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Aqueous shunts for glaucomaMinckler DS, Vedula SS, Li TJ, Mathew MC, Ayyala RS, Francis BA
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SummaryAqueous shunts for glaucomaGlaucoma is a leading cause of blindness worldwide. Treatments for glaucoma include the use of eye drops, laser treatment, and a variety of surgical operations. Surgery is usually considered only after eye drops and lasers have proven to be ineffective. Among surgical operations, aqueous shunts or glaucoma drainage devices which come in a variety of sizes and shapes are often used in complicated cases when traditional types of surgery such as trabeculectomy (making a cleft in the eye wall) have not worked. The typical aqueous shunt includes a tiny rubber tube (drain) that connects the eye fluid chamber to a plate that is attached to the eye wall. The plate or explant stimulates the formation by the body of a space into which eye fluid can drain. This review summarizes previously published randomized and quasi-randomized controlled trial results for aqueous shunts (studies that compare treatment with no treatment or to alternative treatments including a control group). We included 15 trials involving 1153 participants with varied diagnoses of glaucoma. At present there is insufficient evidence to conclude that clinical outcomes of trabeculectomy differ substantially from those of aqueous shunts in similar patients with complicated glaucomas. There is also insufficient evidence to conclude that any specific aqueous shunt is superior to the others currently in widespread use.
This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2008 Issue 2, Copyright © 2008 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).
This version first published online:
April 19. 2006 AbstractBackgroundAqueous shunts are employed for intraocular pressure (IOP) control in primary and secondary glaucomas that fail medical, laser, and other surgical therapies. ObjectivesThis review compares aqueous shunts for IOP control and safety. Search strategyWe searched CENTRAL, MEDLINE, PubMed, EMBASE, NRR all in January 2006, LILACS to February 2004 and reference lists of included trials. Selection criteriaWe included all randomized and quasi-randomized trials in which one arm of the study involved shunts. Data collection and analysisTwo authors independently extracted data for included studies and a third adjudicated discrepancies. We contacted investigators for missing information. We used fixed-effect models and summarized continuous outcomes using mean differences. Main resultsWe included fifteen trials with a total of 1153 participants with mixed diagnoses. Five studies reported details sufficient to verify the method of randomization but only two had adequate allocation concealment. Data collection and follow-up times were variable. Meta-analysis of two trials comparing Ahmed implant with trabeculectomy found trabeculectomy resulted in lower mean IOPs 11 to 13 months later (mean difference 3.81 mm Hg, 95% CI 1.94 to 5.69 mm Hg). Meta-analysis of two trials comparing double-plate Molteno implant with the Schocket shunt was not done due to substantial heterogeneity. One study comparing ridged with standard double-plate Molteno implants found no clinically significant differences in outcome. Two trials investigating the effectiveness of adjunctive mitomycin (MMC) with the Molteno and Ahmed implants found no evidence of benefit with MMC. Two trials that investigated surgical technique variations with the Ahmed found no benefit with partial tube ligation or excision of Tenon's capsule. One study concluded there were outcome advantages with a double versus a single-plate Molteno implant and one trial comparing the 350 mm2 and 500 mm2 Baerveldt shunts found no clinically significant advantage of the larger device but neither of these trials included all patients randomized. One study suggested improved clinical outcome when MMC was employed with a newly described shunt including ultrasound supporting the conclusion. One small study did not demonstrate an outcome advantage to systemic steroid use postoperatively with single-plate Molteno shunts. One study comparing endocyclophotocoagulation (ECP) with Ahmed implant in complicated glaucomas found no evidence of better IOP control with Ahmed implant over ECP. Authors' conclusionsRelatively few randomized trials have been published on aqueous shunts and methodology and data quality among them is poor. To date there is no evidence of superiority of one shunt over another. |