Tube Versus Trabeculectomy Study Research Articles

Visual Field Outcomes in the Primary Tube Versus Trabeculectomy Study

PurposeTo describe visual field outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study. DesignCohort analysis of a prospective multicenter randomized clinical trial. SubjectsA total of 155 eyes from 155 subjects randomly assigned to treatment with tube shunt surgery (n=84) or trabeculectomy with mitomycin C (n=71). MethodsThe PTVT Study was a multicenter randomized clinical trial comparing the safety and efficacy of trabeculectomy and tube shunt surgery in eyes without prior intraocular surgery. Subjects underwent standard automated perimetry (SAP) at baseline and annually for five years. SAP tests were deemed reliable if the false positive rate was ≤15%. Tests were excluded if visual acuity was ≤20/400 or loss of ≥2 Snellen lines from baseline were attributed to a non-glaucomatous etiology. Linear mixed-effects models were used to compare rates of change in SAP mean deviation (MD) between the two treatment groups. Intraocular pressure (IOP) control was assessed by percentage of visits with IOP <18 mmHg and mean IOP. Outcome MeasuresRate of change in SAP MD during follow-up. ResultsA total of 730 SAP tests were evaluated, with an average of 4.7 tests per eye. The average SAP MD at baseline was -12.8±8.3 dB in the tube group and -12.0±8.4 dB in the trabeculectomy group (p=0.57). The mean rate of change in SAP MD was -0.32±0.39 dB/year in the trabeculectomy group and -0.47±0.43 dB/year in the tube group (p=0.23). Eyes with mean IOP 14-17.5 mmHg had significantly faster rates of SAP MD loss compared to eyes with mean IOP <14 mmHg (-0.59±0.13 vs. -0.27±0.08 dB/year, p=0.012) and eyes with only 50-75% of visits with IOP <18 mmHg had faster rates than those with 100% of visits with IOP <18 mmHg (-0.90±0.16 vs. -0.29±0.08 dB/year, p<0.001). Multivariable analysis identified older age and worse IOP control as risk factors for faster progression in both treatment groups. ConclusionsNo statistically significant difference in mean rates of visual field change was observed between trabeculectomy and tube shunt surgery in the PTVT Study. Worse IOP control was significantly associated with faster rates of SAP MD loss during follow-up. Older patients were also at risk for faster progression.

Risk factors for Baerveldt glaucoma drainage implantation for uveitic glaucoma

Uveitic glaucoma (UG) is sometimes intractable, including intricate interaction between intraocular pressure (IOP) elevation associated with inflammation and side effects of steroids. Based on the Tube Versus Trabeculectomy study in refractory glaucoma results in 2012, tube shunt surgeries have been performed for UG, but few reports have focused on UG. We retrospectively examined the surgical efficacy, complications, and risk factors in 62 eyes with UG that underwent Baerveldt glaucoma drainage device (BGD) implantation at Kumamoto University. The IOPs significantly dropped, and the mean number of glaucoma medications was reduced by more than two. Kaplan‒Meier survival curves were presented under 2 conditions: an IOP reduction of 20% and 6 ≤ IOP ≤ 18 mmHg (criterion A) or 6 ≤ IOP ≤ 15 mmHg (criterion B). In criterion A, the median survival times (MST) were 124 days (complete) and 997 days (qualified). In criterion B, the MST was 129 days (complete) and 867 days (qualified). The Cox hazard proportional model found that the hazard ratio was 0.170 for a history of cataract surgery (95% CI 0.0303–0.950) and 8.669 for systemic immunosuppressive therapy (95% CI 1.810–41.51). BGD implantation is effective for treating UG, but the presence of systemic treatment and the lens status should be considered.

Outcomes of Glaucoma Reoperations in the Primary Tube Versus Trabeculectomy Study

To describe the incidence and outcomes of reoperations for glaucoma in the Primary Tube VersusTrabeculectomy (PTVT) Study. Cohort study of patients in a multicenter randomized clinical trial. The PTVT Study enrolled 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery. Randomization assigned 125 patients to placement of a tube shunt (350-mm2 Baerveldt glaucoma implant) and 117 patients to trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes). Data were analyzed from patients who underwent additional glaucoma surgery. Outcome measures included intraocular pressure (IOP), use of glaucoma medications, visual acuity, surgical complications, and failure (IOP > 21 mmHg or reduced by <20%, IOP ≤ 5 mmHg, additional glaucoma surgery, or loss of light perception vision). Additional glaucoma surgery was performed in 21 patients in the tube group and 12 patients in the trabeculectomy group in the PTVT Study, and the 5-year cumulative reoperation rate for glaucoma was 18.0% in the tube group and 10.4% in the trabeculectomy group (P= 0.15). Follow-up (mean ± standard deviation [SD]) after additional glaucoma surgery was 35.1 ± 17.7 months in the tube group and 30.1 ± 17.6 months in the trabeculectomy group (P= 0.44). At 3 years after glaucoma reoperation, IOP (mean ± SD) was 15.5 ± 4.8 mmHg in the tube group and 16.6 ± 7.3 mmHg in the trabeculectomy group (P= 0.71). The number of glaucoma medications (mean ± SD) after 3 years of follow-up was 2.1 ± 1.7 in the tube group and 1.7 ± 1.0 in the trabeculectomy group (P= 0.58). The cumulative probability of failure at 3 years after a glaucoma reoperation was 37.8% in the tube group and 21.3% in the trabeculectomy group (P= 0.47). No significant difference in the rate of reoperation for glaucoma was observed after tube shunt implantation and trabeculectomy with MMC in the PTVT Study. Similar surgical outcomes were observed after additional glaucoma surgery, irrespective of the initial procedure to which the patient was randomized. Proprietary or commercial disclosure may be found after the references.

Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 5 Years of Follow-up

To report 5-year treatment outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study. Multicenter randomized clinical trial. A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group. Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC) (0.4 mg/ml for 2 minutes). The primary outcome measure was the rate of surgical failure, defined as intraocular pressure (IOP) > 21 mmHg or reduced < 20% from baseline, IOP ≤ 5 mmHg, reoperation for glaucoma, or loss of light perception. Secondary outcome measures included IOP, glaucoma medical therapy, and visual acuity. The cumulative probability of failure after 5 years of follow-up was 42% in the tube group and 35% in the trabeculectomy group (P= 0.21; hazard ratio= 1.31; 95% confidence interval= 0.86-2.01). At 5 years, IOP (mean ± standard deviation) was 13.4 ± 3.5 mmHg in the tube group and 13.0 ± 5.2 mmHg in the trabeculectomy group (P= 0.52), and the number of glaucoma medications (mean ± standard deviation) was 2.2 ± 1.3 in the tube group and 1.3 ± 1.4 in the trabeculectomy group (P < 0.001). Trabeculectomy with MMC and tube shunt surgery produced similar IOPs after 5 years of follow-up in the PTVT Study, but fewer glaucoma medications were required after trabeculectomy. No significant difference in the rate of surgical failure was observed between the 2 surgical procedures at 5 years.

Postoperative Complications in the Primary Tube Versus Trabeculectomy Study During 5 Years of Follow-up

To describe postoperative complications encountered in the Primary Tube Versus Trabeculectomy (PTVT) Study during 5 years of follow-up. Multicenter randomized clinical trial. A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group. Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC, 0.4 mg/ml for 2 minutes). Surgical complications, reoperations for complications, visual acuity, and cataract progression. Early postoperative complications occurred in 24 patients (19%) in the tube group and 40 patients (34%) in the trabeculectomy group (P= 0.013). Late postoperative complications developed in 27 patients (22%) in the tube group and 32 patients (27%) in the trabeculectomy group (P= 0.37). Serious complications producing vision loss and/or requiring a reoperation were observed in 3 patients (2%) in the tube group and 9 patients (8%) in the trabeculectomy group (P= 0.11). Cataract progression was seen in 65 patients (52%) in the tube group and 52 patients (44%) in the trabeculectomy group (P= 0.30). Surgical complications were not associated with a higher rate of treatment failure (P= 0.61), vision loss (P= 1.00), or cataract progression (P= 0.77) CONCLUSIONS: A large number of surgical complications were observed in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was higher following trabeculectomy with MMC than with tube shunt surgery. The rates of late postoperative complications, serious complications, and cataract progression were similar with both surgical procedures after 5 years of follow-up. Surgical complications did not increase the risk of treatment failure, vision loss, or cataract progression.

Risk Factors for Failure of Tube Shunt Surgery: A Pooled Data Analysis

To identify the risk factors associated with failure of tube shunt surgery. Pooled analysis of 3 prospective multicenter, randomized clinical trials. A total of 621 patients with medically uncontrolled glaucoma were enrolled, including 276 from the Ahmed Baerveldt Comparison Study, 238 from the Ahmed Versus Baerveldt Study, and 107 from the tube group of the Tube Versus Trabeculectomy Study. Patients were randomized to treatment with an Ahmed glaucoma valve (model FP7) or Baerveldt glaucoma implant (model 101-350). The associations between baseline risk factors and tube shunt failure were assessed using a Cox proportional hazards regression model. The primary outcome measure was the rate of surgical failure defined as intraocular pressure (IOP) > 21 mmHg or reduced <20% from baseline, IOP ≤ 5 mmHg, loss of light perception vision, reoperation for glaucoma, or removal of implant. The cumulative probability of failure after tube shunt surgery was 38.3% after 5 years. In multivariable analyses, baseline factors that predicted tube shunt failure included preoperative IOP (≤ 21 mmHg compared to IOP > 21 and ≤ 25 mmHg; HR, 2.34; 95% CI, 1.52-3.61; P < .001), neovascular glaucoma (HR, 1.79; 95% CI, 1.28-2.52; P = .001), randomized treatment (for Ahmed glaucoma valve; HR, 1.36; 95% CI, 1.04-1.78; P = .025), and age (for 10 year decrease in age; HR, 1.19; 95% CI, 1.09-1.31; P < .001). Lower preoperative IOP, neovascular glaucoma, Ahmed implantation, and younger age were predictors of tube shunt failure. This Study provides the largest prospectively collected dataset on tube shunt surgery.

Visual Field Outcomes in the Tube Versus Trabeculectomy Study

To describe visual field (VF) outcomes in the Tube Versus Trabeculectomy (TVT) Study. Cohort analysis of patients in a multicenter randomized clinical trial. A total of 122 eyes of 122 patients, with 61 eyes in both the tube shunt and trabeculectomy groups. The TVT Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube shunt surgery (350-mm2 Baerveldt implant) and trabeculectomy with mitomycin C (MMC) (0.4 mg/ml for 4 minutes) in patients with previous cataract or glaucoma surgery. Enrolled patients underwent perimetry at baseline and annual follow-up visits. The VFs were included if the false-positive rate was ≤20% and false-negative rate was ≤35%. The VFs were excluded if visual acuity <20/400 or loss of ≥2 Snellen lines from baseline was attributed to an etiology other than glaucoma. Longitudinal linear mixed-effects models with best linear unbiased predictions (BLUPs) were applied to estimate rates of change in mean deviation (MD) for each treatment group. Rate of MD change during follow-up period. A total of 436 reliable VFs were analyzed, with an average of 3.6 VFs per eye. Baseline MD was-13.07 ± 8.4 decibels (dB) in the tube shunt group and-13.18 ± 8.2 dB in the trabeculectomy group (P= 0.99). The rate of change in MD was-0.60 dB/year in the tube group and-0.38 dB/year in the trabeculectomy group (P= 0.34). The 95% confidence intervals for the rates of MD change were-0.77 to-0.44 dB/year in the tube group and-0.56 to-0.20 dB/year in the trabeculectomy group. No significant difference in MD slope was seen when patients were categorized by percentage of visits with intraocular pressure (IOP) <18 mmHg or by average IOP. Univariable and multivariable risk factor analyses identified history of diabetes, elevated IOP, and worse MD as baseline factors associated with more rapid VF loss. Slow rates of VF loss were observed after randomized surgical treatment in the TVT Study, but no significant difference in the rate of VF loss was seen after tube shunt implantation and trabeculectomy with MMC. Patients with diabetes, higher IOP, and more severe VF loss at baseline were at higher risk for VF progression.

Gene Therapy for Glaucoma by Ciliary Body Aquaporin 1 Disruption Using CRISPR-Cas9.

Glaucoma is a common cause of blindness, yet current therapeutic options are imperfect. Clinical trials have invariably shown that reduction in intraocular pressure (IOP) regardless of disease subtype prevents visual loss. Reducing ciliary body aqueous humor production can lower IOP, and the adeno-associated virus ShH10 serotype was identified as able to transduce mouse ciliary body epithelium following intravitreal injection. Using ShH10 to deliver a single vector CRISPR-Cas9 system disrupting Aquaporin 1 resulted in reduced IOP in treated eyes (10.4 ± 2.4 mmHg) compared with control (13.2 ± 2.0 mmHg) or non-injected eyes (13.1 ± 2.8 mmHg; p < 0.001; n = 12). Editing in the aquaporin 1 gene could be detected in ciliary body, and no off-target increases in corneal or retinal thickness were identified. In experimental mouse models of corticosteroid and microbead-induced ocular hypertension, IOP could be reduced to prevent ganglion cell loss (32 ± 4 /mm2) compared with untreated eyes (25 ± 5/mm2; p < 0.01). ShH10 could transduce human ciliary body from post-mortem donor eyes in ex vivo culture with indel formation detectable in the Aquaporin 1 locus. Clinical translation of this approach to patients with glaucoma may permit long-term reduction of IOP following a single injection.

Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 3 Years of Follow-up

To report 3-year results of the Primary Tube Versus Trabeculectomy (PTVT) Study. Unmasked multicenter randomized clinical trial. Two hundred forty-two eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 in the tube group and 117 in the trabeculectomy group. Patients were enrolled at 16 clinical centers and were assigned randomly to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC; 0.4 mg/ml for 2 minutes). The primary outcome measure was the rate of surgical failure, defined as intraocular pressure (IOP) of more than 21 mmHg or reduced less than 20% from baseline, IOP of 5 mmHg or less, reoperation for glaucoma, or loss of light perception vision. Secondary outcome measures included IOP, glaucoma medical therapy, visual acuity, and surgical complications. The cumulative probability of failure after 3 years of follow-up was 33% in the tube group and 28% in the trabeculectomy group (P= 0.17; hazard ratio, 1.39; 95% confidence interval, 0.9-2.2). Mean ± standard deviation IOP was 14.0±4.2 mmHg in the tube group and 12.1±4.8 mmHg in the trabeculectomy group at 3 years (P= 0.008), and the number of glaucoma medications was 2.1±1.4 in the tube group and 1.2±1.5 in the trabeculectomy group (P < 0.001). Serious complications requiring reoperation or producing loss of 2 or more Snellen lines developed in 3 patients (2%) in the tube group and 9 patients (8%) in the trabeculectomy group (P=0.11). There was no significant difference in the rate of surgical failure between the 2 surgical procedures at 3 years. Trabeculectomy with MMC achieved lower IOP with use of fewer glaucoma medications compared with tube shunt surgery after 3 years of follow-up in the PTVT Study. Serious complications producing vision loss or requiring reoperation occurred with similar frequency after both surgical procedures.

Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 1 Year of Follow-up

To report 1-year treatment outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study. Multicenter, randomized clinical trial. Two hundred forty-two eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 in the tube group and 117 in the trabeculectomy group. Patients were enrolled at 16 clinical centers and assigned randomly to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC; 0.4 mg/ml for 2 minutes). Intraocular pressure (IOP), glaucoma medical therapy, visual acuity, visual fields, surgical complications, and failure (IOP of more than 21 mmHg or reduced by less than 20% from baseline, IOP of 5 mmHg or less, reoperation for glaucoma, or loss of light perception vision). The cumulative probability of failure during the first year of follow-up was 17.3% in the tube group and 7.9% in the trabeculectomy group (P= 0.01; hazard ratio, 2.59; 95% confidence interval, 1.20-5.60). Mean± standard deviation IOP was 13.8±4.1 mmHg in the tube group and 12.4±4.4 mmHg in the trabeculectomy group at 1 year (P= 0.01), and the number of glaucoma medications was 2.1±1.4 in the tube group and 0.9±1.4 in the trabeculectomy group (P < 0.001). Postoperative complications developed in 36 patients (29%) in the tube group and 48 patients (41%) in the trabeculectomy group (P= 0.06). Serious complications requiring reoperation or producing a loss of 2 Snellen lines or more occurred in 1 patient (1%) in the tube group and 8 patients (7%) in the trabeculectomy group (P= 0.03). Trabeculectomy with MMC had a higher surgical success rate than tube shunt implantation after 1 year in the PTVT Study. Lower IOP with use of fewer glaucoma medications was achieved after trabeculectomy with MMC compared with tube shunt surgery during the first year of follow-up. The frequency of serious complications producing vision loss or requiring reoperation was lower after tube shunt surgery relative to trabeculectomy with MMC.

The Primary Tube Versus Trabeculectomy Study: Methodology of a Multicenter Randomized Clinical Trial Comparing Tube Shunt Surgery and Trabeculectomy with Mitomycin C

To describe the methodology of the Primary Tube Versus Trabeculectomy (PTVT) Study. Multicenter randomized clinical trial. Patients with medically uncontrolled glaucoma and no prior incisional ocular surgery. Patients are being enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (0.4 mg/ml for 2 minutes). The primary outcome measure is the rate of surgical failure, defined as intraocular pressure (IOP) more than 21 mmHg or reduced by less than 20% from baseline, IOP of 5 mmHg or less, reoperation for glaucoma, or loss of light perception vision. Secondary outcome measures include IOP, glaucoma medical therapy, visual acuity, visual fields, and surgical complications. Practice patterns vary in the surgical management of glaucoma, and opinions differ among surgeons regarding the preferred primary operation for glaucoma. The PTVT Study will provide valuable information comparing the 2 most commonly performed glaucoma surgical procedures.

Quality of Life in the Tube Versus Trabeculectomy Study

To report the vision-specific quality-of-life (QoL) outcomes in the Tube Versus Trabeculectomy (TVT) Study. Multicenter randomized clinical trial. Setting: Seventeen clinical centers. Patients 18-85 years of age with medically uncontrolled glaucoma who had previous cataract and/or glaucoma surgery. Tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with MMC. Vision-specific QoL using the NEI VFQ-25 and estimation of minimally important differences (MID) were the main outcome measures. Cross-sectional distribution- and anchor-based approaches were used to estimate MID. Clinical anchor measures included the mean deviation (MD) and logMAR visual acuity (VA) measurements. Clinically significant changes in anchor were defined as ≥2 dB MD and ≥0.2 logMAR. No significant differences in composite scores were observed between treatment groups, and no significant change in scores were seen over time. Mean (SD; range) values of clinical anchors at baseline were-16.6 (9.3;-32 to-0.5) dB for the surgical eye and 0.2 (0.3;-0.1 to 1.3) logMAR VA in the better-vision eye. For anchor-based cross-sectional analysis, composite score MID (95% CI) was 6.3 (4.6-7.9) for better-eye VA and 1.4 (0.9-1.9) for surgical eye MD. Distribution-based MID for the composite score was 6.0. Trabeculectomy and tube shunt surgery had similar impact on patient-reported vision-specific QoL measured using the NEI VFQ-25. In this cohort of patients with advanced glaucoma, MIDs varied depending on the clinical anchor used. Distribution-based MIDs corresponded well with anchor-based MIDs based on VA measures. The MID values reported here may be useful for others wishing to interpret NEI VFQ-25 scores in their advanced glaucoma patient cohort.

Heterologous, Fresh, Human Donor Sclera as Patch Graft Material in Glaucoma Drainage Device Surgery.

To determine the safety and efficacy of fresh, human sclera allografts as a patch graft material in glaucoma drainage device (GDD) surgery. Retrospective, noncomparative, interventional, consecutive case series. All GDD cases operated between 2008 and 2013 in which fresh human corneoscleral rims were used immediately after the central corneal button was used for penetrating or endothelial keratoplasty. Surgery was performed by 2 surgeons at 2 facilities. The Ahmed Glaucoma Valve (FP-7) was used exclusively in this cohort. Sixty-four eyes of 60 patients were identified; demographic data were recorded along with intraocular pressure (IOP), medication requirements, visual acuity, complications, and subsequent interventions. Incidence of complications. IOP and medication requirements at the last follow-up. Quilified success utilizing Tube Versus Trabeculectomy study criteria. The mean age of the cohort was 66.2±19.1 years; the average preoperative IOP was 33.2±11.1 mm Hg on 4.2±1.3 IOP-lowering agents before GDD surgery. IOP decreased significantly to 14.1±4.7 mm Hg (P<0.001) on 1.6±1.2 IOP-lowering agents (P<0.001) after an average follow-up of 18.2±15.4 months. There were no cases of early or late blebitis or endophthalmitis, and there was 1 case of conjunctival erosion and tube/plate exposure (1.6%) occurring 30 days after surgery. Qualified success was estimated as 90.5% and 81% at 1 and 2 years, respectively, using Tube Versus Trabeculectomy study criteria. Heterologous, fresh, human donor sclera appears to be a safe material for GDD tube coverage. It provides a cost-efficient alternative compared with traditional patch graft materials associated with a low risk of pathogen transmission.

Tube Fenestration in the Tube Versus Trabeculectomy Study

Tube Fenestration in the Tube Versus Trabeculectomy Study

Resident and Fellow Glaucoma Surgical Experience Following the Tube Versus Trabeculectomy Study

Resident and Fellow Glaucoma Surgical Experience Following the Tube Versus Trabeculectomy Study

Clinical Impact of 8 Prospective, Randomized, Multicenter Glaucoma Trials

To determine the impact of 8 multicenter randomized clinical trials (RCTs) on glaucoma practice. An electronic survey was distributed to the members of the American Glaucoma Society (AGS). Each participant was asked 2 study-specific questions and 1 standard question common to all 8 RCTs assessing the study's impact on clinical practice. RCTs included in the survey were the Advanced Glaucoma Intervention Study (AGIS), Collaborative Initial Glaucoma Treatment Study (CIGTS), Collaborative Normal Tension Glaucoma (CNTG) Study, European Glaucoma Prevention Study (EGPS), Early Manifest Glaucoma Trial (EMGT), Glaucoma Laser Trial (GLT), Ocular Hypertension Treatment Study (OHTS), and Tube Versus Trabeculectomy (TVT) Study. A 5-point Likert scale was used for rating all responses. The practice setting and duration of glaucoma practice was determined for all AGS members who responded. A total of 206 (23.0%) of 894 AGS members participated in the survey. Among those who responded, 46.4% were self classified as academic practitioners and 53.6% worked in a private practice setting. Mean Likert scores for the standard question evaluating the overall impact of the RCT were OHTS 4.47, CNTG Study 4.13, AGIS 3.78, TVT Study 3.53, EMGT 3.48, CIGTS 3.44, GLT 3.39, and 2.69 EGPS. Substantial differences were observed in the clinical impact of several RCTs in glaucoma. The reported impact of each study likely reflects several factors including study timing, design, conduct, and interpretation of results.

Complications of tube implants and their management

The use of glaucoma drainage devices (GDD) in the treatment of glaucoma has become widely accepted for cases of refractory glaucoma. Expansion in the indications for implantation of GDD beyond refractory glaucoma is increasingly common. As such, tube implant complications are reviewed to aid in prevention and improve their management. Findings of the Tube Versus Trabeculectomy study resulted in an expanded use of tube implants in cases of refractory glaucoma. As interest in GDD implantation flourished, so too, did investigative comparison between devices; which includes the Ahmed Baerveldt Comparison study and Ahmed Verses Baerveldt study. Comparative analysis of success and complication rates between implantable devices is not only expanding the technology of tube implants, but also building a body of evidence that tube implantation has a strong safety profile and usage among specialists will continue to increase and indications will evolve. Complications resulting from GDD implantation include hypotony, postoperative elevated intraocular pressure, tube erosion, diplopia, motility disturbances, and corneal decompensation. Tube implant use is increasing and indications are expanding beyond refractory glaucoma. Understanding differences in GDD, their complications and management will result in improved patient care.

Outcomes of Glaucoma Reoperations in the Tube Versus Trabeculectomy (TVT) Study

To describe the incidence and outcomes of reoperations for glaucoma in the Tube Versus Trabeculectomy (TVT) Study. Cohort study of patients in a multicenter randomized clinical trial. The TVT Study enrolled 212 patients with medically uncontrolled glaucoma who had previous cataract and/or glaucoma surgery. Randomization assigned 107 patients to surgery with a tube shunt (350 mm(2) Baerveldt glaucoma implant) and 105 patients to trabeculectomy with mitomycin C (0.4 mg/mL for 4 minutes). Data were analyzed from patients who failed their assigned treatment and had additional glaucoma surgery. Outcome measures included intraocular pressure (IOP), use of glaucoma medications, visual acuity, surgical complications, and failure (IOP >21 mm Hg or not reduced by 20%, IOP ≤5 mm Hg, additional glaucoma surgery, or loss of light perception vision). Additional glaucoma surgery was performed in 8 patients in the tube group and 18 patients in the trabeculectomy group in the TVT Study, and the 5-year cumulative reoperation rate was 9% in the tube group and 29% in the trabeculectomy group (P = .025). Follow-up (mean ± SD) after additional glaucoma surgery was 28.0 ± 16.0 months in the tube group and 30.5 ± 20.4 months in the trabeculectomy group (P = .76). At 2 years after a glaucoma reoperation, IOP (mean ± SD) was 15.0 ± 5.5 mm Hg in the tube group and 14.4 ± 6.6 mm Hg in the trabeculectomy group (P = .84). The number of glaucoma medications (mean ± SD) after 2 years of follow-up was 1.1 ± 1.3 in the tube group and 1.4 ± 1.4 in the trabeculectomy group (P = .71). The cumulative probability of failure at 1, 2, 3, and 4 years after additional glaucoma surgery was 0%, 43%, 43%, and 43%, respectively, in the tube group, and 0%, 9%, 20%, and 47% in the trabeculectomy group (P = .28). Reoperations to manage complications were required in 1 patient in the tube group and 5 patients in the trabeculectomy group (P = .63). The rate of reoperation for glaucoma was higher following trabeculectomy with mitomycin C than tube shunt surgery in the TVT Study. Similar surgical outcomes were observed after additional glaucoma surgery, irrespective of initial randomized treatment in the study.

Glaucoma drainage implant surgery - An evidence-based update with relevance to Sub-Saharan Africa

Glaucoma represents a leading cause of preventable vision loss in Sub-Saharan Africa. Recent studies evaluating outcomes of glaucoma drainage implant (GDI) surgery suggest an important role for this approach in the African patient population. The Tube Versus Trabeculectomy study demonstrated a higher success rate with non-valved GDI surgery compared to trabeculectomy with mitomycin C after five years. The Ahmed Baerveldt Comparison study showed no difference in surgical failure rates between the Ahmed Glaucoma Valve and the Baerveldt Glaucoma Implant (BGI) but better intraocular pressure outcomes with the BGI at one year. The Ahmed Versus Baerveldt study demonstrated a lower failure rate for the BGI, but also a requirement for more post-operative interventions. Further study of GDI surgery in the Sub-Saharan Africa is necessary to determine its optimal place in the treatment paradigm for glaucoma patients in the region.

Current Status of Epibulbar Anti-glaucoma Drainage Devices in Glaucoma Surgery

The term "glaucoma" covers a heterogeneous group of progressive optic neuropathies that are accompanied by characteristic visual-field defects. Primary open-angle glaucoma, the most common type, progresses insidiously and causes blindness if untreated. All current forms of treatment aim at lowering the intraocular pressure (IOP) in patients whose IOP is elevated. The implantation of anti-glaucoma drainage systems is one of the available options for surgical treatment. This review is based on pertinent literature retrieved by a selective search, including glaucoma treatment guidelines from Germany and abroad. A paradigm shift is currently underway regarding the indications for the implantation of anti-glaucoma drainage systems. Trabeculectomy (a "fistulating" operation in which the aqueous humor is led out of the eye under the conjunctiva) is still considered the surgical gold standard, but drainage systems have been implanted with increasing frequency in recent years. Studies have shown that these systems are more likely to be beneficial the earlier they are implanted in the course of the patient's disease. Five-year follow-up data from the randomized, multicenter Tube Versus Trabeculectomy (TVT) study have now revealed that anti-glaucoma drainage systems are equivalent to trabeculectomy with respect to long-term IOP reduction, complication rates, and absolute and relative clinical success rates. Glaucoma is a major clinical and socio-economic problem whose surgical treatment increasingly involves the implantation of anti-glaucoma drainage systems.