Joseph F. Panarelli

Evidenced-based comparison of aqueous shunts

Purpose of review This review provides an evidence-based comparison of aqueous shunts in common use. Recent findings Aqueous shunts are being used with increasing frequency in the surgical management of glaucoma. Recent retrospective studies and prospective clinical trials have compared the outcomes of different shunt designs. Larger end-plate size is associated with greater intraocular pressure (IOP) reduction, but there may be an upper limit beyond which a further increase in plate surface area does not contribute beneficially to pressure control. The biocompatibility of plate material may also influence shunt efficacy. The flow restrictor of the Ahmed glaucoma valve provides an added level of safety by reducing the risk of postoperative hypotony, but this implant also appears to have a higher incidence of bleb encapsulation. Summary Several aqueous shunts are commercially available, and all have been shown to be safe and effective in lowering IOP. Studies comparing aqueous shunts have provided valuable information to assist in surgical decision-making in similar patient groups.

Angle closure after Boston keratoprosthesis.

Purpose:To evaluate changes in the anterior chamber angle after Boston keratoprosthesis (KPro) placement. Patients/Methods:Ten patients were serially imaged with anterior segment optical coherence tomography after Boston KPro surgery. Angles were judged to be open or closed in the horizontal axis. Results:Seven of 10 patients had open angles before KPro placement. Within 4 months, 4 of 7 patients developed angle closure. Contact between the iris and the backplate was seen in 3 of these patients. Two of the 4 eyes demonstrated progressive angle closure. Intraocular pressure was elevated in 3 patients postoperatively due to the obstruction of a glaucoma drainage device tube (1 eye) and angle closure (2 eyes). Conclusions:After Boston KPro surgery, patients must be carefully monitored for the onset or progression of glaucoma. Progressive angle closure can occur after placement of a Boston KPro and may be seen in conjunction with irido-backplate touch.

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.

Postoperative management of trabeculectomy and glaucoma drainage implant surgery.

Purpose of review This article describes important aspects of postoperative management after trabeculectomy and glaucoma drainage implant surgery. Recent findings Postoperative management of glaucoma drainage implant surgery includes stabilization of intraocular pressure, possible ligature release, and management of complications such as corneal edema, and tube/plate exposure. Postoperative management of trabeculectomy includes evaluation of bleb encapsulation, management of hypotony, and assessment of need for adjuvant therapy. Recent advances in surgical techniques, device/tissue availability, and imaging continue to shape the postoperative course. Summary Careful preoperative planning and postoperative care may decrease the likelihood of complications in tube surgery or trabeculectomy.

Scleral Fistula Closure at the Time of Glaucoma Drainage Device Tube Repositioning: A Novel Technique

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.

Transscleral diode laser cyclophotocoagulation after baerveldt glaucoma implant surgery.

Purpose:To evaluate the safety and efficacy of transscleral cyclophotocoagulation (TSCPC) in patients requiring intraocular pressure (IOP) reduction despite prior Baerveldt glaucoma implant (BGI) surgery. Participants and Methods:Twenty eyes of 20 patients who had previously undergone BGI placement and subsequently underwent TSCPC with the red (810 nm) diode laser between April 2005 and January 2010 were retrospectively reviewed. Results:All patients underwent BGI placement an average of 34.7±24.2 months before TSCPC. The mean follow-up period after TSCPC was 25.6±17.4 months (range, 2.3 to 56.5 mo). IOPs were reduced from a mean of 21.8±4.6 to 10.8±3.2 mm Hg at the most recent follow–up, which represents a 50.2% reduction in mean IOP. Successful postoperative IOP control was achieved in 16 (80%) of 20 patients. The number of glaucoma medications decreased from 4.2±0.6 to 2.2±1.2. The life-table success rate was 78.6% at 12, 24, and 36 months. Postoperative complications included persistent corneal edema in 1 patient and both persistent corneal edema and cystoid macular edema in another patient. Both patients sustained a >2 line reduction in Snellen visual acuity. Conclusions:TSCPC is safe and effective in the management of patients requiring IOP reduction after BGI surgery. Although our sample size was limited, the safety profile of TSCPC after BGI seems promising.

Vitreous Occlusion of a Glaucoma Drainage Implant-Surgical Management

Vitreous occlusion of a glaucoma drainage implant (GDI) can lead to failure of the device and severely elevated intraocular pressure. The pathophysiology of tube obstruction is related to central and anterior displacement of vitreous that is drawn into and condenses within the proximal lumen of the tube. This can occur from days to years following GDI surgery. Successful management of vitreous-tube obstruction generally requires manual removal of the condensed vitreous plug with end-grasping forceps. This technique achieves reversal of tube blockage and restoration of GDI function. Amputation of the incarcerated vitreous alone with vitrectomy or neodymium:yttrium-aluminum-garnet vitreolysis does not consistently restore GDI function and risks persistent intraluminal tube obstruction.

Transconjunctival Revision With Mitomycin-C Following Failed Trabeculectomy.

Purpose:To evaluate the efficacy of transconjunctival revision (TCR) with mitomycin-C (MMC) following failed trabeculectomy. Materials and Methods:The medical records of 27 patients (27 eyes) who underwent TCR with subconjunctival injection of MMC by a single surgeon between September 2001 and August 2013 were retrospectively reviewed. The same surgical protocol was followed for all patients. Revision was performed using a microvitreoretinal blade through a small conjunctival incision. Main outcome measures included visual acuity, intraocular pressure (IOP), and number of glaucoma medications. Failure was defined as an IOP<5 or >14 mm Hg, loss of light perception, or need for additional glaucoma surgery. Results:Mean interval between trabeculectomy and TCR was 56.4±57.2 months. Mean preoperative IOP was 21.9±6.8 mm Hg using 4.0±1.2 glaucoma medications. Fifteen (55.6%) patients met success criteria. At most recent follow-up, mean IOP and number of glaucoma medications for successful patients were 9.7±3.8 mm Hg and 0.6±1.1, respectively. Kaplan-Meier analysis revealed 1-, 2-, and 3-year success rates of 62%, 58%, and 53%, respectively. Three additional patients achieved success after undergoing a second TCR, and 1 patient achieved success after a third TCR. Postoperative complications included transient choroidal effusion (n=8), shallow anterior chamber requiring reformation (n=5), 5-fluorouracil-related corneal epitheliopathy (n=10), and bleb leak (n=1). Conclusions:TCR with adjunctive MMC is a safe and effective procedure following failure of a trabeculectomy. More than 1 revision may be necessary to achieve long-term IOP reduction.

Long-term Outcomes and Complications of Pars Plana Baerveldt Implantation in Children.

Purpose of the Study: The purpose of the study was to report long-term outcomes and complications of Baerveldt glaucoma implant (BGI) surgery with pars plana tube insertion in children. Materials and Methods: The medical records of consecutive aphakic and pseudophakic children (<16 y of age) who underwent BGI surgery with pars plana tube insertion between 1990 and 2013 were retrospectively reviewed. Main outcome measures were intraocular pressure and number of glaucoma medications. Postoperative complications were recorded. Failure was defined as an intraocular pressure <5 or ≥21 mm Hg (with or without glaucoma medications), loss of light perception, or need for additional glaucoma surgery. Results: Thirty-seven children were identified with a mean age of 6.0±4.7 years (range, 4 mo to 14.5 y). Mean follow-up after pars plana BGI surgery was 6.5±3.4 years (range, 9 mo to 12.8 y) for patients who met success criteria. Mean intraocular pressure and mean number of glaucoma medications at most recent follow-up for patients with successful intraocular pressure control were 13.8±4.1 and 2.3±1.9 mm Hg, respectively. The Kaplan-Meier survival analysis revealed 1-, 3-, 5-, and 7-year success rates of 94.5%, 74.6%, 65.0%, and 45.8%, respectively. Complications included tube exposure in 1 patient (2.7%), tube obstruction in 8 patients (21.6%), and retinal detachment in 9 patients (24.3%). Seventeen patients (45.9%) failed due to inadequate intraocular pressure control, of whom 9 (24.3%) required additional glaucoma surgery. Conclusions: Although pars plana BGI surgery is a reasonable option for managing refractory glaucoma in aphakic and pseudophakic children, surgeons must be aware of the potential need for additional glaucoma surgery and/or posterior segment complications with extended follow-up.

Laser tube ligature release following aqueous shunt implantation in young children

The implantation of non-valved aqueous shunting devices in children is often complicated by intraocular pressure elevation in the early postoperative period, during which time the tube is closed with a temporary suture ligature to avoid hypotony. Release of a polyglactin suture ligature using conventional laser lysis is not possible in young children in the clinic setting. The authors describe a minimally invasive technique using a portable green diode (532-nm) laser delivered through a standard endoprobe and a Hoskins laser suture lysis lens to disrupt a polyglactin suture ligature following pars plana aqueous shunt implantation in a young child.