Asymptomatic Narrow AnglesNCT00347178
Asymptomatic Narrow Angles - Laser Iridotomy Study; Multicentric RCT
A study testing Laser Peripheral Iridotomy in people with Asymptomatic Narrow Angles and Primary Angle Closure Suspects, run by Singapore National Eye Centre at 1 site in Singapore.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 50 years and older
- Conditions the study is for
- Asymptomatic Narrow Angles, Primary Angle Closure Suspects
- What is being tested?
- Laser Peripheral Iridotomy
- Type of treatment
- Surgery or procedure
- How many people
- 544 participants
- Where
- 1 siteSingapore
- Study dates
- Jan 2005to Jan 2013
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 50 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Bilateral Narrow angles
- Age 50 years and above
- Informed consent obtained prior to or at baseline visit
Who cannot join
- 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
Show all 14Show fewer
- 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.
Trial locations and contacts
1 site in 1 country.
Tin - Aung, FRCSEd PhD contact
Singapore1 site, 1 recruiting
- Recruiting
Singapore Eye Research Institute
Singapore, 168751
Tin Aung, FRCSEd, PhD
Steve KL Seah, FRCS (Ed)
About this study
Official title: Prophylactic Laser Iridotomy for Eyes With Narrow Drainage Angles; A Randomised Controlled Trial
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.
Read the detailed description
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.
- Being tested
- Laser Peripheral Iridotomy
- Keywords
- Asymptomatic Narrow Angles, Primary Angle Closure Suspects, Laser Peripheral Iridotomy, Randomised Controlled Trial
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Laser Peripheral IridotomyProcedure or surgery
What is being measured
The primary outcome is the main question the study is designed to answer.
Peripheral anterior synechiae formation
IOP elevation >21 mm Hg
Development of acute angle closure event
Secondary outcomes (6)
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
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Jul 2006 (estimated)
- Study startJan 2005
- Study completionJan 2013
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Asymptomatic Narrow AnglesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 544 participants
Sponsor and investigators
- Lead sponsor
- Singapore National Eye Centre
- Sponsor type
- Other government
- Collaborators
- National Medical Research Council (NMRC), Singapore
- Investigators
- Tin - Aung, FRCSEd PhD, Principal investigator, Singapoe National Eye Centre
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00347178
- Sponsor's protocol ID
- R358/16/2004
- Status last verified
- Jun 2006
- First submitted
- 30 Jun 2006
- Last updated
- 4 Jul 2006
- Results posted
- No
Publications
Tun TA, Yoo C, Servillo A, Baskaran M, Kumar RS, Narayanaswamy A, Foster PJ, Friedman DS, Aung T. Factors Associated With Progression to Primary Angle Closure: A Post Hoc Analysis of the ANA-LIS Trial. JAMA Ophthalmol. 2026 Jul 16:e262554. doi: 10.1001/jamaophthalmol.2026.2554. Online ahead of print.
PubMed 42461625Baskaran M, Kumar RS, Friedman DS, Lu QS, Wong HT, Chew PTK, Lavanya R, Narayanaswamy A, Perera SA, Foster PJ, Aung T. The Singapore Asymptomatic Narrow Angles Laser Iridotomy Study: Five-Year Results of a Randomized Controlled Trial. Ophthalmology. 2022 Feb;129(2):147-158. doi: 10.1016/j.ophtha.2021.08.017. Epub 2021 Aug 26.
PubMed 34453952Narayanaswamy A, Baskaran M, Tun TA, Htoon HM, Aung T. Effect of Pharmacological Pupil Dilatation on Angle Configuration in Untreated Primary Angle Closure Suspects: A Swept Source Anterior Segment Optical Coherence Tomography Study. J Glaucoma. 2020 Jul;29(7):521-528. doi: 10.1097/IJG.0000000000001506.
PubMed 32224802
Study at a glance
From the registry record, last updated by the sponsor on 4 Jul 2006. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prophylactic Laser Iridotomy for Eyes With Narrow Drainage Angles; A Randomised Controlled Trial
- ClinicalTrials.gov ID
- NCT00347178
- Acronym / sponsor ID
- R358/16/2004
- Keywords
- Asymptomatic Narrow Angles, Primary Angle Closure Suspects, Laser Peripheral Iridotomy, Randomised Controlled Trial
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 544 participants
- Lead sponsor
- Singapore National Eye CentreOther government
- Collaborators
- National Medical Research Council (NMRC), Singapore
- Study start
- Jan 2005
- Study completion
- Jan 2013
- First posted
- 4 Jul 2006 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
Who may qualify
- Ages
- 50 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Bilateral Narrow angles
- Age 50 years and above
- Informed consent obtained prior to or at baseline visit
Key exclusion criteria (14 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Laser Peripheral Iridotomy | Procedure or surgery | – |
Primary outcome
Peripheral anterior synechiae formation
IOP elevation >21 mm Hg
Development of acute angle closure event
6 secondary outcomes
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
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Jul 2006.
- Derived from this study: PubMed 42461625Tun TA, Yoo C, Servillo A, Baskaran M, Kumar RS, Narayanaswamy A, Foster PJ, Friedman DS, Aung T. Factors Associated With Progression to Primary Angle Closure: A Post Hoc Analysis of the ANA-LIS Trial. JAMA Ophthalmol. 2026 Jul 16:e262554. doi: 10.1001/jamaophthalmol.2026.2554. Online ahead of print.
- Derived from this study: PubMed 34453952Baskaran M, Kumar RS, Friedman DS, Lu QS, Wong HT, Chew PTK, Lavanya R, Narayanaswamy A, Perera SA, Foster PJ, Aung T. The Singapore Asymptomatic Narrow Angles Laser Iridotomy Study: Five-Year Results of a Randomized Controlled Trial. Ophthalmology. 2022 Feb;129(2):147-158. doi: 10.1016/j.ophtha.2021.08.017. Epub 2021 Aug 26.
- Derived from this study: PubMed 32224802Narayanaswamy A, Baskaran M, Tun TA, Htoon HM, Aung T. Effect of Pharmacological Pupil Dilatation on Angle Configuration in Untreated Primary Angle Closure Suspects: A Swept Source Anterior Segment Optical Coherence Tomography Study. J Glaucoma. 2020 Jul;29(7):521-528. doi: 10.1097/IJG.0000000000001506.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Tin - Aung, FRCSEd PhD contact
Tin - Aung, FRCSEd PhD principal investigator
Singapoe National Eye Centre
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Laser Peripheral Iridotomy in people with Asymptomatic Narrow Angles and Primary Angle Closure Suspects, run by Singapore National Eye Centre at 1 site in Singapore.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 4 Jul 2006. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Singapore. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Tin - Aung, FRCSEd PhD (+65 63224581), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Peripheral anterior synechiae formation. The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00347178, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Jul 2006.