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Sequential Laser Iridotomy Using Argon and Q-Switched 532 nm Frequency Doubled Neodymium Yag Laser: A Pilot Study

This study has been completed.
Information provided by:
National University Hospital, Singapore Identifier:
First received: March 27, 2007
Last updated: May 12, 2008
Last verified: May 2008
Sequential Laser Iridotomy uses argon and Nd:yag laser in the first and second steps, respectively. Using q-switched 532 nm laser in the second step is hypothesized to be as good and effective as the conventional Nd:yag laser, because it selectively targets pigmented cells and delivers a short pulse duration of 3 nanoseconds, causing less thermal and collateral damage.

Condition Intervention
Chronic Angle Closure Glaucoma
Primary Angle Closure
Primary Angle Closure Suspect
Fellow Eyes of Acute Angle Closure Glaucoma
Procedure: Q-switched fd Nd:yag in Laser Iridotomy

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Sequential Laser Iridotomy Using Argon and Q-Switched 532 nm Frequency Doubled Neodymium Yag Laser: A Pilot Study

Resource links provided by NLM:

Further study details as provided by National University Hospital, Singapore:

Primary Outcome Measures:
  • Visual Acuity
  • Intraocular pressure
  • Total power delivered by each laser modality
  • Iridotomy patency and size
  • Pain rating during the procedure
  • Anterior segment inflammation
  • Endothelial cell count
  • Cataract progression
  • Rate of complications

Estimated Enrollment: 10
Study Start Date: November 2006
Study Completion Date: December 2007
Primary Completion Date: December 2007 (Final data collection date for primary outcome measure)
  Show Detailed Description


Ages Eligible for Study:   22 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • More than 21 years old
  • Able to give informed consent
  • Diagnosis of either: chronic angle closure glaucoma (CACG), primary angle closure (PAC), primary angle closure suspect (PACS) or fellow eyes of acute angle closure glaucoma (AACG), and in need of a laser iridotomy

Exclusion Criteria:

  • History of any prior laser treatment or intraocular surgery to the eye
  • History of any corneal disease
  • Any ocular infection/ inflammation within the last two months
  • Inability to give informed consent
  Contacts and Locations
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Please refer to this study by its identifier: NCT00452998

National University Hospital
Singapore, Singapore, 119074
Sponsors and Collaborators
National University Hospital, Singapore
Principal Investigator: Paul Chew, FRCSEd,MMed National University Hospital, Singapore
  More Information

Responsible Party: Cecilia Aquino, MD, National University Hospital, Singapore Identifier: NCT00452998     History of Changes
Other Study ID Numbers: DSRB A/06/293
Study First Received: March 27, 2007
Last Updated: May 12, 2008

Keywords provided by National University Hospital, Singapore:
Sequential Laser Iridotomy
Q-Switched 532 nm Laser
Frequency Doubled Neodymium Yag Laser

Additional relevant MeSH terms:
Glaucoma, Angle-Closure
Acute Disease
Ocular Hypertension
Eye Diseases
Disease Attributes
Pathologic Processes processed this record on May 25, 2017