Treatment outcomes in the Tube Versus Trabeculectomy (TVT) study after five years of follow-up

Comparison of the Ahmed glaucoma valve with the Baerveldt glaucoma implant: a meta-analysis

BACKGROUND

This study aims to compare the efficacy and safety of the Ahmed glaucoma valve (AGV) with the Baerveldt glaucoma implant (BGI) in glaucoma patients.

METHODS

Databases were searched to identify studies that met pre-stated inclusion criteria, involving randomized controlled clinical trials (RCTs) and non-randomized controlled clinical trials. Treatment effect was analyzed using a random-effect model.

RESULTS

Ten controlled clinical trials (1048 eyes) were analyzed, involving two RCTs and eight retrospective comparative studies. Short-term results (6-18 months) and long-term results (>18 months) were analyzed separately. There was no significant difference in the success rate for short-term follow-up between the AGV and BGI groups (5 studies, 714 eyes, odds ratio [OR]: 0.97; 95 % confidence interval [CI]: 0.56, 1.66; P = 0.90). For long-term pooled results (7 studies, 835 eyes), the success rate of AGVs was lower than that of BGIs (OR: 0.73; 95 % CI: 0.54, 0.99, P = 0.04), However, subgroup and sensitivity analyses did not show a significant difference in the success rate between the two groups (P ≥0.05). The AGV group had a higher mean intraocular pressure than the BGI group in short-term (6 studies, 685 eyes, weighted mean difference [WMD]: 2.12 mmHg; 95 % CI: 0.72-3.52; P <0.05) and long-term pooled results (7 studies, 659 eyes, WMD: 1.85 mmHg; 95 % CI: 0.43, 3.28; P = 0.01). The BGI group required fewer glaucoma medications after implantation than the AGV group in two follow-up periods (all P <0.05). The AGV was found to be associated with a significantly lower frequency of total complications (8 studies, 971 eyes, OR: 0.67; 95 % CI: 0.50-0.90; P = 0.007) and severe complications (8 studies, 971 eyes, OR: 0.57; 95 % CI: 0.36-0.91; P = 0.02) than the BGI.

CONCLUSIONS

The study showed no significant difference in success rate between the two groups. The BGI was more effective for control of intraocular pressure and required fewer medications than the AGV, but the AGV had lower incidence of total and severe complications than the BGI.

[Current aspects on the management of normal tension glaucoma]

In a considerable proportion of glaucoma patients (25-50 %) the intraocular pressure (IOP) is not elevated higher than 22 mmHg at first diagnosis and during subsequent follow-up controls. Although the IOP level remains in the low range < 22 mmHg, progression of glaucoma can still occur. A multitude of different factors are assumed to be involved in glaucoma progression, such as very low nocturnal diastolic blood pressure values, a low mean ocular perfusion pressure, extensive fluctuations in perfusion (e.g. in cases of vascular dysregulation), an increased vulnerability of the optic nerve support structures, an increased translaminar pressure gradient and various underlying systemic diseases. The most important evidence-based aspect of treatment in normal tension glaucoma is pharmaceutical or surgical reduction of the IOP by 30 % or more in comparison to the initial pressure level. Vascular and neuroprotective concepts of treatment for normal tension glaucoma have been strongly advocated and the object of experimental and clinical studies. As yet a clear clinical benefit has not been proven by large prospective randomized studies.

New directions in the treatment of normal tension glaucoma

Glaucoma is a progressive optic neuropathy that causes characteristic changes of the optic nerve and visual field in relation to intraocular pressure (IOP). It is now known that glaucoma can occur at statistically normal IOPs and prevalence studies have shown that normal tension glaucoma (NTG) is more common than previously thought. While IOP is believed to be the predominant risk factor in primary open angle glaucoma (POAG), IOP-independent risk factors, such as vascular dysregulation, are believed to play an important part in the pathogenesis of NTG. Though certain distinguishing phenotypic features of NTG have been reported, such as an increased frequency of disc hemorrhages, acquired pits of the optic nerve and characteristic patterns of disc cupping and visual field loss, there is much overlap of the clinical findings in NTG with POAG, suggesting that NTG is likely part of a continuum of open angle glaucomas. However, IOP modification is still the mainstay of treatment in NTG. As in traditional POAG, reduction of IOP can be achieved with the use of medications, laser trabeculoplasty or surgery. Studies now show that the choice of medication may also be important in determining the outcomes of these patients. Though it is likely that future treatment of NTG will involve modification of both IOP and IOP-independent risk factors, current efforts to develop IOP-independent neuroprotective treatments have not yet proven to be effective in humans.

Postoperative Changes in Aqueous Monocyte Chemotactic Protein-1 Levels and Bleb Morphology after Trabeculectomy vs. Ex-PRESS Shunt Surgery

Purpose

To evaluate the postoperative changes in blebs and levels of aqueous monocyte chemotactic protein-1 (MCP-1) after trabeculectomy vs. Ex-PRESS tube shunt surgery.

Methods

Rabbits were subjected to trabeculectomy or Ex-PRESS tube shunt surgery and observed for up to 3 months. Intraocular pressure (IOP) was measured using a rebound tonometer. The MCP-1 level was measured by enzyme-linked immunosorbent assay (ELISA). Bleb morphology was evaluated using photos and anterior-segment optical coherence tomography (OCT).

Results

There were no differences in bleb appearance or IOP at any time between the groups. Bleb wall density in the anterior-segment OCT image was significantly lower 1 week after surgery in the Ex-PRESS group than the trabeculectomy group. The MCP-1 level in control eyes was 304.1 ± 45.2 pg/mL. In the trabeculectomy group, the mean aqueous MCP-1 level was 1444.9, 1914.3, 1899.8, 516.4, 398.3, 427.3, 609.5, 1612.7, 386.2, and 167.9 pg/mL at 3, 6, and 12 h, and 1, 2, 5, 7, 14, 30, and 90 days after surgery, respectively. In the Ex-PRESS group, the corresponding values were 1744.0, 1372.0, 932.5, 711.7, 396.1, 487.3, 799.5, 1327.9, 293.6, and 184.0 pg/mL. There were no significant differences in the aqueous MCP-1 level between the groups at any time point.

Conclusion

The postoperative changes were similar in the Ex-PRESS and trabeculectomy groups, except for bleb wall density in the anterior-segment OCT image. The postoperative aqueous MCP-1 level had bimodal peaks in both groups.

Intraocular pressure control after the implantation of a second Ahmed glaucoma valve

The objective of this study is to evaluate the efficacy and safety of a second Ahmed glaucoma valve (AGV) in eyes with refractory glaucoma that had undergone prior Ahmed device implantation. This multicenter, retrospective study evaluated 58 eyes (58 patients) that underwent a second AGV (model S2-n = 50, model FP7-n = 8) due to uncontrolled IOP under maximal medical therapy. Outcome measures included IOP, visual acuity, number of glaucoma medications, and postoperative complications. Success was defined as IOP <21 mmHg (criterion 1) or 30 % reduction of IOP (criterion 2) with or without hypotensive medications. Persistent hypotony (IOP <5 mmHg after 3 months of follow-up), loss of light perception, and reintervention for IOP control were defined as failure. Mean preoperative IOP and mean IOPs at 12 and 30 months were 27.55 ± 1.16 mmHg (n = 58), 14.45 ± 0.83 mmHg (n = 42), and 14.81 ± 0.87 mmHg (n = 16), respectively. The mean numbers of glaucoma medications preoperatively at 12 and 30 months were 3.17 ± 0.16 (n = 58), 1.81 ± 0.2 (n = 42), and 1.83 ± 0.35 (n = 18), respectively. The reductions in mean IOP and number of medications were statistically significant at all time intervals (P < 0.001). According to criterion 1, Kaplan-Meier survival curves disclosed success rates of 62.9 % at 12 months and 56.6 % at 30 months. According to criterion 2, Kaplan-Meier survival curves disclosed success rates of 43.9 % at 12 months and 32.9 % at 30 months. The most frequent early complication was hypertensive phase (10.3 %) and the most frequent late complication was corneal edema (17.2 %). Second AGV implantation may effectively reduce IOP in eyes with uncontrolled glaucoma, and is associated with relatively few complications.

Long-Term Outcomes and Prognostic Factors of Trabeculectomy following Intraocular Bevacizumab Injection for Neovascular Glaucoma

PURPOSE

To evaluate long-term outcomes and identify prognostic factors of trabeculectomy following intraocular bevacizumab injection for neovascular glaucoma.

METHODS

Sixty-one eyes of 54 patients with neovascular glaucoma treated by trabeculectomy following intraocular bevacizumab injection were consecutively enrolled. Surgical success criteria were sufficient intraocular pressure (IOP) reduction (IOP ≤ 21 mmHg, ≥ 20% IOP reduction, no additional medications or glaucoma surgeries) without devastating complications (loss of light perception, phthisis bulbi, and endophthalmitis) or significant hypotony (IOP ≤ 5 mmHg continued ≥ 6 months and until the last follow-up visit or hypotony requiring intervention). Kaplan-Meier survival curves and Cox regression analysis were used to examine success rates and risk factors for surgical outcomes.

RESULTS

The follow-up period after trabeculectomy was 45.0 ± 22.2 months (mean ± standard deviation). Surgical success rate was 86.9 ± 4.3% (± standard error), 74.0 ± 6.1%, and 51.3 ± 8.6% at 1, 3, and 5 years. Multivariate Cox regression analysis identified two risk factors; lower preoperative IOP (≤ 30 mmHg) for surgical failure and hypotony [hazard ratio (HR), 2.92, 6.64; 95% confidence interval (CI), 1.22 to 7.03, 1.47 to 30.0; P = 0.018, 0.014, respectively], and vitrectomy after trabeculectomy for surgical failure with or without hypotony criteria (HR, 2.32, 4.06; 95% CI, 1.02 to 5.28, 1.30 to 12.7; P = 0.045, 0.016, respectively).

CONCLUSIONS

The long-term outcomes of trabeculectomy following intraocular bevacizumab injection for neovascular glaucoma were favorable. Lower baseline IOP was associated with development of significant hypotony, while additional vitrectomy was related to insufficient IOP reduction.

The use of endoscopic cyclophotocoagulation for moderate to advanced glaucoma

Endoscopic Cyclophotocoagulation (ECP) is a glaucoma surgery designed to reduce the intraocular pressure (IOP) by partially ablating the ciliary processes to decrease aqueous humour production and secretion. The aim of this paper is to review the literature regarding the background, indications and results of the surgery. Although there are case reports of visually devastating complications, including persistent hypotony and phthisis, the use of ECP is often reported in eyes with advanced diseases. When compared with both trabeculectomy and aqueous shunt implantation, the visual outcomes were better with ECP while the IOP outcomes were very similar. The evidence supports ECP as a very effective surgical option in recalcitrant glaucoma while some evidence supports its safety for use as a primary procedure.

Managing Drawbacks in Unconventional Successful Glaucoma Surgery: A Case Report of Stent Exposure

Traditional options in managing failed trabeculectomy (bleb needling, revision, additional incisional surgery and tube surgery) have a relatively high failure and complication rate. The use of microinvasive glaucoma surgery (MIGS) has generally been reserved to mild to moderate glaucoma cases, proving good safety profiles but significant limitations in terms of efficacy. We describe a patient who underwent MIGS (XEN Aquesys subconjunctival shunt implantation) after a prior failed trabeculectomy. After the surgery, the IOP was well controlled but as the stent was close to an area of scarred conjunctiva of the previous trabeculectomy, it became partially exposed. As a complete success was achieved, we decided to remove the conjunctiva over the exposed area and replace it by an amniotic membrane transplantation and a conjunctiva autograft. Six months after surgery, the unmedicated IOP is still well controlled with complete visual acuity recovery.

Use of Gamma-Irradiated Cornea to Plug Sclerostomy Site During Tube Shunt Revision

Tube shunt implantation is a common procedure for control of intraocular pressure (IOP). However, tube revision and repositioning must sometimes be performed, and this involves removing the tube from its sclerostomy site. This site is prone to leaking and this may cause postoperative hypotony. We describe a novel and cosmetically acceptable technique of plugging and covering the sclerostomy site with gamma-irradiated corneal tissue.

Results of Trabectome Surgery Following Failed Glaucoma Tube Shunt Implantation: Cohort Study

To evaluate the safety and efficacy of Trabectome after failed tube shunt surgery.Twenty patients with prior failed tube shunt surgery who underwent Trabectome alone were included. All patients had at least 3 months of follow-up. Outcomes measured included intraocular pressure (IOP), glaucoma medications, and secondary glaucoma surgeries. The success for Kaplan-Meier survival analysis is defined as IOP ≤21 mm Hg, IOP reduced by at least 20% from preoperative IOP, and no secondary glaucoma surgery.Mean preoperative IOP was 23.7 ± 6.4 mm Hg and mean number of glaucoma medications was 3.2 ± 1.5. At 12 months, IOP was reduced to 15.5 ± 3.2 mm Hg (P = 0.05) and number of medications was reduced to 2.4 ± 1.5 (P = 0.44). Survival rate at 12 months was 84% and 3 patients required additional glaucoma surgery with 15 patients reaching 12 months follow-up. Other than failure of IOP control and transient hypotony (IOP < 3 mm Hg) day 1 in 2 cases, there were no adverse events.Trabecular bypass procedures have traditionally been considered an approach appropriate for early-to-moderate glaucoma; however, our study indicates benefit in refractory glaucoma as well. Eyes that are prone to conjunctival scarring and hypertrophic wound healing, such as those who have failed tube shunt surgery, may benefit from procedures that avoid conjunctival incision such as Trabectome. This study indicates potential benefits in this patient population.Trabectome was safe and effective in reducing IOP at 1-year follow-up in patients with prior failed tube shunt surgery, but not effective in reducing medication reliance in these patients.

One Year of Glaucoma Research in Review-2013 to 2014

PURPOSE

The purpose of this study was to provide the practicing clinical ophthalmologist with an update on relevant glaucoma literature published from 2013 to 2014.

DESIGN

This study is a literature review.

METHODS

The authors conducted a 1-year (October 1, 2013, to September 30, 2014) English-language glaucoma literature search on PubMed of articles containing "glaucoma" or "glaucomatous" with title/abstract as a filter. Medical subject headings filtered searching was not performed because of the newness of the reviewed material.

RESULTS

Literature search yielded 2314 articles, after which we excluded reviews and letters to the editor. We highlighted articles featuring new or updated approaches to the pathophysiology, diagnosis, or treatment of glaucoma and gave preference to human research.

CONCLUSIONS

This review features literature that is of interest to ophthalmologists in practice and also highlights studies that may provide insight on future developments applicable to clinical ophthalmology.

Use of Various Glaucoma Surgeries and Procedures in Medicare Beneficiaries from 1994 to 2012

PURPOSE

Determine how procedural treatments for glaucoma have changed between 1994-2012.

DESIGN

Retrospective, observational analysis.

PARTICIPANTS

Medicare Part B beneficiaries.

METHODS

We analyzed Medicare fee-for-service paid claims data between 1994-2012 to determine the number of surgical/laser procedures performed for glaucoma in the Medicare population each year.

MAIN OUTCOME MEASURES

Number of glaucoma-related procedures performed.

RESULTS

Trabeculectomies in eyes without previous scarring decreased 52% from 54 224 in 1994 to 25 758 in 2003, and a further 52% to 12 279 in 2012. Trabeculectomies in eyes with scarring ranged from 9054 to 13 604 between 1994-2003, but then decreased 48% from 11 018 to 5728 between 2003-2012. Mini-shunts done via an external approach (including ExPRESS [Alcon Inc, Fort Worth, TX]) increased 116% from 2718 in 2009 to 5870 in 2012. The number of aqueous shunts to the extraocular reservoir increased 231% from 2356 in 1994 to 7788 in 2003, and a further 54% to 12 021 in 2012. Total cyclophotocoagulation procedures increased 253% from 2582 in 1994 to 9106 in 2003, and a further 54% to 13 996 in 2012. Transscleral cyclophotocoagulations decreased 45% from 5978 to 3268 between 2005-2012; over the same period, the number of endoscopic cyclophotocoagulations (ECPs) increased 99% from 5383 to 10 728. From 2001 to 2005, the number of trabeculoplasties more than doubled from 75 647 in 2001 to 176 476 in 2005, but since 2005 the number of trabeculoplasties decreased 19% to 142 682 in 2012. The number of laser iridotomies was fairly consistent between 1994-2012, increasing 9% over this period and ranging from 63 773 to 85 426. Canaloplasties increased 1407% from 161 in 2007 to 2426 in 2012. Between 1994-2012, despite a 9% increase in beneficiaries, the total number of glaucoma procedures and the number of glaucoma procedures other than laser procedures decreased 16% and 31%, respectively.

CONCLUSIONS

Despite the increase in beneficiaries, the number of glaucoma procedures performed decreased. Glaucoma procedures demonstrating a significant increase in use include canaloplasty, mini-shunts (external approach), aqueous shunt to extraocular reservoir, and ECP. Trabeculectomy use continued its long-term downward trend. The continued movement away from trabeculectomy and toward alternative intraocular pressure-lowering procedures highlights the need for well-designed clinical trials comparing these procedures.

Serial changes in the bleb wall after glaucoma drainage implant surgery: characteristics during the hypertensive phase

PURPOSE

To investigate serial changes in the bleb wall using anterior segment optical coherence tomography (AS-OCT) in patients who had undergone Ahmed glaucoma valve (AGV) implantation.

METHODS

A total of 52 patients who had undergone AGV implantation were enrolled. Reflectivity and mean thickness of the bleb wall were examined using AS-OCT at 1 day, 1 week, 1 month, 3 months and 6 months postoperatively. Intra-ocular pressure (IOP) and the number of glaucoma medications were evaluated. The hypertensive phase was defined as IOP >21 mmHg during the first 3 months after surgery. Patients were divided into two groups: hypertensive and non-hypertensive groups.

RESULTS

Following AGV implantation, IOP decreased at each time-point during postoperative follow-up (p value < 0.001, all) with a peak in the first month. Mean bleb wall thickness showed a U-shaped curve postoperatively, being thinnest 1 month after the operation. Reflectivity showed an inverted U-shaped curve postoperatively, being brightest 1 month after the operation. A hypertensive phase was observed in 44 patients (84.6%). The bleb wall was significantly more reflective (130.67 ± 27.00 versus 106.57 ± 10.35; p = 0.044) in the hypertensive group than in non-hypertensive group 1 month postoperatively.

CONCLUSIONS

Hypertensive phase peaked at 1 month after aqueous shunt surgery. At that time, the bleb wall had the highest reflectivity. The unique IOP pattern after tube surgery is related to fibrosis of the bleb wall qualitatively. Specific modulation of wound healing may be the target for attempts to decrease the development of hypertensive phase.

Clinical Outcomes of FP-7/8 Ahmed Glaucoma Valves in the Management of Refractory Glaucoma in the Mainland Chinese Population

Background

To evaluate the efficacy and safety of the Ahmed glaucoma valve (AGV) and the risk factors associated with AGV implantation failure in a population of Chinese patients with refractory glaucoma.

Method

In total, 79 eyes with refractory glaucoma from 79 patients treated in our institution from November 2007 to November 2010 were enrolled in this retrospective study. The demographic data, preoperative and postoperative intraocular pressures (IOPs), best corrected visual acuity (BCVA), number of anti-glaucoma medications used, completed and qualified surgery success rates and postoperative complications were recorded to evaluate the outcomes of AGV implantation. Factors that were associated with implant failure were determined using Cox proportional hazard regression model analysis and multiple linear regression analysis.

Principle Findings

The average follow-up time was 12.7±5.8 months (mean±SD). We observed a significant reduction in the mean IOP from 39.9±12.6 mm Hg before surgery to 19.3±9.6 mm Hg at the final follow-up. The complete success rate was 59.5%, and the qualified success rate was 83.5%. The number of previous surgeries was negatively correlated with qualified success rate (P<0.05, OR=0.736, 95% CI 0.547-0.99). Patients with previous trabeculectomy were more likely to use multiple anti-glaucoma drugs to control IOP (P<0.01). The primary complication was determined to be a flat anterior chamber (AC).

Conclusion

AGV implantation was safe and effective for the management of refractory glaucoma. Patients with a greater number of previous surgeries were more likely to experience surgical failure, and patients with previous trabeculectomy were more likely to use multiple anti-glaucoma drugs to control postoperative IOP.

Effect of Two Novel Sustained-Release Drug Delivery Systems on Bleb Fibrosis: An In Vivo Glaucoma Drainage Device Study in a Rabbit Model

PURPOSE

To evaluate two drug delivery systems, a nonbiodegradable poly(2-hydroxyethyl methacrylate) (P[HEMA]) system with mitomycin C (MMC) and a biodegradable poly(lactic-co-glycolic acid) (PLGA) system with 5-fluorouracil (5-FU) with and without MMC for their ability to reduce fibrosis when attached to an Ahmed glaucoma valve (AGV) and implanted in a rabbit model.

METHODS

New Zealand albino rabbits (48) were divided into six equal groups, and AGVs, modified as described below, were implanted in the right eye of each rabbit. The groups included (1) PLGA alone; (2) P(HEMA) plus MMC (6.5 μg); (3) PLGA plus 5-FU (0.45 mg); (4) PLGA plus 5-FU (1.35 mg); (5) PLGA plus 5-FU and MMC (0.45 mg and 0.65 μg, respectively); (6) PLGA plus 5-FU and MMC (1.35 mg and 0.65 μg, respectively). The rabbits were followed for 3 months prior to euthanasia.

RESULTS

The bleb wall thickness was significantly less in groups 2, 5, and 6 compared to the rest. At 3 months, the PLGA polymer had completely disappeared, while the P(HEMA) polymer remained intact. There were no statistical differences in the degree of clinically graded conjunctival injection, histologic inflammation, or histologic fibrosis among the six groups.

CONCLUSIONS

We successfully created a sustained-release drug delivery system that decreased the postoperative fibrosis using both a nonbiodegradable P(HEMA) polymer and a biodegradable (PLGA) polymer. Both systems appear to work equally well with no side effects.

TRANSLATIONAL RELEVANCE

These results are supportive of the antifibrotic effect of the slow-release drug delivery system following glaucoma drainage device implantation, thus paving the way for human pilot studies.

Complications of glaucoma drainage device surgery: a review

PURPOSE

To review current literature on the complications of the use of glaucoma drainage device surgery.

SUMMARY

The use of glaucoma drainage devices has increased significantly in recent years for both primary treatment of glaucoma and refractory glaucoma. The efficacy and safety of glaucoma drainage devices has been well established, so they are a viable surgical option in patients who fail medical therapy. With the increased use of these devices, understanding their complications is essential in managing these patients. The prevention and management of complications associated with glaucoma drainage device insertion has some similarities to that of a trabeculectomy. The glaucoma drainage devices have additional complications associated with the fact that hardware is left within the eye. There have been no definitive answers as to the perfect surgical technique to prevent complications but careful surgical performance, tube placement and use of a double-layered graft over the tube are likely to lead to a better outcome. The rate of complications also dictates careful follow up to identify these complications early in their process as early intervention will likely lead to better outcomes.

A Randomized Trial of a Schlemm's Canal Microstent with Phacoemulsification for Reducing Intraocular Pressure in Open-Angle Glaucoma

PURPOSE

To assess the safety and effectiveness of the Hydrus Microstent (Ivantis, Inc, Irvine, CA) with concurrent cataract surgery (CS) for reducing intraocular pressure (IOP) in open-angle glaucoma (OAG).

DESIGN

Prospective, multicenter, randomized, single-masked, controlled clinical trial.

PARTICIPANTS

One hundred eyes from 100 patients 21 to 80 years of age with OAG and cataract with IOP of 24 mmHg or less with 4 or fewer hypotensive medications and a washed-out diurnal IOP (DIOP) of 21 to 36 mmHg.

METHODS

On the day of surgery, patients were randomized 1:1 to undergo CS with the microstent or CS alone. Postoperative follow-up was at 1 day, 1 week, and 1, 3, 6, 12, 18, and 24 months. Washout of hypotensive medications was repeated at 12 and 24 months.

MAIN OUTCOME MEASURES

Response to treatment was defined as a 20% or more decrease in washed out DIOP at 12 and 24 months of follow-up compared with baseline. Mean DIOP at 12 and 24 months, the proportion of subjects requiring medications at follow-up, and the mean number of medications were analyzed. Safety measures included change in visual acuity, slit-lamp observations, and adverse events.

RESULTS

The proportion of patients with a 20% reduction in washed out DIOP was significantly higher in the Hydrus plus CS group at 24 months compared with the CS group (80% vs. 46%; P = 0.0008). Washed out mean DIOP in the Hydrus plus CS group was significantly lower at 24 months compared with the CS group (16.9±3.3 mmHg vs. 19.2±4.7 mmHg; P = 0.0093), and the proportion of patients using no hypotensive medications was significantly higher at 24 months in the Hydrus plus CS group (73% vs. 38%; P = 0.0008). There were no differences in follow-up visual acuity between groups. The only notable device-related adverse event was focal peripheral anterior synechiae (1-2 mm in length). Otherwise, adverse event frequency was similar in the 2 groups.

CONCLUSIONS

Intraocular pressure was clinically and statistically significantly lower at 2 years in the Hydrus plus CS group compared with the CS alone group, with no differences in safety.

Retrospective review of pars plana versus anterior chamber placement of Baerveldt glaucoma drainage device

PURPOSE

To evaluate outcomes of pars plana (PP) versus anterior chamber (AC) placement of Baerveldt glaucoma drainage device (GDD).

METHODS

This study is a nonrandomized, retrospective case series evaluating 63 eyes that underwent GDD insertion with Baerveldt 350 device under the supervision of 2 surgeons at 5 centers. The drainage tube was either inserted into the AC or through the PP into the vitreous cavity where eyes had been vitrectomized. Surgery was conducted between 2003 and 2010 with minimum patient follow-up of 6 months. Data on postoperative intraocular pressure (IOP), visual acuity, number of hypotensive medications, and surgical complications were recorded.

RESULTS

Of the 63 drainage device surgeries, 34 tubes were placed in the AC and 29 were placed into the posterior segment through the PP. Preoperative mean IOP was 32.3±20.3 mm Hg in the AC group and 32.8±18.4 mm Hg in the PP group. Postoperative mean IOP was reduced at all follow-up time points in both the groups. Postoperative mean IOP in the anterior tube group was 14.0, 12.9, and 14.0 mm Hg and in the PP group was 14.2, 14.2, and 14.0 mm Hg, at the 1-, 2-, and 3-year follow-up, respectively. The qualified success rate at 2 years was 94% for the PP group and 91% for the AC group, whereas absolute success was 35% for the PP group and 27% for the AC group at 2-year follow-up.

CONCLUSIONS

Insertion of the tube of the Baerveldt GDD into the PP is a safe and effective method for IOP control in aphakic, pseudophakic, and vitrectomized eyes where there is a need to avoid anterior tube placement such as coexisting corneal pathology. IOP control results appear comparable to conventional AC placement.

Limbus- versus fornix-based trabeculectomy for open-angle glaucoma eyes with prior ocular surgery: the Collaborative Bleb-Related Infection Incidence and Treatment Study

We compared the surgical successes of limbus- and fornix-based trabeculectomies in open-angle glaucoma (OAG) eyes that had prior ocular surgery in the Collaborative Bleb-Related Infection Incidence and Treatment Study (CBIITS), Japan. From the 1,098 glaucoma eyes in 34 clinical centers in CBIITS, 195 OAG eyes that had undergone previous trabeculectomy and/or lens extraction were included. Limbus- or fornix-based trabeculectomy with mitomycin C were performed. Surgical failure (IOP ≥ 21, 18, or 15 mmHg for criterion A, B or C, respectively; <20% decrease from baseline; reoperation for glaucoma; or loss of light perception vision) was counted. There were 106 and 89 eyes treated with limbus- and fornix-based trabeculectomies, respectively. At 3 years, IOP (mean ± SD) was 12.5 ± 5.9 and 14.1 ± 6.4 mmHg and the cumulative probabilities of failure during 3 years were 30.2% and 50.5% for criterion A, 40.3% and 57.4% for criterion B, and 57.9% and 65.8% for criterion C in the limbus- and the fornix-based group, respectively. Fornix-based incisions were associated with surgical failure in Cox-proportional multivariable analysis for criterion A [relative risk (RR) = 1.96], and B [RR = 1.60]. Limbus-based trabeculectomy had a higher probability of success in OAG eyes with prior ocular surgery.

Pre-operative intraocular pressure does not influence outcome of trabeculectomy surgery: a retrospective cohort study

Background

To investigate whether pre-operative intraocular pressure (IOP) predicts outcome of trabeculectomy surgery in patients with primary open angle glaucoma over a 3-year period of follow-up.

Methods

Retrospective cohort study, of a total of 61 patients (80 procedures) who had undergone trabeculectomy surgery after failed medical management at a single centre between 2000 and 2011. Patients were identified through surgical logbooks. A subsequent case note-review identified 61 patients (80 procedures) with primary open angle glaucoma (POAG). The primary outcome was success of trabeculectomy surgery, with failure defined as intraocular pressure (IOP) > 21 mmHg, ≤ 5 mmHg or not reduced by 20% at two consecutive follow-up visits 3-months post-operatively. Qualified success was defined as surgical success with the use of supplemental medical therapy. Secondary outcomes included visual acuity, Humphrey visual field MD, surgical complications and post-operative interventions.

Results

At 3 years, the odds ratio of failure was 0.93 per mmHg pre-operative IOP (95% C.I. 0.83-1.03, p = 0.15 Wald Χ² test), and the odds ratio of failure or qualified success was 0.96 (95% C.I. 0.89-1.04, p = 0.35). The incidence of surgical complications showed an odds ratio of 1.02 per mmHg pre-operative IOP (95% C.I. 0.95-1.10, p = 0.55 Wald Χ² test). The incidence of post-operative interventions showed an odds ratio of 1.01 per mmHg pre-operative IOP (95% C.I. 0.94-1.09, p = 0.80 Wald Χ² test).

Conclusions

Pre-operative IOP does not predict success of trabeculectomy surgery in POAG patients during the first 3 years of follow-up. The incidence of surgical complications and post-operative interventions shows no association with pre-operative IOP.

Clinical impact of 8 prospective, randomized, multicenter glaucoma trials

PURPOSE

To determine the impact of 8 multicenter randomized clinical trials (RCTs) on glaucoma practice.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Surgical outcomes of superior versus inferior glaucoma drainage device implantation

PURPOSE

To compare the safety and intraocular pressure (IOP) lowering efficacy of initial glaucoma drainage device (GDD) implantation performed at the superior versus inferior limbus.

METHODS

A retrospective chart review was conducted to identify patients with glaucoma who had undergone initial Baerveldt GDD surgery at the inferior limbus for uncontrolled IOP. All eyes of patients had a minimum of 6 months of postoperative follow-up. These eyes were frequency-matched to eyes with initial Baerveldt GDD implantation performed at the superior limbus, within 5 years of age and 6 months of follow-up. Baseline demographic and clinical information, as well as preoperative and postoperative IOP, visual acuity, and number of antiglaucoma medications were extracted. Failure was defined as IOP>21 mm Hg or not reduced by 20% below baseline on 2 consecutive follow-up visits after 3 months, IOP≤5 mm Hg on 2 consecutive follow-up visits after 3 months, reoperation for glaucoma, or loss of light perception vision. Statistical methods consisted of Student t tests, χ test, and Kaplan-Meier time to failure analysis.

RESULTS

Fifty eyes (17 inferior, 33 superior) of 43 patients were enrolled. Mean postoperative follow-up in both groups were similar (mean 26.2±15.2 mo for inferior and 23.9±10.43 mo for superior, P=0.54). Trabeculectomy had been performed previously in 8/17 (47%) and 11/33 (33%) eyes (P=0.34) with inferior and superior implants, respectively. Mean preoperative IOP (mm Hg) in the superior group (26±11) was significantly higher (P=0.02) when compared with the inferior group (21±7). Success rates were similar (P>0.05) between the inferior and superior GDD groups during the study period, with 64.7% and 75.8% classified as successful at 1-year of follow-up and 43.1% and 65.7% at 2 years of follow-up, respectively. There was no difference in cumulative proportions of eyes failing between the groups (P=0.20, log-rank test). The mean postoperative IOP and number of antiglaucoma medications were similar (all P>0.05) in both groups during the first 2 years of postoperative follow-up. The frequency and types of postoperative complications in both the groups were similar. The 36-month cumulative reoperation rates for IOP control were 33.8% and 9.1%, respectively, in the inferior and superior GDD groups (P=0.04 log-rank test).

CONCLUSIONS

No differences were observed in the overall success rates of initial GDD implantation performed at the superior and inferior limbus in this cohort. However, inferior GDD implantation was associated with a greater incidence of reoperation for IOP control.

A novel antiproliferative drug coating for glaucoma drainage devices

PURPOSE

The implantation of a glaucoma drainage device (GDD) is often necessary for intractable cases of glaucoma. Currently, the success rate of GDD implants is relatively low because fibrosis that develops during the wound-healing process ultimately blocks fluid drainage. We describe herein a novel porous coating for Ahmed glaucoma valves based on biodegradable poly(lactic-co-glycolic acid) (PLGA).

MATERIALS AND METHODS

Thin films of PLGA were fabricated using a spin-coating technique. The procedure led to an asymmetric pore structure that was exploited to control the rate of dissolution. Double-layered porous films were constructed to achieve continuous drug release. A cell culture system was used to test the efficacy of these coatings.

RESULTS

Double-layered films were manufactured to provide a burst of mitomycin C (MMC) release followed by a slow release of 5-fluorouracil (5-FU), which together prevented fibrosis over the most active period of postoperative wound healing (0 to 28 d). Double-layered films containing 5-FU only in the bottom layer showed a 3- to 5-day delay in drug release, followed by a sharp increase that continued for ~28 days. MMC was stable only when surface-loaded, and this drug was therefore surface-loaded onto the top PLGA layer to provide a continuous release of antifibrotics over the wound-healing period.

CONCLUSIONS

The combined use of both MMC and 5-FU in a biodegradable device inhibits cell proliferation in a tissue culture model and has the potential to reduce fibrosis and increase the success rate of GDD implants. The design is simple and can be scaled for commercial production.

Comparison of the changes in corneal endothelial cells after pars plana and anterior chamber ahmed valve implant

Purpose. To compare the changes in corneal endothelial cells after pars plana Ahmed glaucoma valve (AGV) implantation with those after the anterior chamber AGV implantation for refractory glaucoma. Methods. The medical records of 18 eyes with pars plana implantation of AGV (ppAGV) were reviewed retrospectively and were compared with 18 eyes with the anterior chamber AGV (acAGV) implant. The preoperative and postoperative endothelial cells, intraocular pressure (IOP), and postoperative complications during the follow-up in both groups were compared. Results. The average follow-up was 18 months. The postoperative endothelial cells in the ppAGV and acAGV groups were 2044 ± 303 and 1904 ± 324, respectively (P = 0.25). The average percentage decrease in the endothelial cells in the ppAGV and acAGV groups at 18 months was 12.5% and 18.4%, respectively, and showed significant difference between the 2 groups (P = 0.01). No difference in IOP control and the number of postoperative glaucoma medications was observed between the 2 groups. Conclusions. Endothelial cell damage in the ppAGV group for refractory glaucoma appeared to be lower than that in the acAGV group. Therefore, pars plana implantation of AGV may be preferred as it may have lower level of endothelial cell damage while maintaining similar level of IOP control.

Two-year outcome of repeat trabeculectomy with mitomycin C in primary open-angle and PEX glaucoma

PURPOSE

To evaluate the effectiveness of repeat trabeculectomy with risk factor-adjusted mitomycin C (MMC) application in primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PEXG) over 2 years.

METHODS

A total of 58 patients (43 with POAG, 15 with PEXG) who had undergone repeat trabeculectomy with MMC were included in this retrospective study. Exposure time of MMC 0.3 mg/mL was adjusted according to a standardized protocol. Main outcome measures were best-corrected visual acuity (BCVA), intraocular pressure (IOP) reduction, surgical success rate (criteria were defined as A: IOP ≤21 mm Hg and a reduction of IOP ≥20%; B: IOP ≤18 mm Hg and a reduction of IOP of ≥30%; C: IOP ≤15 mm Hg and a reduction of IOP of ≥40% from baseline), and number of medications at baseline, 3 months, and 2 years postoperatively.

RESULTS

The BCVA remained stable for 2 years after surgery (0.47 ± 0.47 at baseline, 0.49 ± 0.64 logMAR units after 2 years, respectively). Mean IOP decreased from 22.2 ± 7.0 mm Hg at baseline to 12.7 ± 3.1 mm Hg at 3 months and 12.9 ± 4.3 mm Hg 2 years after surgery. The qualified success rate for criterion A was 75.4%, for criterion B 66.6%, and for criterion C45.6%. Complete success rates were 42.9%, 37.5%, and 32.1%, respectively. Two years after repeat trabeculectomy, the mean IOP was reduced by 38.8%, and the number of medications was reduced significantly.

CONCLUSIONS

Repeat trabeculectomy with MMC is successful at lowering IOP in POAG and PEXG and permits a significant and safe reduction of antiglaucomatous medication for at least 2 years after surgery.

The optimal trabeculectomy: patient and procedure

Guarded external fistulization procedures remain important surgical options for patients who are experiencing progressive vision loss caused by glaucoma. The progenitor procedure, the trabeculectomy, has undergone continuous modifications over the past 40 or more years, rendering the surgery safer and the outcomes more predictable. Studies are cumulating to show that very low intraocular pressures can both reduce glaucomatous vision loss and positively change the rate of progression. Optimal patient selection and patient preparation, as well as some guiding procedural principles, are described in this review.

Five-year treatment outcomes in the Ahmed Baerveldt comparison study

PURPOSE

To compare the 5-year outcomes of the Ahmed FP7 Glaucoma Valve (AGV) (New World Medical, Cucamonga, CA) and the Baerveldt 101-350 Glaucoma Implant (BGI) (Abbott Medical Optics, Abbott Park, IL) for the treatment of refractory glaucoma.

DESIGN

Multicenter, randomized, controlled clinical trial.

PARTICIPANTS

A total of 276 patients, including 143 in the AGV group and 133 in the BGI group.

METHODS

Patients aged 18 to 85 years with previous intraocular surgery or refractory glaucoma and intraocular pressure (IOP) of ≥18 mmHg in whom glaucoma drainage implant (GDI) surgery was planned were randomized to implantation of an AGV or a BGI.

MAIN OUTCOME MEASURES

Surgical failure, IOP, visual acuity (VA), use of glaucoma medications, and complications.

RESULTS

At 5 years, IOP (mean ± standard deviation [SD]) was 14.7±4.4 mmHg in the AGV group and 12.7±4.5 mmHg in the BGI group (P = 0.015). The number of glaucoma medications in use at 5 years (mean ± SD) was 2.2±1.4 in the AGV group and 1.8±1.5 in the BGI group (P = 0.28). The cumulative probability of failure during 5 years of follow-up was 44.7% in the AGV group and 39.4% in the BGI group (P = 0.65). The number of subjects failing because of inadequately controlled IOP or reoperation for glaucoma was 46 in the AGV group (80% of AGV failures) and 25 in the BGI group (53% of BGI failures; P = 0.003). Eleven eyes in the AGV group (20% of AGV failures) experienced persistent hypotony, explantation of implant, or loss of light perception compared with 22 eyes (47% of failures) in the BGI group. Change in logarithm of the minimum angle of resolution VA (mean ± SD) at 5 years was 0.42±0.99 in the AGV group and 0.43±0.84 in the BGI group (P = 0.97).

CONCLUSIONS

Similar rates of surgical success were observed with both implants at 5 years. The BGI produced greater IOP reduction and a lower rate of glaucoma reoperation than the AGV, but the BGI was associated with twice as many failures because of safety issues.

The "Pull-Through" Suture; Facilitating Watertight Anterior Chamber Entry and Minimizing Early Hypotony in Glaucoma Tube Surgery

Tube procedures are increasing world wide. One failing of all tube procedures is early hypotony; most commonly attributable to entry site leak as ligature and stent sutures become standard surgical practice. The tube versus trabeculectomy and primary tube versus trabeculectomy study protocols employ 21 G anterior chamber entry; however, entry site leaks can still occur often requiring suturing. Twenty-three-gauge entry produces a reliably watertight seal but can be technically challenging. The "Pull-Through" suture facilitates efficient and reproducible tube insertion while avoiding entry site trauma.

Brinzolamide plus brimonidine for the treatment of glaucoma: an update

INTRODUCTION

Glaucoma is a common sight-threatening condition that is primarily treated by lowering intraocular pressure (IOP). Today the mainstay of treatment is topical ocular hypotensive medications; many patients require more than one agent to achieve target IOP. For such patients, fixed combination formulations have several advantages including simplicity of treatment regimen, adherence to the treatment regimen, efficacy, improved ocular surface comfort and reduced cost. All currently available fixed combinations contain a β-blocker, which is contraindicated in some patients. Hence there is a clinical need for fixed-combination preparations without a β-blocker. This paper reviews the current literature on a new fixed-combination drug containing brinzolamide 1% and brimonidine 0.2% (BBFC).

AREAS COVERED

A PubMed, Embase and ClinicalTrials.gov registry search was performed to identify all relevant studies. Four published clinical papers pertaining to three randomized controlled trials were identified for review. All studies demonstrated a significant reduction (p < 0.01) in mean IOP in patients administered with BBFC compared with its individual components, brinzolamide 1% or brimonidine 0.2%. Adverse effects from BBFC were no different from each of the individual components, the most common being blurred vision, eye irritation and dysgeusia (abnormal taste sensation). Although BBFC use was associated with more adverse effects compared with the individual components used as monotherapy (p < 0.001), the cumulative adverse effect profile from BBFC did not appear greater than one would expect from the simultaneous use of the two components.

EXPERT OPINION

BBFC is a potential alternative to other fixed-combination medications and is especially useful when topical β-blockers are contraindicated. Longer-term experience will determine if additional adverse effects occur or if efficacy is maintained over longer periods.

Use of Mitomycin C to reduce the incidence of encapsulated cysts following ahmed glaucoma valve implantation in refractory glaucoma patients: a new technique

Background

To evaluate the surgical outcome of Ahmed glaucoma valve (AGV) implantation with a new technique of mitomycin C (MMC) application.

Methods

This is a retrospective study. All patients with refractory glaucoma underwent FP-7 AGV implantation. Two methods of MMC application were used. In the traditional technique, 6 × 4 mm cotton soaked with MMC (0.25–0.33 mg/ml) was placed in the implantation area for 2–5mins; in the new technique, the valve plate first was encompassed with a thin layer of cotton soaked with MMC, then inserted into the same area. A 200 ml balanced salt solution was applied for irrigation of MMC. The surgical success rate, intraocular pressure (IOP), number of anti-glaucoma medications used, and postoperative complications were analyzed between the groups.

Results

The surgical outcomes of two MMC applied techniques were compared. The new technique group had only one case (2.6%) of encapsulated cyst formation out of 38 eyes, while there were eight (19.5%) cases out of 41 eyes the in traditional group. The difference was statistically significant (P = 0.030). According to the definition of success rate, there was 89.5% in the new technique group and 70.7% in the traditional group at the follow-up end point. There was a significant difference between the two groups (P = 0.035). Mean IOP in the new technique group were significantly lower than those of the traditional group at 3 and 6 months (P < 0.05).

Conclusions

By using a thin layer of cotton soaked with MMC to encompass the valve plate, the new MMC application technique could greatly decrease the incidence of encapsulated cyst and increase the success rate following AGV implantation.

Outcomes of ab interno trabeculectomy with the trabectome after failed trabeculectomy

Aim

To evaluate outcomes of ab interno trabeculectomy (AIT) with the trabectome following failed trabeculectomy.

Methods

Prospective study of AITs and phaco-AITs after a failed trabeculectomy. The indication for AIT was intraocular pressure (IOP) above target on maximally tolerated therapy, and for phaco-AIT a visually significant cataract and need to lower IOP or glaucoma medications. Outcomes included IOP, medications, complications, secondary procedures and success, defined as IOP of less than 21 mm Hg and a greater than 20% reduction from baseline without further surgery. Exclusion criteria were trabeculectomy less than 3 months prior to AIT or follow-up under 1 year.

Results

Seventy-three eyes of 73 patients with 1 year follow-up were identified. At 1 year, mean IOP in AIT significantly decreased by 28% from 23.7±5.5 mm Hg, and medications from 2.8±1.2 to 2±1.3 (n=58). In phaco-AIT, the mean IOP decreased 19% from 20±5.9 mm Hg and medications from 2.5±1.5 to 1.6±1.4 (n=15). Transient hypotony occurred in 7%, and further surgery was necessary in 18%. For AIT and phaco-AIT, the 1-year cumulative probability of success was 81% and 87%, respectively.

Conclusions

Both AIT and phaco-AIT showed a reduction in IOP and medication use after 1 year, suggesting that AIT with or without cataract surgery is a safe and effective option following failed trabeculectomy.

Hypertensive phase and early complications after Ahmed glaucoma valve implantation with intraoperative subtenon triamcinolone acetonide

Objective

To evaluate intraoperative subtenon triamcinolone acetonide (TA) as an adjunct to Ahmed glaucoma valve (AGV) implantation.

Design

Retrospective comparative case series.

Participants

Forty-two consecutive cases of uncontrolled glaucoma undergoing AGV implantation: 19 eyes receiving intraoperative subtenon TA and 23 eyes that did not receive TA.

Methods

A retrospective chart review was performed on consecutive pseudophakic adult patients with uncontrolled glaucoma undergoing AGV with and without intraoperative subtenon TA injection by a single surgeon. Clinical data were collected from 42 eyes and analyzed for the first 6 months after surgery.

Main outcome measures

Primary outcomes included intraocular pressure (IOP) and number of glaucoma medications prior to and after AGV implantation. The hypertensive phase (HP) was defined as an IOP measurement of greater than 21 mmHg (with or without medications) during the 6-month postoperative period that was not a result of tube obstruction, retraction, or malfunction. Postoperative complications and visual acuity were analyzed as secondary outcome measures.

Results

Five out of 19 (26%) TA cases and 12 out of 23 (52%) non-TA cases developed the HP (P=0.027). Mean IOP (14.2±4.6 in TA cases versus [vs] 14.7±5.0 mmHg in non-TA cases; P=0.78), and number of glaucoma medications needed (1.8±1.3 in TA cases vs 1.6±1.1 in the comparison group; P=0.65) were similar between both groups at 6 months. Although rates of serious complications did not differ between the groups (13% in the TA group vs 16% in the non-TA group), early tube erosion (n=1) and bacterial endophthalmitis (n=1) were noted with TA but not in the non-TA group.

Conclusions

Subtenon TA injection during AGV implantation may decrease the occurrence of the HP but does not alter the ultimate IOP outcome and may pose increased risk of serious complications within the first 6 months of surgery.

Clinical characteristics and current treatment of glaucoma

Glaucoma is a neurodegenerative disorder in which degenerating retinal ganglion cells (RGC) produce significant visual disability. Clinically, glaucoma refers to an array of conditions associated with variably elevated intraocular pressure (IOP) that contributes to RGC loss via mechanical stress, vascular abnormalities, and other mechanisms, such as immune phenomena. The clinical diagnosis of glaucoma requires assessment of the ocular anterior segment with slit lamp biomicroscopy, which allows the clinician to recognize signs of conditions that can produce elevated IOP. After measurement of IOP, a specialized prismatic lens called a gonioscope is used to determine whether the angle is physically open or closed. The structural manifestation of RGC loss is optic nerve head atrophy and excavation of the neuroretinal rim tissue. Treatment is guided by addressing secondary causes for elevated IOP (such as inflammation, infection, and ischemia) whenever possible. Subsequently, a variety of medical, laser, and surgical options are used to achieve a target IOP.

Outcomes of glaucoma reoperations in the Tube Versus Trabeculectomy (TVT) Study

PURPOSE

To describe the incidence and outcomes of reoperations for glaucoma in the Tube Versus Trabeculectomy (TVT) Study.

DESIGN

Cohort study of patients in a multicenter randomized clinical trial.

METHODS

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).

RESULTS

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).

CONCLUSIONS

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.