A new self-adjustable glaucoma valve.

Introduction: Glaucoma, the leading cause of irreversible blindness globally, affects more than 70 million people across the world. When initial treatments prove ineffective, especially for cases with high intraocular pressure (IOP), the preferred approach involves employing glaucoma drainage devices (GDDs). Methods: This study introduces a novel self-adjustable glaucoma drainage device (SAGDD) designed to maintain IOP within the desired biological range (10 mmHg < IOP <18 mmHg) by dynamically modulating its fluidic resistance. Inspired by the starling resistor, we designed a circular valve with a thin, flexible membrane placed over the valve's inlet and outlet. To achieve the ideal design for the SAGDD and optimize its parameters, we utilized fluid-solid interaction (FSI) numerical models and conducted parametric studies, wherein simulations demonstrated the validity of the concept. Subsequently, to confirm and validate the numerical results, we fabricated a SAGDD at a 3:1 scale and subjected it to in vitro testing. Results: Our findings demonstrate that, on a 3:1 scale, a circular SAGDD with a diameter of 8.1 mm and a stainless-steel membrane with a thickness of 10 µm effectively maintained IOP within the target range when the membrane exposed to external pressures of 7.5 or 10 mmHg. Discussion: In summary, our study establishes a strong foundation for further exploration of the potential efficacy of SAGDD as a promising treatment for glaucoma. The cost-effectiveness and simplicity of its design, devoid of costly instrumentation, hold considerable promise in addressing the challenges associated with glaucoma.

eyeWatch™ System Combined with Non-plated Intraorbital Tube Insertion for the Management of Refractory Glaucoma: A Case Series.

INTRODUCTION: The eyeWatch™ is a novel device in glaucoma surgery aiming at the control of aqueous flow through the use of an external magnetic control unit. We propose the modification of this approach through the use of an injectable perforated tube rather than a plated valve. MATERIALS AND METHODS: Procedures were performed at the Department of Ophthalmology of the University of Crete. Three blind painful eyes of three patients were included. All patients were operated under topical anesthesia. A purpose designed blunt-ended injector was used to insert intraorbitally a perforated 4 cm-long silicone tube. The tube was then connected to an eyeWatch™ device which was placed in a standard fashion along the superior-temporal quadrant of the eyeball. The procedure was uneventful in cases I and II, whereas in case III the tube had to be trimmed by 1.5 cm because of cicatricial changes in the orbit. The eyeWatch™ was left closed (position VI) at the conclusion of surgeries. Patients were examined on the 1-day, 1-week, 2-week, 1-month, 3-month, and 6-month intervals and in one case on the 12-month interval. RESULTS: No major complications were observed. The intraocular pressure (IOP) remained under 15 mm Hg without anti-glaucomatous medications in all postoperative intervals in cases I and 2 with readjustment of eyeWatch™ at position IV. In case III, despite the change of the eyeWatch™ to the open position, the IOP remained high (40 mm Hg). DISCUSSION: The combination of the eyeWatch™ with an insertable perforated tube instead of a standard non-valved plate may prove a valid minimally invasive option. Modifications of the technique, such as an increased number and diameter of tube perforations, increased inserted tube length, perhaps aided by a sharp-ended injector, and selection of the insertion quadrant, may increase the effectiveness of the method. CLINICAL SIGNIFICANCE: eyeWatch™ combined with a single tube instead of a plated valve is a feasible, quick, and minimally invasive technique that can be used in glaucoma surgery. HOW TO CITE THIS ARTICLE: Detorakis ET, Villamarin A, Roy S, et al. eyeWatch™ System Combined with Non-plated Intraorbital Tube Insertion for the Management of Refractory Glaucoma: A Case Series. J Curr Glaucoma Pract 2020;14(2):64-67.

Comparison Between the eyeWatch Device and the Ahmed Valve in Refractory Glaucoma.

PURPOSE: To assess the efficacy and safety of a glaucoma procedure to control intraocular pressure (IOP) using the adjustable eyeWatch glaucoma drainage device compared with Ahmed glaucoma valve (AGV) in refractory glaucoma. PATIENTS AND METHODS: Monocentric, retrospective, comparative clinical trial. Patients suffering from refractory glaucoma after failed surgeries and requiring a further glaucoma procedure including an aqueous shunt were enrolled in this study. The first group AGV included patients with an AGV. The second group eW-B included patients receiving an eyeWatch used in connection with a Baerveldt glaucoma implant. The primary outcome was the success rate, defined as an IOP≤16 mm Hg and reduction of >20% from baseline, and IOP≥5 mm Hg. Secondary outcomes were mean IOP, number of antiglaucoma medications, visual acuity, number and type of complications. RESULTS: Twenty-one patients were included. The mean follow-up time was 13.2±3.4 months. Mean IOP decreased from 24.8±9.0 mm Hg before surgery to 13.8±3.6 mm Hg at 12 months for group AGV, and 27.3±7.0 to 12.8±2.4 mm Hg for group eW-B, respectively (P<0.05). Mean number of glaucoma medications decreased from 3.0±0.7 before surgery to 0.3±0.7 at last control for group AGV, and 2.9±0.8 before surgery to 0.2±0.4 for group eW-B, respectively (P<0.05). The complete and overall success rates were 50% and 58% for group AGV, and 67% and 89% for group eW-B, respectively. CONCLUSIONS: The postoperative adjustability of the eyeWatch is believed to help with getting fewer complications and better IOP management whereas AGV cannot be adjusted postoperatively.

Initial Clinical Results of the eyeWatch: a New Adjustable Glaucoma Drainage Device Used in Refractory Glaucoma Surgery.

PRéCIS:: In this study, we report clinical results after implantation of an adjustable glaucoma drainage device. The intraocular pressure (IOP) profile was efficiently controlled postoperatively as the resistance to aqueous humor outflow was finely adjusted. PURPOSE: The main purpose of this study was to evaluate the safety and efficacy of the new adjustable glaucoma drainage device eyeWatch used in conjunction with a Baerveldt glaucoma implant in refractory glaucoma. PATIENTS AND METHODS: This was a multicentric, prospective, noncomparative clinical trial. Patients older than 18 years of age suffering from refractory glaucoma after failed surgeries, with IOP of ≥20 mm Hg, in whom a further glaucoma procedure using an aqueous shunt was planned, were enrolled in this study. The primary outcome was the success rate, defined as an IOP≤18 mm Hg and reduction of >20% from baseline, IOP≥6 mm Hg. Secondary outcomes were mean IOP, visual acuity, number of antiglaucoma medications, number, and type of complications. RESULTS: Fifteen patients were included. The mean follow-up time was 15.6±3.5 months. The mean baseline IOP decreased from 26.2±6.8 mm Hg before surgery to 11.9±2.8 mm Hg at 12 months (P<0.001). The mean number of glaucoma medications decreased from 3.0±0.7 before surgery to 0.8±0.9 at last visit (P<0.001). The success rate was 40% for complete success and 93% for overall success at last follow-up. Complication rate was 7%. CONCLUSIONS: The novel glaucoma device allows for perioperative and postoperative noninvasive adjustments of the resistance to aqueous humor outflow. This leads to better management of IOP during the early postoperative period, preventing ocular hypotony and eliminating the need for obstructive elements and reinterventions. The rate of complications was low, IOP was adequately controlled and lowered, with a substantial reduction in the number of antiglaucoma medication.

In vivo testing of a novel adjustable glaucoma drainage device.

PURPOSE: We report on the in vivo testing of a novel noninvasively adjustable glaucoma drainage device (AGDD), which features an adjustable outflow resistance, and assess the safety and efficiency of this implant. METHODS: Under general anesthesia, the AGDD was implanted on seven white New Zealand rabbits for a duration of 4 months under a scleral flap in a way analogous to the Ex-PRESS device and set in an operationally closed position. The IOP was measured on a regular basis on the operated and control eyes using a rebound tonometer. Once a month the AGDD was adjusted noninvasively from its fully closed to its fully open position and the resulting pressure drop was measured. The contralateral eye was not operated and served as control. After euthanization, the eyes were collected for histology evaluation. RESULTS: The mean preoperative IOP was 11.1 ± 2.4 mm Hg. The IOP was significantly lower for the operated eye (6.8 ± 2 mm Hg) compared to the nonoperated eye (13.1 ± 1.6 mm Hg) during the first 8 days after surgery. When opening the AGDD from its fully closed to fully open position, the IOP dropped significantly from 11.2 ± 2.9 to 4.8 ± 0.9 mm Hg (P < 0.05). CONCLUSIONS: Implanting the AGDD is a safe and uncomplicated surgical procedure. The fluidic resistance was noninvasively adjustable during the postoperative period with the AGDD between its fully closed and fully open positions.

A new adjustable glaucoma drainage device.

PURPOSE: This work is focused on the testing of a new experimental noninvasively adjustable glaucoma drainage device (AGDD) that allows for the control of its outflow resistance to modulate intraocular pressure (IOP) in a customized fashion. METHODS: Six AGDDs were directly connected to a pressure transducer and a perfusion system continuously delivering saline solution at rate of 2 µL/min. The steady-state pressure was measured and reported as a function of the angular position of the AGDD disk. Ex vivo experiments were conducted on six freshly enucleated rabbit eyes. The IOP was measured, and the flow rate was increased with a syringe pump to simulate elevated IOP associated with glaucoma. After insertion of the implant in the anterior chamber, the position of the disk was sequentially adjusted. RESULTS: The relation between the pressure drop and the angular position of the AGDD disk is nonlinear. The functional range lies between 80° and 130°, which allows for four or five different reproducible adjustment positions. Above 130° the implant is considered to be closed (no outflow), and below 80° it is considered to be open (minimum resistance to flow). CONCLUSIONS: The resistance to outflow of the experimental AGDD can be adjusted to keep IOP in the desired physiological range. This feature could be useful for addressing the risk of hypotony in the early postoperative stages and could provide a means to achieve optimal IOP under a wide range of postoperative conditions.