GlaucomaPhase 3ALPINCT00980473
Argon Laser Peripheral Iridoplasty for Primary Angle Closure Glaucoma
A Phase 3 study testing Argon Laser Iridoplasty and Travatan/ Timolol/Azopt in people with Glaucoma, run by Singapore National Eye Centre at 1 site in Singapore.
Trial 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. Read more about this study
- Who is it for?
- Ages 21 years and older
- Conditions the study is for
- Glaucoma
- What is being tested?
- Argon Laser Iridoplasty and Travatan/ Timolol/Azopt
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 80 participants
- Where
- 1 siteSingapore
- Study dates
- Sep 2007to Sep 2011
- Phase
- Phase 3
- 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 21 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Show all 12Show fewer
- 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.
Trial locations and contacts
1 site in 1 country.
Singapore1 site, 1 recruiting
- Recruiting
Singapore National Eye Centre
Singapore, 168751
Tin Aung, FRCOphth
About this study
Official title: Argon Laser Peripheral Iridoplasty for Primary Angle Closure Glaucoma: A Randomised Controlled Trial
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.
Read more
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.
Read the detailed description
AIMS AND OBJECTIVES
The primary aim of the study is to determine whether argon laser peripheral iridoplasty (ALPI) is an effective treatment in terms of intraocular pressure (IOP) control for cases of primary angle closure glaucoma (PACG) in which the drainage angle remains narrow following laser iridotomy. Primary outcome measures will be the proportion of patients requiring medical or surgical treatment to maintain IOP control, number of medications required to control IOP at 12 months follow up.
The secondary aim is determine whether ALPI significantly alters the configuration of the drainage angle when compared with conventional treatment (medication) following laser iridotomy. Secondary outcomes will be the change in appearance of the drainage angle based on gonioscopy, ultrasound biomicroscopy and anterior segment OCT at 1, 6 and 12 months follow up.
The safety of ALPI and the detrimental effects of iridoplasty on the corneal endothelium and the lens will also be investigated.
STUDY DESIGN
The study design for this project is a prospective randomized controlled trial. It will not be possible to blind either the subject or observer to the intervention due to the use of laser in the intervention group.
STUDY POPULATION
The study population will be patients with primary angle closure glaucoma attending the Singapore National Eye Centre and National University Hospital, who fulfil the inclusion criteria and are willing to take part in the study.
Wash out regimen
Eligible patients who are already on one or two-glaucoma medications are required to complete a washout period before being randomized. Washout periods will vary according to the previous medication used and are as follows:
Prostaglandin analogues 4 weeks Beta blockers 3 weeks Adrenergic agonist 2 weeks Cholinergic agonist 5 days Carbonic Anhydrase Inhibitors 5 days
Pre-study washout period check
Patients who are on prostaglandin analogues or beta blockers prior to the study will be required to undergo a washout period of 3 and 4 weeks respectively prior to the study. For this group of patients, there will be a safety check during the second week. Patients whose IOP>30 mm Hg during this washout check will be stopped from further washout and be withdrawn from the study.
PLANNED INTERVENTIONS
Iridoplasty group
For those randomised to laser iridoplasty, the procedure will be performed as follows:
A drop of brimonidine will be instilled in to the eye to be treated 15 minutes prior to the procedure. Topical anaesthesia will be administered and an Abrahams lens used for the procedure.
Laser burns will be placed over 360 degrees of the peripheral iris (approximately 25 burns in total).
The argon laser setting used are as follows:
Initial treatment (SEAGIG Guidelines) 28 We request to modify our laser settings for initial treatment in the laser arm to Spot size: 200-500 microns (changed from 500 microns) Power: 150-400 milliwatts (mw) increasing until desired end point is achieved (changed from 100-300mw) Duration: 0.2 -0.5 seconds.
Repeat treatment (one month - three months) Laser settings 29 Spot size: 200 microns Power: 100-300 milliwatts increasing until desired end point is achieved Duration: 0.5 -0.7 seconds.
The patient will be given a 2 week course of topical steroids four times a day for the treated eye.
Intraocular pressure will be checked one hour after the procedure. IOP spikes > 25mmHg will be treated.
RE-TREATMENT
If at follow up the angle remains as narrow as before on gonioscopy and UBM/ ASOCT then one further treatment of ALPI will be given to the patient to try and achieve the endpoint of widening the angle. This treatment will be administered between one and three months
CONTROL GROUP
Those patients randomized to the control group will not undergo further procedures at this visit. The patients will be commenced on topical treatment to lower the IOP. The first line agent for lowering IOP will be a prostaglandin analogue, and a stepwise addition of Timoptol 0.5% or dorzolamide will be implemented until IOP is controlled.
If both eyes of an individual patient fulfil the inclusion criteria they will both undergo intervention as allocated by randomization of the patient. (see randomization and data analysis)
- Conditions
- Glaucoma
- Being tested
- Argon Laser Iridoplasty, Travatan/ Timolol/Azopt
- Keywords
- Primary Angle Closure Disease
- Medical subject headings
- Glaucoma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Argon Laser IridoplastyProcedure or surgery
Travatan/ Timolol/AzoptDrug
| Study group | Role | What they receive |
|---|---|---|
| Iridoplasty | Active comparator | Not described Receives: Procedure: Argon Laser Iridoplasty |
| Control (Medication) | Active comparator | Not described Receives: Drug: Travatan/ Timolol/Azopt |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: one year
Secondary outcomes (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.
Measured: one year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Sep 2009 (estimated)
- Study startSep 2007
- Primary completionSep 2011 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for GlaucomaStudies 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 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Singapore National Eye Centre
- Sponsor type
- Other government
- Collaborators
- National University Hospital, Singapore
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00980473
- Sponsor's protocol ID
- R399/57/2004
- Acronym
- ALPI
- Status last verified
- Nov 2009
- First submitted
- 18 Sep 2009
- Last updated
- 17 Jun 2011
- Results posted
- No
- Data monitoring committee
- No
Publications
Narayanaswamy A, Baskaran M, Aung T. Reply. Ophthalmology. 2016 Aug;123(8):e50-e51. doi: 10.1016/j.ophtha.2016.01.051. No abstract available.
PubMed 27450828
Study at a glance
From the registry record, last updated by the sponsor on 17 Jun 2011. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Argon Laser Peripheral Iridoplasty for Primary Angle Closure Glaucoma: A Randomised Controlled Trial
- ClinicalTrials.gov ID
- NCT00980473
- Acronym / sponsor ID
- ALPI / R399/57/2004
- Conditions
- Glaucoma
- Keywords
- Primary Angle Closure Disease
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Unknown status
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- Singapore National Eye CentreOther government
- Collaborators
- National University Hospital, Singapore
- Study start
- Sep 2007
- Primary completion
- Sep 2011 (estimated)
- First posted
- 21 Sep 2009 (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.
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.
Detailed description
AIMS AND OBJECTIVES
The primary aim of the study is to determine whether argon laser peripheral iridoplasty (ALPI) is an effective treatment in terms of intraocular pressure (IOP) control for cases of primary angle closure glaucoma (PACG) in which the drainage angle remains narrow following laser iridotomy. Primary outcome measures will be the proportion of patients requiring medical or surgical treatment to maintain IOP control, number of medications required to control IOP at 12 months follow up.
The secondary aim is determine whether ALPI significantly alters the configuration of the drainage angle when compared with conventional treatment (medication) following laser iridotomy. Secondary outcomes will be the change in appearance of the drainage angle based on gonioscopy, ultrasound biomicroscopy and anterior segment OCT at 1, 6 and 12 months follow up.
The safety of ALPI and the detrimental effects of iridoplasty on the corneal endothelium and the lens will also be investigated.
STUDY DESIGN
The study design for this project is a prospective randomized controlled trial. It will not be possible to blind either the subject or observer to the intervention due to the use of laser in the intervention group.
STUDY POPULATION
The study population will be patients with primary angle closure glaucoma attending the Singapore National Eye Centre and National University Hospital, who fulfil the inclusion criteria and are willing to take part in the study.
Wash out regimen
Eligible patients who are already on one or two-glaucoma medications are required to complete a washout period before being randomized. Washout periods will vary according to the previous medication used and are as follows:
Prostaglandin analogues 4 weeks Beta blockers 3 weeks Adrenergic agonist 2 weeks Cholinergic agonist 5 days Carbonic Anhydrase Inhibitors 5 days
Pre-study washout period check
Patients who are on prostaglandin analogues or beta blockers prior to the study will be required to undergo a washout period of 3 and 4 weeks respectively prior to the study. For this group of patients, there will be a safety check during the second week. Patients whose IOP>30 mm Hg during this washout check will be stopped from further washout and be withdrawn from the study.
PLANNED INTERVENTIONS
Iridoplasty group
For those randomised to laser iridoplasty, the procedure will be performed as follows:
A drop of brimonidine will be instilled in to the eye to be treated 15 minutes prior to the procedure. Topical anaesthesia will be administered and an Abrahams lens used for the procedure.
Laser burns will be placed over 360 degrees of the peripheral iris (approximately 25 burns in total).
The argon laser setting used are as follows:
Initial treatment (SEAGIG Guidelines) 28 We request to modify our laser settings for initial treatment in the laser arm to Spot size: 200-500 microns (changed from 500 microns) Power: 150-400 milliwatts (mw) increasing until desired end point is achieved (changed from 100-300mw) Duration: 0.2 -0.5 seconds.
Repeat treatment (one month - three months) Laser settings 29 Spot size: 200 microns Power: 100-300 milliwatts increasing until desired end point is achieved Duration: 0.5 -0.7 seconds.
The patient will be given a 2 week course of topical steroids four times a day for the treated eye.
Intraocular pressure will be checked one hour after the procedure. IOP spikes > 25mmHg will be treated.
RE-TREATMENT
If at follow up the angle remains as narrow as before on gonioscopy and UBM/ ASOCT then one further treatment of ALPI will be given to the patient to try and achieve the endpoint of widening the angle. This treatment will be administered between one and three months
CONTROL GROUP
Those patients randomized to the control group will not undergo further procedures at this visit. The patients will be commenced on topical treatment to lower the IOP. The first line agent for lowering IOP will be a prostaglandin analogue, and a stepwise addition of Timoptol 0.5% or dorzolamide will be implemented until IOP is controlled.
If both eyes of an individual patient fulfil the inclusion criteria they will both undergo intervention as allocated by randomization of the patient. (see randomization and data analysis)
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Iridoplasty | Active comparator | Procedure: Argon Laser Iridoplasty |
| Control (Medication) | Active comparator | Drug: Travatan/ Timolol/Azopt |
Who may qualify
- Ages
- 21 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (12 listed)
- 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.
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 |
|---|---|---|
| Argon Laser Iridoplasty | Procedure or surgery | Iridoplasty |
| Travatan/ Timolol/Azopt | Drug | Control (Medication) |
Primary outcome
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
1 secondary outcome
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
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Jun 2011.
- Derived from this study: PubMed 27450828Narayanaswamy A, Baskaran M, Aung T. Reply. Ophthalmology. 2016 Aug;123(8):e50-e51. doi: 10.1016/j.ophtha.2016.01.051. No abstract available.
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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.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Argon Laser Iridoplasty and Travatan/ Timolol/Azopt in people with Glaucoma, 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 5 inclusion and 12 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 17 Jun 2011. 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.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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, FRCOphth (62277255, aung_tin@yahoo.co.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). 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 NCT00980473, which also lists 1 linked publication.
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 17 Jun 2011.