Glaucoma Drainage Device Tube Research Articles

The "Pocket" Technique: A Novel Surgical Technique for Repair of Glaucoma Drainage Device Tube Exposure.

Exposure of glaucoma tube shunts is an uncommon post-operative complication which poses a significant risk to the patient and may be difficult to repair. In this case series, the authors present two cases utilizing a novel surgical technique, the "pocket" technique, to place a scleral patch graft to address tube exposure. Patient 1 remained free of tube exposure at most recent follow up visit after 21 months, and patient 2 remained free of tube exposure at most recent follow up visit after 4 months. This technique offers an elegant surgical option that has multiple benefits; It allows for stability of the scleral patch graft even in cases of scarred down, thinned conjunctiva with minimal Tenons, allows for repair along the entire length of the tube shunt including perilimbal exposures, and allows for secondary healing when there is not enough conjunctiva to cover both the opening and the patch. These advantages make the "pocket" technique a quick to perform, minimally invasive surgical approach that is useful for addressing both difficult and straightforward tube exposure cases.

Clinical and surgical outcomes of glaucoma drainage device tube in ciliary sulcus versus anterior chamber in North Indian glaucoma patients.

To evaluate the outcome of glaucoma drainage device (GDD) insertion of tube through ciliary sulcus (CS) versus anterior chamber (AC) placement in the North Indian population. This retrospective comparative case series included 43 patients in CS group and 24 in AC group, who underwent GDD implantation, from March 2014 to February 2020. The main outcome measures were intraocular pressure (IOP), number of anti-glaucoma medications, best corrected visual acuity (BCVA), and complications. Sixty-seven eyes of 66 patients were included in study with mean follow-up of 25.04 months (range, 12-69 months) in the CS group and 17.4 months (range, 13-28 months) in the AC group. Preoperatively the two groups were similar except for postpenetrating keratoplasty glaucoma (PPKG) and pseudophakic patients, which were higher in the CS group (P < 0.05). Both groups showed statistically insignificant difference in postoperative IOP and BCVA at last follow-up (P = 0.173, P = 0.495, respectively). Postoperative complications were similar, except for corneal decompensation which was significantly higher in the AC group (P = 0.042). Our findings suggest that there was no statistically significant difference in mean IOP between the CS and AC groups at the last follow-up. CS placement of tube of GDD appears to be effective and safe technique. However, CS placement of tube resulted in lesser corneal decompensation and thus should be preferred in pseudophakic/aphakic patients, especially PPKG.

Periosteal graft and conjunctival pedicle flap for re‐exposed glaucoma drainage device tube

AbstractPurpose: To report the management of exposed glaucoma drainage device (GDD) tube using periosteal graft.Methods: A case report of patient from ophthalmology outpatient clinic in Dr. Saiful Anwar general Hospital.Results: A 26‐year‐old male with history of steroid induced glaucoma came to ophthalmology clinic. Patient already underwent several procedures to control his intraocular pressure (IOP), including trabeculectomy and implantation of GDD. Implantation of GDD is widely used to control IOP in glaucoma patients. One month after implantation, patient experienced exposed GDD tube. Exposed GDD tube is one of the most common complications. The incidence is about 12% and tend to happen in eyes that already underwent many surgeries previously. This condition needs a further operative procedure such as adding patch graft on exposed area, in this case patient underwent conjunctival and pericardial graft. One month after additional patch graft procedure, patient felt uncomfortable sensation and redness on his right eye, even though IOP was 12 mmHg. During anterior segment examination, tube expose was found again. Patient underwent periosteal graft from his right tibial bone and conjunctival pedicle flap. After 2 months of evaluation, the graft is attached and IOP controlled at 14 mmHg.Conclusions: Periosteal graft and conjunctival pedicle flap could be one of the appropriate choices to cover re‐exposed GDD tube.

Risk factors and management of choroidal effusions.

Choroidal effusions are recognized as a common early postoperative complication of glaucoma surgery, and although often benign, they may cause significant ocular morbidity. This article aims to summarize current research on the risk factors and management of choroidal effusions. Glaucoma drainage device (GDD) implantation and trabeculectomy are the most commonly performed surgeries for the management of moderate to severe glaucoma. Common postoperative complications of these procedures include hypotony and the development of choroidal effusions. Choroidal effusions have recently been associated with the oral administration of certain drugs, including select monoclonal antibody, antiseizure and bisphosphonate medications. Risk factors for effusion development include specific patient characteristics such as pseudoexfoliative glaucoma, older age and hypertension. Although choroidal effusions typically resolve with medical therapy alone, surgical intervention may be required. Various methods of surgical intervention, such as surgical drainage or GDD tube ligation, can be utilized to treat choroidal effusions when conservative management with medical treatment fails, but themselves carry alternative risks that must be considered. Minimizing the incidence and duration of hypotony following ophthalmic surgery and careful monitoring of patients starting certain oral medications are important in limiting the occurrence of choroidal effusions. Risk factors for choroidal effusions have been recently identified in the literature. A better understanding of these risk factors, as well as the outcomes of choroidal effusion management, can help to reduce the occurrence of effusions overall and minimize ocular morbidity.

Tube-in-tube: A Solution for Retracted Tube.

Tube retraction after Ahmed glaucoma valve (AGV) implantation is an infrequent but known complication. The management option includes the use of a commercially available AGV tube extender, 22 G angiocatheter, resisting the existing glaucoma drainage device (GDD), or insertion of a new GDD. Each of the methods described in the literature has its limitations. We describe the successful management of this complication by using a cost-effective technique of connecting the silicone tube segment to the existing tube to lengthen the tube, so that it could be inserted in the anterior chamber again. The silicone tubes used for the technique were the extra length of the GDD tube, which was cut short and leftover during other GDD implantation surgeries.Clinical significanceDuring any GDD implantation, the tube is cut short before entering the anterior chamber. We retrieved the short segments of the tube immediately after the GDD was opened on the table and sterilized them again using plasma technology, available in our operating room. Hence, it provides a cost-effective alternative since the tube is usually trimmed to the desired length in all cases of GDD implantation (valved/non-valved), which can be subsequently sterilized and reused for lengthening the short tube in cases with tube retraction or inadvertently cut tube.How to cite this articlePandav SS, Gautam N, Thattaruthody F. Tube-in-tube: A Solution for Retracted Tube. J Curr Glaucoma Pract 2021;15(1):44–46.

Glycerin-preserved Human-donor Corneoscleral Patch Grafts for Glaucoma Drainage Devices.

Glycerin-preserved, human-donor, corneoscleral patch grafts are effective and safe for glaucoma drainage device (GDD) implantation, and they are comparable to previously reported materials. It can be preserved with the sterile technique for up to 12 months. To evaluate the efficacy and safety of glycerin-preserved human donor corneoscleral tissue as the patch graft for GDD implantation. This was a retrospective noncomparative study from the medical records of 102 eyes from 102 glaucoma patients who underwent GDD implantation by or under supervision of a single surgeon (N.K.) at the Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand between January 2006 and December 2016. The glycerin-preserved human-donor corneoscleral tissue was used as the patch graft to cover the tube portion of GDD over the sclera. The primary outcome measure was the occurrence of patch graft-related complications. There were 64 males and 38 females with the mean age of 52.8±18.5 years. The underlying diseases included failed filtration surgery with primary open-angle glaucoma 32 eyes and primary angle-closure glaucoma 15 eyes, congenital glaucoma 3 eyes and secondary glaucoma 52 eyes. The mean of ocular surgeries before GDD implantation was 2.3±1.1. Patch graft-related complications included tube exposure in 4 eyes (3.9%) and wound leakage in 4 eyes (3.9%). Eyes with tube exposure underwent regrafting 3 eyes and tube reposition 1 eye. Eyes with wound leaking resolved spontaneously 2 eyes and underwent conjunctival resuturing 2 eyes. The 5-year survival rate of the corneoscleral graft was 95.7%. There was no recurrence of graft-related complications after surgical procedure to correct the complications. Postoperatively, the mean of intraocular pressure and antiglaucoma medications decreased significantly from 27.4±9.8 mm Hg and 3.8±0.93 to 13.8±6.4 mm Hg (P<0.001) and 1.6±1.5 (P<0.001) at the last visit, respectively. The mean follow-up time was 59.9 months (range, 1 to 144.7 mo). The glycerin-preserved human-donor corneoscleral tissue using as the patch graft was a safe alternative for GDD tube coverage. The patch graft-related complications was comparable to other materials.

Outcomes of the Shunt Tube Exposure Prevention Study: A Randomized Clinical Trial

To compare the long-term safety and efficacy of amniotic membrane-umbilical cord (AM-UC) and pericardium patch grafts in reducing glaucoma shunt tube exposure. Multicenter, prospective, randomized clinical trial. Adults with uncontrolled glaucoma undergoing glaucoma drainage device (GDD) implantation. Patients were randomized to receive GDD with either AM-UC or pericardium patch grafts to cover GDD tubes. Patients were followed up clinically with anterior segment (AS) OCT to assess patch graft stability and host-tissue integration prospectively. Tube exposure, graft thinning, and graft-related complications. A total of 81 eyes of 81 patients (50 women, 31 men) with a mean age of 67±13 years underwent GGD implantation using Baerveldt (n= 72) or Ahmed valve (n= 9). Tubes were inserted in the anterior chamber (n= 71), sulcus (n= 6), or pars plana (n= 4). Tube ligation was performed with Baerveldt GDD along with fenestration (n= 51) or orphan trabeculectomy (n= 21). Tubes were covered with AM-UC (n= 41) or pericardium (n= 40). The mean follow-up time was 29±8 months (range, 13-40 months). Tube exposure occurred in 1 eye (2%) in the AM-UC group at 3 months and in 2 eyes (5%) in the pericardium group at 2 and 6 months (P= 0.54). Sequential AS OCT showed better host-tissue integration and significantly less graft thinning in the AM-UC group. Early graft thinning (≤3 months) occurred in 5 eyes (12%) in the AM-UC group and in 17 eyes (43%) in the pericardium group (P= 0.002). Late thinning occurred in 2 eyes (5%) and 11 eyes (28%) in the AM-UC and pericardium groups, respectively (P= 0.007). Graft translucency and cosmetic appearance of the AM-UC graft were superior to those of the pericardium graft. No evidence of graft rejection or infection was associated with the patch grafts in either group. Amniotic membrane-umbilical cord grafts are well tolerated and offer an alternative to pericardium for safe and stable tube shunt coverage. Its high-tensile strength, low immunogenicity, and excellent host-tissue integration significantly reduced graft thinning.

Repair of Exposed Ahmed Glaucoma Valve Tubes: Long-term Outcomes.

To assess the long-term outcomes of glaucoma drainage device (GDD) exposure repair with corneal lamellar patch graft covered by a buccal mucous membrane graft sutured to surrounding conjunctiva. In this retrospective longitudinal study, the charts of all patients who underwent buccal mucous membrane grafts combined with corneal lamellar patch grafts for exposed GDD tubes between the years 2006 to 2013 were reviewed. A minimum follow-up of 3 years was required for inclusion. Primary outcomes were categorized as complete success: adequate coverage throughout the study period without further intervention after 1 repair; qualified success: adequate coverage despite minor additional procedures (eg, suturing); failure: re-erosion of the GDD tube. A total of 23 tube exposures were included. Average time from GDD insertion to first erosion was 54.0±38.9 months (range, 5 to 120). Complete success was achieved in 19 cases (82.6%), and qualified success in 1 case (4.3%). There were 3 failures (13.1%). Overall success (complete+qualified) after 1 or 2 buccal mucous membrane graft repairs was achieved in 22 of 23 cases (95.7%). Average follow-up time for the successful cases (complete+qualified) was 69.5±25.4 months (median, 72.5; range, 36 to 124). There was no difference in time to first erosion between the success (complete+qualified) and failure groups: 53.8±38.3 months (range, 5 to 120) and 62.3±51.6 months (range, 5 to 105), respectively (P=0.78). Buccal mucous membrane grafts in combination with a lamellar corneal patch graft is a viable surgical strategy for eroded GDDs, providing good long-term outcomes; however, later interventions may be needed.

Corneal endothelial cell loss after Baerveldt glaucoma drainage device implantation in the anterior chamber.

PurposeTo investigate central and peripheral corneal endothelial cell density (ECD) in relation to Baerveldt (BV) glaucoma drainage device (GDD) tube corneal (TC) distance.MethodsProspective study of all patients scheduled for glaucoma tube surgery with 36 months follow‐up. A BV GDD was inserted into the anterior chamber (AC). Anterior segment optical coherence tomography (AS‐OCT) scans were made to determine the TC distance. Central and peripheral ECD was measured, preoperatively and at 3, 6, 12, 24 and 36 months postoperatively.ResultsFifty‐three eyes were included [primary open‐angle glaucoma, (n = 13); secondary glaucoma, (n = 30); and primary angle‐closure glaucoma, (n = 10)]. Central ECD significantly decreased during follow‐up, with a mean decrease of 4.54% per year (p < 0.001), and 6.57% in the peripheral quadrant closest to the BV GDD tube (PQC, p < 0.001). In the PQC, a yearly decrease of 1.57% was shown after transiridial tube placement versus 7.43% after placement ‘free’ into the AC (p = 0.006). Endothelial cell (EC) loss was related to TC distance (mean 1.69 mm), with a central loss of 6.20% and 7.25% in the PQC per year with shorter TC distances, versus a central loss of 4.11% and 5.77% in the PQC per year with longer TC distances (outside mean ± 2SD, p < 0.001). A difference in EC loss by glaucoma subtype was not identified.ConclusionThe TC distance is of significant influence on corneal ECD, a shorter TC distance causing more severe EC loss, especially in the PQC. Transiridial placement of the BV GDD tube seems safer than placement ‘free’ into the AC.

Double Layer of Processed Dry Amniotic Membrane for an Exposed Glaucoma Drainage Device Tube

To present a case of the use of a double layer of processed dry amniotic membrane to cover an exposed Baerveldt Glaucoma Drainage Device (GDD) tube where no more autologous conjunctiva was available for harvesting.

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

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

Technique for Tube Extender Implantation

To describe a novel technique to facilitate Tube Extender implantation. Two Tube Extender implantations were performed on 2 eyes of 2 patients. Before implanting the Tube Extender onto the cut tube of the glaucoma drainage device, a 30-G cannula, coated with viscoelastic, is threaded through the distal end of the extender and emerges from the proximal end. The cannula, with the extender laced over it, is then inserted into the cut tube, and the surgeon slides the Tube Extender down the cannula for insertion onto the cut tube. Retraction of the glaucoma drainage device from the anterior chamber occurs for various reasons, often the growth of the globe in pediatric patients. Tube Extenders can be implanted to lengthen the glaucoma drainage device to reenter the anterior chamber. However, the surgical technique can often be technically difficult to perform due to the flexibility of the glaucoma drainage device tube. We present a novel technique for Tube Extender implantation that makes the procedure easier to perform.

Partial thickness corneal tissue as a patch graft material for prevention of glaucoma drainage device exposure

BackgroundTo protect from erosion of the tube in glaucoma drainage device (GDD), the tube is covered by a biologic tissue which is roofed by the conjunctiva. Sclera, pericardium, dura mater and cornea are available as a patch graft. Drawbacks of some of these materials may include high cost and poor appearance. The purpose of this study is to report the long-term outcomes of partial thickness corneal grafts to cover the tube and prevent its exposure, in GDD surgeries.MethodsThis was a retrospective review of all patients who underwent Ahmed glaucoma valve implantation and had a minimum follow-up of 12 months. The tube was covered by a 300-micron partial thickness corneal graft taken either from a previous Descemet stripping endothelial keratoplasty procedure or cut from a whole corneal graft button unsuitable for keratoplasty.ResultsForty-four patients (45 eyes, mean follow-up of 27.6 ± 11.4 months) were enrolled. The partial thickness corneal grafts maintained clarity throughout follow-up with satisfactory cosmetic results. Mild conjunctival retraction occurred in 4 eyes (8.9 %) between 1 and 12 months after the surgery. Corneal graft melting occurred in 3 (6.7 %) eyes. Tube exposure and additional surgery to re-patch or suture the conjunctiva over the tube was needed in 1 (2.2 %) eye. None of the patients had graft infection or immunologic rejection.ConclusionsPartial thickness corneal grafts have favorable long-term outcome as a patch for GDD tubes with low rates of tube exposure and other complications.

Ultrasound evaluation of glaucoma drainage devices in children

This study evaluated B-scan ultrasound as a technique for assessing glaucoma drainage device (GDD) patency/function in refractory pediatric glaucoma. We retrospectively evaluated 70 eyes of 52 patients after Ahmed (n = 40 eyes), Baerveldt (n = 27 eyes) and Molteno (n = 5 eyes) GDD implantation; 2 eyes each had 2 GDDs. Median age was 6.5 years. Glaucoma diagnoses included primary congenital glaucoma (n = 19) and secondary glaucoma associated with aphakia (n = 16), aniridia (n = 5), Peters anomaly (n = 3), uveitis (n = 2), and other conditions (n = 7). B-scan ultrasound evaluation proved helpful to clinical assessment when the GDD tube was not seen because of opaque corneas (n = 20 eyes), the bleb was not visualized (n = 21 eyes), or IOP was elevated (n = 28 eyes). Ultrasound findings suggesting a nonpatent or malfunctioning GDD were further confirmed by subsequent intraoperative bleb needling (n = 2 eyes) and GDD revision (n = 7 eyes). B-scan ultrasound evaluation can serve as a useful adjunct in evaluating GDD patency/function in selected eyes with refractory pediatric glaucoma and may aid in clinical management.

Glaucoma Drainage Device Tube Retraction and Blockage in a Patient with Iridocorneal Endothelial Syndrome Treated With Nd:YAG Membranectomy

Purpose: To report on a case that demonstrates the successful treatment of tube blockage of the Ahmed Glaucoma Valve at its aqueous entry site by Nd:YAG laser membranectomy. Method: We report a case of refractory intraocular pressure elevation in a patient with iridocorneal endothelial syndrome after glaucoma drainage device due to blocked tube from the iridocorneal endothelial syndrome membrane. In July 2014, our patient presented with sudden right eye elevated intraocular pressure to 67 mmHg despite a well-controlled intraocular pressure in the range of teens with timolol alone over the last 2 years. Gonioscopy showed total synechial angle closure and increasing her medical treatment failed to control the intraocular pressure. Ahmed glaucoma valve was implanted successfully. However, recurrence of raised intraocular pressure from partial tube retraction and tube blockage at its aqueous entry site by an endothelial membrane was noted at 2 weeks after the surgery. Nd:YAG laser membranectomy was performed on 2 occasions to restore the patency of the tube shunt. After the second laser membranectomy, the patient’s intraocular pressure returned to, and remained at, normal level since. Conclusion: Tube occlusion by membrane is a well-known complication following glaucoma drainage device tube in patients with iridocorneal endothelial syndrome. Nd:YAG membranectomy is effective to restore the patency of tube lumen without subjecting patients to more invasive surgical interventions including tube extender or another glaucoma drainage device. However, more studies are required to ascertain the long term effect of laser membranectomy to a blocked tube, in comparison to other treatment modalities. To our knowledge, this is the first reported case of using laser membranectomy alone in treating Ahmed glaucoma valve tube obstruction due to a retracted tube blocked by endothelial membrane.

Scleral Fistula Closure at the Time of Glaucoma Drainage Device Tube Repositioning

Repositioning a glaucoma drainage device tube from the anterior chamber to the ciliary sulcus or pars plana can be a challenging procedure owing to the difficulty in obtaining tight closure of the original limbal fistula. Failure to achieve watertight and airtight closure of the fistula can result in substantial difficulty in completing other key portions of the surgery and may lead to postoperative hypotony and associated complications. A novel technique using a Tutoplast scleral plug, polyglactin sutures, and, in certain cases, fibrin tissue sealant to close a limbal fistula at the time of glaucoma drainage device tube repositioning is described. This technique can be replicated with ease and provides a tight seal so that other concurrent surgical procedures can safely be completed and postoperative hypotony is avoided.

Double Use of Corneal Graft for Descemet Stripping Automated Endothelial Keratoplasty and Coverage of Glaucoma Drainage Device Tube

To describe the efficacy and safety of using a single corneal graft for 2 different ocular surgeries, Descemet stripping automated endothelial keratoplasty in one patient and coverage of a glaucoma drainage device tube in another patient. The records of 12 consecutive patients who underwent Ahmed glaucoma valve implantation using the anterior lamella of a donor cornea that had been previously used for Descemet stripping automated endothelial keratoplasty were reviewed. Nine eyes (75%) had superotemporal Ahmed valve implantation and 3 eyes (25%) had inferotemporal implantation. No intraoperative complications were encountered in any of these cases. During postoperative follow-up there were no graft rejections, wound dehiscences, tube exposures, or any glaucoma drainage device-related complications. In 1 patient, graft thinning was noticed 12 months after surgery, but without erosion of the conjunctiva or exposure of the tube. Mean intraocular pressure (IOP) before surgery was 32.8±9.3 mm Hg. The mean postoperative IOPs were 13.2±6.8 mm Hg (P<0.001) at day 1, 10.5±2.7 (P<0.001) at week 1, 12.2±3.5 (P<0.001) at month 1, 12.9±3.0 (P<0.001) at month 3, 14.2±7.0 (P<0.001) at month 6, and 13.0±6.4 (P<0.001) at the final visit. The mean reduction in IOP was 59%. Mean follow-up time after surgery was 21.7±7.5 months. The use of the anterior corneal graft cap for patching a tube is safe and effective. The double use of a corneal graft is economically worthwhile and especially useful in countries where there is shortage of donor corneal tissues.

Outcomes of Descemet Stripping Automated Endothelial Keratoplasty in Patients With Previous Glaucoma Drainage Device Insertion

To report the outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) in patients with a previously inserted glaucoma drainage device (GDD). The clinical records of patients who had DSAEK surgery with a history of GDD insertion were reviewed. Eleven eyes of 10 patients (7 men and 3 women) were included. The mean age for DSAEK surgery was 67.2 ± 20.4 years (range, 22-93 years). The mean follow-up after DSAEK surgery was 20.2 ± 10.7 months (range, 3-37 months). Preoperative mean logarithm of the minimum angle of resolution (logMAR)-corrected distance visual acuity was 1.8 ± 0.6 (range, 20/100 to hand motions), and this improved to 0.9 ± 0.8 (range, 20/40 to hand motions) at the final follow-up (P < 0.01). There was no statistical difference in mean pre-DSAEK versus final post-DSAEK intraocular pressure (P = 0.88). Six of 11 eyes (54.5%) had double GDD insertion before DSAEK surgery. GDD tubes were trimmed in 6 eyes (54.5%), and no eyes required further glaucoma surgical intervention after DSAEK surgery. Postoperative complications included early postoperative graft dislocation in 4 eyes (36.4%) that were successfully repositioned. Four eyes (36.4%) had an episode of endothelial rejection, with 2 patients (18.2%) requiring repeat endothelial keratoplasty for endothelial failure. The mean donor endothelial cell count was 2740 cell per square millimeter preoperatively and reduced to 858 cells per square millimeter at the final follow-up, a significant mean reduction of 69%. This was significantly greater than previously reported endothelial cell loss after DSAEK alone at our institution. Although surgery may be more challenging, the presence of GDD is not a contraindication to DSAEK surgery. In this series, there was a high rate of dislocation that was successfully managed with rebubbling. DSAEK seems to be a reasonable alternative to penetrating keratoplasty for corneal decompensation after GDD.

Internal Glaucoma Drainage Device Tube Fenestration for Uncontrolled Postoperative Intraocular Pressure

To describe a novel approach to early postoperative intraocular pressure (IOP) control after glaucoma drainage device (GDD) implantation. Two patients with elevated IOP after GDD implantation underwent internal GDD tube fenestration using a 30-gauge needle to perforate the GDD tube. IOP was lowered in each case by over 50% without complication. Transanterior chamber internal GDD tube fenestration is a novel, straightforward approach to early IOP control after GDD implantation. This procedure adds to our armamentarium of methods for controlling IOP during the early postoperative period.

Penetrating Keratoplasty With Pars Plana Glaucoma Drainage Devices

To study the outcome of penetrating keratoplasty (PK) in eyes undergoing simultaneous insertion or repositioning of a glaucoma drainage device (GDD) through the pars plana. The medical records of all patients who underwent PK and primary placement or repositioning of a GDD through the pars plana from April 1, 1997, through December 1, 2005, were reviewed. Intraocular pressure (IOP) control was defined as maintenance of IOP > or = 5 and < or = 21 mm Hg (without loss of light perception vision or needing further glaucoma surgery). Kaplan-Meier life table survival analysis was used to estimate the success of graft survival (clarity) and glaucoma control. Eighty-three eyes of 80 patients (34 men and 46 women) were identified. Mean follow-up was 16 months (range, 6-96 months). PK and pars plana vitrectomy were performed with primary pars plana GDD insertion (57 eyes) or tube repositioning from the anterior chamber to pars plana (26 eyes). Grafts remained clear in 93% of eyes (76/83) at 6 months, 87% (56/66) at 1 year, and 59% (19/32) at 2 years. IOP was controlled in 87% (72/83) of eyes at 6 months, 95% (57/63) at 1 year, and 83% (20/24) at 2 years. PK with simultaneous pars plana GDD repositioning or placement showed comparable short- and long-term IOP control to that of previous studies with limbal-based GDD. The rate of corneal graft failure and the rate of immunologic rejection were comparable to or lower than those reported in other series with primary limbal-based GDD.