Re-Trabeculectomy Versus Ahmed Glaucoma Valve Implantation in Secondary Surgical Management of Patients With Refractory Glaucoma

Study Overview
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Brief Summary
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The purpose of this study is to compare three-year outcomes of re-trabeculectomy with those of Ahmed glaucoma valve implantation in secondary surgical management of patients with primary open angle glaucoma (POAG) and a history of previous failed trabeculectomy.

Detailed Description
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Currently, lowering intraocular pressure (IOP) is the only treatment modality to prevent or slow progression of glaucomatous optic nerve damage. Incisional procedures are indicated when medical therapy and/or laser procedures cannot adequately reduce IOP. Trabeculectomy is the most common glaucoma incisional procedure globally. On the other hand, glaucoma drainage devices that have been historically reserved for cases of glaucoma deemed at high risk of failure have increasingly gained popularity particularly in eyes with previous history of glaucoma surgery. There is still no agreement on the appropriate surgical procedure in those with prior glaucoma surgery. The five-year tube versus trabeculectomy (TVT) study, which evaluated the efficacy and safety of Baerveldt glaucoma implant versus trabeculectomy, showed that both surgical procedures had similar IOP reduction and use of anti-glaucoma medication; tube shunt surgery had a higher success rate than trabeculectomy with mitomycin C (MMC); the trabeculectomy/MMC had higher incidence of early postoperative complications compared to tube shunt surgery; and rates of late postoperative complications, reoperation for complications, and cataract extraction were comparable in both treatment groups. In this study, the investigators compared three-year outcomes of re-trabeculectomy with those of Ahmed glaucoma valve implantation in secondary surgical management of patients with primary open angle glaucoma and a previous history of failed trabeculectomy.

Official Title
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Re-Trabeculectomy Versus Ahmed Glaucoma Valve Implantation in Secondary Surgical Management of Patients With Refractory Primary Open Angle Glaucoma: a Three-year Comparative Study

Conditions
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Refractory Primary Open Angle Glaucoma

Intervention / Treatment
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* Procedure: Implantation of Ahmed glaucoma tube shunt, and Trabeculectomy with MMC


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Uncontrolled glaucoma defined as (1) IOP not achieving previously assigned target pressure despite prior trabeculectomy and use of maximally tolerated anti-glaucoma medication; and (2) recent progression of the disease based on glaucomatous changes in optic disc appearance and/or worsening of the visual field exam. In the case of two eligible eyes, only the first eye being operated on was enrolled Exclusion Criteria: Younger than 40 years old Visual acuity of no light perception Lens opacity Elevated IOP associated with silicone oil Prior ocular surgeries other than one trabeculectomy with MMC Previous cyclodestructive treatment Increased risk of endophthalmitis Posterior segment disorders Pre-existing ocular comorbidities (e.g. pterygium,phacodonesis,corneal opacity, or corneal endothelial dystrophies)

Ages Eligible for Study
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Minimum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Ahmed glaucoma implant<br> | Procedure: Implantation of Ahmed glaucoma tube shunt, and Trabeculectomy with MMC<br>* In the Ahmed implant group, the tube shunts used were the valved 184-mm2 surface area (Model FP7; New World Medical, Inc, Rancho Cucamonga, California, USA). In the Trabeculectomy group, a routine trabeculectomy surgery was performed.<br>|
| Trabeculectomy with mitomycin C (MMC)<br> | Procedure: Implantation of Ahmed glaucoma tube shunt, and Trabeculectomy with MMC<br>* In the Ahmed implant group, the tube shunts used were the valved 184-mm2 surface area (Model FP7; New World Medical, Inc, Rancho Cucamonga, California, USA). In the Trabeculectomy group, a routine trabeculectomy surgery was performed.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in target intraocular pressure (IOP) | All patients had a target IOP that had been assigned for them by the same surgeon prior to their initial failed trabeculectomy/MMC. The routine practice of the surgeon has been to set target IOP based on the Best Practice Treatment Algorithm for POAG. This was based on at least 25% reduction in baseline IOP. Target IOP needs constant reevaluation during the follow-up based on disease progression. In our study, success and failure were considered to be assessed based on change in the target pressure. | day 1, week 1, months 1,3,6,9,12,18,24,30,36 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of anit-glaucoma medications |  | day 1, week 1, months 1,3,6,9,12,18,24,30,36 | 
| Visual Acuity |  | day 1, week 1, months 1,3,6,9,12,18,24,30,36 | 
| Mean deviation of visual field exam | Only visual field results where consecutive field tests did not show an improvement of 2 dB or more in the mean deviation (MD) over the baseline reading were included as we considered the phenomenon of learning effect in our analysis. | Months 6,12,18,24,30,36 | 
| Surgical Success | Surgical failure was defined as persistent IOP of more than target pressure on maximally tolerated medications or IOP less than 6 mm Hg on two consecutive visits, phthisis bulbi, reduction of vision to no light perception, removal of the shunt implant, reoperation for glaucoma, or any devastating intraoperative and postoperative complications. | day 1, week 1, months 1,3,6,9,12,18,24,30,36 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Refractory primary open angle glaucoma, trabeculectomy, ahmed valve implant