Clinical Study of LPI With Different Laser Wavelengths

Not Applicable

• Conditions: Glaucoma
• Interventions: Procedure: 561nm laser group; Procedure: 532nm laser group

• Registration Number: NCT02901730
• Lead Sponsor: First Affiliated Hospital of Fujian Medical University

Brief Summary

Glaucoma is the second cause of blindness worldwide. Laser peripheral iridoplasty (LPI) is a simple and effective treatment for angle closure glaucoma. LPI can widen or reopen an existing angle close or angle adhesion in order to reduce the risk of attack of the angle closure glaucoma. However, there are very little research on the laser site, laser wavelengths, laser energy and laser spot intervals. The purpose of this study is to determine the optimum laser wavelengths of LPI.

Detailed Description

Glaucoma is the second cause of blindness worldwide. Laser peripheral iridoplasty (LPI) is a simple and effective treatment for angle closure glaucoma. LPI can widen or reopen an existing angle close or angle adhesion in order to reduce the risk of attack of the angle closure glaucoma. However, there are very little research on the laser site, laser wavelengths, laser energy and laser spot intervals.Conventional LPI uses wavelength 532nm laser. However, our preclinical studies have found that the laser penetration of the laser wavelength 561nm is stronger than that of the laser wavelength 532nm. It can produce a stronger contraction effect.

The purpose of this study is to determine the optimum laser wavelengths of LPI. Baseline and 7days, 1 month, 3 months after LPI, the structure of anterior chamber, including angle anterior chamber depth(ACD), angle of anterior chamber (AA), anterior chamber angle opening distance 750(AOD750) are measured with ultrasound biomicroscopy. Baseline and 7days, 1 month, 3 months after LPI, the outflow resistance of aqueous humor are evaluated with C value. Baseline and 1hour, 1days, 3day, 7days, 1 month, 3 months after LPI, intraocular pressure are measured with Goldmann tonometry. Baseline and 3 months after LPI, retinal nerve layer thickness and the optic disc cup disc ratio are measure with optical coherence tomography.

Study Timeline

• Status Verified: 2016-09
• Study Start: 2016-09
• Study First Submitted: 2016-09-11
• Study First Submitted QC: 2016-09-11
• Last Update Submitted: 2016-09-11
• Study First Posted: 2016-09-15
• Last Update Posted: 2016-09-15
• Primary Completion: 2017-12
• Study Completion: 2017-12

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• Patients with primary angle closure suspect (PACS), primary angle closure (PAC) or primary angle closure glaucoma (PACG).
• PACS is diagnosed in eyes with an occludable angle but no other abnormality.
• PAC is diagnosed in eyes with an occludable angle, normal optic discs and visual fields and any of the following: raised IOP (>19 mm Hg), PAS, pigment smearing in the superior angle, or sequelae of acute angle closure (iris whirling or glaucomatous fleck).
• PACG is diagnosed in eyes with an occludable angle and glaucomatous optic neuropathy. Evidence of glaucomatous optic neuropathy is defined as a cup: disc ratio (CDR) of >0.7 or >0.2 CDR asymmetry.
• An occludable angle is defined as one in which three quarters of the posterior pigmented trabecular meshwork is not visible on viewing with a Goldmann two mirror lens in the primary position of gaze without indentation.

Exclusion Criteria

• Patients with previous ocular surgery, and those with secondary angle closure, such as lens intumescence or subluxation, iris neovascularisation and a history of uveitis.
• Patients who have systemic contraindications to medical therapy (including renal impairment, sulfur allergy, asthma and heart failure), pre-existing corneal opacities obstructing laser access to more than one quadrant of the peripheral iris and single-eyed patients are also excluded.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
561nm laser group	561nm laser group	LPI with 561nm laser.
532nm laser group	532nm laser group	LPI with 532nm laser.

Primary Outcome Measures

Name	Time	Method
Change of anterior chamber angle(AA)	Baseline and 3 months after LPI.	Anterior chamber angle (AA) is measured with ultrasound biomicroscopy.

Secondary Outcome Measures

Name	Time	Method
Change of anterior chamber angle opening distance 750(AOD750)	Baseline and 3 months after LPI.	Anterior chamber angle opening distance 750(AOD750) is measured with ultrasound biomicroscopy.
Change of anterior chamber depth(ACD)	Baseline and 3 months after LPI.	Anterior chamber depth(ACD) is measured with ultrasound biomicroscopy.
Change of C value	Baseline and 7days, 1 month, 3 months after LPI.	IOP is measured with Schφtz tonometry.
Change of retinal nerve layer thickness	Baseline and 3 months after LPI.	Retinal nerve layer thickness is measured with optical coherence tomography.
Change of optic disc cup disc ratio	Baseline and 3 months after LPI.	Optic disc cup disc ratio is measured with optical coherence tomography.
Change of mean sensitivity	Baseline and 3 months after LPI.	Mean sensitivity is measured with computer perimetry.
Change of scotoma	Baseline and 3 months after LPI.	Scotoma is measured with computer perimetry.
Change of intraocular pressure (IOP)	Baseline and 1hour, 1days, 3day, 7days, 1 month, 3 months after LPI.	IOP is measured with Goldmann tonometry.
Change of mean defect	Baseline and 3 months after LPI.	Mean defect is measured with computer perimetry.