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.

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.

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.