Long-term follow-up after implantation of a telemetric intraocular pressure sensor in patients with glaucoma: a safety report

Long-term astigmatism after intraocular pressure sensor implantation and nonpenetrating glaucoma surgery: EYEMATE-SC trial

PURPOSE

To investigate long-term astigmatism after combined nonpenetrating glaucoma surgery (NPGS) and implantation of the first miniaturized suprachoroidal intraocular pressure (IOP) sensor EYEMATE-SC.

SETTING

The study was conducted in 5 medical centers in 2 different countries.

DESIGN

Retrospective multicenter clinical study.

METHODS

Astigmatism of patients instrumented with the EYEMATE-SC IOP sensor was assessed over a follow-up period of 3 years. Refraction and corrected distance visual acuity (CDVA) were obtained preoperatively, after 6 months, 1, 2, and 3 years. A canaloplasty-operated patient cohort served as control. Astigmatism was evaluated using 3-dimensional power vector analysis involving the spherical equivalent M, and the Jackson crossed cylinder projections J 0 and J 45 . Exclusion criteria included neovascular and angle-closure glaucoma, myopia, axial length outside 22 to 26 mm, other ocular diseases, prior glaucoma surgery, other ocular surgery within 6 months (cataract surgery within 3 months) before NPGS, serious generalized conditions, and other active medical head/neck implants.

RESULTS

Multivariate analysis indicated no changes in astigmatism along the observation period in both the EYEMATE-SC (n = 24) and the canaloplasty (n = 24) group ( P > .05 or nonsignificant after Bonferroni correction). Astigmatism was unchanged between the EYEMATE-SC and the canaloplasty group at all timepoints ( P > .05). CDVA did not change along the observation period of 3 years in each of both groups ( P > .05).

CONCLUSIONS

Despite its suprachoroidal localization, this study indicated that the miniaturized EYEMATE-SC IOP sensor did not negatively affect long-term astigmatism after combined implantation with NPGS.

Advancements in Wearable and Implantable Intraocular Pressure Biosensors for Ophthalmology: A Comprehensive Review

Glaucoma, marked by its intricate association with intraocular pressure (IOP), stands as a predominant cause of non-reversible vision loss. In this review, the physiological relevance of IOP is detailed, alongside its potential pathological consequences. The review further delves into innovative engineering solutions for IOP monitoring, highlighting the latest advancements in wearable and implantable sensors and their potential in enhancing glaucoma management. These technological innovations are interwoven with clinical practice, underscoring their real-world applications, patient-centered strategies, and the prospects for future development in IOP control. By synthesizing theoretical concepts, technological innovations, and practical clinical insights, this review contributes a cohesive and comprehensive perspective on the IOP biosensor's role in glaucoma, serving as a reference for ophthalmological researchers, clinicians, and professionals.

Safety and performance of a suprachoroidal sensor for telemetric measurement of intraocular pressure in the EYEMATE-SC trial

AIM

To investigate the safety and performance of a telemetric suprachoroidal intraocular pressure (IOP) sensor (EYEMATE-SC) and the accuracy of its IOP measurements in open angle glaucoma (OAG) patients undergoing simultaneous non-penetrating glaucoma surgery (NPGS).

METHODS

Prospective, multicentre, open-label, single-arm, interventional clinical trial. Twenty-four eyes of 24 patients with OAG regularly scheduled for NPGS (canaloplasty or deep sclerectomy) were simultaneously implanted with an EYEMATE-SC sensor. Six-month follow-up on the sensor's safety and performance as well as on the level of agreement between the EYEMATE-SC measurements and IOP measurements with Goldmann applanation tonometry (GAT).

RESULTS

The eyes underwent canaloplasty (n=15) or deep sclerectomy (n=9) and achieved successful implantation of the sensor. No device migration, dislocation or serious device-related complications occurred. A total of 367 comparisons were included in the IOP agreement analysis. The overall mean difference between GAT and EYEMATE-SC measurements was 1.31 mm Hg (lower limit of agreement (LoA) 7.55 mm Hg; upper LoA -4.92 mm Hg). The maximum difference of 2.5 mm Hg ±3.96 (LoA 0.30-2.29) was reached on day 10 and continuously improved to an agreement of -0.15 mm Hg ±2.28 (LoA -1.24 to 0.89) after 6 months. Accordingly, the percentage of eyes within an IOP difference of ±5 mm Hg improved from 78% (day 3) to 100% (6 months).

CONCLUSIONS

After 6 months, the EYEMATE-SC sensor was safe and well tolerated, and allowed continual IOP monitoring.

TRIAL REGISTRATION NUMBER

NCT03756662.

EYEMATE-SC Trial: Twelve-Month Safety, Performance, and Accuracy of a Suprachoroidal Sensor for Telemetric Measurement of Intraocular Pressure

PURPOSE

Measuring and controlling intraocular pressure (IOP) provide the foundation for glaucoma treatment. Self-tonometry has been proposed as an alternative to measure IOP throughout the entire day better. The novel EYEMATE-SC sensor (Implandata) is implanted in the suprachoroidal space to enable contactless continual IOP monitoring. The aim of the present study was to investigate the 1-year safety, performance, and accuracy of the EYEMATE-SC in patients with primary open-angle glaucoma undergoing simultaneous nonpenetrating glaucoma surgery (NPGS).

DESIGN

Prospective, multicenter, open-label, single-arm, interventional clinical trial.

PARTICIPANTS

Twenty-four eyes of 24 patients with primary open-angle glaucoma who were due to undergo NPGS (canaloplasty or deep sclerectomy).

METHODS

An EYEMATE-SC sensor was implanted during NPGS. Goldmann applanation tonometry (GAT) measurements were compared with the sensors' IOP measurements at all postoperative visits through 12 months.

MAIN OUTCOME MEASURES

Device position and adverse events.

RESULTS

Fifteen eyes underwent canaloplasty, and 9 underwent deep sclerectomy. Successful implantation of the sensor was achieved in all eyes with no reported intraoperative difficulties. Through the 12-month follow-up, no device migration, dislocation, or serious device-related complications were recorded. A total of 536 EYEMATE-SC measurements were pairwise included in the IOP agreement analysis. The overall mean difference between GAT and EYEMATE-SC measurements was 0.8 mmHg (95% confidence interval [CI] of the limits of agreement [LoA], -5.1 to 6.7 mmHg). The agreement gradually improved, and from 3 months after surgery until the end of the follow-up, the mean difference was -0.2 mmHg (95% CI of LoA, -4.6 to 4.2 mmHg) over a total of 264 EYEMATE-SC measurements, and 100% of measurements were within ±5 mmHg of GAT.

CONCLUSIONS

The EYEMATE-SC sensor was safe and well tolerated through 12 months. Moreover, it allowed accurate, continuous IOP monitoring.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Telemetric non-contact intraocular pressure monitoring with an implanted sensor in patients with glaucoma: long-term safety report and monitoring data

BACKGROUND/AIMS

Glaucoma is a chronic disease that requires lifelong monitoring and treatment. However, its control is limited due to discontinuous intraocular pressure (IOP) monitoring related to the practitioners' office hours. Implantable telemetric IOP sensors have made self-measurements possible and provide important information regarding the IOP profiles of patients. However, limited long-term monitoring data are currently available.

METHODS

In the ARGOS-01 study, a telemetric IOP sensor was implanted in the ciliary sulcus of six patients with open-angle glaucoma during cataract surgery between 2011 and 2012. This study reports telemetric monitoring data collected by self-tonometry and automated measurements and during outpatient visits, including an analysis of one active patient with several years of follow-up. The long-term safety, tolerability and functionality were assessed in the remaining patients during the last visit.

RESULTS

The follow-up period was up to 10 years, in which almost 25 000 IOP measurements were performed. The patients had excellent tolerance of the implanted sensor and did not experience sensor-related discomfort or complications. The active patient reported easy handling of self-tonometry and did not experience long-term restrictions in activities of daily living due to the implanted sensor. Telemetric data provide an insight into patients' measurement routines and IOP fluctuations.

CONCLUSION

So far, our data suggest good long-term safety, tolerability and functionality of the implanted sensors up to almost ten years. Such sensors may help facilitate patients' self-measurements of IOP. This disease monitoring method should be investigated further to determine if it helps improve wider patient experience, engagement and visual prognosis for those being treated for complex glaucoma.

Continuous 24-hour measurement of intraocular pressure in millimeters of mercury (mmHg) using a novel contact lens sensor: Comparison with pneumatonometry

PURPOSE

To address the unmet need of continuous IOP monitoring, a Pressure-Measuring Contact Lens (PMCL) was developed to measure IOP in millimeters of mercury (mmHg) continuously over 24 hours. The present study assessed the reliability of the novel PMCL.

METHODS

In this prospective open-label clinical study, healthy and open-angle glaucoma (OAG) subjects were fitted with the PMCL, and pneumatonometry was performed on study eyes (in absence of the PMCL) and on fellow eyes before, during, and after provocative tests. The primary outcome measures were (1) mean IOP difference between same-eye measurements, and (2) percentage of timepoints at which IOP measured by the PMCL was within 5 mmHg of that measured by pneumatonometry in the fellow eye.

RESULTS

Eight subjects were analysed (4 healthy, 4 OAG). The average difference in successive IOP measurements made by pneumatonometry and with the PMCL was 2.0±4.3mmHg at placement-time, and 6.5±15.2mmHg at removal time. During water drinking test, a significant increase in IOP was detected both by PMCL in the study eye (2.4±2.5mmHg, p = 0.03) and by pneumatonometry in the fellow eye (1.9±1.9mmHg, p = 0.02). Over the 24-hour recording, 88.0% of IOP variations measured by the PMCL were within 5mmHg of that measured with the pneumatonometer in the fellow eye. A transient corneal erosion of severe intensity was observed following removal of the PMCL on one single eye, and may have affected measurement accuracy in that eye.

CONCLUSIONS

This study is a proof-of-concept for this novel PMCL, and its results are encouraging, with a fair accuracy in IOP values measurement and good sensitivity to subtle IOP variations.

Influence of electromagnetic radiation emitted by daily-use electronic devices on the Eyemate® system in-vitro: a feasibility study

BACKGROUND

Eyemate® is a system for the continual monitoring of intraocular pressure (IOP), composed of an intraocular sensor, and a hand-held reader device. As the eyemate®-IO sensor communicates with the hand-held reader telemetrically, some patients might fear that the electronic devices that they use on a daily basis might somehow interfere with this communication, leading to unreliable measurements of IOP. In this study, we investigated the effect of electromagnetic radiation produced by a number of everyday electronic devices on the measurements made by an eyemate®-IO sensor in-vitro, in an artificial and controlled environment.

METHODS

The eyemate®-IO sensor was suspended in a sterile 0.9% sodium chloride solution and placed in a water bath at 37 °C. The antenna, connected to a laptop for recording the data, was positioned at a fixed distance of 1 cm from the sensor. Approximately 2 hrs of "quasi-continuous" measurements were recorded for the baseline and for a cordless phone, a smart-phone and a laptop. Repeated measures ANOVA was used to compare any possible differences between the baseline and the tested devices.

RESULTS

For baseline measurements, the sensor maintained a steady-state, resulting in a flat profile at a mean pressure reading of 0.795 ± 0.45 hPa, with no apparent drift. No statistically significant difference (p = 0.332) was found between the fluctuations in the baseline and the tested devices (phone: 0.76 ± 0.41 hPa; cordless: 0.787 ± 0.26 hPa; laptop: 0.775 ± 0.39 hPa).

CONCLUSION

In our in-vitro environment, we found no evidence of signal drifts or fluctuations associated with the tested devices, thus showing a lack of electromagnetic interference with data transmission in the tested frequency ranges.

Use of a novel telemetric sensor to study interactions of intraocular pressure and ganglion-cell function in glaucoma

Aims

(1) To test the feasibility of simultaneous steady-state pattern electroretinogram (ssPERG) and intraocular pressure (IOP) measurements with an implanted IOP sensor. (2) To explore the scope of this approach for detecting PERG changes during IOP manipulation in a model of lateral decubitus positioning (LDP; lateral position).

Methods

15 healthy controls and 15 treated glaucoma patients participated in the study. 8 patients had an IOP sensor (Eyemate-IO, Implandata Ophthalmic Products GmbH) in the right eye (GLAIMP) and 7 had no sensor and with glaucoma in the left eye. (1) We compared PERGs with and without simultaneous IOP read-out in GLAIMP. (2) All participants were positioned in the following order: sitting1 (S1), right LDP (LDR), sitting2 (S2), left LDP (LDL) and sitting3 (S3). For each position, PERG amplitudes and IOP were determined with rebound tonometry (Icare TA01i) in all participants without the IOP sensor.

Results

Electromagnetic intrusions of IOP sensor read-out onto ssPERG recordings had, due to different frequency ranges, no relevant effect on PERG amplitudes. IOP and PERG measures were affected by LDP, for example, IOP was increased during LDR versus S1 in the lower eyes of GLAIMP and controls (5.1±0.6 mmHg, P0.025=0.00004 and 1.6±0.6 mmHg, P0.025=0.02, respectively) and PERG amplitude was reversibly decreased (−25±10%, P0.025=0.02 and −17±5%, P0.025, respectively).

Conclusions

During LDP, both IOP and PERG changed predominantly in the lower eye. IOP changes induced by LDP may be a model for studying the interaction of IOP and ganglion-cell function.

Highly Transparent and Sensitive Graphene Sensors for Continuous and Non-invasive Intraocular Pressure Monitoring

Intraocular pressure (IOP) is the prime indicator for the diagnosis and treatment of glaucoma. IOP has circadian rhythm changes and is dependent on body gestures; therefore, a single measurement in the clinic can be misleading for diagnosis. Herein, few-layer graphene is utilized to develop non-invasive sensors with high transparency, sensitivity, linearity, and biocompatibility for 24 h continuous IOP monitoring. The graphene Wheatstone bridge consisting of two strain gauges and two compensating resistors is designed to improve the sensitivity and accuracy of IOP measurement. Testing results on a silicone eyeball indicate that the output voltage of the sensor is proportional to the IOP fluctuation. Under the various ranges and speeds of IOP fluctuation, the sensor exhibits excellent performance of dynamic cycles and step responses with an average sensitivity of 150 μV/mmHg. With the linear relationship, the average relative error between the calibrated IOP and the standard pressure is maintained at about 5%. More than 100 cycles and interval time measurements illustrate that the sensor possesses significant stability, durability, and reliability. Furthermore, a wireless system is designed for the sensor to realize IOP monitoring using a mobile phone. This sensor, with the average transparency of 85% and its ease of fabrication, as well as its portability for continuous IOP monitoring, brings new promise to the diagnosis and treatment of glaucoma.

Telemetric Intraocular Pressure Monitoring after Boston Keratoprosthesis Surgery Using the Eyemate-IO Sensor: Dynamics in the First Year

PURPOSE

To analyze the dynamics of telemetrically measured intraocular pressure (IOP) during the first year after implantation of a Boston keratoprosthesis type I (BI-KPro) cornea and to compare agreement of telemetric IOP measurements with finger palpations.

DESIGN

Prospective, open-label, multicenter, single-arm clinical trial.

METHODS

In the ARGOS (NCT02945176) study, 12 individuals underwent implantation of an Eyemate-IO intraocular system. Follow-up after surgery took place 12 months later with 13 visits planned per patient. During BI-KPro surgery, an electromagnetic induction sensor ring enabling telemetric IOP data transfer to a hand-held reading device outside the eye was implanted into the ciliary sulcus with or without trans-scleral suture fixation. Comprehensive ophthalmic examinations and IOP assessments through the telemetric system were compared to IOP assessed by finger palpation by 2 experts.

RESULTS

Preoperative IOP measured by Goldmann tonometry was 13.4 ± 6.2 mm Hg. Telemetric IOP peaked at 23.1 ± 16.5 mm Hg at the first postoperative day. On day 5, mean IOP was 16.0 ± 5.2 mm Hg and 20.95 ± 6.5 mm Hg after 6-12 months. IOP estimation by finger palpation was grouped in 4 categories: normal, A; soft/hypotonic, B; borderline, C; and hypertonic, D. Mean telemetric IOP was 18.2 ± 6.1 mm Hg in category A, 8.9 ± 2.8 mm Hg in B, 22.4 ± 4.9 mm Hg in C, and 34.3 ± 11.0 mm Hg in D. Differences in mean telemetric IOPs per category were statistically significant (P < .001). Daily IOP fluctuations and peaks could be identified.

CONCLUSIONS

Telemetric IOP assessment seems to be able to identify postoperative IOP peaks and a longitudinal increase of IOP after BI-KPro surgery. IOP measurements using the telemetric Eyemate-IO sensor showed a satisfactory agreement with those of finger palpations by 2 experts.

Role of 24-Hour Intraocular Pressure Monitoring in Glaucoma Management

Glaucoma is the leading cause of irreversible blindness worldwide and the prevalence is on the rising trend. Intraocular pressure (IOP) reduction is the mainstay of treatment. The current practice of IOP monitoring is based on spot measurements during clinic visits during office hours. However, there are up to 50% of glaucoma patients who had normal initial IOP, while some treated patients continued to have progressive glaucomatous optic nerve damage even with a low IOP. Recent studies have shown that the IOP of glaucoma patients fluctuated during the day with different patterns, and some of them had peak IOP outside office hours. These findings provided us with new insights on the role of 24-hour IOP monitoring in managing normal tension glaucoma and patients with progressive deterioration despite apparently well-controlled IOP. Nevertheless, results to date are rather inconsistent, and there is no consensus yet. In this review, we briefly highlighted the current modalities of 24-hour IOP monitoring and summarized the characteristic 24-hour IOP pattern and the clinical relevance of IOP parameters in predicting glaucomatous progression in different glaucoma subtypes. We also discussed the therapeutic efficacy of current glaucoma treatment modalities with respect to the mentioned 24-hour IOP profiles, so as to strengthen the role of 24-hour IOP monitoring in identifying and stratifying the risks of progression in glaucoma patients, as well as optimizing treatments according to their IOP profiles.

Miniaturization in Glaucoma Monitoring and Treatment: A Review of New Technologies That Require a Minimal Surgical Approach

In the management of glaucoma, recent and upcoming innovations have the potential to contribute to both the efficacy of intraocular pressure (IOP) monitoring and the number of available treatment options. These new devices and procedures have two things in common: they are part of the trend in medicine towards miniaturization, and they require a limited surgical procedure to become effective. This review focuses on the Eyemate (Argos) intraocular sensor, which offers a new way to reliably measure 24 h IOP, and on intraocular sustained release systems for pharmacological glaucoma therapy. It also briefly reflects on the miniature implants currently used in minimally invasive glaucoma surgery (MIGS).

Automated, Noncontact Intraocular Pressure Home Monitoring after Implantation of a Novel Telemetric Intraocular Pressure Sensor in Patients with Glaucoma: A Feasibility Study

Purpose

Reliable and regular assessment of intraocular pressure (IOP) is important for the monitoring of patients with glaucoma. The purpose of this study was to evaluate the feasibility of a novel system for the automated, noncontact measurement of IOP.

Patients and Methods

A first-generation telemetric IOP sensor was previously implanted in the ciliary sulcus of six patients with open-angle glaucoma during cataract surgery. Using this technology, automated noninvasive tonometry may be performed in a home setting. In the present study, a modified sleep mask and a modified eyepatch with incorporated coil antennae for measurements during nighttime and daytime, respectively, were tested on a single patient.

Results

In this feasibility study, the 24 h wear of the prototype measuring apparatus was well tolerated. Three sequences of 24 h IOP measurements with at least 200 IOP measurements per day were performed (Sequence 1: mean 19.6 ± 2.7 mmHg, range 13.4–28.7 mmHg; Sequence 2: mean 21.0 ± 3.0 mmHg, range 13.1–30.5 mmHg; Sequence 3: mean 19.9 ± 2.4 mmHg, range 12.6–27 mmHg).

Conclusions

For the first time, repeated and automated 24-hour measurements are possible using a prototype noncontact reading system after implantation of a novel telemetric IOP sensor in patients with glaucoma.

New Technologies for Glaucoma Detection

This review describes some of the most recent advances in the development and application of new technologies for detecting and managing glaucoma, including imaging, visual function testing, and tonometry. The widespread availability of mobile technology in the developing world is improving health care delivery, for example, with smartphones and mobile applications that allow patient data to be assessed remotely by health care providers.