Biometric Changes After Intervention of Anterior Chamber Angle : an Observational Study

Recruiting

• Conditions: Goniotomy; Minimally Invasive Glaucoma Surgery; Goniosynechialysis; Angle-closure Glaucoma; Glaucoma
• Interventions: Procedure: various types of angle interventions

• Registration Number: NCT06492538
• Lead Sponsor: Zhongshan Ophthalmic Center, Sun Yat-sen University

Brief Summary

The drainage angle in the anterior chamber of the eye mediates the outflow of aqueous humor, and pathological changes here can lead to high intraocular pressure and glaucoma. Minimally invasive glaucoma surgery, particularly angle surgery, has advanced recently, allowing clear visualization of angle structures like the trabecular meshwork and Schlemm's canal using surgical goniolens. Techniques for angle intervention include widening the angle, reopening closed angles, and rebuilding outflow pathways using methods such as laser peripheral iridotomy, Argon laser peripheral iridoplasty, and mechanical separation of adhered tissues. Our research team plans to conduct imaging studies to track the healing of angle tissues post-surgery, aiming to support innovation and standardization of minimally invasive angle surgery.

Detailed Description

Pathological elevated intraocular pressure is one of the most important disease characteristics of glaucoma. Blockage of aqueous humor outflow within the eye is the primary cause of high intraocular pressure. The drainage angle in the anterior chamber of the eye mediates the outflow of aqueous humor. Pathological changes in this area can lead to the development of high intraocular pressure and glaucoma, such as primary angle closure glaucoma (PACG) caused by angle closure. Minimally invasive glaucoma surgery has rapidly developed in recent years, with angle surgery being a major branch. With the use of surgical goniolens, structures within the angle, such as trabecular meshwork and Schlemm's canal, can be visualized clearly during surgery. Methods for angle intervention include but not limit ed to widening the peripheral anterior chamber angle, reopening adhered or appositionally closed angles, and rebuilt outflow pathways by incising diseased areas to increase aqueous humor outflow. Techniques include laser peripheral iridotomy (LPI) to relieve pupillary block and deepen the peripheral anterior chamber, Argon laser peripheral iridoplasty (ALPIP) to stimulate iris contraction and widen the angle, and mechanical separation of adhered angle tissues using instruments like goniosynechialysis hooks or iris repositors. Surgical incision using instruments such as Microhook, trabeculectomy hooks, or cannulas can be performed to remove the diseased inner wall of Schlemm's canal and the diseased trabecular meshwork either partially or circumferentially. However, the healing and outcomes of angle tissues following invasive angle interventions, and their impact on surgical outcomes, remain unclear. Therefore, our research team proposes to conduct imaging observation studies to track, observe, and quantify the status of the angle, exploring the healing process of angle tissues. This aims to provide theoretical support for the innovation and standardization of minimally invasive angle surgery.

Study Timeline

• Study Start: 2023-12-01
• Status Verified: 2024-07
• Study First Submitted: 2024-07-01
• Study First Submitted QC: 2024-07-01
• Last Update Submitted: 2024-07-01
• Study First Posted: 2024-07-09
• Last Update Posted: 2024-07-09
• Primary Completion: 2025-12-30
• Study Completion: 2025-12-30

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 300

Inclusion Criteria

• Glaucoma patients eligible for standalone or combined angle intervention surgeries, such as LPI, LPIP, goniosynechialysis, trabeculotomy alone or combined with surgical iridectomy or phacoemulsification and intraocular lens implantation;
• Patients capable of undergoing preoperative examinations including CASIA2-OCT (anterior segment OCT), UBM, slit-lamp gonioscopy, IOL Master (or other optical biometry);
• Patients willing to participate in this study, signing informed consent, and agreeing to follow-up according to the study protocol.

Exclusion Criteria

• Patients with severe ocular conditions such as corneal infection, ulcer, trauma, ocular tumors, retinal vascular occlusion, and retinal detachment;
• Those with various types of eye diseases that affect ocular parameter acquisition or interfere with visual field examination;
• Long-term local or systemic use of glucocorticoids;
• Patients with severe systemic diseases;
• Pregnant or lactating women;
• Unable to complete 12-month postoperative follow-up.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
laser peripheral iridotomy/iridoplasty group	various types of angle interventions	based on angle closure mechanism, procedures were chosen LPI alone or combined with ALPIp. LPI: laser peripheral iridotomy; ALPIp: argon laser peripheral iridoplasty.
peripheral iridectomy based surgery combo	various types of angle interventions	SPI combined with GSL or GSL+GT SPI: surgical peripheral iridectomy GSL:goniosynechialysis GT: goniotomy GSL and GT are both guided by surgical goniolens
phacoemulsification and intraocular lens implantation based surgery combo	various types of angle interventions	PEI: phacoemulsification and intraocular lens implantation surgery combo includes GSL alone or GSL+GT.
ab interno goniotomy	various types of angle interventions	GT was performed in the nasal-inferior quadrant or nasal quadrant because the collector channels were mainly concentrated in the nasal quadrant, by inserting the tip of a microblade (TMH; Tanito Microhook, Inami \& Co., Ltd., Tokyo, Japan) into Schlemm's canal, and then the inner wall of Schlemm's canal and trabecular meshwork was incised over 120°
Schlemm canaloplasty	various types of angle interventions	performed in the nasal quadrant by the collector channels were mainly concentrated in the nasal quadrant, by inserting the tip of a microblade (TMH; Tanito Microhook, Inami \& Co., Ltd., Tokyo, Japan) into Schlemm's canal, and then the inner wall of Schlemm's canal and trabecular meshwork was incised over 120°

Primary Outcome Measures

Name	Time	Method
Changes in biological parameters of the anterior chamber angle	12 months	Biological parameter changes in the anterior chamber following angle intervention surgery will be measured using Casia2-OCT

Secondary Outcome Measures

Name	Time	Method
success rate of angle intervention surgeries	12 months	complete success was defined as postoperative IOP within the range of 6-18 mmHg, and a reduction of 20% from baseline without loss of light perception, additional ocular hypotensive medication, and reoperation. The definition of qualified success was similar to that of complete success, except for the need for ocular hypotensive medications. Postoperative ocular hypotensive medications were adjusted according to the IOP at each visit.

Trial Locations

Locations (1)

Zhongshan ophthalmic center; 🇨🇳 Guangzhou, Guangdong, China