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PLEASANTON, Calif. — This year, RadiusXR has been recognized by Fast Company in their annual ranking of The World’s Most Innovative Companies. Fast Company honored RadiusXR as a top ten innovator in the medical devices category, “for bringing flexibility to eye exams.”
Monitoring visual field change over time is central to glaucoma care. Clinicians are trying to answer two essential questions: is the visual field worsening, and if so, where and how fast?
Visual field testing is inherently variable. Patient attention, fatigue, learning effects, and measurement noise all contribute to fluctuation. Distinguishing true deterioration from normal variability remains one of the most difficult aspects of longitudinal interpretation.¹
To address this challenge, RadiusXR® has implemented pointwise progression analysis. The goal is not to simplify progression into a single number, but to make longitudinal change more visible, more transparent, and more interpretable at the level of individual test locations.
Visual field progression analysis generally falls into two categories: trend-based and event-based.
Trend-based analysis uses linear regression to measure change over time in summary metrics such as mean deviation, pattern standard deviation, or visual field index. It produces a rate of change, typically expressed in decibels per year.
Event-based analysis compares baseline tests with follow-up tests to determine whether an “event” has occurred. A widely used example is Guided Progression Analysis® (GPA®), which defines an event as a statistically significant change at a certain number of test locations (e.g., 5 locations in 5-point GPA).
GPA uses a proprietary normative database to determine statistical significance. Instead of attempting to replicate this proprietary normative database, RadiusXR implements a pointwise progression analysis that combines both trend-based and event-based methods.
In RadiusXR’s pointwise progression analysis, linear regression (trend-based) is applied at each test location, and a previously validated permutation method (PoPLR) combined with an evidence-based threshold (a minimum rate of change used to reduce the effect of measurement noise) defines whether the rate of change is statistically significant.
The result is a spatial map of rate-of-change values at each test location within the visual field rather than a single global metric. Unlike GPA, in RadiusXR’s pointwise progression analysis, no decision is made on clinical significance. There is no minimum number of points required to show statistically significant rates of change to define an “event” because the spatial distribution of points matters. The determination of clinical relevance remains with the clinician.
Even advanced statistical methods depend on sufficient data.
A large simulation study using real-world clinical datasets demonstrated that diagnostic accuracy for detecting moderate and rapid visual field worsening over two years is often below 50 percent when testing frequency is low. Accuracy improves as more tests are performed.³
This underscores a key principle. Estimating rates of change with confidence requires adequate longitudinal data. More frequent testing improves the reliability of regression-based slope estimates and strengthens statistical evaluation.
Other modeling work has similarly shown that testing strategy influences how quickly progression can be detected.⁴
Pointwise progression analysis in RadiusXR benefits from the same principle. The more data available, the more stable the slope estimates and permutation-based statistical assessments become.
RadiusXR is transforming visual field testing and eye care with an advanced digital platform that enables unrivaled patient access, streamlines operations, and creates more confidence at the point of care. Our clinically validated portable platform integrates seamlessly into existing systems, with customized software and cloud technology to securely manage data and a lightweight, purpose-built headset. With our advanced wearable technologies, we continue developing disruptive technologies that challenge the healthcare status quo.
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