Handheld home tonometer gathers IOP readings outside office hours
The Focus column presents the perspectives of optometrists who have firsthand experience with a new product.
A 51-year-old woman with a family history of glaucoma presents with an IOP of 17 mmHg OD and 24 mmHg OS. Central corneal thickness readings are 515 μm OD and 518 μm OS; BCVA is 20/20 OD and 20/30 OD. Her slit lamp exam is normal. Cup-to-disc ratio OD is 0.1 and OS is 0.0. Her follow-up appointment nets similar IOPs, and gonioscopy reveals Grade 4 open angles OU with light pigment.
Given the patient’s borderline IOPs and family history of glaucoma, we prescribed the Icare HOME Tonometer, a handheld device, from Icare USA Inc., used to monitor “off-hours” IOP. We explained: “Knowing whether your pressures are increased outside of our office can give us enhanced insights as to the behavior of your eye pressures, and we can then provide you with the best of care.”
The Icare HOME Tonometer uses rebound tonometry, which employs a tiny probe projected onto the corneal surface. As the probe bounces off the cornea, the velocity of the rebound is measured by an onboard computer.
The device is indicated for patients suspected of having so-called normal pressure glaucoma. IOP measurements are gathered at various times of day to provide O.D.s with more data to inform their treatment decisions. About 75% of individuals have peak IOP outside office hours, according to JAMA Ophthalmology.
The process is innocuous and requires no anesthesia. The patient is prescribed the device for about a week in an effort to obtain three to five days of random IOP readings.
About 73% of patients were found to accurately measure their own IOP after a short training session, according to JAMA Ophthalmology. That said, teaching the Icare HOME self-measuring technique has shown to be a bit more challenging in the Medicare population. Performing self-tonometry requires a steady hand, so if any patient has any sort of tremor, etc., this device may not be appropriate.
The IOPs are blindly stored in the device. At follow-up, the information is downloaded from the device and into the patient file for the doctor.
The practice purchases the Icare HOME device to loan out to patients. The patient is charged an out-of-pocket, non-insurance covered fee determined by the practice. For Medicare patients, an Advance Beneficiary Notice of Noncoverage is advisable.
We have been using the device for nearly a year; it has augmented our decision-making in caring for several patients. About 20% of glaucoma suspect patients present a diagnostic challenge, and gaining the out-of-office IOP readings can be an enormous help.
The monitoring of the patient’s IOP recorded her peak IOP OD at 26 mmHg and OS at 28 mmHg. Because this did not go over 30 mmHg, we decided to follow-up at six-month intervals, at which VF and OCT retinal nerve fiber layer testing can be monitored. Icare HOME Tonometer weighs 150 g and measures 11 cm x 8 cm x 3 cm. OM