Comparing Nd:YAG Laser and Sequential Double Frequency YAG-Nd:YAG Laser Iridotomy

Study Overview
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Brief Summary
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No single type of laser or set of laser parameters is appropriate for all type of irides. Pure Nd:YAG laser iridotomy is very effective in the light color irides. It was considered as the gold standard for iridotomy. It, however, is less effective and causes some complication such as iris hemorrhage especially in patients with dark iris.

Detailed Description
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By using the double frequency YAG to make the initial bore and the Nd:YAG laser to complete the perforation, the technique should be able to effectively combine most of the advantages of both lasers whilst avoiding their disadvantages. It is possibly the ideal iridotomy technique to use in the Asian irides. The investigators aim to study the energy use for laser iridotomy comparing between the two techniques as well as objectively measure the variables associated with complications.

Official Title
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Randomized Clinical Trial Comparing Neodynium:Ytrium-aluminium-garnet (Nd:YAG) Laser and Sequential Double Frequency YAG-Nd:YAG Laser Iridotomy in Patients With Dark Iris

Conditions
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Angle Closure Glaucoma

Intervention / Treatment
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* Device: The sequential technique
* Device: The pure Nd:YAG laser technique


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient in need to have a laser iridotomy primary angle closure glaucoma or primary angle closure or primary angle closure suspect (needed repeated pupil dilation) or fellow eyes of acute angle closure crisis, and Age of at least 18 years, and Dark iris patients (only black and dark brown color) Exclusion Criteria: Eye with acute angle closure crisis Active conjunctiva or corneal infection or inflammation Active anterior uveitis History of any prior laser treatment History intraocular surgery Eye with corneal scar Corneal haziness obscure iridotomy site Endothelial cell count less than 1000 cells/mm2 (pre-laser) Iris color other than black or dark brown Inability to sit at the slit lamp to have laser done

Ages Eligible for Study
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Minimum Age: 18 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: The sequential technique<br>By using the double frequency YAG laser to make the initial bore and the Nd:YAG laser to complete the perforation on iris. | Device: The sequential technique<br>* By using 'the double frequency YAG laser' to make the initial bore and 'the Nd:YAG laser' to complete the perforation on iris.<br>|
| Active Comparator: The pure Nd:YAG laser technique<br>By using the pure Nd:YAG to make a complete perforation on iris. | Device: The pure Nd:YAG laser technique<br>* By using 'the pure Nd:YAG laser' to make a complete perforation on iris.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Laser energy | Total energy used to create patency on the iris | 1-hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bleeding | iris bleeding immediate after laser reported as Yes or No | 1-hour | 
| Corneal endothelial cell count | Corneal endothelial cell count directly over the area of laser | 12-month | 
| Central corneal thickness | Central corneal thickness | 12-month | 
| Patency of iridotomy | Iridotomy patency is confirmed objectively reported as yes or no | 12-month | 
| Intraocular pressure spike | Intraocular pressure spike if present mean that IOP evelation of at least 8mmHg from baseline intraocular pressure | 1-hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Iridotomy