Early Postoperative Hypotony Research Articles

The use of intraluminal PRESERFLO stenting in avoiding early postoperative hypotony.

Postoperative hypotony following PRESERFLO MicroShunt (PMS) implantation is a frequent cause of complications such as choroidal detachment and hypotony maculopathy. This study aims at evaluating the impact of intraluminal stenting of the PMS during the early postoperative period. We retrospectively analyzed the data of 97 patients who underwent PMS implantation with intraoperative placement of a Nylon 10-0 suture as intraluminal stent (PStent) and compared the outcomes to those of an existing database of the traditional MicroShunt implantation technique (PTrad, n = 120). The primary outcome measure was the intraocular pressure (IOP) at one week postoperatively. As a secondary outcome measure, adverse hypotony, defined as an IOP ≤ 5mmHg with significant choroidal effusion and/or anterior chamber shallowing or the presence of macular folds was also assessed. Additionally, the time to stent removal and the IOP one week after stent removal were reported. Preoperative median IOP was 25.0 (20.5-30.3) mmHg in PStent and 25.0 (19.3-32.0) mmHg in PTrad (p = 0.62). One week after surgery, the median IOP dropped to 10.0 (8.0-13.0) mmHg in PStent and 7.0 (5.0-9.0) in PTrad (p < 0.01). At one month, the IOP was 12.0 (10.0-14.0) mmHg in PStent and 10.0 (8.0-11.0) mmHg in PTrad (p < 0.01). After 3months, both groups showed similar median IOP levels of 11.0 (8.0-13.5) mmHg and 10.0 (9.75-13.0) mmHg in PStent and PTrad, respectively (p = 0.66). The presence of adverse hypotony was significantly lower in PStent compared to PTrad (6.2% vs 15.8%, p < 0.05). In PStent the stent was removed after 30.0 (21.0-42.5) days. One week after stent removal the mean IOP drop was 6.1 ± 0.5mmHg (p < 0.01). In the early follow-up period, intraluminal stenting of the PMS appears to be safe and effective in controlling the IOP while reducing early postoperative hypotony. Surgical success is not compromised by stent placement. Based on our data, it is recommended to remove the suture two to six weeks after surgery for most patients with uncomplicated postoperative clinical findings.

A modified sutureless intrascleral fixation technique for secondary intraocular lens implantation - a pilot study.

To demonstrate possible complications of a new IOL (intraocular lens) for sutureless secondary scleral implantation and modifications of the surgical technique to optimise outcomes. Retrospective study of 16 eyes (16 patients) who underwent a secondary IOL implantation using the Carlevale IOL (Soleko, Italy) with two anchor haptics for intrascleral implantation (mean follow-up 2.2 months). Visual acuity did not improve statistically significantly postoperatively (p = 0.601). Seven (44 %) patients suffered from postoperative hypotonia (intraocular pressure < 5 mmHg) during the first three postoperative days. Due to the early postoperative hypotony, we decided to modify the surgical technique. We present several suggestions to optimize the technique and outcome like positioning the sclerotomies at the 2 and 8 o'clock positions, using 27 G trocars only and suturing the frown incisions using self-resorbing sutures.

Systematic Preserflo MicroShunt Intraluminal Stenting for Hypotony Prevention in Highly Myopic Patients: A Comparative Study.

Transient hypotony is the most common early complication after Preserflo MicroShunt (PMS) implantation. High myopia is a risk factor for the development of postoperative hypotony-related complications; therefore, it is advisable that PMS implantation in patients should be performed while employing hypotony preventive measures. The aim of this study is to compare the frequency of postoperative hypotony and hypotony-related complications in high-risk myopic patients after PMS implantation with and without intraluminal 10.0 nylon suture stenting. This is a retrospective, case-control, comparative study of 42 eyes with primary open-angle glaucoma (POAG) and severe myopia that underwent PMS implantation. A total of 21 eyes underwent a non-stented PMS implantation (nsPMS), while in the remaining eyes (21 eyes), PMS was implanted with an intraluminal suture (isPMS group). Hypotony occurred in six (28.57%) eyes in the nsPMS group and none in the isPMS group. Choroidal detachment occurred in three eyes in the nsPMS group; two of them were associated with the shallow anterior chamber and one was associated with macular folds. At 6 months after surgery, the mean IOP was 12.1 ± 3.16 mmHg and 13.43 ± 5.22 mmHg (p = 0.41) in the nsPMS and isPMS group, respectively. PMS intraluminal stenting is an effective measure to prevent early postoperative hypotony in POAG highly myopic patients.

Incidence, outcomes, and risk of surgical failure after development of early hypotony following Aurolab aqueous drainage implant surgery.

To report the incidence, outcomes, and risk of surgical failure after early postoperative hypotony following Aurolab Aqueous Drainage Implant (AADI) surgery for adult and pediatric refractory glaucoma. Medical records of patients who underwent AADI between January 2013 and March 2017 with a minimum of 2-years follow-up were retrospectively reviewed. Early postoperative hypotony was defined as IOP ≤5 mmHg within the first 3 months after AADI. Surgical failure of AADI was defined as IOP >21 mmHg or reduced <20% below baseline on two consecutive follow-up visits after 3 months, IOP ≤5 mmHg on two consecutive follow-up visits after 3 months, reoperation for glaucoma or a complication, or loss of light perception vision. Early postoperative hypotony was seen in 15/213 eyes (7%) in the adult group and in 6/101 eyes (6%) in the pediatric group. The onset of hypotony was significantly earlier in the pediatric group (median = 39 days post AADI, IQR = 20-58 days) compared with adult eyes (median = 51 days post AADI, IQR = 30-72 days) (P = 0.02). Eyes with early postoperative hypotony did not have an increased risk of cumulative surgical failure as compared with eyes without hypotony in both adult (33.3% vs. 23.7%; P = 0.48) and pediatric (33.3% vs. 13.7%; P = 0.16) refractory glaucoma. All eyes recovered from hypotony, though one adult eye developed retinal detachment and one pediatric eye developed corneal decompensation and lost vision. Early postoperative hypotony was an infrequent complication post AADI and occurred earlier in pediatric eyes. Early postoperative hypotony did not increase risk of surgical failure up to 2 years.

Efficacy and safety of ab interno trabeculectomy revision with 5-fluorouracil in advanced glaucoma due to subconjunctival fibrosis

ObjectifDécrire les résultats obtenus chez les patients qui ont subi une révision de trabéculectomie ab interno dans un seul œil, accompagnée de 5-fluorouracil. NatureÉtude de cohorte rétrospective. ParticipantsEnsemble des patients qui avaient subi une révision de trabéculectomie ab interno dans un seul établissement de soins tertiaires pendant les 5 années de l’étude. Tous les patients inclus présentaient une neuropathie optique glaucomateuse avancée, sans égard à l’âge et au sous-type de glaucome. MéthodesAu nombre des paramètres d’évaluation, mentionnons la réussite de l'intervention chirurgicale, le nombre de collyres visant à abaisser la pression intraoculaire (PIO), la meilleure acuité visuelle corrigée, la déviation moyenne du champ visuel ainsi que les complications postopératoires. La réussite à 12 mois reposait sur 2 critères : critère A (PIO < 15 mm Hg et baisse de > 20 % de la PIO) et critère B (PIO < 12 mm Hg et baisse de > 20 % de la PIO). Pour chacun des critères de réussite, on a réparti les patients en 2 groupes selon que la baisse de la PIO a été obtenue sans collyre (réussite complète) ou avec l'ajout de collyres (réussite partielle). RésultatsLa présente étude regroupe 46 yeux de 46 patients. De ce nombre, 34 patients ont été suivis pendant au moins 12 mois après l'intervention aux fins d’évaluation de la réussite. Parmi ces 34 patients, le taux de réussite selon le critère A a été de 68 % (réussite complète : 53 %; réussite partielle : 15 %) et le taux de réussite selon le critère B, de 47 % (réussite complète : 38 %; réussite partielle : 9 %). Une hypotonie précoce a été observée dans 68 % des yeux, sans qu'elle soit associée à des résultats négatifs au chapitre de l'acuité visuelle ou des champs visuels. ConclusionsDans l'ensemble, 47 % des patients présentaient une PIO < 12 mm Hg et une baisse de > 20 % de la PIO (avec ou sans recours aux collyres) lors du suivi à 12 mois. On peut s'attendre à l'apparition d'une hypotonie précoce postopératoire transitoire après une révision de trabéculectomie ab interno.

Frequency of Post-Operative Hypotony with Sutureless Sclerotomy versus Intrascleral Hydration in 23-Gauge Pars-Plana Vitrectomy

Purpose: To compare the frequency of hypotony after 23-gauge (G) pars plana vitrectomy (PPV) with suture-less sclerotomy versus intrascleral hydration for sclerotomy closure in eyes with air/gas tamponade. Study Design: Quasi-experimental study. Place and Duration of Study: College of Ophthalmology and Allied Vision Sciences, Mayo Hospital, Lahore from November 2021 to May 2022. Methods: A total of 90 eyes were included who underwent PPV with air/gas tamponade. One group underwent PPV with suture-less sclerotomy while the other got intrascleral hydration for sclerotomy closure. Intraocular pressure (IOP) was measured pre and post-operatively at day one and day seven by applanation tonometry in all eyes. IOP of 6 mmHg or less was defined as hypotony. Primary endpoint measure was rate of early post-operative hypotony. Results: A total of 90eyes of 90 patients, 40 (44.4%) males, and 50 (55.6%) females were included in the study. Five (5.6%) patients reported hypotony, out of which, only one (2.2%) case was seen in the intrascleral hydration group while rest (8.9%) were of the sutureless group. Sclerotomies requiring sutures were 4.44% (6 of 135) in sutureless group while 0.74% (1 of 135) in intrascleral hydration group. Paired sample T-test for the means of pre-operative and post-operative IOP was significantly different in both groups. For suture-less PPV, mean difference was 3.089 ± 7.960 mmHg (P = 0.013), while for the intra scleral hydration group, it was 3.778 ± 7.048 mmHg (p = 0.001). Conclusion: Intrascleral hydration is a suitable option for PPV sclerotomy closure without having any side effects.

Double versus single suture stenting to manage hypertensive spikes after glaucoma drainage device implantation.

To evaluate the safety and efficacy of double compared to single intraluminal suture stenting in reducing early postoperative hypertensive spikes (HS) and hypotony after Baerveldt glaucoma implant surgery. For this retrospective study, we reviewed the medical charts of 60 patients (60 eyes) who underwent Baerveldt drainage device surgery between 2017 and 2019. Two groups were formed according to whether a single suture stent was placed within the tube (5-0 polypropylene, 30 eyes, group 1) or a double suture (5-0 and 6-0 polypropylene, 30 eyes, group 2). Intraocular pressure (IOP) was measured at baseline, at 6 h, and on postoperative days 1, 2, 5, 7, 14, 21, 30, 60, 90, 180. The occurrence of HS (IOP ⩾ 30 mmHg), anterior chamber reformation, decompressive paracentesis, anti-glaucoma medication, and adverse events were recorded. There was a greater decrease in IOP from baseline at days 1, 2, and 21 (p < 0.05) and number of HS at 6 h (p = 0.006) and postoperative day 1 (p < 0.001) in group 2. The mean number of decompressive paracentesis, anterior chamber reformation procedures, and topical anti-glaucoma medications was the same in both groups; the need for oral acetazolamide was significantly lower in group 2 at days 1, 21, and 30 (p < 0.05). While both stenting methods provide a gradual, controlled decrease in IOP, the double stenting technique was associated with a sooner and greater postoperative reduction in IOP and a good safety profile thanks to fewer HS in the early postoperative period and less need for oral acetazolamide.

Ahmed glaucoma valve in vitrectomized eyes: An implantation technique to minimize early postoperative fluid-loss hypotony.

To describe the application of a modified Ahmed glaucoma valve (AGV) surgical implantation technique in vitrectomized eyes, in order to minimize the risk of early postoperative hypotony, which leads to hemorrhagic complications. Data of patients implanted with AGV using the surgical technique described were retrospectively reviewed. Inclusion criterion: glaucomatous eyes with previous history of pars plana vitrectomy. Intraocular pressure (IOP) measurement and ophthalmic examination were performed preoperatively and postoperatively weekly for 1 month for the detection of early hypotony, choroidal effusion/detachment, intraocular hemorrhage. The surgical technique consisted in creating a 5 mm long scleral tunnel with a 23 G needle reaching the anterior chamber at the iridocorneal angle, in which the Ahmed glaucoma valve tube was inserted. Ten eyes of 10 patients were included. Median preoperative IOP was 30.5 mmHg [interquartile range (IQR) 28.3-33.0]; median postoperative IOP was 12.0 mmHg (IQR 9.3-13.0) at 1 week, and 12.5 mmHg (IQR 11.0-15.0) at 1 month. In no cases postoperative IOP was <8 mmHg. On the first postoperative day, five (50%) eyes showed few blood clots in the anterior chamber. On the second-week appointment, moderate choroidal effusion was observed in two eyes (20%). No hemorrhagic complications were observed. The creation of a long intrascleral tunnel with a 23 G needle for AGV implantation in vitrectomized eyes could be effective in decreasing leakage through the space between the valve tube and the sclerocorneal tissue. This technique is safe, easy to perform, feasible and fast. Due to its advantages and good postoperative results, it could also be adopted in non-vitrectomized eyes.

Intraluminal Stent Optimization for the Baerveldt Glaucoma Implant: An Experimental Study.

Our laboratory study determined the approximate suture diameter for use in intraluminal stenting of the Baerveldt glaucoma implant (BGI) to prevent postoperative hypotony. Commercial 3-0 monofilament nylon sutures which are commonly used may vary significantly outside of this diameter. Postoperative hypotony is a complication of surgical treatment of glaucoma using the BGI. One method utilized to prevent early postoperative hypotony is intraluminal stenting of the implant with monofilament sutures. The present study attempted to determine optimal stent diameter in microns for 3-0 monofilament sutures to reduce outflow and thereby reduce the risk of postoperative hypotony using the BGI. A laboratory bench model of the anterior chamber was utilized to measure the outflow rate of balanced salt solution through the BGI at pressures of 20 and 40 mm Hg while utilizing commercially available 3-0 monofilament nylon stents of various diameters. The BGI tube has an inner diameter of 300 µm. In addition, 3-0 nylon sutures were studied for variability by measuring the diameters at 10 equally spaced points along the length of each sample using a digital micrometer. Average experimental flow rates decreased with increasing intraluminal stent diameter and increased with increasing pressure. An intraluminal stent diameter of 250 µm yielded a flow rate of 40 µL/min at a nominal pressure of 20 mm Hg. Diameters of the tested 3-0 monofilament nylon sutures were all within the United States Pharmacopeia diameter range of 200 to 250 µm, but diameters varied significantly depending on the manufacturer. In our laboratory model, the optimal stent diameter to reduce aqueous flow to a level approaching the normal aqueous production is at least 250 µm. Secondarily, commercially available 3-0 monofilament nylon suture materials showed variable diameters within the United States Pharmacopeia diameter range.

INCIDENCE AND RISK FACTORS FOR HYPOTONY AFTER 25-GAUGE PARS PLANA VITRECTOMY WITH NONEXPANSILE ENDOTAMPONADE

The purpose of this study was to assess the incidence and risk factors for early postoperative hypotony after 25-gauge pars plana vitrectomy with nonexpansile endotamponade. A retrospective study of consecutive patients who underwent 25-G pars plana vitrectomy. Hypotony was defined as an intraocular pressure of 5 mmHg or less after surgery and ocular hypertension as an intraocular pressure greater than 21 mmHg. Overall, 307 eyes of 307 patients with a mean age of 61.7 ± 14.3 of which 56.7% were males were included. Hypotony was identified in 5.2% of cases (n = 16) at Day 1 and 0.7% (n = 2) at Week 1 with no hypotony-related complications. The hypotony group had a higher number of previous vitreoretinal surgeries (1.5 ± 1.1 vs. 0.4 ± 0.7, P < 0.001) and a higher prevalence of preoperative ocular hypertension (22.2% vs. 4.8%, P = 0.02), pseudophakia (77.8% vs. 48.4%, P = 0.01), silicone oil removal (61.1% vs. 8.3%, P < 0.001), and external diathermy performed (55.6% vs. 20.1%, P = 0.001). In stepwise multivariate analysis, significant parameters were silicone oil removal (R = 16.34%, odds ratio 13.45, P < 0.001), pseudophakia (R = 5.69%, odds ratio 3.65, P = 0.03), and younger age (R = 2.68%, odds ratio 0.96, P = 0.04). Silicone oil removal is a significant risk factor for early postoperative hypotony after 25-G pars plana vitrectomy.

A modified technique for intraluminal stenting of glaucoma drainage devices: The guide-wire technique.

Glaucoma drainage tubes have become increasingly popular in the surgical management of uncontrolled glaucoma. Flow restriction is essential to prevent early postoperative hypotony with non-flow restrictive glaucoma drainage devices. Herein, we describe a new way of using a 3–0 Supramid suture as an intraluminal stent. This technique confers no risk of stent exposure, can be removed ab interno without disturbing the conjunctiva, and aids insertion of the tube into the anterior chamber through a scleral tunnel.

Biomechanical analysis of ligatures and technique for managing drainage tubes in pediatric glaucoma

Absorbable ligatures are often used with glaucoma drainage tubes to avoid early postoperative hypotony. We sought to measure the force required to ligate a drainage tube and to develop a modified technique to promote earlier release in pediatric patients, where plate encapsulation occurs more quickly than in adults.

Cyclophotocoagulation in the Control of Glaucoma in Patients With the Boston Keratoprosthesis Type 1.

To evaluate the outcomes of transscleral cyclophotocoagulation (CPC) in the control of glaucoma in eyes with a Boston keratoprosthesis (KPro) type 1. This study is a retrospective case series of patients who have undergone at least 1 CPC treatment after KPro implantation. Eighteen eyes of 17 patients were included. Intraocular pressure (IOP) (assessed by digital palpation) and the number of classes of glaucoma medications were recorded at 1 week, 1 to 3 months, 4 to 6 months, and 1 year postoperatively. Optic nerve status, visual field parameters, and perioperative and postoperative complications were recorded. Twenty-one CPC sessions were administered overall. Seven eyes (39%) had IOP < 20 mm Hg preoperatively, and this increased to 15 eyes (83%) at the 1-year postoperative follow-up. The mean number of glaucoma medications used was 3.9 preoperatively and did not change significantly after treatment. Seven eyes (39%) had glaucoma progression despite CPC treatment. Three eyes (17%) initially responded to CPC but later failed at 3, 6, and 12 months. Two of them responded to repeat CPC, and 1 continued to progress despite retreatment. Two eyes (11%) developed early postoperative hypotony, 1 eye (6%) developed cystoid macular edema, 1 eye (6%) developed bacterial endophthalmitis with subsequent enucleation, and 1 eye (6%) lost light perception because of glaucoma. CPC was useful to control IOP in some KPro eyes with refractory glaucoma, although it did not significantly reduce concurrent medical therapy. In addition, caution must be taken because microbial infection can occur after CPC because of the lack of biointegration between the host cornea and the device.

Biomechanical Analysis of Ligatures and Technique for Managing Drainage Tubes in Pediatric Glaucoma.

Absorbable ligatures are often used with glaucoma drainage tubes to avoid early postoperative hypotony. We sought to measure the force required to ligate a drainage tube, and develop a modified technique to promote earlier release in pediatric patients, where plate encapsulation occurs more quickly than adults. A precision digital force gauge was used to measure the tensile strength of several common ophthalmic sutures, and the necessary tensile force required to achieve tube ligation. A novel technique for tube ligation was devised to allow sutures as small as 10-0 to be effectively used. The mean tensile strengths of unknotted sutures varied from 55.50±8.50 g for 10-0 vicryl to 477±69 g for 6-0 chromic gut. The mean tensile force required to ligate a Baerveldt or Ahmed tube was 35.9±0.9 g. However, 9-0 or 10-0 vicryl could not be reliably used for ligation, because of breakage, unless a modified technique was used, wherein the tube was first stretched to reduce its thickness and diameter. Frictional forces inherent to knot tying make it unfeasible to reliably use 9-0 or 10-0 vicryl to ligate a drainage tube, despite the unknotted threads possessing apparently sufficient tensile strength. Our modified ligation technique overcomes this issue, allowing a wider range of suture choices, and the potential for achieving more rapid release in pediatric cases.

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

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. 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. 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). 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.

Outcome of fixed volume intracameral sodium hyaluronate 1.4% injection for early postoperative hypotony after Baerveldt glaucoma implant.

Using an ophthalmic viscoelastic device to manage early postoperative hypotony after Baerveldt glaucoma implant (BGI). To determine the outcome of intracameral sodium hyaluronate injection for early postoperative hypotony treatment after BGI. A retrospective study. One-hundred-and-thirty-eight patients (176 eyes) had BGI from January 2012 to November 2015. Those who had hypotony within 3 months postoperatively were studied. Hypotonous eyes were injected with 0.1 mL sodium hyaluronate 1.4% intracameral on the slit-lamp. The patients were followed up weekly and the injection repeated up to 3 times if hypotony persisted. The tube was tied surgically as a last resort. The intraocular pressure and best-corrected visual acuity at week 1, 2, 3, 4, 6 and month 4 were assessed. Thirty (17.0%) out of 176 eyes developed early postoperative hypotony. The median intraocular pressure and median best-corrected visual acuity when hypotony first presented were 3 mmHg and 0.8 logMAR. Two eyes were excluded as they had more than 0.1 mL injection. Eight (29%) of the 28 hypotonous eyes resolved after one injection, seven (25%) required two and 10 (36%) needed three injections. Three (11%) eyes had surgical tube tie. The median intraocular pressures were 5, 7, 8, 10, 11 and 13 mmHg at week 1, 2, 3, 4, 6 and month 4 post-injection. The median best-corrected visual acuity were 0.60, 0.50, 0.50, 0.45, 0.40 and 0.40 logMAR for the same period. Standardised intracameral 0.1 mL sodium hyaluronate 1.4% is an effective and safe way to manage early postoperative hypotony after BGI.

Short-term outcomes after EX-PRESS implantation versus trabeculectomy alone in patients with neovascular glaucoma.

BackgroundThe purpose of this study was to investigate postoperative clinical outcomes in patients with neovascular glaucoma (NVG) who underwent trabeculectomy or EX-PRESS implantation and to identify predictors of successful EX-PRESS implantation.MethodsThe study designed as a retrospective observational analysis and was set in a single tertiary center. Eighty-nine patients (89 eyes) with NVG, were treated using trabeculectomy alone (Trab group; n=39) or EX-PRESS implantation (EX group; n=50). All patients with a history of glaucoma surgery were excluded. The main outcome measures were postoperative intraocular pressure (IOP), visual acuity (VA), number of medications, complications, additional therapy, and success rate.ResultsThe mean follow-up duration was 4.6 months in the Trab group and 4.2 months in the EX group. There was no significant difference in IOP between the groups except at 1-month follow-up (P=0.045). The number of patients with early postoperative hypotony, a shallow anterior chamber, hyphema, or anterior chamber irrigation was significantly lower in the EX group than in the Trab group (P=0.016, 0.008, 0.019, and 0.014, respectively). The other outcomes, ie, VA, number of medications, and success rate, were similar between the two groups. In the EX group, the success rate was significantly lower in 15 patients with a history of vitrectomy compared to that in 35 patients without a history of vitrectomy (P=0.047).ConclusionImplantation of an EX-PRESS device may be more effective and safer than trabeculectomy alone in patients with NVG. However, a history of vitrectomy may affect the surgical success rate when using EX-PRESS.

Development of a biodegradable flow resisting polymer membrane for a novel glaucoma microstent.

Within this paper we analyzed the technical feasibility of a novel microstent for glaucoma therapy. For lowering of intraocular pressure, the flexible polyurethane (PUR) implant is designed to drain aqueous humour from the anterior chamber of the eye into subconjunctival, or alternatively suprachoroidal, space. The microstent includes a biodegradable, flow resisting polymer membrane serving as temporary flow resistance for the prevention of early postoperative hypotony. A biodegradable local drug delivery (LDD)-device was designed to prevent fibrous encapsulation. Biodegradable components were made of flexible, nonwoven membranes of Poly(4-hydroxybutyrate) (P(4HB)). Polymer samples and microstent prototypes were manufactured by means of dip coating, electrospinning and femtosecond-laser micromachining and characterized in vitro with regard to structural and fluid mechanical properties, degradation behavior and drug release. Bending stiffness of PUR-tubing (62.53±7.57 mN mm2) is comparable to conventional glaucoma drainage devices in a tube-plate design. Microstent prototypes yield a flow resistance of 2.4±0.6mmHg/μl min-1 which is close to the aspired value corresponding to physiological pressure (15mmHg) and aqueous humour flow (2μl min-1) conditions inside the eye. Degradation of electrospun P(4HB) specimens was found to be almost completely finished after six months in vitro. Within this time frame, flow capacity of the microstent increases, which is beneficial to compensate potentially increasing flow resistance of fibrous tissue in vivo. Fast drug release of the LDD-device was found. One microstent prototype was implanted into a porcine eye ex vivo. Future preclinical studies will allow further information about Microstent performance.

Ahmed glaucoma valve implant: surgical technique and complications.

Implantation of Ahmed glaucoma valve is an effective surgical technique to reduce intraocular pressure in patients affected with glaucoma. While in the past, the use of this device was reserved to glaucoma refractory to multiple filtration surgical procedures, up-to-date mounting experience has encouraged its use also as a primary surgery for selected cases. Implantation of Ahmed glaucoma valve can be challenging for the surgeon, especially in patients who already underwent previous multiple surgeries. Several tips have to be acquired by the surgeon, and a long learning curve is always needed. Although the valve mechanism embedded in the Ahmed glaucoma valve decreases the risk of postoperative hypotony-related complications, it does not avoid the need of a careful follow-up. Complications related to this type of surgery include early and late postoperative hypotony, excessive capsule fibrosis around the plate, erosion of the tube or plate edge, and very rarely infection. The aim of this review is to describe surgical technique for Ahmed glaucoma valve implantation and to report related complications.

Ex-PRESS implantation versus trabeculectomy in Chinese patients with POAG: fellow eye pilot study.

To compare the outcomes of Ex-PRESS implantation in one eye versus trabeculectomy with mitomycin C in the fellow eye in Chinese patients with primary open-angle glaucoma (POAG). This was a prospective, non-randomized comparative study. Forty-eight eyes of 24 patients with bilateral POAG necessitating surgery were included and underwent Ex-PRESS implantation under the scleral flap in one eye and trabeculectomy in the other eye according to patients' choice. Primary outcome measures included mean intraocular pressure (IOP) and success rate. Secondary outcome measures were aqueous flare, postoperative medication use, visual acuity, and incidence of complications. All 24 patients finished a 1-year follow-up. Both groups maintained significant reductions in IOP after surgery throughout the follow-up period. At any point in time, the IOP of the two groups did not differ significantly. The Kaplan-Meier survival curve analysis showed no significant differences in success between the two groups (P=0.289). The mean number of anti-glaucoma medicines and visual acuity in both groups were not significantly different. Eyes with Ex-PRESS implantation had lower aqueous flare values on days 1 and 3 (both P<0.05). Instances of early postoperative hypotony and choroidal effusion were significantly fewer in frequency after Ex-PRESS implantation under the scleral flap compared with those after trabeculectomy (P<0.001). Ex-PRESS is comparable to trabeculectomy in terms of IOP, success rate, number of glaucoma medications used, and visual acuity. However, Ex-PRESS resulted in fewer cases of inflammation and a lower rate of complications.