Temporary ab interno suture cyclopexy for closing a cyclodialysis cleft during cataract surgery.

Cyclodialysis clefts are often associated with ocular hypotony and attendant maculopathy. However, these clefts create an alternative aqueous outflow pathway that can be useful to maintain intraocular pressure (IOP) at physiologic levels under some conditions. At normal levels of IOP, they might prevent glaucoma damage and avoid maculopathy of hypotony. Indeed, historically, cyclodialysis was a planned surgical method for managing glaucoma, and more recently, a minimally invasive glaucoma surgery device that created a small-stented cyclodialysis was in use until removed from the market for unrelated concerns. Cataract surgery in the presence of a cleft, however, might be complicated by extensive fluid misdirection through the cleft with resultant large suprachoroidal effusion. A technique of ab interno temporary suture cyclopexy was devised for a patient needing cataract surgery with an existing traumatic cyclodialysis cleft that was vital for long-term management of IOP. The suture was used to close the cleft transiently during surgery and was removed at the close of the procedure to reestablish patency and preserve the cleft.

Conjunctival bleb compression sutures: An effective method of addressing hypotony after trabeculectomy or trabeculectomy-related procedures.

PURPOSE:: Over-filtration is a well-known complication of trabeculectomy and related procedures, especially with adjunctive antimetabolites. Secondary hypotony can result in reduced visual acuity and compromise long-term surgical success. Persistent hypotony requires intervention and we describe an effective adaptation of placing conjunctival compression sutures directly over the scleral flap. METHODS:: A retrospective consecutive case series of all patients who underwent conjunctival compression suturing from 2012 to 2014 at Manchester Royal Eye Hospital, UK. Under sub-tenon's anaesthesia, two 9/0 nylon figure-of-eight transconjunctival sutures were placed horizontally across the bleb: the first over the anterior flap/ostium and the second over the posterior flap edge to reduce flow through the trabeculectomy flap. RESULTS:: A total of 10 patients underwent conjunctival compression suturing, and all patients had successful reversal of hypotony and symptom resolution within 1 week with corresponding clinical improvement. Intraocular pressure control was maintained without topical pressure-lowering agents in seven patients (median = 10 mmHg, range = 7-12 mmHg) with a median follow-up of 35.9 months (range = 11-61 months). Two patients required topical therapy to maintain intraocular pressure ≤ 14 mmHg and one patient's hypotony returned after 10 months but remained untreated due to pre-existing poor vision. No patients required a return to theatre. CONCLUSION:: This series demonstrates that conjunctival compression sutures can successfully provide long-term control of trabeculectomy-bleb-related hypotony. This technique offers an effective alternative for glaucoma surgeons in addressing post-trabeculectomy hypotony.

Control and optimisation of fluid flow in glaucoma drainage device surgery.

Avoidance of hypotony in the early post-operative phase following glaucoma drainage device surgery is paramount, if serious complications are to be avoided. Current strategies of preventing early hypotony are either a valve mechanism, as those found in Ahmed Glaucoma Valve or flow restrictor as used in Baerveldt or Molteno implants. The Ahmed glaucoma valve has a pre-tensioned valve which opens and closes at the pre-determined level of intra-ocular pressure. Although the opening and closing pressure can be slightly inconsistent, coinciding with the change of material used in the plate construction, the reliability appears to have improved in recent years. Flow restrictor method, such as vicryl tie and Supramid suture stenting, used in non-valved implants utilised the Poissuille's equation in predicting the pressure gradient across the tube and thereby avoiding the risk of hypotony. Newer generations of glaucoma drainage devices such as Xen, Microshunt, and eyeWatch all use the same principle. However, most of these do not address the issue of unnecessary residual flow resistance once the bleb resistance has formed around the drainage tube or plate except for the EyeWatch device.

XEN-augmented Baerveldt: A New Surgical Technique for Refractory Glaucoma.

BACKGROUND: Glaucoma drainage devices have traditionally been reserved for patients with refractory glaucoma. However, these devices are prone to various sight-threatening complications. To prevent hypotony after placement of the Baerveldt tube, surgeons traditionally tie the tube with an absorbable suture until encapsulation occurs around the plate. We hypothesized that combining the XEN tube, placing it in the anterior chamber and connecting it to the Baerveldt tube posteriorly, outside the anterior chamber, would minimize 2 main potentially blinding complications: hypotony and corneal disease. PURPOSE: To describe a new surgical technique for refractory glaucoma, combining both the Baerveldt and the XEN tubes in the same surgery. SURGICAL TECHNIQUE: The Baerveldt implant was positioned in the superotemporal quadrant and sutured to the sclera. A scleral flap was executed extending from the anterior margin of the plate for the entire length of the tube to the limbus. The Baerveldt tube was correctly positioned by removing a deeper scleral flap. The XEN tube was then inserted ab externo and inserted into the Baerveldt tube's lumen. The newly formed double tube was then sutured and covered by the first scleral flap and usual suturing of the conjunctiva was performed. CONCLUSIONS: This technique is simple and potentially increases the safety of refractory glaucoma surgeries.

Use of a 350-mm2 Baerveldt glaucoma drainage device to maintain vision and control intraocular pressure in dogs with glaucoma: a retrospective study (2013-2016).

OBJECTIVE: To evaluate the 350-mm2 Baerveldt glaucoma drainage device (GDD) in dogs with refractory glaucoma when modifications to address postoperative hypotony (extraluminal ligature; intraluminal stent) and the fibroproliferative response (intraoperative Mitomycin-C; postoperative oral colchicine and prednisolone) are implemented as reported in human ophthalmology. DESIGN: Retrospective case series. ANIMALS: Twenty-eight client-owned dogs (32 eyes) including seven dogs (nine eyes) with primary glaucoma and 21 dogs (23 eyes) with secondary glaucoma. METHODS: The medical records of all dogs undergoing placement of a 350-mm2 Baerveldt GDD at a veterinary ophthalmology referral service between 2013 and 2016 were reviewed. Signalment, diagnosis, duration and previous treatment of glaucoma, previous intraocular surgery, IOP, visual, and surgical outcomes were recorded. RESULTS: IOP was maintained <20mmHg in 24 of 32 (75.0%) eyes. Fourteen eyes (43.8%) required no adjunctive treatments to maintain this IOP control. Fewer doses of glaucoma medication were required following surgery. Vision was retained in 18 of 27 (66.7%) eyes with vision at the time of surgery. No eyes that were blind at the time of surgery (n = 5) had restoration of functional vision. Complications following surgery included hypotony (26/32; 81.3%), intraocular hypertension (24/32; 75.0%), and fibrin formation within the anterior chamber (20/32; 62.5%). The average follow-up after placement of the GDD was 361.1 days (median 395.6 days). CONCLUSION: Efforts to minimize postoperative hypotony and address the fibroproliferative response following placement of a 350-mm2 Baerveldt GDD showed an increased success rate to other reports of this device in dogs and offers an alternative surgical treatment for controlling intraocular pressure in dogs with glaucoma.

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.

ExPRESS Shunt Surgery for Glaucoma with Post-Traumatic Aniridia.

A 76-year-old male presented with post-traumatic aphakia and aniridia in the right eye. The ocular pressure was 24 mmHg despite treatment with mixed eyedrops of timolol 0.5% and dorzolamide, brimonidine 0.1%, and Latananoprost 0.005%. The glaucomatous cup excavation was 0.8. Because it was his only eye, we informed him of the possibility of the Ex-PRESS implant as a possible prevention measure of possible postoperative hypotony. Seidel, hypotony, and choroidal detachment were not observed in the postoperative period. In the first two postoperative months, the pressure remained at 14 mmHg. The ocular pressure reached 20 mmHg at three months, so he was treated with mixed eyedrops of timolol 0.5% and brimonidine 0.1%. The ocular pressure decreased to 12 mmHg and remained at that level at the 10-month follow-up. The absence of serious postoperative complications suggest that this procedure may be an alternative in selected situations, such as for our patient.

Intraoperative testing of opening and closing pressure predicts risk of low intraocular pressure after Ahmed glaucoma valve implantation.

PURPOSE: The aim of this study was to assess whether intraoperative testing of silicone Ahmed glaucoma valves (AGVs) would identify valves with an increased risk of low postoperative intraocular pressure (IOP). METHODS: In 30 consecutive cases of glaucoma surgery with AGV implantation, after priming the AGV, we intraoperatively measured the opening pressure A, closing pressure B, and re-opening pressure C using the active infusion pump of a phako-machine. IOP was checked postoperatively on the same day. Low IOP was defined as <5 mm Hg. Intraoperatively measured pressure characteristics of the valve function were analysed for their ability to predict postoperative IOP outcomes. RESULTS: Opening A, closing B, and re-opening C pressures (mean, (SD)) were 18.4 (5.1), 8.3 (4.7), and 11.7 (4.8)mm Hg, respectively. Ten patients (33.3%) had low IOP. An opening pressure of ≤18 mm Hg predicted low postoperative IOP with a sensitivity (10/10) of 100% (95% CI, 69.2-100) and a specificity (13/20) of 65.0% (95% CI, 40.8-84.6). CONCLUSIONS: AGVs have a high variability of opening, closing, and re-opening pressures. An opening pressure of ≤18 mm Hg, a closing pressure of ≤10 mm Hg, or a re-opening pressure of ≤11 mm Hg identified all patients with low postoperative IOP.

[Prevention of intraocular pressure elevation after argon laser trabeculoplasty in primary open angle glaucoma].

INTRODUCTION: Argon laser trabeculoplasty (ALT) is an intraocular pressure lowering method that is overall safe and powerful, but often complicated by transient postoperative intraocular pressure rises. In prevention of this complication, we frequently use two potent alpha-adrenergic agonists--brimonidine and apraclonidine. OBJECTIVE: The aim of this study was to compare brimonidine 0.2% and apraclonidine 0.5% efficacy and safety in prevention of intraocular pressure elevation after ALT. METHODS: This was a prospective, randomized, double-masked and comparative study. This study included 27 POAG patients, 15 received 0.2% brimonidine, and 12 received 0.5% apraclonidine before laser surgery (22 eyes in both groups). Intraocular pressure readings were taken 1, 2, 3, 24 hours and 7 days after ALT. Student's t-test was used to analyse data between two groups, and chi2 test to compare data within groups. Value p less than 0.05 was considered statistically significant. RESULTS: We found statistically significantly lower IOP in eyes that received 0.2% brimonidine at readings taken 1 hour after ALT (p = 0.001). There were no statistically significant differences in other IOP readings between two groups. CONCLUSION: A single preoperative drop of brimonidine 0.2% had similar efficacy and safety as apraclonidine 0.5% in preventing transient IOP elevations after ALT.

Adjunctive use of a novel releasable suture technique in transconjunctival vitrectomy.

PURPOSE: The purpose of this study was to determine the merits of a transconjunctival vitrectomy with the releasable suture technique in a large series of 20-gauge, 23-gauge, and hybrid trocar vitrectomy and to assess its effectiveness in minimizing the occurrence of incompetent wound closures. METHODS: One hundred and one patients, with a variety of vitreoretinal disorders, and totaling 125 eyes, were enrolled. Each entry site wound was closed, with the releasable suture technique using 8-0 nylon. Postoperatively, sutures were released under a slit lamp at the office a mean 22.9 hours after surgery. In addition to the usual intraoperative and postoperative identification of complications, preoperative and postoperative intraocular pressures were monitored. RESULTS: The full results from all 337 sclerotomies (206, 20 gauge; and 131, 23 gauge) were assessed. It was observed that there were no significant differences between preoperative and postoperative intraocular pressure measurements (P > 0.05); no eyes required fluid or gas supplements, there was no significant wound leakage or hypotony; and no significant complications occurred, such as endophthalmitis or choroidal detachment. CONCLUSION: These results indicate that transconjunctival vitrectomy with releasable sutures, including those conducted with larger instrument trocar systems, offer patients excellent chances for a favorable outcome without incidences of postoperative wound leakage or hypotony.

Three-step incision for 23-gauge vitrectomy reduces postoperative hypotony compared with an oblique incision.

BACKGROUND AND OBJECTIVE: to assess the efficacy and safety of the newly developed three-step incision method of performing 23-gauge vitrectomy. PATIENTS AND METHODS: a retrospective comparative study in which a consecutive series of 45 eyes that underwent the three-step incision type of 23-gauge vitrectomy was compared with a series of 27 consecutive eyes that had previously undergone the oblique incision type of 23-gauge vitrectomy. RESULTS: no cases of postoperative hypotony (< 6 mm Hg) were noted in the three-step group compared with 3 cases (11%) in the oblique group (P = .05). The three-step incision resulted in a significantly higher mean intraocular pressure than the conventional incision on postoperative day 1 (14.1 ± 6.7 mm Hg vs 10.9 ± 3.7 mm Hg; P = .05), but there was no significant difference after 1 week. CONCLUSION: the three-step incision for performing 23-gauge vitrectomy effectively prevented postoperative hypotony and demonstrated a safety profile comparable to that of the oblique incision.

Primary trabeculectomy with mitomycin C: safety and efficacy at 2 years.

PURPOSE: To examine the rates of intermediate-term intraocular pressure (IOP) control after trabeculectomy with adjunctive mitomycin C (MMC) and assess for associated complications. METHODS: Medical records of patients undergoing primary trabeculectomy with MMC at Concord Repatriation Hospital, Sydney between January 1997 and December 2005 were reviewed. All eyes with a minimum of 2-year follow up were included. Follow-up data were collected in a standardized form on postoperative IOP, bleb-related and other complications. Success was measured as IOP ≤ 18 mmHg and ≥ 6 mmHg (criteria 1) with (qualified success) or without (absolute success) the use of glaucoma medications. A secondary outcome measure was an IOP reduction of greater than 20% from baseline (criteria 2). Eyes with preoperative IOP of 18 mmHg or less were included, but also analysed separately to those eyes with preoperative IOP above 18 mmHg. RESULTS: Sixty eyes from 42 patients were included in the study, with 3-year follow up on 48 eyes. Mean preoperative IOP was 25.3 mmHg (range 8-45) and mean postoperative IOP was 14.0 mmHg at 1- and 2-year follow up, and 14.7 mmHg at 3 years (ranges: 3-31, 4-30 and 8-45 mmHg respectively). Cumulative success for criteria 1 was 85.0% at 2 years and 83.3% at 3 years, and for criteria 2 it was 80.0% and 79.2%, respectively. The number of eyes on glaucoma medications was reduced from 51 preoperatively to 30 at 3 years. Complications were infrequent. There was one eye with a shallow anterior chamber beyond the immediate postoperative period. One eye required cataract surgery at 1-year follow up. Subgroup analysis was performed using the first operated eye only, and results did not differ significantly from overall results. CONCLUSION: MMC-augmented trabeculectomy can significantly reduce IOP in the short and intermediate term, with a favourable safety profile.

Twenty-three gauge cannula system with microvitreoretinal blade trocar.

AIMS: To report on a 23-gauge cannula with a microvitreoretinal (MVR) blade trocar which improved wound closure after vitrectomy and reduced the incidence of postoperative hypotony. METHODS: The resistance of inserting a 23-gauge MVR trocar-cannula through the porcine sclera was compared with that with the conventional 23-gauge trocar-cannula. The incidence of postoperative hypotony (intraocular pressure <6 mm Hg) was determined for 48 eyes that underwent vitrectomy with the 23-gauge MVR trocar-cannula and 30 eyes with the conventional 23-gauge trocar-cannula. The eyes were examined on postoperative days 1, 2 and 7. The closure of the sclerotomies was examined by optical coherence tomography in nine eyes in each group on postoperative days 1, 3 and 7, and 1 month. RESULTS: The resistance of inserting the MVR trocar-cannula was lower than that with the conventional trocar-cannula. In patients, a transient hypotony was found at postoperative day 1 after the vitrectomy in two eyes (4%) with the MVR trocar-cannula, and in seven eyes (23%) with the conventional trocar-cannula (p=0.023). An unclosed incision was detected in nine sclerotomies (50%) with the MVR trocar-cannula and 16 sclerotomies (89%) with the conventional trocar-cannula (p=0.028) on postoperative day 1, and the incidence of an opened incision was also significantly higher with the conventional trocar-cannula on days 3 and 7 but not after 1 month (p=0.003, p=0.008, p=0.486, respectively). CONCLUSION: The MVR trocar-cannula leads to better postoperative wound closure and reduces the incidence of postoperative hypotony.

Tube shunt complications and their prevention.

PURPOSE OF REVIEW: Glaucoma drainage devices (GDDs) have been generally accepted as a treatment of refractory glaucoma. GDDs have their own unique set of complications that are important to evaluate to prevent them. RECENT FINDINGS: Tube shunts are typically used in eyes with refractory glaucoma. There is increased interest in studying the efficacy of GDDs. Most of the attention has been focused on comparing trabeculectomy with the Baerveldt implant (Advanced Medical Optics, Inc., Santa Anna, California, USA). The other leading implant is the Ahmed Glaucoma Valve. There are several retrospective studies comparing these two devices and a prospective study is ongoing. There is great interest in the complication rate of tube shunts and these have been published both retrospectively and prospectively. Complications such as hypotony, diplopia, strabismus, proptosis, tube erosion, failure, corneal decompensation, endophthalmitis, and visual loss are all important and some have recently been reviewed in the literature. Moreover, the use of glaucoma drainage implants in the pediatric population has been evaluated. SUMMARY: Glaucoma drainage implants have been a powerful tool in our surgical fight to prevent blindness; however, they are not without complications or controversy.

Risk factors of shallow anterior chamber other than hypotony after Ahmed glaucoma valve implant.

PURPOSE: To find the risk factors of shallow anterior chamber following hypotony after Ahmed glaucoma valve implant. METHOD: The retrospective study was carried out with patients who had postoperative intraocular pressure 5 mm Hg or below at 2 consecutive visits after Ahmed glaucoma valve implant surgery. They were divided into 2 groups by the depth of anterior chamber and various factors were compared including age, sex, diabetes, hypertension, glaucoma type, previous intraocular surgery, preoperative visual acuity, refractive error, lens status, corneal thickness, endothelial cell count, axial length, preoperative intraocular pressure, number of preoperative glaucoma medications, use of carbonic anhydrase inhibitor, gonioscopic examination results, and use of ligation suture. RESULTS: Groups with younger age (P=0.041), myopia (P=0.003), and fewer previous intraocular surgeries (P=0.000) showed higher risk and partial ligation of the tube (P=0.000) showed protective effect of shallow anterior chamber by hypotony after Ahmed valve implant. CONCLUSIONS: When performing Ahmed glaucoma valve implant surgery in patients with more risk factors of shallow anterior chamber, preventive procedures and proper management can improve the success rate of the implant and reduce its complications.

Rebound tonometry in conscious, conditioned mice avoids the acute and profound effects of anesthesia on intraocular pressure.

AIMS: The aims of this study were to evaluate the accuracy, repeatability, and safety of multiple intraocular pressure (IOP) measurements by a commercially available rebound tonometer in conscious, conditioned mice, and to characterize the acute and profound effects of anesthesia on IOP in mice. METHODS: To test the accuracy of the tonometer, IOPs of CD-1 mice under ketamine/xylazine anesthesia were experimentally set and monitored with a water manometer/transducer system following transcorneal cannulation while simultaneously performing tonometry. The long- and short-term repeatability of the tonometer was tested in conscious, restrained mice, as measurements were taken once-daily in the afternoon for 4 consecutive days. On day 5, IOPs were measured in the same mice once every 4 min for 32 min. On 2 separate days, mice were administered ketamine/xylazine or 2,2,2-tribromoethanol anesthesia, in a crossover design, and IOPs were measured once every 2 min for 32 min. Rebound tonometry was performed in conscious mice before and 1 hour after 1 drop of timolol maleate (10 microL of 0.5%) application to 1 eye. RESULTS: IOP measurements by rebound tonometry correlated well with manometry for pressures between 8 and 38 mmHg (y = 0.98x - 0.32, R(2) = 0.94; P < 0.001). The average tonometric IOP was invariant over 4 days (range, 11.7-13.2 mmHg). IOPs dropped significantly ( P < or = 0.05) within 6 min (ketamine/xylazine) or 10 min (2,2,2-tribromoethanol) postadministration of anesthesia but not with conscious restraint. Timolol significantly (P < 0.001) lowered IOP from 12.8 +/- 0.3 (mean +/- standard error of the mean) to 10.1 +/- 0.6 mmHg, as measured by the tonometer. CONCLUSIONS: Rebound tonometry can be used to obtain accurate IOP measurements in conscious, restrained mice while avoiding the rapid and profound ocular hypotensive effects of general anesthesia. Small changes in IOP with an aqueous-flow suppressant are readily detectable with conscious restraint that may be missed with chemical restraint.

Two-step oblique incision during 25-gauge vitrectomy reduces incidence of postoperative hypotony.

The efficacy of a two-step, oblique incision procedure during 25-gauge vitrectomy on postoperative hypotony was evaluated by a retrospective, case-control study. The transconjunctival incision during 25-gauge vitrectomy was made in two steps: penetration with a microvitreoretinal blade followed by a penetrater instrument of a blunt trocar. The two-step procedure was performed on 89 eyes and with the conventional incision on 68 eyes. The incidence of hypotony (intraocular pressure <6 mmHg) on the first postoperative day and after 1 week and 1 month was compared. Hypotony was found in two eyes (2%) with the two-step method and 12 eyes (18%) with the conventional incision on the first postoperative day (P = 0.001, Fisher's exact probability test). The preoperative intraocular pressure was not significantly different in the two groups but was significantly higher in the two-step group than in the conventional method group on the first postoperative day (P = 0.001, Wilcoxon rank test). Twenty-five-gauge vitrectomy with two-step oblique incisions will reduce the incidence of postoperative hypotony on the first postoperative day.

Proper wound construction to prevent short-term ocular hypotony after clear corneal incision cataract surgery.

PURPOSE: To evaluate the stability of 2.2 mm and 3.0 mm clear corneal cataract incisions with square or nearly square surface architecture. SETTING: Private practice ambulatory surgical center, Century City, California, USA. METHODS: A retrospective chart review of 60 patients who had clear corneal cataract extraction between January and September 2006 was conducted. Fifty patients had clear corneal cataract extraction with a square 2.2 mm incision and 10 patients with a nearly square 3.0 mm incision. For the 2.2 mm incision subset, cataract surgery and intraocular lens implantation were accomplished through an unenlarged 2.2 mm clear corneal cataract incision using the Alcon Infiniti unit and an Ultrasleeve for infusion. For the 3.0 mm subset, the Allergan Sovereign unit was used. Intraocular pressure (IOP) was measured intraoperatively at the conclusion of each procedure with a Schiötz or Barraquer tonometer and set between 15 mm Hg and 20 mm Hg. Wound sealing was confirmed by intraoperative Seidel testing in all cases. Intraocular pressure was measured by a Tono-Pen (Medtronic) or Goldmann applanation tonometry between 2 hours and 6 hours after the conclusion of each procedure. RESULTS: The mean postoperative IOP was 19.2 mm Hg +/- 4.9 (SD) (median 18 mm Hg; range 11 to 35 mm Hg) in the group with a 2.2 mm square incision and 16.6 +/- 5.2 mm Hg (median 16.0 mm Hg; range 10 to 25 mm Hg) in the group with a 3.0 mm nearly square clear corneal incision. No patient had an IOP less than 10 mm Hg, and there was no evidence of hypotony or wound leakage by Seidel testing in either group. CONCLUSIONS: Clear corneal wounds of square or nearly square surface architecture that are meticulously checked for sealing were stable postoperatively as demonstrated by the absence of hypotony and wound leakage. In the presence of a sealed clear corneal wound, IOP remained reasonably stable relative to the level set at the conclusion of the procedure.