MRI after successful eyeWatchTM implantation.

The eyeWatchTM is a new glaucoma drainage device that includes an adjustable mechanism that can vary the resistance to aqueous humor outflow during the postoperative period to reduce the burden of postoperative intraocular pressure (IOP) management. The mechanism contains a magnetic rotor that can be adjusted using an external magnetic control unit. Adjustments of the position of the rotor are performed mostly in the initial postoperative follow-up period in order to reach the target IOP. However, for some patients, it might be necessary to perform MRI for the sake of medical investigations. As the MRI is creating a strong magnetic field, this magnetic field is likely to interact with the adjustable rotor of the eyeWatchTM, resulting in modification of the IOP. We report the case of an 82-old female patient successfully operated with the implantation of an eyeWatchTM. The patient underwent a cerebral MRI for persistent headache. Shortly after the MRI procedure, the patient was checked at the eye clinic to assess the position of the rotor and to measure the IOP. The eyeWatchTM was readjusted to the former position set before undergoing the MRI. No complications were reported in the follow-up after MRI. This case demonstrates that MRI examinations can be safely performed after glaucoma surgery using an eyeWatchTM without compromising on the quality of the imaging or the stability of the IOP. This is a complication-free procedure that only requires checking the new position of the rotor and re-adjusting the implant, if necessary, to achieve the target IOP.

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.

EyeWatch Rescue of Refractory Hypotony After Baerveldt Drainage Device Implantation: Description of a New Technique.

The most effective way to control glaucoma is by lowering intraocular pressure (IOP) in order to prevent the progression of the disease. Glaucoma drainage devices (GDDs) are surgical option reserved for refractory cases and have been designed to address known complications of conventional filtering surgery. They are, however, associated with a higher rate of complications related to early hypotony and late corneal decompensation. In the case of the commonly used Baerveldt Glaucoma Implant (BGI), techniques exist in an attempt to prevent early postoperative hypotony but can be highly variable and surgeon dependent. Moreover, the additional steps required can result in unstable IOP in the immediate postoperative period. In 2014, Villamarin and colleagues described for the first time an adjustable GDD, called the eyeWatch implant, designed to better control IOP fluctuations and avoid hypotony during the early postoperative period via magnetic control of the device tube lumen. This innovation provides the possibility to adjust the amount of aqueous humor outflow after device implantation in a noninvasive manner. We report the case of an 83-year-old patient with advanced pseudoexfoliative glaucoma, referred to our tertiary center because of disease progression despite topical therapy and having undergone deep sclerectomy. First, a BGI was implanted but was unfortunately complicated by a 3-month chronic refractory hypotony from day 8, and choroidal detachment despite medical management, choroidal drainage, and viscoelastic injections. After 3 months, the decision was made to rescue the situation with an eyeWatch adjunction to the BGI. Postoperatively, the IOP was successfully controlled through fine adjustments of the eyeWatch opening position, until the last visit 8 months after the rescue, with complete resolution of the choroidal detachment and without any medications. This demonstrates that the eyeWatch may offer an answer not only to the immediate postoperative hypotonic phase of the GDD surgery but also to the later cystic bleb hypertonic phase.

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.

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.

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.

Eye vessel compliance as a function of intraocular and arterial pressure and eye compliance.

PURPOSE: The purpose of our study is to develop and validate a methodology to measure the compliance of the vascular network in the eye using biomechanical parameters, namely arterial pressure, intraocular pressure (IOP), and ocular compliance of the eyeball (OC). METHODS: In vitro experiments were conducted on 6 freshly enucleated rabbit eyes. An inflatable catheter was inserted in the posterior chamber. The balloon was inflated and its volume changed periodically at a rate of 1-2 Hz, yielding variations in the intraocular volume; thus, emulating the volume pulsations of the vascular network in the eye. The IOP was measured continuously with a pressure transducer and the OC was calculated using the outflow facility. The compliance of the balloon, mimicking the compliance of the vascular network, was estimated indirectly from the measurements of IOP, balloon pressure, and OC. The estimated balloon compliance was compared to direct estimates of balloon compliance, based on the balloon pressure-volume curve. In vivo study included 5 white New-Zealand rabbits. The method to estimate the vascular compliance of the eye was tested under normal conditions and after administration of norepinephrine, which induced a vasoconstriction leading to reduction in vascular compliance. RESULTS: In vitro comparison of direct versus indirect estimates of compliance showed a difference that was not significant (0.075 vs. 0.077 µL/mm Hg, P = 0.86). Results from the in vivo study indicated that norepinephrine significantly increased the arterial pulse pressure amplitude, while compliance of vascular network of the eye decreased from 0.18 ± 0.12 to 0.10 ± 0.08 µL/mm Hg (P = 0.001). CONCLUSIONS: The eye vascular compliance can be predicted using the IOP, arterial pressure, and OC of the eyeball.

3D simulation of the aqueous flow in the human eye.

Glaucoma results in an increase in the resistance of the aqueous humor outflow, which in turn leads to an increase of the intraocular pressure (IOP). Several treatments are proposed to reduce and stabilize the IOP that include medications, filtering surgery and glaucoma drainage devices (GDD). So far computational fluid dynamics (CFD) modeling of the eye drainage system has not yet been well studied. Therefore our goal was to provide a 3D CFD model of the eye based on the anatomy of a real human eye. Such a tool would serve for future evaluation of new glaucoma surgical techniques involving, for example, GDD. The model was based on stacks of microphotographs from human eye slides from which digital processing of the images of the eye structure and 3D reconstruction of the model were performed. Simulations of the distribution of pressure and flow velocity in the model of a healthy eye gave results comparable to physiology references. Mimicking glaucoma conditions led to an increase of the IOP from normal range, which went down to lower values after a filtering procedure. Further refinements in the boundary conditions for the filtering procedure shall improve the accuracy of this innovative tool for modeling glaucoma surgery.