Introduction
Glaucoma management is evolving with home-based intraocular pressure (IOP) monitoring. Traditionally, eye pressure is checked only during office visits, but new devices let patients measure IOP at home or wear sensors in their eyes. In fact, by 2026 several clinical trials began incorporating these technologies. Home tonometers (like the FDA-approved iCare HOME rebound tonometer (pmc.ncbi.nlm.nih.gov)) allow patients to check their own IOP without anesthesia. Smart contact lenses equipped with sensors (e.g. the Sensimed Triggerfish® CLS) can continuously record 24-hour pressure patterns (pmc.ncbi.nlm.nih.gov). These trials explore how such data can improve efficacy outcomes and trigger safety interventions, while ensuring data quality and patient comfort.
Trials with Home IOP Monitoring
Several recent and upcoming trials (starting around April 2026) include home tonometry in their protocols. For example, an academic study at Wills Eye Hospital is testing home monitoring for mild‐to‐moderate glaucoma patients. Participants use the iCare HOME tonometer at home, measuring IOP multiple times and uploading data, alongside a portable perimeter for visual field testing (www.withpower.com). Similarly, a large Guangdong/Hong Kong trial randomizes newly diagnosed glaucoma patients to (1) home telemonitoring with iCare HOME plus a smartphone coaching program, or (2) standard care with smartphone support (ichgcp.net). In that trial, patients in the home-monitoring arm upload six IOP readings weekly (two days per week, thrice daily) to a secure cloud platform (iCare CLINIC) (ichgcp.net). Another “diurnal monitoring” trial in Switzerland (NCT04485897) compares 24-hour hospital-based IOP monitoring to patient self-tonometry at home. In that study, patients use the iCare device on themselves and investigators analyze how well the home pressure curve matches the clinic curve (clinicaltrials.gov). These and other trials explicitly incorporate home IOP data into their endpoints and decision rules.
Trials with Continuous Contact-Lens Sensing
A parallel line of research uses smart contact lenses to measure IOP continuously. For example, the Mon-BH/Barcelona ISRCTN65401232 trial is studying glaucoma patients who undergo minimally invasive iStent surgery. Both the surgery group and a control group get 24-hour monitoring with the Sensimed Triggerfish® contact lens sensor at baseline and follow-up (e.g. 1 or 3 months later) (clinicaltrials.gov). The Triggerfish is a soft silicone lens (~14.1 mm diameter, 585 μm thick) embedded with micro-strain gauges, a chip, and an antenna (pmc.ncbi.nlm.nih.gov). It transmits pressure-related data to an adhesive orbital antenna and portable recorder worn by the patient (pmc.ncbi.nlm.nih.gov). Such trials use the sensor output to quantify circadian IOP patterns. For instance, the Spanish iStent trial defines the primary outcome as the amplitude of a fitted 24-hour IOP curve derived from the lens data (clinicaltrials.gov). In short, modern protocols combine traditional endpoints (like average IOP or nerve fiber thinning) with novel continuous IOP measurements from these contact lenses.
Device Specifications and Calibration
Home tonometers such as the iCare HOME are rebound tonometers: a lightweight handheld probe gently bounces a small disposable tip off the cornea to compute pressure (pmc.ncbi.nlm.nih.gov). The iCare HOME (model TA022) was FDA-cleared in 2017 (pmc.ncbi.nlm.nih.gov) and comes with disposable tips (~40 mm probes) that eliminate the need for anesthesia (pmc.ncbi.nlm.nih.gov) (pmc.ncbi.nlm.nih.gov). Rebound tonometers do not require regular calibration like some other tonometers (pmc.ncbi.nlm.nih.gov). Patient training is needed, however: before using the device independently, each patient is “certified” by a trained professional. Training includes learning to position the device and support it against the cheek and forehead, which are measured and recorded for consistency (pmc.ncbi.nlm.nih.gov). Only after meeting the manufacturer’s accuracy criteria (e.g. taking consistent triplicate readings) can a patient use the device routinely (pmc.ncbi.nlm.nih.gov).
Contact lens sensors like the Triggerfish are one-size-fits-all (with a few base curves) and require no patient calibration. An eye doctor fits the lens at the clinic for a 24-hour recording session (pmc.ncbi.nlm.nih.gov). The device itself (a soft hydrogel lens) contains strain gauges and electronics. When pressure or ocular expansion changes the lens curvature, the strain gauges detect it and send data via the external antenna (pmc.ncbi.nlm.nih.gov). Because these sensors output a relative signal (not a direct mmHg reading), protocols often calibrate each session by fitting models (like a 24h cosinor) to the recorded waveform instead of matching Goldmann measurements. In sum, home tonometers need a one-time patient certification and have built-in stability (no on-going calibration). Contact lenses require skilled fitting but minimal patient effort during wear.
Patient Training and Adherence Support
Studies invest heavily in training and reminders to ensure accurate use. In the iCare Home trials, patients must demonstrate proficiency at an initial visit (pmc.ncbi.nlm.nih.gov). After training, trials often employ digital tools to encourage compliance. In the Hong Kong trial, for instance, patients receive automated text messages via a smartphone app. Every four weeks they get messages telling them whether their IOP readings have met target goals and reminders to take medications, and the patients reply via text to confirm adherence (ichgcp.net). Similarly, home tonometer data are uploaded automatically to an online portal (e.g. iCare CLINIC), letting clinicians track if measurements are missed (ichgcp.net). For contact lenses, adherence simply means wearing the device for the required period: researchers typically supervise insertion and ask patients to note any errors or remove the lens early. In all cases, clear protocols and digital reminders help maintain high adherence to scheduled self-monitoring.
Integrating Home Data into Endpoints and Safety Triggers
Home-collected IOP data can strengthen efficacy assessments. For example, one trial treats the clinic-measured IOP over time (via Goldmann applanation tonometry) as the primary outcome, but uses home tonometry to guide therapy. The Hong Kong trial hypothesizes that having frequent home IOP readings will lower mean IOP and slow nerve-fiber loss compared to standard care (ichgcp.net). In analysis, they plan to correlate the home-derived metrics (like mean IOP and IOP fluctuations) with structural outcomes (RNFL thinning) (ichgcp.net). In another study, home self-tonometry is directly compared to 24h in-hospital profiles: the primary endpoint is simply the agreement between the two IOP patterns (clinicaltrials.gov). And continuous lens data can be turned into summary endpoints: e.g. the Barcelona trial uses the fitted “amplitude” of the 24h IOP curve from the CLS data as its main outcome (clinicaltrials.gov).
Home readings can also serve as early safety signals. Protocols typically pre-specify pressure thresholds or warning rules. For instance, the majority of trials set rules like: if home IOP readings consistently exceed the treatment goal by a large margin, study staff intervene. In the Hong Kong trial, participants were withdrawn if they met safety criteria—such as two consecutive visits with IOP ≥35 mmHg (ichgcp.net). Likewise, the Swiss diurnal-monitoring study includes a secondary outcome of “treatment changes triggered by IOP peaks,” meaning any detected spike (at home or in hospital) prompts a medication change (clinicaltrials.gov). In practice, trial teams review uploads and will call patients if a reading is dangerously high. Thus, home data feed directly into efficacy endpoints by providing a fuller IOP profile and into safety triggers by alerting clinicians to out-of-range pressures (ichgcp.net) (clinicaltrials.gov).
Data Quality Assurance and Patient Burden
Ensuring reliable home data is crucial. Devices often take repeated measurements and average them; for example, the iCare HOME’s readings are based on multiple probe contacts to smooth out error. Some trials exclude patients who cannot meet quality criteria: one Hong Kong study disqualified anyone who failed the iCare certification at baseline (ichgcp.net). Others compare a subset of home readings to technician measurements to check accuracy. Despite these checks, home measurements tend to be slightly noisier: studies report small average biases (e.g. a ~1 mmHg underestimation of true IOP) and wider spread than clinic tonometry (journals.lww.com) (pmc.ncbi.nlm.nih.gov).
From the patient’s viewpoint, home monitoring adds tasks. Most iCare home‐tonometry studies instruct patients to measure IOP several times daily or weekly. For example, one protocol required thrice-daily measurements for a week every quarter (www.withpower.com). These routines impose time and skill demands: fortunately, training seems effective. A recent review found that about 82.5% of patients could successfully learn self-tonometry (journals.lww.com). Most participants report the device is easy (median ~72% found it easy to use) and comfortable (~92% found wear acceptable) (journals.lww.com). Learning typically took under 20 minutes and patients often felt confident at home.
Contact lens sensors carry a different kind of burden. Patients must wear a tight-fitting lens for a full day, which usually causes mild irritation. In one study of the Triggerfish sensor, 82.5% of patients experienced transient blurred vision and 80.0% had some redness during wear (pmc.ncbi.nlm.nih.gov). These effects were attributed to the lens prescription and corneal molding, and most were mild (measured by a tolerability visual‐analogue scale of only ~25/100 (pmc.ncbi.nlm.nih.gov)). No serious harms were reported, but not all patients tolerate the lens (trials often screen for severe dry eye or corneal issues first).
Overall, while home IOP monitoring increases patient effort, studies find it is feasible and well accepted (journals.lww.com) (journals.lww.com). Patients largely do not mind adding IOP checks if it means better care. Researchers ensure quality by training, certification, and electronic logging of readings. In the end, these trials will clarify how to balance the extra data with the extra work – aiming to improve outcomes without overburdening patients.
Conclusion
Emerging clinical trials around April 2026 are pioneering the use of home tonometers and contact-lens pressure sensors in glaucoma care. These protocols detail the devices (from iCare HOME rebound tonometers to Sensimed Triggerfish lenses), rigorous patient training and certification, and adherence support (like smartphone reminders). They explicitly incorporate home IOP data into trial endpoints (for efficacy) and into action thresholds (for safety) (ichgcp.net) (clinicaltrials.gov). As patients measure more IOP readings outside the clinic, the trials also address data quality checks and patient burden. All evidence so far suggests that motivated patients can effectively use these tools, and that continuous monitoring may reveal pressure peaks missed in the office. By 2026, home-monitoring trials will help determine how best to integrate these novel sensors into routine glaucoma management, enhancing patient engagement and potentially improving disease control (journals.lww.com) (pmc.ncbi.nlm.nih.gov).