Findings from a study recently published in Translational Vision Science & Technology evaluated the feasibility, accuracy, and repeatability of unsupervised, at-home, multi-day glaucoma testing using the Olleyes VisuALL Virtual Reality Platform (VRP) and the iCare HOME handheld self-tonometer.
Give me some background.
Glaucoma requires regular in-office visual field (VF) testing and intraocular pressure (IOP) measurements to guide treatment decisions and prevent visual field loss.
However: Multiple in-office VF tests and IOP checks can be impractical and costly due to insurance coverage or travel limitations.
Keep going…
The coronavirus disease-19 (COVID-19) pandemic accelerated the adoption of telemedicine and at-home testing for glaucoma management.
Fortunately, the recent introduction of remote physiologic monitoring (RPM) and remote therapeutic monitoring (RTM) codes have made remote patient monitoring more financially feasible.
Meaning: As healthcare increasingly financially supports remote chronic disease monitoring, a research team from Stanford University sought to elucidate the efficacy of unsupervised, at-home VF testing for glaucoma patients.
Talk about these remote patient monitoring devices.
The Olleyes VisuALL VRP is a commercially available VR headset with two independent 4K resolution displays that allow each eye to be presented with stimuli separately with a field of view up to 100°.
- Note: A web-enabled device is required for test management and administration.
The iCare HOME handheld tonometer is a second-generation device that uses a disposable probe to measure eye pressure via rebound tonometry.
- Note: The iCare HOME2 tonometer was released after the completion of this study and features a screen that can better convey error messages and has a more ergonomic design.
Now talk about the study.
In this pilot study, investigators enrolled 15 participants (mean age: 60.2 years; 73.3% male) and trained them to use two FDA-registered or approved devices before conducting self-tests at home over three consecutive days.
VRP VF tests were performed once daily, and the iCare HOME IOP measurements were collected four times daily per eye—with each measurement requiring the probe to rebound off the eye six times—equating to the device contacting the eye 48 times per day.
The results were compared with:
- One in-clinic Humphrey Field Analyzer (HFA) VF test performed on the day of device training
- iCare HOME tonometer measurements by the trainer
- The last five Goldmann applanation tonometer (GAT) results
Findings?
In total, 9 participants (60%) completed the study, and 62.5% of participants adhered to the testing schedule for three consecutive days.
The 6 excluded participants could not self-measure using the iCare HOME device, and this was particularly noticeable in patients with central VF loss, making it less useful for patients with more advanced glaucoma.
There was a significant correlation between the average mean deviation (MD) values of the at-home VRP tests and in-clinic HFA testing (r2 = 0.8793, P < 0.001).
- Further: The average of the sensitivities in five of the six Garway-Heath sectors were significantly correlated.
Anything else?
VRP test duration was shorter than in-clinic HFA testing (P < 0.001), and at-home tonometry yielded statistically similar values compared to trainer-obtained iCare HOME values.
The mean and range of at-home tonometry were also statistically similar to those for in-clinic GAT, but at-home tonometry demonstrated higher maximum IOP values (P = 0.0429).
Expert opinion?
On average, the at-home iCare HOME measurements agreed with the in-clinic iCare HOME and GAT measurements but captured statistically significant higher pressures that were not visible in the clinic.
What this suggested: “At-home testing during or outside of office hours may provide information to physicians that could warrant a change in care or further evaluation,” the study authors explained.
Limitations?
These included:
- The small cohort size
- Each eye was treated as a subject, and analyses assumed that each subject was independent of one another; however, there is some degree of inter-eye correlation in IOP and VF defects
- This study did not include reminders for patients to perform their at-home tests
- Glaucoma medication adherence in relation to device use was not analyzed
- The study design excluded patients who were unable to complete data collection for either device
Take home.
These findings suggest that unsupervised, at-home, multi-day glaucoma testing using the iCare HOME tonometer resulted in the capture of higher maximum IOPs than in the clinic and good MD correlation of VRP compared to HFA.
However: 40% of participants could not self-measure IOP using the iCare HOME tonometer.