Asymptomatic Narrow Angles - Laser Iridotomy Study; Multicentric RCT

Study Overview
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Brief Summary
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This is a multicentric, randomised, controlled study comparing Laser Iridotomy (LI) to no treatment in subjects with asymptomatic narrow angles (ANA).One eye of each subject with ANA will be randomised to undergo LI and the other eye will be left alone and will serve as an internal control. Subjects are proposed to be followed up once a year for 5 years.

Detailed Description
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Objective: This study will compare LI versus no treatment in subjects with asymptomatic narrow angles, the anatomical trait that predisposes to primary angle closure glaucoma (PACG), in order to assess the effectiveness of prophylactic treatment in the prevention of blindness due to PACG. Eligibility: 1. Bilateral Narrow angles; 2. Age 50 years and above; 3. Informed consent obtained prior to or at baseline visit. Trial Design: Subjects with asymptomatic ANA undergoes randomisation after comprehensive ocular exam followed by randomisation to LI in one eye and no treatment in the other eye. Follow up is done for 5 years with yearly examination.

Official Title
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Prophylactic Laser Iridotomy for Eyes With Narrow Drainage Angles; A Randomised Controlled Trial

Conditions
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Asymptomatic Narrow Angles, Primary Angle Closure Suspects

Intervention / Treatment
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* Procedure: Laser Peripheral Iridotomy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Bilateral Narrow angles Age 50 years and above Informed consent obtained prior to or at baseline visit Exclusion Criteria: Presence of PAS IOP > 21 mm Hg Glaucomatous optic neuropathy and/or CDR > 0.7 Secondary angle closure such as uveitis, neovascularisation etc. Prior intraocular surgery or penetrating eye injury Corneal disorders such as corneal endothelial dystrophy except mild corneal guttae Evidence of prior acute angle closure event High risk of acute angle closure. Significant cataract and visual acuity less than 20/40 Constant use of contact lens for refractive correction Chronic use of topical or systemic steroids Established retinopathies on ocular treatments (e.g. Diabetic) Any other disease which is likely to cause field loss in next 3 years Severe health problems decreasing life expectancy to less than one year.

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Procedure: Laser Peripheral Iridotomy|nan|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peripheral anterior synechiae formation |  |  | 
| IOP elevation >21 mm Hg |  |  | 
| Development of acute angle closure event |  |  | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in the grading of Modified Schaffer Grading |  |  | 
| Development of glaucomatous optic neuropathy |  |  | 
| Development of corresponding visual field loss by automated perimetry |  |  | 
| Change in HRT optic disc parameters |  |  | 
| Change in UBM angle parameters |  |  | 
| Formation of disc pallor |  |  | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Asymptomatic Narrow Angles, Primary Angle Closure Suspects, Laser Peripheral Iridotomy, Randomised Controlled Trial