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Intraocular Pressure (IOP) Lowering Effect of Selective Laser Trabeculoplasty Versus Prostaglandin Analogues in Angle Closure Glaucoma

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01004900
Recruitment Status : Unknown
Verified May 2010 by Singapore Eye Research Institute.
Recruitment status was:  Recruiting
First Posted : October 30, 2009
Last Update Posted : May 12, 2010
Information provided by:
Singapore Eye Research Institute

Brief Summary:

Glaucoma affects 66 million people worldwide and is the leading cause of irreversible blindness, and Primary angle-closure glaucoma (PACG) is a major form of glaucoma in Asia.

Laser peripheral iridotomy (LPI) has been advocated as the first line treatment in all cases of PACG. In addition to relieving the relative pupil block element of the condition, it can open up the drainage angle, alleviating appositional and synechial angle-closure and in the long-term this may control intraocular pressure (IOP) and prevent progression of glaucomatous optic neuropathy. 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.

Laser trabeculoplasty has been a recognized treatment option for Primary open angle glaucoma (POAG) since the 1980s. Recently a more selective and less destructive method of performing laser trabeculoplasty has evolved. Selective Laser Trabeculoplasty (SLT) specifically targets the pigmented trabecular meshwork cells without producing collateral damage and destruction to adjacent structures. Morphologic study performed on human autopsy eyes treated with SLT noted no structural or collateral thermal damage to the trabecular beams in the uveal and corneoscleral meshwork. As SLT specifically has its effect on the targeted pigmented trabecular meshwork it is unlikely to generate PAS. It may be a useful treatment option for PACG patients in whom the angle has widened following laser peripheral iridotomy.

The proposed study is a randomized controlled trial to assess the effectiveness of SLT in reducing IOP in cases of PACG in which the angle has opened up following LPI, but IOP remains high(>21 mmHg). 100 subjects will be randomized to receive either SLT or medical treatment to achieve IOP control. They will be followed up for 6 months.

Condition or disease Intervention/treatment Phase
Glaucoma Procedure: Selective Laser Trabeculoplasty Drug: Travoprost/ Timolol/ Azopt/ Brimonidine Phase 3

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 90 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Comparison of Selective Laser Trabeculoplasty With Prostaglandin Analogues for Lowering Intraocular Pressure in Eyes With Primary Angle Closure Glaucoma
Study Start Date : June 2009
Estimated Primary Completion Date : March 2011
Estimated Study Completion Date : March 2011

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Glaucoma
Drug Information available for: Travoprost

Arm Intervention/treatment
Active Comparator: Trabeculoplasty Procedure: Selective Laser Trabeculoplasty
This is a laser procedure used to treat glaucoma by reducing the pressure in the eye. SLT works by using laser light to stimulate the body's own healing response to lower your eye pressure. Using a special wavelength and energy, the laser affects only pigmented (melanin containing) cells of your eye. SLT improves the flow of fluid in the eye, which in turn lowers your eye pressure.

Active Comparator: Control (Medication) Drug: Travoprost/ Timolol/ Azopt/ Brimonidine
Travoprost (Topical eye drops) administered once daily before sleep

Primary Outcome Measures :
  1. Intraocular Pressure [ Time Frame: 6 months ]
    Fluid pressure inside the eye

Information from the National Library of Medicine

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

Inclusion Criteria:

  • Diagnosis of primary angle closure or primary angle closure glaucoma with documented pre-LPI angle closure of ≥180 degrees of the angle (Trabecular meshwork not visible in primary position using gonioscopy)
  • One month post LPI, angle has opened up (visibility of trabecular meshwork) for at least 180 degrees of the angle
  • Intraocular pressure between 21-≤30 mmHg without treatment following LPI OR Intraocular pressure between 21-≤30 mmHg after wash out regimen as described below for patients who are already medications following LPI.
  • Informed Consent
  • Age more than 21 years

Exclusion Criteria:

  • 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 or visual field constriction involving <100 of the central visual field performed with the Humphrey Visual Field Analyzer II using the SITA STD algorithm with a 24-2 test pattern.
  • 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.
  • Previous intraocular surgery, SLT, ALT, refractive surgery or iridoplasty.
  • Documented previous history of angle closure.
  • 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 identifier (NCT number): NCT01004900

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Contact: Tin Aung, FRCOphth 62277255

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Singapore National Eye Centre Recruiting
Singapore, Singapore, 168751
Contact: Tin Aung, FRCOphth    62277255   
Principal Investigator: Tin Aung, FRCOphth         
Sponsors and Collaborators
Singapore Eye Research Institute
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Principal Investigator: Tin Aung, FRCOphth Singapore National Eye Centre
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: A/ Prof Aung Tin, A/ PROF & CONSULTANT, Singapore National Eye Centre Identifier: NCT01004900    
Other Study ID Numbers: R657/07/2009
First Posted: October 30, 2009    Key Record Dates
Last Update Posted: May 12, 2010
Last Verified: May 2010
Keywords provided by Singapore Eye Research Institute:
Glaucoma, Angle Closure
Selective laser trabeculoplasty
Primary Angle Closure Disease
Additional relevant MeSH terms:
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Glaucoma, Angle-Closure
Ocular Hypertension
Eye Diseases
Brimonidine Tartrate
Adrenergic beta-Antagonists
Adrenergic Antagonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Anti-Arrhythmia Agents
Antihypertensive Agents
Adrenergic alpha-2 Receptor Agonists
Adrenergic alpha-Agonists
Adrenergic Agonists