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Argon Laser Peripheral Iridoplasty for Primary Angle Closure Glaucoma (ALPI)

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ClinicalTrials.gov Identifier: NCT00980473
Recruitment Status : Unknown
Verified November 2009 by Singapore National Eye Centre.
Recruitment status was:  Recruiting
First Posted : September 21, 2009
Last Update Posted : June 17, 2011
National University Hospital, Singapore
Information provided by:
Singapore National Eye Centre

Brief Summary:

Glaucoma is the leading cause of irreversible blindness worldwide. With ageing of the population, glaucoma morbidity will rise, causing increased health care costs and economic burden for a condition in which visual loss, once established, cannot be reversed. In contrast to western countries, primary angle closure glaucoma (PACG) is a major form of glaucoma in Asia. In a recent population based survey in Singapore, the prevalence of glaucoma was 3.2% in the Chinese population over 40. Glaucoma was the leading cause of blindness, with PACG the most visually destructive form of the disease.

Laser iridotomy is the current first line treatment for PACG. It acts by relieving pupil block, which in turn may reduce intraocular pressure (IOP) and prevent progression of glaucoma. However recent data indicate that iridotomy is not successful in controlling IOP in the long term, and the majority of cases develop a clinically significant rise in IOP requiring medical therapy or surgery.

Argon laser peripheral iridoplasty (ALPI) offers a new therapeutic option for PACG. The procedure consists of placing contraction burns in the iris periphery which results in contraction of the iris stroma and opening of the angle.

The proposed study is a 2-centre randomized controlled trial to determine whether ALPI is an effective and safe treatment in the management of PACG. 210 patients with PACG and high IOP (>21 mmHg) following laser iridotomy will be randomized to receive ALPI or medical treatment to achieve IOP control. Subjects will be followed up for 12 months and the outcome criteria will be the rate of medical treatment and surgery in each group, and the angle width and configuration.

This will be the first RCT worldwide to address the role of ALPI in PACG. The study findings will have great relevance for the prevention of glaucoma blindness in the elderly.

Condition or disease Intervention/treatment Phase
Glaucoma Procedure: Argon Laser Iridoplasty Drug: Travatan/ Timolol/Azopt Phase 3

  Show Detailed Description

Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 80 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Primary Purpose: Treatment
Official Title: Argon Laser Peripheral Iridoplasty for Primary Angle Closure Glaucoma: A Randomised Controlled Trial
Study Start Date : September 2007
Estimated Primary Completion Date : September 2011

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Glaucoma
U.S. FDA Resources

Arm Intervention/treatment
Active Comparator: Iridoplasty Procedure: Argon Laser Iridoplasty
Active Comparator: Control (Medication) Drug: Travatan/ Timolol/Azopt

Primary Outcome Measures :
  1. The primary outcome will be the number of patients in each group on medical treatment or having had surgical treatment at 12 months. The mean number of medications required to control IOP in each group will also be analyzed. [ Time Frame: one year ]

Secondary Outcome Measures :
  1. The secondary outcome will be the change in angle width and configuration as measured by gonioscopic examination, ultrasound biomicroscopy (UBM) and anterior segment OCT assessment at 1 month, 6 months and 12 months following entry into the study. [ Time Frame: one year ]

Information from the National Library of Medicine

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Ages Eligible for Study:   21 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Persistent narrow angle in the presence of a patent laser peripheral iridotomy. A narrow angle is defined as an angle width of 0-10º in 2 or more quadrants of either eye or where the pigmented trabecular meshwork is not visible in for 2 or more quadrants on gonioscopic examination
  • Intraocular pressure > 21mmHg on or off topical medication at least four weeks following laser iridotomy
  • Intra ocular pressure > 21 mm Hg after wash out regimen as described below for patients who are already on one medication and Iridotomy has been done at least 4 weeks ago.
  • Informed Consent
  • Age more than 21 years

Exclusion Criteria:

  • Age less than 21 years
  • Secondary causes of angle closure like subluxed lens, uveitis, trauma and neovascular glaucoma
  • Presence of advanced sight-threatening glaucoma defined as vertical cup-disc ratio > 0.9
  • Presence of significant synechial angle closure with > 6 clock hours of peripheral anterior synechiae (defined as abnormal adhesions of the iris to the angle that are at least half a clock hour in width and be at least to the anterior trabecular meshwork or higher on indentation gonioscopy)
  • Cataract that is deemed significant enough to require surgery during the course of the trial or that makes field testing or optic disc imaging not technically possible- visual acuity less than 20/40 due to any type of cataract.
  • Corneal endothelial cell count less than 1000 cells/mm2
  • Corneal abnormalities or infection
  • Previous intraocular surgery
  • Use of contact lens
  • Chronic use of topical or systemic steroids
  • Participation in another therapeutic drug study within the last 30 days
  • Severe health problems precluding follow-up such as end-stage heart disease, kidney disease, respiratory disease, or cancer and life expectancy less than one year.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00980473

Contact: Tin Aung, FRCOphth 62277255 aung_tin@yahoo.co.uk

Singapore National Eye Centre Recruiting
Singapore, Singapore, 168751
Principal Investigator: Tin Aung, FRCOphth         
Sponsors and Collaborators
Singapore National Eye Centre
National University Hospital, Singapore

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: A/Prof Aung Tin. A/PROF & CONSULTANT, Singapore National Eye Centre
ClinicalTrials.gov Identifier: NCT00980473     History of Changes
Other Study ID Numbers: R399/57/2004
First Posted: September 21, 2009    Key Record Dates
Last Update Posted: June 17, 2011
Last Verified: November 2009

Keywords provided by Singapore National Eye Centre:
Primary Angle Closure Disease

Additional relevant MeSH terms:
Glaucoma, Angle-Closure
Ocular Hypertension
Eye Diseases
Adrenergic beta-Antagonists
Adrenergic Antagonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Anti-Arrhythmia Agents
Antihypertensive Agents