SONDA is cleared for clinical use in glaucoma only. Every other application on this page is for research purposes and is not part of the cleared clinical use.
The science
One Signal, Many Patterns
Traditional psychophysical methods for estimating visual sensitivity, and conventional eye-tracking paradigms, require patients to perform many repetitive trials before a meaningful metric emerges. This is taxing and time-consuming, and it rests on the assumption that samples are independent in time.
Visual and neural processes are dynamic. SONDA’s patented method, based on continuous psychophysics, captures this dynamic behaviour and translates it into patterns that can be associated with different pathologies.
The method
Functional Oculomics
While structural oculomics reads static images of the eye to assess its anatomy, functional oculomics reads eye behaviour to measure the dynamic processes behind vision. SONDA treats eye movement as a continuously varying signal rather than a sequence of discrete events, and derives its features accordingly. The result is a powerful, multi-purpose, rapid test.
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One continuous signal
The eye follows a moving target for about two minutes. The recording is kept whole, one continuously varying signal per axis, rather than cut into fixations, pursuits and saccades.
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Features of the signal
Stimulus and eye are compared as time series: how closely and with what delay one follows the other, and how far the two drift apart. The features are built for a continuous signal; the spatio-temporal properties shown here are examples of them.
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The oculomotor fingerprint
Normalised against age-matched controls, the features form one oculomotor fingerprint. A healthy fingerprint stays close to the median; how it departs from the median differs between conditions, which is what makes it a candidate digital biomarker.
Why a continuous signal
Validity
Following a moving target estimates the same perceptual variables as classical forced-choice psychophysics, and the two agree closely where they have been compared. SONDA measures visual function directly, through the movement of the eyes.
Efficiency
Two minutes of continuous tracking yield tens of thousands of data points, where a forced-choice test yields one per trial. This is why a whole set of parameters can be estimated from a single short recording.
Temporal resolution
The response is recorded as it unfolds, so delays and dynamics are part of the measurement. Processing differences of a few milliseconds can be resolved within one person, and not only between groups.
Accessibility
Following a target requires no instructions, no training and no button. The method works for children and for patients with cognitive or motor impairment, who often cannot complete a classical task.
Burge & Bonnen, Continuous psychophysics: past, present, future. Trends Cogn Sci 2025;29(5):481–493. SONDA is among the clinical applications discussed.
Digital biomarker
Different Conditions, Different Patterns
The oculomotor fingerprint of a healthy visual system has a characteristic shape. Departures from it differ between conditions: which properties change, and by how much. Reading the shape of the departure is what makes one recording a digital biomarker for more than one question.
Healthy control
Fifty age-matched controls define the reference: 0 is the group median and the light band spans ±2 normalised IQR. This control’s own fingerprint stays inside the band on every parameter.
Healthy control
Data pooled from Grillini et al. 2020, Demaria et al. 2020 and Vrijling et al. 2025. See the peer-reviewed research
Pipeline
Where Each Application Stands
SONDA is cleared for clinical use in glaucoma. Every other clinical application is undergoing research at the stage shown.
Research partners
Work with us on the next application
Peer-reviewed research first; then a conversation about a joint study.