctors have also noticed a "partial" form of this block, which can slowly cause the eye's drainage angle to close again without immediate severe symptoms.

The purpose of this prospective, observational study is to identify which patients are at the highest risk for developing classic or partial ciliary block after this combined surgery. Researchers will use standard, non-invasive eye imaging tools-such as ultrasound biomicroscopy (UBM) and optical coherence tomography (OCT)-to take highly detailed measurements of the front of the eye before surgery. They will specifically look at factors like the width of the anterior chamber, the thickness of the lens, and the eye's overall length. To ensure accuracy, patients with a very short eye length (less than 19mm) will not be included in the study.

Because this is an observational study, participation will not change a patient's standard surgical plan. Patients will undergo their scheduled surgery and be monitored for 12 months during routine follow-up visits to track their eye pressure, vision, and any structural changes in the eye.

By confirming which pre-surgery measurements predict ciliary block, researchers hope to validate a risk-warning model. This will help eye surgeons take preventive steps-such as administering specific medications like mannitol before surgery-to make the procedure safer and improve long-term outcomes for patients with PACD.

Study Overview

• Status: Not yet recruiting
• Conditions: Primary Angle-Closure Glaucoma

• Study Type: Observational
• Enrollment (Estimated): 1150

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

Patients with Primary Angle-Closure Disease (PACD)-spanning PACS, PAC, and PACG-who require surgical intervention with phacoemulsification combined with goniosynechialysis. Participants will be enrolled from the routine clinical care settings across multiple participating tertiary ophthalmic centers.

Description

Inclusion Criteria:

1. Diagnosis of Primary Angle-Closure Disease (PACD), including Primary Angle-Closure Suspect (PACS), Primary Angle-Closure (PAC), or Primary Angle-Closure Glaucoma (PACG).
2. Clinical indication for phacoemulsification combined with intraocular lens implantation and goniosynechialysis (Phaco+GSL), due to poorly controlled intraocular pressure, extensive peripheral anterior synechiae (PAS), or the presence of a clinically significant cataract.
3. Ability to cooperate with required preoperative imaging examinations, including Ultrasound Biomicroscopy (UBM), IOLMaster, and Anterior Segment Optical Coherence Tomography (AS-OCT).

Exclusion Criteria:

1. Secondary angle closure (e.g., neovascular glaucoma, uveitic glaucoma, iridocorneal endothelial [ICE] syndrome, or intraocular tumors/cysts).
2. Specific lens abnormalities that confound anatomical assessment, including lens subluxation, hypermature intumescent cataract, or traumatic cataract.
3. Previous intraocular surgery, including glaucoma filtering surgeries (e.g., trabeculectomy, tube shunts) or vitreoretinal surgeries (Note: Previous laser peripheral iridotomy is permitted).
4. Use of systemic or topical medications known to affect ciliary body morphology or pupillary function (e.g., topiramate, cholinergic agonists) during the time of imaging.
5. Poor quality or uninterpretable preoperative UBM or OCT images due to corneal opacity, edema, or other media opacities.
6. Axial length shorter than 19mm.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
CB Group; Patients who develop classic or partial ciliary block (CB) during the 12-month follow-up period after phacoemulsification combined with goniosynechialysis.
Non-CB Group; Patients who do not develop any form of ciliary block during the 12-month follow-up period after the surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Ciliary Block (Classic and Partial)	The primary outcome is the occurrence rate of classic or partial ciliary block (CB) following phacoemulsification combined with goniosynechialysis. Classic CB is diagnosed by a shallow or flat anterior chamber with elevated intraocular pressure, excluding pupillary block or choroidal effusion. Partial (subclinical) CB is defined by meeting at least two of the following criteria: an unexpected shallow anterior chamber (e.g., less than the expected 3mm or significantly smaller than the contralateral eye), a significant myopic shift (≥ -1.50D) indicating IOL-iris diaphragm anterior shift, UBM/OCT evidence of ciliary body anterior rotation, or significant deepening of the anterior chamber after cycloplegic administration. Intraoperative aqueous misdirection is also recorded as a primary endpoint event.	Up to 12 months postoperatively

Collaborators and Investigators

• Sponsor: Peking University People's Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): April 20, 2026
• Primary Completion (Estimated): April 19, 2030
• Study Completion (Estimated): April 19, 2031

Study Registration Dates

• First Submitted: April 18, 2026
• First Submitted That Met QC Criteria: April 18, 2026
• First Posted (Actual): April 24, 2026

Study Record Updates

• Last Update Posted (Actual): April 24, 2026
• Last Update Submitted That Met QC Criteria: April 18, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Eye Diseases; Ocular Hypertension; Glaucoma; Glaucoma, Angle-Closure
• Other Study ID Numbers: PekingUPHOphthalmology004