Surgical treatment for primary angle closure – glaucoma: a meta analysis
Methodological quality of the review: Low confidence
Author: Deng BL, Jiang C, Ma B, Zhang WF, Lü P, Du YY, Jiu XD, Yang LX, Tian J
Geographical coverage: Not reported
Sector: Glaucoma
Sub-sector: Treatment of primary angle closure – glaucoma
Equity focus: None specified
Review type: Effectiveness review
Quantitative synthesis method: Meta-analysis
Qualitative synthesis method: Not applicable
Background: Glaucoma is the second-most important cause of blindness that can be classified into primary open angle glaucoma (POAG) or primary angle-closure glaucoma (PACG). The main therapy of PACG is surgery. Three surgeries involving trabeculectomy (Trab), phacotrabeculectomy (Phacotrab) plus intraocular lens implantation (Phacotrab+IOL group) and phacoemulsification with IOL (Phaco+IOL) are commonly used in treating PACG. However, there are still some controversies over efficacy, safety and complications.
Objectives: To assess the efficacy and safety of trabeculectomy (Trab), phacotrabeculectomy (Phacotrab) plus intraocular lens implantation (phacotrab+IOL group) and phacoemulsification with IOL (Phaco+IOL) in PACG.
Main findings: Current evidence suggests that the Phacotrab+IOL group was superior than the Trab group, which was also superior than the Phaco+IOL group in decreasing IOP. The Phacotrab group and Phaco group are both deeper than the Trab group in the anterior chamber depth. The Phacotrab group was superior than Phaco group in the use of IOP-lowering drugs.
Sixteen eligible trials were included in the final meta-analysis. They included five randomised controlled trials (RCTs) and 11 clinical controlled trials (CCTs). The total sample capacity was 1495 eyes. Three trials involved Trab, Phacotrab+IOL group and Phaco+IOL. Two trials compared Trab with Phacotrab, five trials compared Trab with Phaco, six trials compared Phacotrab with Phaco. Geographical coverage of included studies was not specified. In terms of study quality assessment, five trials which did not mentioned location and masking were randomised controlled trials, in which four trials used tables of random numbers, and one trial did not account for the particular method. The other 11 trials were non-randomised controlled trials, and as such were not appraised.
The meta-analysis showed that the Phacotrab+IOL group was superior than the Trab group (MD -3.93), which was also superior than the Phaco+IOL group (MD 0.52) in decreasing IOP. The Phacotrab group (MD -1.45) and Phaco group (MD-1.12) are both deeper than the Trab group in the anterior chamber depth. In increasing the co-efficient of outflow facility of aqueous humour (C values), there was no statistical difference in the three groups. There was no statistical difference between the Phacotrab groups and Phaco groups in visual acuity, though the Phacotrab group was superior than the Phaco group (MD 1.07) in the use of IOP-lowering drugs. There was no statistical difference among the three groups. Authors note that future studies should use RCT strictly.
Methodology: The Cochrane Library, PUBMED, EMBASE, Wanfang Database online, Chinese Journal Full-Text Database and Chinese Scientific Journals Full-Text were searched for randomised control trial (RCT) and clinical control trial (CCT). Pre-defined search terms were used. The bibliographies of retrieved articles were also checked for relevant studies. The quality of included trials was evaluated according to the Dutch Cochrane Centre. This was done independently by two reviewers. RevMan 5.0 software was used for meta-analysis.
Authors performed a meta-analysis of included studies, and quantified heterogeneity using the I2 statistic.
Applicability/external validity: The authors did not discuss the applicability/external validity of the results.
Geographic focus: Authors did not discuss the geographical location of included studies.
Summary of quality assessment: Overall there is low confidence in the conclusions about the effects of this study as important limitations were identified. Although authors conducted a search on relevant databases and bibliographies of included articles, language bias was not avoided and authors/experts were not contacted as part of the search strategy. Authors do not mention in the review whether two reviewers independently screened full text for inclusion in the review and extracted data of included studies. Appropriate methods were used to quality assess RCTs included in the review, however non-randomised controlled trials were not appraised, and as such it’s not clear which studies are subject to high risk of bias and its impact on the overall conclusion of the review. Overall, authors used appropriate methods to analyse the findings of included studies, and acknowledged that most trials did not use randomised controlled methods strictly. Therefore, authors did not draw strong policy conclusions.
