Clinical Experience with the Baerveldt 250-mm2 Glaucoma Implant

Racial Disparities Affecting Black Patients in Glaucoma Diagnosis and Management

Black patients are more affected by glaucoma and suffer from more advanced disease. Diagnostic challenges among black patients with glaucoma include lower rates of diagnostic testing and thinner average central corneal thickness, the latter of which affects intraocular pressure measurement. Treatment challenges include poor follow-up, medication adherence, and trust in providers. Black patients undergoing trabeculectomy have higher rates of failure compared to white patients. Race is not a definitive factor affecting success for tube shunts, laser trabeculoplasty, cyclophotocoagulation, and micro-invasive glaucoma surgeries, but the body of evidence is limited by low inclusion of black patients in these studies. Future steps should include increased attention toward improving trust between patients and providers, improving access to care, and increased representation of black patients in glaucoma research to better understand factors affecting racial disparities in glaucoma management and outcomes in this population disproportionately affected by the disease.

Racial Disparities Affecting Black Patients In Glaucoma Diagnosis And Management

Black patients are more affected by glaucoma and suffer from more advanced disease. Diagnostic challenges among black patients with glaucoma include lower rates of diagnostic testing and thinner average central corneal thickness, the latter of which affects intraocular pressure measurement. Treatment challenges include poor follow-up, medication adherence, and trust in providers. Black patients undergoing trabeculectomy have higher rates of failure compared to white patients. Race is not a definitive factor affecting success for tube shunts, laser trabeculoplasty, cyclophotocoagulation, and micro-invasive glaucoma surgeries, but the body of evidence is limited by low inclusion of black patients in these studies. Future steps should include increased attention toward improving trust between patients and providers, improving access to care, and increased representation of black patients in glaucoma research to better understand factors affecting racial disparities in glaucoma management and outcomes in this population disproportionately affected by the disease.

Differences in the Surgical Outcomes of Glaucoma Surgery in Patients of African Caribbean Descent

PURPOSE

People of African Caribbean Descent (ACD) have a higher prevalence of glaucoma compared to people of European Descent (ED) and there is uncertainty if treatment outcomes are equivalent between the two groups. To assess surgical failure rates comparing ACD with ED focusing on trabeculectomy, aqueous shunt implantation, non-penetrating filtering surgery (NPFS), and minimally invasive glaucoma surgery (MIGS) by performing a systematic review in accordance with the PRISMA guidelines and to determine whether there is any evidence in to show a difference in success rates based on race.

METHODS

A systematic review of articles using the CENTRAL, Ovid MEDLINE, PubMed, EMBASE, and ClinicalTrials.gov databases was completed. Additional studies were identified by contacting clinical experts and searching bibliographies. All retrospective and prospective studies on trabeculectomy, aqueous shunt implantation, NPFS, and MIGS that included at least 20% ACD were included. Two review authors independently screened search results for eligibility and inclusion and extracted the data using pre-determined fields.

RESULTS

A total of 76 studies were identified for inclusion in the review. Glaucoma surgical outcomes in ACD appear to be poorer compared to ED overall, particularly for trabeculectomy. Data on NPFS are limited, but the studies completed thus far demonstrate surprisingly good results for ACD, particularly when compared to ED, who have significantly lower pre-operative IOPs. Evidence from studies investigating aqueous shunts does not suggest that ACD have poorer outcomes than ED. There is not enough data on MIGS to provide a significant conclusion.

CONCLUSION

In a population where trabeculectomy may no longer be the gold standard, sufficiently powered studies assessing surgical outcomes in aqueous shunts, NPFS, and MIGS are needed to guide clinicians.

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

PURPOSE

To identify the risk factors associated with failure of tube shunt surgery.

DESIGN

Pooled analysis of 3 prospective multicenter, randomized clinical trials.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Biocompatibility and feasibility of VisiPlate, a novel ultrathin, multichannel glaucoma drainage device

BACKGROUND

Glaucoma is the leading cause of blindness worldwide. Glaucoma drainage devices and minimally invasive glaucoma surgeries (MIGS) often present with tradeoffs in safety and durability of efficacy. Using a rabbit model, we examined the biocompatibility and feasibility of VisiPlate, a novel, ultrathin, tubeless subconjunctival shunt comprised of a network of microchannels.

METHODS

Six naive female New Zealand White rabbits received implants (three only in the right eye with contralateral eye untreated and three in both eyes) composed of a 400-nm-thick aluminum oxide core coated with 2 µm of parylene-C, manufactured with microelectromechanical systems (MEMS) techniques. Tonometry, slit lamp exam, clinical exam, fluorescein patency testing, and histopathology were performed.

RESULTS

VisiPlate demonstrated IOP-lowering of 20-40% compared to baseline at each time point over the course of 3 months in the nine implanted eyes. All eyes developed blebs over the implant, and fluorescein testing demonstrated fluid patency at 22 days post-implantation. Slit lamp and clinical observations showed that VisiPlate was well tolerated, with low levels of conjunctival congestion, conjunctival swelling, aqueous flare, hyphema, and iris involvement from surgery that resolved over time. At sacrifice time points of 93 days and 180 days, the only notable observations were mild levels of conjunctival congestion in implanted eyes. Histopathology showed minimal tissue response and no obvious inflammation, fibrosis, or necrosis around the implant.

CONCLUSIONS

The results of this in vivo study demonstrate the biocompatibility and IOP-lowering effect of a multichannel, ultrathin subconjunctival shunt in a rabbit model. The data suggest that VisiPlate may safely enhance aqueous outflow and significantly reduce intraocular pressure.

Treatment outcomes in the neovascular glaucoma tube versus trabeculectomy study

PURPOSE

To compare surgical outcomes between patients who underwent Baerveldt glaucoma implantation versus trabeculectomy (TLE) for the treatment of neovascular glaucoma.

METHODS

We performed a prospective, randomized, controlled clinical trial at Hiroshima University and Tsukazaki Hospital, Japan. Patients were randomized to Baerveldt glaucoma implantation (23 patients) or TLE (27 patients). The primary outcome measure was the rate of intraocular-pressure control. Secondary outcome measures included complications and interventions. We defined "failure" as intraocular pressure ≥ 22 mmHg or < 20% reduction from baseline pressure, on two consecutive follow-up visits; need for additional glaucoma surgery; vision-threatening complications; or loss of light perception. Kaplan-Meier analysis was used to determine surgical success rates. Postoperative complications and interventions were compared between the two groups with Pearson Chi-square tests.

RESULTS

There were no significant differences in demographic or ocular characteristics between the treatment groups at baseline. The postoperative follow-up was 26.6 ± 19.4 months in the Baerveldt group and 27.3 ± 20.1 months in the TLE group. There were no statistical differences (Mann-Whitney nonparametric tests with Bonferroni correction) in postoperative intraocular pressure measured at 6-month intervals. Success rates were 59.1 and 61.6% at 1-year after Baerveldt glaucoma implantation and TLE, respectively. Kaplan-Meier analysis showed no significant difference in success between groups (P = 0.71, log-rank test). Medication use, visual acuity, and interventions were similar between groups. Thirteen late postoperative complications developed in the Baerveldt glaucoma implantation group and four complications developed in the TLE group. Tube exposure was the most common late complication.

CONCLUSION

These two procedures produced similar surgical success, intraocular-pressure reductions, visual acuity, and number of medications at the last visit. The TLE group showed smaller numbers of late complications and patients who lost more than two lines of visual acuity. Therefore, TLE might be a safer and better way to treat patients with neovascular glaucoma.

[Glaucoma Drainage Devices - Evaluation of Surgical Modifications to Avoid Postoperative Complications]

BACKGROUND

In glaucoma therapy, there are many treatment options, such as glaucoma drainage devices (GDI). The aim of this study is to compare postoperative outcomes after using different surgical techniques.

MATERIAL AND METHODS

269 eyes of 250 patients who received a GDI at the ophthalmological center at the university hospital in Cologne between February 2010 and September 2016 were included in this study. The patients' baseline parameters were collected: age, sex, intraocular pressure, visual acuity, glaucoma medication, diagnosis, operated eye (right or left), number of previous eye surgeries (including laser therapy), duration-of-stay at the hospital as well as all glaucoma complications and complication-related reoperations.

RESULTS

The mean individual pressure reduction was 39, 42 and 46% after 6, 12 and 24 months respectively, while the use of medication was reduced by 38, 42 and 50%. The success rates after 1 to 5 years was 75, 60, 57, 50 and 37% with a median survival of 48 months. 86 eyes (32%) experienced early complications and 156 eyes (56%) experienced late complications. 52% of the eyes (n = 139) had to be re-operated. The technique of creating a track to enter the anterior chamber had statistically significant influence on the early postoperative hypotony (p < 0,001). Fibrin glue had no influence on early hypotony. In the univariate analysis of early postoperative hypertension requiring paracentesis, the implant type (p = 0,009), tracking-technique with a paracentesis knife or a 22-gauge needle (p = 0,004), the occlusion method (p = 0,001) and the application of viscoelastics (p = 0,001) were statistically significant parameters. If GDI were implanted as a second implant, significantly more conjunctival erosion was recorded (p = 0.040).

CONCLUSION

The use of a 22-gauge needle entering the anterior chamber reduces the hypotony risk when compared to fibrin glue. That risk is not increased by adding venting slits. When implanting GDI as a second implant, the higher risk of conjunctival erosion should be considered.

Glaucoma Drainage Device Coated with Mitomycin C Loaded Opal Shale Microparticles to Inhibit Bleb Fibrosis

Excessive fibrosis is the topmost factor for the defeat of surgical glaucoma drainage device (GDD) implantation. Adjuvant drug approaches are promising to help reduce the scar formation and excessive fibrosis. Opal shale (OS), as a natural state and noncrystalline silica substance with poriferous nature and strong adsorbability, is highly likely to undertake drug loading and delivery. Here, we employed OS microparticles (MPs) by ultrasound and centrifugation and presented an innovative and improved GDD coated with OS MPs, which were loaded with mitomycin C (MMC). MMC-loaded OS MPs were physically absorbed on the Ahmed glaucoma valve surface through OS' adsorbability. About 5.51 μg of MMC was loaded on the modified Ahmed glaucoma valve and can be released for 18 days in vitro. MMC-loaded OS MPs inhibited fibroblast proliferation and showed low toxicity to primary Tenon's fibroblasts. The ameliorated drainage device was well tolerated and effective in reducing the fibrous reaction in vivo. Hence, our study constructed an improved Ahmed glaucoma valve using OS MPs without disturbing aqueous humor drainage pattern over the valve surface. The modified Ahmed glaucoma valve successfully alleviated scar tissue formation after GDD implantation surgery.

Conjunctival repair after glaucoma drainage device exposure using collagen-glycosaminoglycane matrices

Background

To report the results of the repair of conjunctival erosions resulting from glaucoma drainage device surgery using collagen-glycosaminoglycane matrices (CGM).

Methods

Case series of 8 patients who underwent revision surgery due to conjunctival defects with exposed tubes through necrosis of the overlying scleral flap and conjunctiva after Baerveldt drainage device surgery. The defects were repaired by lateral displacement of the tube towards the sclera, with a slice of a CGM as a patch, covered by adjacent conjunctiva.

Result

Successful, lasting closure (follow-up of 12 to 42 months) of the conjunctival defects was achieved without any side-effects or complications in all eight cases.

Conclusions

Erosion of the drainage tube, creating buttonholes in the conjunctiva after implantation of glaucoma drainage devices, is a potentially serious problem. It can be managed successfully using a biodegradable CGM as a patch.

Performance and Safety of a New Ab Interno Gelatin Stent in Refractory Glaucoma at 12 Months

PURPOSE

To evaluate the intraocular pressure (IOP)-lowering performance and safety of an ab interno gelatin stent (XEN 45 Gel Stent, Allergan plc, Irvine, California, USA), a minimally invasive glaucoma surgery device, in refractory glaucoma.

DESIGN

Single-arm, open-label, multicenter clinical study.

METHODS

Following mitomycin C pretreatment, the stent was placed ab interno in patients who failed prior filtering/cilioablative procedure or had uncontrolled IOP on maximum-tolerated medical therapy, with medicated IOP ≥20 and ≤35 mm Hg and visual field mean deviation ≤-3 dB. Primary performance outcomes: patients (%) achieving ≥20% IOP reduction from baseline on the same or fewer medications and mean IOP change from baseline at month 12. Procedure-related complications and ocular adverse events (AEs) were assessed.

RESULTS

Sixty-five patients were implanted (intent-to-treat/safety population). At 12 months, 75.4% (46/61; observed data) reported ≥20% IOP lowering from baseline on the same or fewer medications. Mean IOP change from baseline was -9.1 mm Hg (95% confidence interval [CI]: -10.7, -7.5) (n = 52; observed data) at 12 months, excluding patients with missing data (n = 4) and those requiring a glaucoma-related secondary surgical intervention (n = 9). Mean medication count decreased from 3.5 (baseline) to 1.7 (12 months). No intraoperative complications or unexpected postoperative AEs were reported. Most AEs were mild/moderate; common AEs included needling (without sight-threatening complications), nonpersistent loss of best-corrected visual acuity, and transient hypotony (requiring no surgical intervention).

CONCLUSIONS

The gelatin stent reduced IOP and medication use without raising unexpected safety concerns, offering a minimally invasive surgical option for refractory glaucoma patients.

Long-term Outcomes of a Modified Technique Using the Baerveldt Glaucoma Implant for the Treatment of Refractory Glaucoma

PURPOSE OF THE STUDY

The purpose of the study was to evaluate the long-term effectiveness and safety profile of Baerveldt glaucoma implant (BGI) in patients with refractory glaucoma operated using a modified technique to avoid postoperative complications.

PATIENTS AND METHODS

A total of 160 eyes from 147 glaucomatous patients were enrolled in a consecutive interventional noncomparative case series. All the patients were treated with a 350-mm BGI using a modified technique. Intraocular pressure (IOP), the number of medications, the complications, and the postoperative interventions were reported preoperatively and during the follow-up. Postoperative IOP and the rate of complications were the primary outcome measures. The complete and qualified surgical success was the second endpoint.

RESULTS

BGI obtained a mean IOP reduction from 31.8±6.4 mm Hg (baseline) to 14.4±3.5 mm Hg after a mean follow-up period of 38.4±9.6 months. The mean number of medications reduced between preoperative (n=3.17±1.03) and postoperative period (n=0.58±0.83) (P<0.0001). Cumulative probability of maintaining an IOP between 5 and 21 mm Hg and/or a 25% or greater reduction in IOP was 78.7% at 1 year and 72.1% at 4 years, including 39 eyes (24.4%) in which postoperative interventions were required (qualified success). If we exclude those eyes from the analysis, the probability of complete success was 93.4% at 1 year and 91.4% at 4 years in 75.4% of the eyes.

CONCLUSIONS

This modified technique achieved a high percentage of surgical success during the whole follow-up time and was effective in preventing the most serious immediate complications of nonvalved tube shunts.

Vision Loss and Recovery after Baerveldt Aqueous Tube Shunt Implantation

This study aims to determine the course of vision loss after Baerveldt aqueous tube shunt placement and identify risk factors associated with unexplained severe long-term vision loss, or snuff-out. We retrospectively reviewed 247 eyes of 222 patients who underwent Baerveldt implantations at one of two academic institutions. Postoperative vision loss at 6 months following surgery was categorized as mild-to-moderate versus severe and long-term versus transient. Long-term vision loss, defined as 3 or more lines of Snellen visual acuity (VA) loss compared with preoperative VA, occurred in 63 of 247 eyes (25.5%), and 39 had mild-to-moderate and 24 had severe loss. Of these 63 eyes, 18 had no identifiable cause of vision loss. On multivariate analysis, poorer Snellen VA on postoperative day 1 (POD1) was found to be a significant risk factor for long-term vision loss (p = 0.005). In addition, the negative change in preoperative versus POD1 Snellen VA (p = 0.021) and the presence of split fixation involving the inferonasal quadrant on preoperative Humphrey visual field (p = 0.044) were significant risk factors for snuff-out. Transient vision loss occurred in 76 of 242 eyes (30.8%). In conclusion, vision loss is not uncommon after Baerveldt surgery, with snuff-out occurring in 2.4% of cases in this study.

Neovascular glaucoma: a review

Neovascular glaucoma (NVG) is a secondary glaucoma generally associated with poor visual prognosis. The development of new vessels over the iris and the iridocorneal angle can obstruct aqueous humor outflow and lead to increased intraocular pressure. The underlying pathogenesis in most cases is posterior segment ischemia, which is most commonly secondary to proliferative diabetic retinopathy or central vein retinal occlusion. The neovascularization process in the eye is driven by the events that alter the homeostatic balance between pro-angiogenic factors, such as the vascular endothelial growth factor and anti-angiogenic factors, such as the pigment-epithelium-derived factor. Early diagnosis of this condition through slit lamp examination of the iris, iridocorneal angle and retina can help to avoid the development of goniosynechia and obstruction of aqueous humor outflow, with consequent intraocular pressure elevation. Historically, NVG treatment was focused on reducing the posterior segment ischemic process that caused the formation of new vessels, through panretinal photocoagulation. Recently, several studies have investigated the application of intravitreal anti-VEGF therapies in NVG. If clinical treatment with the use of hypotensive topical drops is not sufficient, laser and/or surgical procedures are required for intraocular pressure control.

Long-term Outcomes of Ahmed Glaucoma Valve Implantation in Refractory Glaucoma at Farabi Eye Hospital, Tehran, Iran

PURPOSE

To describe long-term outcomes and complications of Ahmed glaucoma valve (AGV) implantation in subjects with refractory glaucoma at Farabi Eye Hospital, Tehran, Iran.

MATERIALS AND METHODS

This retrospective cohort study evaluated patient records of all subjects with refractory glaucoma who had undergone AGV implantation up to January 2013. The main outcome measure was the surgical success rate. Complete success was defined as intraocular pressure (IOP) <22 mmHg, without anti-glaucoma medications or additional surgery. Qualified success was IOP <22 mmHg regardless of number of anti-glaucoma medications. In all cases, loss of vision (no light perception) was considered an independent indicator of failure. Data were also collected on intraoperative and postoperative complications.

RESULTS

Twenty-eight eyes were included in the study. With a mean follow-up of 48.2 ± 31.7 months (median: 40.50 months; range: 3-124 months), the IOP decreased from a mean preoperative value of 30.8 ± 5.6 mmHg to 20.0 ± 6.4 mmHg at last visit. The number of medications decreased from 3.7 ± 0.4 preoperatively to 2.5 ± 1.1 postoperatively. Cumulative qualified success was achieved in 69% of eyes. Mean time to failure according to qualified success criteria was 92.3 ± 9.4 months. Postoperative complications were recorded in 16 (57.1%) eyes. The most common complication was focal endothelial corneal decompensation at the site of tube-cornea touch.

CONCLUSION

AGV implantation with adjunctive topical anti-glaucoma drops controlled IOP in approximately 70% of eyes with refractory glaucoma with a median of 40.5 months of follow-up. However, complication rates were higher.

Surgical Outcome of Ahmed Valve Implantation in Mexican Patients with Neovascular Glaucoma

Purpose: To describe clinical results of Ahmed glaucoma valve implantation in Mexican patients with neovascular glaucoma (NVG).

Materials and methods: We reviewed records of 60 eyes of 60 patients with NVG who underwent Ahmed valve implantation, with a follow-up period of 1 year. We identified successful and failed cases and compared baseline and follow-up characteristics to identify possible differences between both groups.

Results: We classified 36 eyes (60%) as successful and 24 (40%) as failed cases. We found a significant difference in success rate in patients who had a hypertensive phase at any time during the follow-up period (OR = 5.15, CI = 1.49-20.15, p = 0.004). Patients in the success group showed a statistically significant decrease in the number of glaucoma medications 1 year after surgery (p <0.0001). We found a statistically significant difference in success rate in patients who had preoperative best corrected visual acuity (BCVA) better than logmar 0.70 (odds ratio 4.31, CI = 1.1-19.3, p = 0.03086).

Conclusion: A hypertensive postoperative phase and a preoperative BCVA worse or equal to 20/100 seem to be risk factors for Ahmed valve surgical failure in patients with NVG.

How to cite this article: Hernandez-Oteyza A, Lazcano-Gomez G, Jimenez-Roman J, Hernandez-Garciadiego C. Surgical Outcome of Ahmed Valve Implantation in Mexican Patients with Neovascular Glaucoma. J Curr Glaucoma Pract 2014;8(3):86-90.

Intravitreal bevacizumab and Ahmed glaucoma valve implantation in patients with neovascular glaucoma

AIM

To explore the efficacy of preoperative intravitreal bevacizumab (IVB) injection combined with Ahmed glaucoma valve (AGV) implantation in the treatment of neovascular glaucoma (NVG).

METHODS

This retrospective study included 35 eyes from 35 patients who underwent preoperative IVB and AGV implantation for treatment of NVG. Findings such as intraocular pressure (IOP) number of anti-glaucoma medications, visual acuity (VA), surgical success rates, and complications were recorded.

RESULTS

After AGV implantation, IOP was 18.2±4.0 mm Hg, 15.5±3.3 mm Hg and 9.8±2.6 mm Hg at 6, 12 and 36mo, significantly decreased compared with pre-IOP (P<0.01). The number of anti-glaucoma medications was 0.9±0.5, 0.8±0.9 and 0.8±0.6 at 6, 12 and 36mo, significantly decreased compared to pre-treatment (P<0.01). At last visit, there were 19 eyes with stable VA, 4 with VA improvement, 12 with diminished VA and 3 with complete loss light perception. There were 7 cases that failed during 3-year fellow up period. Cumulative probabilities of valve survival by Kaplan-Meier analysis were 82.9%, 74.1% and 71.0% at 12, 24 and 36mo, respectively. Cox stepwise regression analysis found that the survival time was significant associated with the pre-visual acuity <2/400 (P<0.05). Post-operative complications occurred in 8 eyes, of which hyphema presented in 2 eyes, choroidal effusion in 2 eyes.

CONCLUSION

The procedure of preoperative IVB and AGV implantation should be one of treatments for NVG because of its safety and effectiveness.

Baerveldt 250 mm2 Glaucoma Drainage Devices in Eyes With Preexisting Scleral Buckles

PURPOSE

To evaluate eyes with preexisting scleral buckles (SBs) that underwent placement of a 250 mm Baerveldt glaucoma drainage device (GDD).

PATIENTS AND METHODS

Records of all patients with a preexisting SB who underwent 250 mm Baerveldt GDD placement at the Kellogg Eye Center between January 1, 2005 and September 30, 2012 were reviewed. Outcome measures included visual acuity (VA), intraocular pressure (IOP), and number of glaucoma medications prescribed.

RESULTS

Seventeen eyes of 17 patients were analyzed. Mean follow-up was 23.9 months. Twelve eyes (70.6%) achieved successful control of IOP (<22 mm Hg, not requiring additional IOP reduction procedures, and no devastating complications). Preoperatively, mean IOP was 25.5 mm Hg, mean number of glaucoma medications was 3.5, and mean logMAR VA was 1.1 (Snellen equivalent 20/200). At 1 and 2 years postoperatively, mean IOP was 9.2 and 8.8 mm Hg (P<0.001), and mean number of glaucoma medications was 0.9 and 0.3 (P<0.001), respectively. There were no statistically significant changes in logMAR VA at 1 and 2 years postoperatively (P=0.45 and 0.99, respectively). Complications included conjunctival dehiscence (4 eyes, 24%), wound leak (2 eyes, 12%), tube and plate exposure requiring removal of drainage device (2 eyes, 12%), phthisis (2 eyes, 12%), and hemorrhagic choroidal detachment (1 eye, 6%).

CONCLUSIONS

In eyes with preexisting SBs, the Baerveldt 250 mm GDD effectively lowers IOP and reduces the number of glaucoma medications. Complications related to conjunctival dehiscence are not uncommon in these eyes with significantly scarred conjunctiva.

Previous cyclodestruction is a risk factor for late-onset hypotony and suprachoroidal haemorrhage after glaucoma drainage device surgery

AIM

To investigate whether previous cyclodestructive (eg, cyclophotocoagulation and cyclocryodestruction) procedures have any influence on the general outcome and pressure level after glaucoma drainage device (GDD) surgery.

METHODS

Retrospective analysis of 110 consecutive patients who had undergone GDD (Baerveldt 250 mm(2) and 350 mm(2) implant, AMO, USA) surgery with a minimum follow-up of 3 months. The patients were divided into patients with previous cyclodestructive surgery before GDD surgery (I; 47 patients) and patients without previous cyclodestructive surgery (II; 63 patients). Intraocular pressure (IOP), medication score, best-corrected visual acuity and surgical treatments were recorded before and after drainage device implantation.

RESULTS

Patients of group I had a mean preoperative IOP of 32.1 mm Hg and a mean medication score of 4.8; patients of group II had a mean preoperative IOP of 29.2 mm Hg (p=0.18) and a mean medication score of 4.9 (p=0.84). All patients who developed suprachoroidal haemorrhage (six cases) belonged to group I (6/47=12.8%), no patient of group II (0/63=0%) developed suprachoroidal haemorrhage (Fisher's test: p=0.01). Twelve patients developed late-onset (>6 weeks after GDD surgery) hypotony, nine of them belonging to group I (9/47=19.1%) and three of them to group II (3/63=4.8%) (Fisher's test: p=0.03).

CONCLUSIONS

While taking potential bias arising from the retrospective nature of the study into consideration, a history of previous cyclodestructive procedures before GDD surgery seems to be a major risk factor for suprachoroidal haemorrhage and for late-onset postoperative hypotony.

Evaluation of Ahmed glaucoma valve implantation through a needle-generated scleral tunnel in Mexican children with glaucoma

Purpose:

To evaluate the results and extrusion rates of the Ahmed glaucoma valve (AGV) implantation through a needle-generated scleral tunnel, without a tube-covering patch, in children.

Materials and Methods:

A retrospective review of the charts of 106 Mexican children implanted with 128 AGVs operated between 1994 and 2002, with the needle track technique, at our institution, with at least six months follow up was done. Main outcome measures were intraocular pressure (IOP) control, tube extrusions or exposure and other complications.

Results:

Kaplan-Meier analysis demonstrated a 96.9% survival rate at six months, 82.4% at one year, 78.7% at two years, 70% at three years and 41.6% at four years. Total success at the last follow-up (IOP between 6 and 21 mm Hg without medications) was achieved in 30 eyes (23.5%), 58 eyes (45.3%) had qualified success (only topical hypotensive drugs) and 40 eyes (31.3%) were failures. The mean pre- and post-operative IOP at the last follow up was 28.4 mmHg (SD 9.3) and 14.5 mmHg (SD 6.3), respectively. No tube extrusions or exposures were observed. Tube-related complications included five retractions, a lens touch and a transitory endothelial touch. The risk of failure increased if the eye had any complication or previous glaucoma surgeries.

Conclusion:

Medium-term IOP control in Mexican children with glaucoma can be achieved with AGV implantation using a needle-generated tunnel, without constructing a scleral flap or using a patch to cover the tube. There were no tube extrusions, nor any tube exposures with this technique.

Capsule excision and Ologen implantation for revision after glaucoma drainage device surgery

BACKGROUND

There is little information available about surgical management after failed glaucoma drainage device (GDD) surgery. We present the outcome of capsule excision after failed GDD surgery compared to capsule excision with additional use of a biodegradable implant (Ologen, version 2) as a placeholder.

METHODS

In an observational comparative case series of 19 patients undergoing excision of the GDD capsule, ten prospectively observed consecutive patients were treated by excision of the capsule, topical mitomycin C application, and implantation of an 10 x 10 x 2 mm-sized Ologen implant (group A) while 9 retrospectively observed consecutive patients were treated by excision of the capsule and topical mitomycin C application alone (group B).

RESULTS

Mean preoperative IOP was 29.4 mmHg for group A and 27.6 mmHg for group B, while mean postoperative IOP at the last follow-up (mean follow-up 11.2 (group A) and 8.6 (group B) months) was 17.3 mmHg for group A and 19.3 mmHg for group B (p > 0.05). Follow-up of the two groups demonstrated a significant difference in success rate (log-rank test, p = 0.04) in favor of group A. No further pressure-reducing surgery was necessary in any of the patients in group A, but it was needed in three of nine patients in group B.

CONCLUSIONS

Although our study has the limitations of small sample size and observational study design, it shows that further investigation is warranted into the potential of Ologen in revision surgery after GDD implantation.

Modern concepts in antiglaucomatous implant surgery

BACKGROUND

Antiglaucomatous implant surgery is a continously evolving field in glaucoma treatment.

METHODS

A literature search with the terms "glaucoma implant surgery", "aqueous shunts" and "glaucoma drainage devices" was carried out, especially giving prominence to innovative surgical developments in glaucoma implant surgery and to recently established clinical evidence on traditional shunt surgery.

RESULTS

Episcleral glaucoma drainage devices have recently proven their efficacy in large studies. Longterm data about their clinical efficacy and their risk/safety profile are sufficiently available. New antiglaucomatous devices try to target alternative drainage routes, for example trabecular or uveoscleral outflow. Valid longterm data from prospective randomized clinical trials are not available for these devices as yet.

CONCLUSIONS

Although valid data on clinical application of the new glaucoma implants are not available as yet, profound knowledge about their theoretical concept and their practical management is obligatory for all glaucoma clinicians.

Long-term outcomes of Ahmed glaucoma valve implantation in refractory glaucomas

PURPOSE

To evaluate the long-term efficacy of intraocular pressure (IOP) reduction and complications of Ahmed glaucoma valve (AGV) implantation (New World Medical, Inc, Rancho Cucamonga, California, USA) in refractory glaucoma.

DESIGN

Retrospective cohort study.

METHODS

Retrospective medical records from 64 patients (78 eyes) with refractory glaucoma who underwent AGV implantation with a minimum of three years of follow-up were reviewed. Data regarding age, gender, race, eye laterality, specific glaucoma diagnosis, best-corrected visual acuity (BCVA), number of medications, IOP, visual fields, surgical complications, and follow-up interval were collected from all visits and were analyzed. The primary outcome measure was cumulative probability of success defined as IOP of less than 21 mm Hg and of 5 mm Hg or more with a minimum of 15% reduction from baseline IOP, without additional glaucoma surgery or loss of light perception. Secondary outcomes included IOP and number of medications at three, six, 12, 24, 36, 48, and 60 months after surgery, surgical complications, and final BCVA.

RESULTS

The cumulative probability of success was 80% and 49% at one and five years, respectively. IOP was reduced from a mean of 30.4 +/- 10.7 mm Hg to 17.0 +/- 5.0 mm Hg at 12 months and 15.9 +/- 3.0 mm Hg at 60 months (P < .001). The number of medications decreased from 3.2 +/- 1.0 medications at baseline to 1.6 +/- 0.4 at 12 months and 2.1 +/- 0.2 at 60 months (P < .001). Prior glaucoma surgery and the silicone type of AGV were statistically significant risk factors for failure (P < .001).

CONCLUSIONS

Approximately 50% of single-plate AGV implantations in refractory glaucoma were considered successful after five years of follow-up. Prior glaucoma surgery was a statistically significant risk factor for failure.