Abstract
Background
Angle‐closure glaucoma is a leading cause of irreversible blindness in the world. Treatment is aimed at opening the anterior chamber angle and lowering the IOP with medical and/or surgical treatment (e.g. trabeculectomy, lens extraction). Laser iridotomy works by eliminating pupillary block and widens the anterior chamber angle in the majority of patients. When laser iridotomy fails to open the anterior chamber angle, laser iridoplasty may be recommended as one of the options in current standard treatment for angle‐closure. Laser peripheral iridoplasty works by shrinking and pulling the peripheral iris tissue away from the trabecular meshwork. Laser peripheral iridoplasty can be used for crisis of acute angle‐closure and also in non‐acute situations.
Objectives
To assess the effectiveness of laser peripheral iridoplasty in the treatment of narrow angles (i.e. primary angle‐closure suspect), primary angle‐closure (PAC) or primary angle‐closure glaucoma (PACG) in non‐acute situations when compared with any other intervention. In this review, angle‐closure will refer to patients with narrow angles (PACs), PAC and PACG.
Search methods
We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 12), MEDLINE (January 1950 to January 2012), EMBASE (January 1980 to January 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled‐trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 5 January 2012.
Selection criteria
We included only randomised controlled trials (RCTs) in this review. Patients with narrow angles, PAC or PACG were eligible. We excluded studies that included only patients with acute presentations, using laser peripheral iridoplasty to break acute crisis.
Data collection and analysis
No analysis was carried out as only one trial was included in the review.
Main results
We included one RCT with 158 participants. The trial reported laser peripheral iridoplasty as an adjunct to laser peripheral iridotomy compared to iridotomy alone. The authors report no superiority in using iridoplasty as an adjunct to iridotomy for IOP, number of medications or need for surgery.
Authors' conclusions
There is currently no strong evidence for laser peripheral iridoplasty’s use in treating angle‐closure.
Plain language summary
Laser peripheral iridoplasty for angle‐closure glaucoma
Glaucoma is a leading cause of irreversible blindness in the world. Angle‐closure glaucoma describes one of the mechanisms which leads to glaucoma. In angle‐closure, the "angles" that act as drains for the aqueous in the eye are closed which leads to high eye ball pressure. Treatment is aimed at opening the drainage system and lowering the pressure in the eye with medical or surgical treatment or both. Laser peripheral iridoplasty is used in patients with angle‐closure when other treatments fail to open the anterior drainage system. It works by shrinking and pulling the peripheral iris tissue away from the trabecular meshwork (angles). Although one randomised controlled trial with 158 participants was found, due to its limitations and the lack of a statistically significant difference observed with laser peripheral iridoplasty intervention, this review found no strong evidence for the use of laser peripheral iridoplasty in the treatment of angle‐closure in the non‐acute setting.
Background
Angle‐closure glaucoma is a leading cause of irreversible blindness in the world. Treatment is aimed at opening the angles and lowering the intraocular pressure (IOP) in the eye with medical or surgical treatment or both. Laser peripheral iridoplasty is used in patients with angle‐closure when other treatments fail. It works by shrinking and pulling the peripheral iris tissue away from the trabecular meshwork. This review found no strong evidence for the use of laser peripheral iridoplasty in the treatment of angle‐closure.
Description of the condition
Glaucoma has been defined as a progressive optic neuropathy with characteristic appearances of the optic discs and specific pattern of visual field defects. Based on the appearance of the anterior chamber angle it can be classified into open‐angle or closed‐angle glaucoma. In the latter, an elevated IOP occurs as a consequence of an obstruction of the outflow pathway located in the anterior chamber angle (i.e. trabecular meshwork) by the peripheral iris. Closure of the anterior chamber angle can be appositional (reversible) or synechial (permanent, due to adherent uveal tissue). Among patients with appositional closure of the anterior chamber angle, many have normal IOP without any signs of glaucoma. They are usually described as having “narrow angles” or “primary angle closure suspects” (PACs). If the IOP is elevated and/or there are parts of the angle with synechial closure (but without signs of glaucomatous damage), the preferred term is 'primary angle‐closure' (PAC). The term 'primary angle‐closure glaucoma' (PACG) is reserved for those patients with angle‐closure and evidence of glaucomatous optic disc damage and/or visual field loss. In this review, angle‐closure will refer to patients with narrow angles, PAC and PACG.
Primary angle‐closure glaucoma is a leading cause of irreversible blindness in the world. Sixty‐seven million people worldwide are affected by glaucoma. Open‐angle glaucoma is more common than PACG but the latter is more likely to result in bilateral blindness (Quigley 1996; Resnikoff 2004). Primary angle‐closure glaucoma is more common in Asians and women. Foster et al estimated that the number of persons with narrow angles in China, based on previous studies in Mongolia (Foster 1996) and Singapore (Foster 2000) is 28.2 million, while 9.1 million would have angle‐closure. Furthermore, of the 1.7 million persons bilaterally blind from glaucoma in China, 91% are caused by PACG. Foster et al concluded that PACG might be the leading cause of glaucoma blindness in the world today (Foster 2001).
Patients with angle‐closure may present with acute symptoms of highly elevated IOP but the majority of patients have a chronic course with no symptoms in the early stages of the disease. Interventions for acute presentation of angle‐closure are being evaluated in another Cochrane review and will not be considered in this review.
Description of the intervention
Argon laser is applied using a contact lens (e.g. Abraham contact lens) to the iris periphery, approximately six shots per quadrant. The argon laser is typically set at 500‐micron spot size, with a duration of 0.5 seconds, and an initial starting laser energy of 50 to 200 mW. This laser energy level is gradually increased if iris stromal shrinkage is not observed initially. It has been suggested that heat shrinkage of collagen may be responsible for the short‐term response to laser peripheral iridoplasty, and that contraction of the fibroblastic membrane may be responsible for its long‐term effects (Sassani 1993). Laser peripheral iridoplasty can be used as a primary treatment or after laser peripheral iridotomy for acute angle‐closure attacks.
How the intervention might work
Treatment of angle‐closure is aimed at (1) opening the anterior chamber angle, most commonly by laser iridotomy, and (2) lowering the IOP with medical and/or surgical treatment (e.g. trabeculectomy, lens extraction). Laser iridotomy works by eliminating pupillary block and widens the anterior chamber angle in the majority of patients, although in some of them the anterior chamber angle remains closed. The latter situation may be due to plateau iris syndrome or a prominent and thick peripheral iris. When laser iridotomy fails to open the anterior chamber angle, laser peripheral iridoplasty may be recommended as one of the options in current standard treatment for angle‐closure.
Laser peripheral iridoplasty tries to pull away and 'remove' iris tissue away from the trabecular meshwork by shrinking the peripheral iris tissue.
Why it is important to do this review
Laser peripheral iridoplasty is part of the standard treatment for angle‐closure and is indicated in patients who do not respond to laser iridotomy. The use of laser peripheral iridoplasty appears to be increasingly reported in the literature and among experts in specialist meetings (Agarwal 1991; Lai 1999; Lam 1992; Weinreb 2006). So far, there has been no systematic review to assess the effectiveness of laser peripheral iridoplasty in the treatment of eyes with angle‐closure in non‐acute situations.
Objectives
The objective of this review was to assess the effectiveness of laser peripheral iridoplasty in the treatment of eyes with angle‐closure in non‐acute situations when compared with any other intervention including observation, medical treatment, laser peripheral iridotomy or surgical interventions such as trabeculectomy or cataract extraction.
Methods
Criteria for considering studies for this review
Types of studies
Randomised controlled trials were eligible for inclusion in this review. Trials included should have analysis based on one eye per patient.
Types of participants
Patients with narrow angles (PACs), PAC or PACG were eligible. It was anticipated that some trials would include patients with a previous history of acute presentations while others would evaluate participants with non‐acute conditions only. Studies that included only patients with acute presentations, using laser peripheral iridoplasty to break the acute phase were excluded. We included studies which had participants with a past history of an acute presentation but had not had laser peripheral iridoplasty during the attack. There were no restrictions with respect to previous treatments (i.e. peripheral iridotomy), age, gender, ethnicity or the number of participants.
Types of interventions
We only included trials that compared laser peripheral iridoplasty with or without medical treatment versus a control group (i.e., without laser peripheral iridoplasty) and with similar management in both groups.
Types of outcome measures
Primary outcomes
Progression of the disease. For PACs and patients with PAC, conversion rates were estimated using life‐table analysis (Kaplan Meier and Cox hazard model). Conversion rates of a) or b) between one to five years follow up, based on survival data, were then reported. For patients with PACG progression rates of the disease were also estimated using life‐table analysis.
a) From narrow angle (IOP < 21), to PAC (IOP ≧ 21), and/or
b) From PAC to PACG (with glaucomatous disc damage and/or glaucomatous visual field damage; see below for definition).
Glaucomatous optic disc damage would include the presence of thinning or "notching" of the neuroretinal rim, vertical enlargement of cup, or asymmetry greater than 0.2 in the cup‐disc ratio without differences in disc size or refractive error between eyes.
Glaucomatous visual field (VF) damage was defined for Humphrey perimeter as a reproducible defect in at least two consecutive and reliable VFs of (1) (a) two or more contiguous points with P < 0.01 loss or greater, or (b) three or more contiguous points with P < 0.05 loss or greater, or (c) a 10‐dB difference across the nasal horizontal midline at two or more adjacent points in the total deviation plot; (2) a Glaucoma Hemifield Test (GHT) outside normal limits in the same sector. For other perimeters, equivalent criteria was used.
c) Progression of the disease was defined as a reliable and repeatable deterioration of the visual field test as pre‐defined in the trial protocol. Any event analysis or trend analysis used by the authors to measure visual field loss was accepted.
Secondary outcomes
Post‐treatment the data below was collected at all reported times. From this data, the variable at one and five years post‐treatment was used for data analysis.
1. Intraocular pressure as measured by Goldmann's (mmHg). 2. Number of anti‐glaucoma medications. 3. Opening of the anterior chamber angle, determined clinically by a masked clinician or with imaging technology. 4. Any additional laser or surgical interventions for glaucoma. 5. Best‐corrected visual acuity. 6. Quality of life measures will be tabulated if reported.
Search methods for identification of studies
Electronic searches
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) 2011, Issue 12, part of The Cochrane Library. www.thecochranelibrary.com (accessed 5 January 2012), MEDLINE (January 1950 to January 2012), EMBASE (January 1980 to January 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled‐trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 5 January 2012.
See: Appendices for details of search strategies for CENTRAL (Appendix 1), MEDLINE (Appendix 2), EMBASE (Appendix 3), LILACS (Appendix 4), mRCT (Appendix 5), ClinicalTrials.gov (Appendix 6) and the ICTRP (Appendix 7).
Searching other resources
We searched the reference lists of retrieved articles for details of further relevant studies. We did not handsearch journals or conference proceedings specifically for this review.
Data collection and analysis
Selection of studies
Two authors independently assessed the titles and abstracts of all reports identified by the electronic and manual searches. Each report was labelled A (definitely exclude), B (unsure), or C (definitely include). Full text articles of abstracts labelled as 'unsure' were reassessed according to the inclusion criteria for this review. Studies labelled 'definitely exclude' were excluded from the review. Studies labelled as 'definitely include' were assessed for methodological quality. We resolved any differences between the two authors by discussion. One study was identified
Data extraction and management
Two authors extracted data independently using a paper form developed by Cochrane Eyes and Vision Group. One author entered data into RevMan and the second author checked the data to verify the data entered.
Assessment of risk of bias in included studies
Two authors independently assessed the include study for sources of systematic bias according to the guidelines in Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). The study was evaluated for the following criteria: allocation concealment (selection bias), masking of outcome assessors (detection bias), and rates of follow up and intention‐to‐treat analysis (attrition bias).
(a) Allocation concealment was 'adequate'. In future updates, if the adequacy of allocation concealment is unclear from the trial report we will contact the primary investigators for clarification. If they do not respond within six weeks we will classify the study based on available information and update it as more information becomes available.
(b) Masking of participants was not be possible with this interventions.
(c) Rates of follow up: approximately 20% of patients in each group did not complete the 1 year follow‐up visit. The authors carried forward the last observation for further analysis and the results were similar
(d) Investigators measuring IOP outcomes were masked, but investigators evaluating the opening of the anterior chamber angle (gonioscopy) were not masked.
We resolved disagreements through discussion and reached a consensus. In future updates, we will contact the authors of the studies for additional information on issues that are categorised as 'unclear' from information available in the report. If there is a failure to communicate with the primary investigators, or if they do not respond within a reasonable period of time, we will assess the methodological quality based on the available information.
Methods to be used in future updates to the review
As more studies are identified in the future, they will be included in the review using the following methods.
Measures of treatment effect
Data analysis will be done according to the guidelines set out in Chapter 9 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2011). Outcomes will be summarised as a relative risk, or mean difference.
Unit of analysis issues
We will only include studies with analysis on an one eye per patient basis.
Dealing with missing data
We expect studies to be analysed on an intention‐to‐treat basis. There will be concern regarding the validity of the study if there is no information on the characteristics of the missing data or whether this may introduce any bias. Where data are missing or unclear, the authors will be contacted for clarification and further information.
Assessment of heterogeneity
Should more than one trial become available we will attempt to quantify the proportion of variability within included randomised studies that is explained by heterogeneity using the I2 statistic (Higgins 2002). If the I2 statistic is greater than 50% we will consider it as substantial heterogeneity and will not combine the study results in a meta‐analysis. Instead we will present the studies in a tabulated or narrative summary.
Assessment of reporting biases
Selection, detection, performance and attrition biases will be assessed as above. Funnel plots will be used to detect the presence of any publication bias.
Data synthesis
Data analysis will be performed according to the guidelines set out in Chapter 9 of the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2011). Dichotomous outcomes will be summarised as risk ratios and continuous outcomes will be summarised as a mean difference. Standardised mean difference will be calculated when outcomes are measured on different scales. If there is no substantial heterogeneity as per the I2 statistic we will combine the results of the included studies in a meta‐analysis using a random‐effects model. We will use a fixed‐effect model if there are fewer than three studies. This is to avoid reporting potentially poor effect estimates due to random‐effects models in situations with very few trials. Meta‐analysis will be performed on the primary outcomes and difference in mean Goldmann IOP and its standard error.
Sensitivity analysis
We will examine the impact of excluding studies with lower methodological quality, unpublished data and industry funded data in sensitivity analyses.
Results
Description of studies
We found one randomised controlled trial and two case series which assessed laser peripheral iridoplasty in angle‐closure. These case series were excluded from analysis but are mentioned in the 'Discussion' section and characteristics of these studies can be found in Table 1.
1. Other studies assessing laser iridoplasty in non‐acute ACG.
| Study name | Methods | Participants | Intervention | Outcomes |
| Lai 2000 | prospective case series | n=5 patients with chronic angle‐closure | inferior 180 goniosynechialysis is followed by laser peripheral iridoplasty | intraocular pressure and number of medications |
| Ritch 2004 | retrospective case series | n=14 patients with plateau iris syndrome treated with laser peripheral iridoplasty | argon laser peripheral iridoplasty | need of repeat laser peripheral iridoplasty or additional means of intervention |
Results of the search
The searches were designed to include a filter to identify RCTs. However, when the filter was applied the search retrieved very few references. We decided to run the searches without the filters to retrieve any type of study discussing the use of laser peripheral iridoplasty for the treatment of angle‐ closure glaucoma.
The electronic searches retrieved three references from The Cochrane Library, 79 references from MEDLINE, 68 references from EMBASE and five references from LILACS. After deduplication the search identified a total of 96 references. The Trials Search Co‐ordinator scanned the results and removed any references that were not relevant to the scope of the review. The authors then excluded twenty‐seven references which assessed laser peripheral iridoplasty in acute angle‐closure glaucoma. Only two studies reported its use in the non‐acute setting but neither were RCTs nor case controlled studies. Hence, no trials were available for further analysis.
An update search was done in January 2012. After deduplication the search identified a total of 34 references. We assessed these references which were made up of eight abstracts from clinical trial registers and 26 abstracts from journals. The abstracts were independently assessed by two authors. We obtained a full‐text copy of one paper by Sun 2010 for potential inclusion in the review.
Included studies
One randomised controlled trial was eligible for analysis. Sun 2010 looked at the effects of laser peripheral iridotomy with adjunctive laser peripheral iridoplasty compared to laser peripheral iridotomy alone. More information on the trial can be found in 'Characteristics of included studies' table.
Risk of bias in included studies
See "Risk of Bias Table" below.
Allocation
The treatment intervention was randomised and combined with allocation sequence concealment whereby the investigators who made the diagnoses were not aware of the patient's treatment assignment. Allocation concealment was deemed adequate.
Blinding
Masking of participants were not possible due to the nature of the intervention and was not assessed. Investigators measuring IOP outcomes were masked, but investigators evaluating the opening of the anterior chamber angle (gonioscopy) were not masked.
Incomplete outcome data
Rates of follow up was reasonable with 79.7% of the included population completing one year follow‐up. Both cohorts were similar in one year follow‐up rates, 79.2% in the iridotomy group and 80.2% in the iridotomy plus iridoplasty group. Reason for loss to follow up was not mentioned. An analysis carrying the last observation forward was conducted and the results did not change.
Selective reporting
Outcome reporting in this study appears to be sufficiently complete.
Other potential sources of bias
We did not find any other potential sources of bias.
Effects of interventions
Primary outcomes
Only data from one year follow up was reported in Sun 2010. Conversion rates for narrow angle to PAC, and from PAC to PACG (see 'Types of outcome measures' for definition) were not reported.
Secondary outcomes
Post treatment intraocular pressure was found to be significantly reduced in both cohorts at one year follow‐up. However, there was no statistically significant difference between the two groups for final IOP and difference in reduction of IOP. Opening of the anterior chamber angle was determined clinically by a clinician who was not masked to the intervention. They reported a statistically significant difference in peripheral anterior synechiae reduction post laser iridoplasty. There was no statistically significant difference in number of anti‐glaucoma medications, need for surgery (trabeculectomy if IOP not reduced to 21 mmHg with maximum medical treatment), best‐corrected visual acuity and visual field mean deviation between both groups.
Deterioration of visual field loss was not measured and quality of life measures were not reported.
Discussion
Literature surrounding the use of laser peripheral iridoplasty in non‐acute angle‐closure is scarce. There are relatively more studies reporting its efficacy in breaking attacks of angle‐closure where it can be used in medically unbreakable attacks. However, in a recent consensus meeting among glaucoma experts (Weinreb 2006) laser iridoplasty was considered a standard treatment in patients with persistent appositional angle‐closure after peripheral iridotomy.
We have found only one RCT (Sun 2010) which reports laser peripheral iridoplasty as an adjunct to laser peripheral iridotomy compared to iridotomy alone. The authors report no superiority in using iridoplasty as an adjunct to iridotomy for IOP, number of medications or need for surgery. However, they noted a significant reduction in peripheral anterior synechiae (PAS) reduction post iridoplasty. The authors acknowledge that there were several limitations in their method of assessing PAS, which was with a Goldmann lens and not an indentation lens which indents better. The non‐masking of the outcome assessors may also introduce some extent of bias to this very subjective assessment. This may have been overcome by the use of anterior segment imaging.
Difference in IOP between the groups may not have shown much of a difference due to the low study power as well as the short follow‐up of only one year.
Despite the inherent limitations of this study, it is still a well designed RCT which adds value to the literature surrounding laser peripheral iridoplasty. Moreover, it is reassuring to see that there were no complications reported with laser peripheral iridoplasty or ill effects on the cornea or the corneal endothelial cell count.
Apart from Sun 2010, two non‐RCT studies were found to report the effectiveness of laser peripheral iridoplasty. Ritch et al carried out a retrospective case series involving 23 eyes of 14 patients (Ritch 2004). They had a mean follow up of 78.9 months and found that in all patients the anterior chamber angle did open after treatment, and only three eyes needed repeat laser peripheral iridoplasty. They also suggested that it is a safe and effective procedure with a satisfactory long term success rate.
Lai et al recruited five patients with PACG and 360° peripheral anterior synechiae for inferior 180° goniosynechialysis (Lai 2000). Laser peripheral iridoplasty was then applied on day four after surgery and the functional success rate (defined as having an IOP of less than 20 mmHg at last follow up) was observed in four patients. The authors suggested laser peripheral iridoplasty as an adjunct to goniosynechialysis for treatment of angle‐closure with total synechial angle‐closure.
Although at present there is no strong evidence for the use of laser peripheral iridoplasty alone in angle‐closure, these studies and the consensus among experts suggest that it is worth conducting an RCT to determine its effectiveness in angle‐closure treatment and not just as an adjunct.
Summary of main results
A single RCT assessing laser peripheral iridoplasty plus peripheral iridotomy reported it to be similar than iridotomy alone in the control of IOP in angle‐closure glaucoma.
Overall completeness and applicability of evidence
No strong evidence was found.
Quality of the evidence
There was no strong evidence for the use of laser peripheral iridoplasty in treating angle‐closure.
Authors' conclusions
Implications for practice.
It has been proposed that laser peripheral iridoplasty may be effective in patients with angle‐closure (non‐acute setting) when laser iridotomy fails to open the anterior chamber angle. However, there is currently no evidence for its role in the treatment of angle‐closure.
Implications for research.
Future trials to evaluate the role of laser iridoplasty will need to include patients with residual angle‐closure after peripheral iridotomy, with different spectrum of the disease (PACs, PAC, PACG). Laser iridoplasty should be compared with a control group without this intervention. A RCT would be the ideal study design. Comparison of argon laser iridoplasty with other interventions designed to open the anterior chamber angle (e.g. lens extraction) would also be of interest. Description of the methods to examine the anterior chamber angle, before and after intervention, would be essential. If clinical examination is going to be used, masking and standardisation of grading would be important. The use of imaging techniques (such as anterior segment optical coherence tomography (OCT) or ultrasound biomicroscopy) would complement qualitative evaluation of the anterior chamber angle and would be recommended. Mid and long‐term effectiveness would be measured in terms of IOP, extension of anterior chamber angle‐closure, visual field changes, visual acuity, and vision‐related quality of life. Outcomes would need to be assessed by masked investigators. Standard ethical requirements would apply.
What's new
| Date | Event | Description |
|---|---|---|
| 14 December 2011 | New citation required but conclusions have not changed | Issue 2, 2012: One new trial (Sun 2010) was included in the review and the review text was updated accordingly. |
| 14 December 2011 | New search has been performed | Issue 2, 2012: Electronic searches were updated. |
History
Protocol first published: Issue 3, 2007 Review first published: Issue 3, 2008
| Date | Event | Description |
|---|---|---|
| 24 April 2008 | Amended | Converted to new review format. |
| 23 November 2007 | New citation required and conclusions have changed | Substantive amendment |
Acknowledgements
The Cochrane Eyes and Vision Group created and ran the electronic searches. We thank Catey Bunce, Scott Fraser and Tianjing Li for providing peer referee comments.
Richard Wormald (Co‐ordinating Editor for CEVG) acknowledges financial support for his CEVG research sessions from the Department of Health through the award made by the National Institute for Health Research to Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology for a Specialist Biomedical Research Centre for Ophthalmology. The views expressed in this publication are those of the authors and not necessarily those of the Department of Health.
Appendices
Appendix 1. CENTRAL search strategy
#1 MeSH descriptor Glaucoma, Angle‐Closure #2 glaucoma* #3 angle* near close* #4 narrow near angle* #5 (#1 OR #2 OR #3 OR #4) #6 iridoplast* #7 (#5 AND #6)
Appendix 2. MEDLINE (OVID) search strategy
1. exp glaucoma,angle closure/ 2. (angle$ adj3 close$).tw. 3. (narrow adj2 angle$).tw. 4. (occlud$ adj3 angle$).tw. 5. or/1‐4 6. iridoplast$.tw. 7. 5 and 6
Appendix 3. EMBASE (OVID) search strategy
1. exp closed angle glaucoma/ 2. (angle$ adj3 close$).tw. 3. (narrow adj2 angle$).tw. 4. (occlud$ adj3 angle$).tw. 5. or/1‐4 6. "iridoplasty"/ 7. argon laser peripheral iridoplasty/ 8. iridoplast$.tw. 9. or/6‐8 10. 5 and 9
Appendix 4. LILACS search strategy
iridoplast$
Appendix 5. metaRegister of Controlled Trials search strategy
iridoplasty
Appendix 6. ClinicalTrials.gov search strategy
Iridoplasty
Appendix 7. ICTRP search strategy
iridoplasty
Characteristics of studies
Characteristics of included studies [ordered by study ID]
Sun 2010.
| Methods | Randomised controlled trial | |
| Participants | 158 patients from a Chinese population | |
| Interventions | Laser peripheral iridotomy and laser peripheral iridoplasty versus laser peripheral iridotomy | |
| Outcomes | Pre and post (1 year) intraocular pressure (IOP), IOP reduction, extent of peripheral anterior synechiae, best corrected visual acuity, visual field mean deviation, corneal endothelial cell count, number of medications, need for surgery | |
| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Consecutive cases of primary angle‐closure and primary angle‐closure glaucoma patients seeking treatment who fit the inclusion criteria were recruited. Treatment intervention was randomised |
| Allocation concealment (selection bias) | Low risk | Investigators who made the diagnoses were not aware of the participant's treatment assignment |
| Blinding of participants and personnel (performance bias) All outcomes | High risk | Masking was not possible due to the nature of the intervention |
| Blinding of outcome assessment (detection bias) All outcomes | High risk | Technicians who measured IOP outcomes were masked to group assignment. Investigators evaluating the opening of the anterior chamber angle (gonioscopy) were not masked |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Rates of follow up was reasonable with 79.7% of the included population completing one year follow‐up. Both cohorts were similar in one year follow‐up rates, 79.2% in the iridotomy group and 80.2% in the iridotomy plus iridoplasty group. Reason for loss to follow up was not mentioned. An analysis carrying the last observation forward was conducted and the results did not change |
| Selective reporting (reporting bias) | Low risk | Outcome reporting in this study appears to be sufficiently complete in this study |
| Other bias | Unclear risk | None found |
Differences between protocol and review
The title was changed from chronic angle‐closure glaucoma to angle‐closure. Angle‐closure refers to patients with narrow angles, angle‐closure and angle‐closure glaucoma.
Contributions of authors
AAB conceived the review question, provided a clinical, policy and consumer perspective, provided general advice on the review, secured funding for the review and performed previous work that was the foundation of the current study. WSN co‐ordinated the review and organised retrieval of full‐text copies. AAB and WSN entered data in to RevMan, analysed data and provided a methodological perspective. AAB, WSN and GSA screened initial search results, screened full‐text copies against inclusion criteria and appraised quality of papers, extracted data from papers.
Update of the review Issue 2, 2012 WSN and AAB screened the updated search results, extracted data for the included trial and updated the review text accordingly.
Declarations of interest
None known.
New search for studies and content updated (no change to conclusions)
References
References to studies included in this review
Sun 2010 {published data only}
- Sun X, Liang YB, Wang NL, Fan SJ, Sun LP, Li SZ, et al. Laser peripheral iridotomy with and without iridoplasty for primary angle‐closure glaucoma: 1‐year results of a randomized pilot study. American Journal of Ophthalmology 2010;150(1):68‐73. [DOI] [PubMed] [Google Scholar]
Additional references
Agarwal 1991
- Agarwal HC, Kumar R, Kalra VK, Sood NN. Argon laser iridoplasty : a primary mode of therapy in primary angle closure glaucoma. Indian Journal of Ophthalmology 1991;39(3):87‐90. [PubMed] [Google Scholar]
Deeks 2011
- Deeks JJ, Higgins JPT, Altman DG (editors). Chapter 9: Analysing data and undertaking meta‐analyses. In: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.
Foster 1996
- Foster PJ, Baasanhu J, Alsbirk PH, Munkhbayer D, Uranchimeg D, Johnson GJ. Glaucoma in Mongolia ‐ a population‐based survey in Hovsgol Province, northern Mongolia. Archives of Ophthalmology 1996;114(10):1235‐41. [DOI] [PubMed] [Google Scholar]
Foster 2000
- Foster PJ, Oen FT, Machin DS, Ng TP, Devereux JG, Johnson GJ, et al. The prevalence of glaucoma in Chinese residents of Singapore. A cross‐sectional population survey in Tanjong Pagar district. Archives of Ophthalmology 2000;118(8):1105‐11. [DOI] [PubMed] [Google Scholar]
Foster 2001
- Foster PJ, Johnson GJ. Glaucoma in China: how big is the problem?. British Journal of Ophthalmology 2001;85(11):1277‐82. [DOI] [PMC free article] [PubMed] [Google Scholar]
Higgins 2002
- Higgins JP, Thompson SG. Quantifying heterogeneity in a meta‐analysis. Statistics in Medicine 2002;21(11):1539‐58. [DOI] [PubMed] [Google Scholar]
Higgins 2011
- Higgins JPT, Altman DG, Sterne JAC (editors). Chapter 8: Assessing risk of bias in included studies. In: Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 (updated March 2011). The Cochrane Collaboration, 2011. Available from www.cochrane‐handbook.org.
Lai 1999
- Lai JS, Tham CC, Lam DS. Limited argon laser peripheral iridoplasty as immediate treatment for an acute attack of primary angle closure glaucoma: a preliminary study. Eye 1999;13(Pt 1):26‐30. [DOI] [PubMed] [Google Scholar]
Lai 2000
- Lai JS, Tham CC, Chua JK, Lam DS. Efficacy and safety of inferior 180 degrees goniosynechialysis followed by diode laser peripheral iridoplasty in the treatment of chronic angle‐closure glaucoma. Journal of Glaucoma 2000;9(5):388‐91. [DOI] [PubMed] [Google Scholar]
Lam 1992
- Lam DS, Lai JS, Tham CC. Immediate argon laser peripheral iridoplasty as treatment for acute attack of primary angle‐closure glaucoma: a preliminary study. Ophthalmology 1998;105(12):2231‐36. [DOI] [PubMed] [Google Scholar]
Quigley 1996
- Quigley HA. Number of people with glaucoma worldwide. British Journal of Ophthalmology 1996;80(5):389‐93. [DOI] [PMC free article] [PubMed] [Google Scholar]
Resnikoff 2004
- Resnikoff S, Pascolini D, Etya'ale D, Kocur I, Pararajasegaram R, Pokharel GP, et al. Global data on visual impairment in the year 2002. Bulletin of the World Health Organization 2004;82(11):844‐51. [PMC free article] [PubMed] [Google Scholar]
Ritch 2004
- Ritch R, Tham CC, Lam DS. Long‐term success of argon laser peripheral iridoplasty in the management of plateau iris syndrome. Ophthalmology 2004;111(1):104‐8. [DOI] [PubMed] [Google Scholar]
Sassani 1993
- Sassani JW, Ritch R, McCormick S, Liebmann JM, Eagle RC Jr, Lavery K, et al. Histopathology of argon laser iridoplasty. Ophthalmic Surgery 1993;24(11):740‐5. [PubMed] [Google Scholar]
Weinreb 2006
- Weinreb RN, Friedman DS. Angle closure and angle closure glaucoma. The Hague, The Netherlands: Kugler Publications, 2006. [Google Scholar]
References to other published versions of this review
Ng 2008
- Ng WS, Ang GS, Azuara‐Blanco A. Laser peripheral iridoplasty for angle‐closure. Cochrane Database of Systematic Reviews 2008, Issue 3. [DOI: 10.1002/14651858.CD006746.pub2] [DOI] [PubMed] [Google Scholar]