How Home IOP Monitoring Is Changing Glaucoma Care: Insights from Dr. Paul Chamberlain

Why a Single Office Reading Is Not Enough

In this 59-minute webinar, Dr. Paul Chamberlain presents a clinical case for why home IOP monitoring with the iCare HOME2 should become a routine part of glaucoma management. Drawing on published research and real-world patient cases, he argues that the single spot-check IOP taken during an office visit — often the sole data point driving treatment decisions — captures a matter of seconds out of 31 million seconds in a year. IOP fluctuates with position, sleep, time of day, cortisol levels, exercise, and fluid intake. Patients continue to progress even when office pressures appear controlled, and clinicians are left making high-stakes decisions with incomplete information.

IOP Fluctuation as an Independent Risk Factor

Dr. Chamberlain reviews key literature establishing IOP fluctuation as an independent predictor of glaucoma progression. Sanjay Asrani's work on normal tension glaucoma suggests that fluctuation greater than 3 mmHg may be linked to progression. More dramatically, the SIGTS study by David Musch followed patients over 9 years and found that those with more than 8.5 mmHg delta change — regardless of their baseline IOP at study entry — had directly correlated visual field progression. This means a patient fluctuating between 12 and 20 mmHg, who looks perfectly normal in the office, could be sustaining damage from the variability alone.

The Circadian Biology of IOP

A fascinating 1973 study by an endocrinologist measured cortisol levels every 20 minutes and IOP every hour in 11 patients kept overnight in a sleep lab. Cortisol spiked first in the early waking hours, followed by IOP, leading the researcher to conclude that hormonal and vascular factors drive a circadian rhythm of intraocular pressure. Over 50 years later, this biology remains underappreciated in clinical practice. Dr. Chamberlain notes that the early morning IOP window — the same period when patients are most vulnerable to ischemic optic neuropathies, strokes, and heart attacks — is precisely when nocturnal and early-waking spikes occur and when no clinic is open to measure them.

Not All Therapies Work the Same Over 24 Hours

Dr. Chamberlain explains that prostaglandins and carbonic anhydrase inhibitors tend to work better during sleep, while beta-blockers traditionally lose efficacy at night — which is why they are dosed once in the morning. Surgical interventions vary as well. Published data from Iowa showed that switching an exfoliation patient from latanoprost to netarsudil (a rho-kinase inhibitor that addresses episcleral venous pressure) dramatically flattened early morning spikes that had been reaching 43 mmHg despite in-office pressures in the teens. SLT has also been shown to flatten diurnal variability, consistent with findings from the LiGHT study that SLT patients had less visual field progression than those on topical drops over six years. PreserFlo, which bypasses the outflow system entirely, completely flatlines the diurnal curve in his experience.

Validation and Research Infrastructure

The iCare HOME2 uses rebound tonometry, a technology validated over 20 years in both clinical and veterinary settings. Multiple studies beginning in 2016 compared HOME2 readings against Goldmann applanation tonometry for sensitivity and specificity across normal, normal-tension glaucoma, and POAG populations. The device slightly underestimates at low pressures (about 2 mmHg below GAT at IOP ~10) and slightly overestimates at the high end, but within the normal IOP range it tracks within plus-one to plus-two of GAT. Ongoing IRB-approved studies at Moran Eye Center, Harvard, and Wilmer Eye Institute are investigating who spikes, when they spike, and how many days of monitoring are needed for a representative profile.

Case Evidence: When Home Data Changes the Plan

Dr. Chamberlain presents several cases illustrating how home tonometry altered clinical management. A published case from Moran showed a patient with reproducible early-morning spikes between 17 and 28 mmHg over a week — a delta far exceeding the 8.5 mmHg threshold linked to progression in the SIGTS study — who appeared controlled during office hours. An Iowa case involved a surgeon with exfoliation spiking to 43 mmHg in the early morning while consistently measuring in the teens during clinic visits; switching to netarsudil flattened the curve. A 76-year-old woman with unilateral exfoliation appeared normal at 17–18 in clinic, but HOME2 revealed regular spikes into the high 20s in the affected eye; SLT flattened the spike to match the healthy eye. A 37-year-old with uveitic glaucoma complained of intermittent headaches despite teens-to-low-twenties in-office; HOME2 caught spikes into the 40s, and a goniotomy eliminated the variability entirely.

Patient Empowerment and Anxiety Reduction

An 84-year-old cardiologist with exfoliation glaucoma had lost vision to count fingers in his right eye after undetected post-operative IOP spikes following cataract surgery. When cataract surgery was needed in his remaining left eye, HOME2 monitoring gave him the confidence to proceed — he could detect spikes in real time and alert his team immediately rather than waiting a week for a follow-up visit. The surgery was successful, and he achieved 20/20 vision. Dr. Chamberlain emphasizes that rather than increasing patient anxiety, home monitoring consistently reduces it by replacing uncertainty with data and giving patients ownership of their disease management.

The MyEyes Concierge Service

Ericka Shepard, Vice President of Patient Success at MyEyes and a glaucoma patient herself, explains how the service removes operational burden from prescribing clinics. The physician writes a prescription; MyEyes handles shipping (within 24 hours), patient onboarding via phone with glaucoma-patient ambassadors, troubleshooting during the rental, data download, and polished PDF report delivery back to the prescribing provider. The clinic receives the report when the rental is complete — no tech time, no device inventory, no patient training required. MyEyes reports a 95% customer satisfaction rating, a 98% patient success rate with the device, and 96% of inbound calls answered live. The team is partnering with Harvard and Johns Hopkins on Epic EHR integration to deliver reports directly into patient charts.

Insurance, Pricing, and the Road to Standard of Care

While Medicare does not yet reimburse for home tonometry, MyEyes has seen growing success with private insurers. The company provides patients with everything needed to submit claims after the fact, and an increasing number of patients are receiving partial or full reimbursement. MyEyes is a registered DME provider and a preferred vendor with United Healthcare. Rental pricing starts at $249 for the first week with $149 for each additional week. A new aftercare subscription ($299/month, 3-month minimum) supports pre-, during, and post-surgical monitoring. The device is available for purchase at $2,999 with payment plans and HSA/FSA eligibility.