Clinical Neuro-Optic Research Initiative
The pupil is a two-millimetre window onto the brainstem.
CNRI builds instruments that read it — the pupillary light reflex frame by frame, and the static shape of the pupil margin — and write down what they measured, in units, with the assumptions attached.
Everything runs on the device in front of the patient. No cloud, no account, no telemetry — and no patient record that leaves the room.
- Pupil diameter sampled every frame, five-point median smoothed
- Dark-adapted baseline the reference every amplitude is measured from
- Applications
- Research · Neuro · Drug Monitor
- Platforms
- Windows · Android · macOS · iOS
- Languages
- 18 languages, 20 locales
- Patient data
- Local to the device. Always.
Three applications, one measurement engine
They share a capture stack, a pupil-detection pipeline and an export format. They differ in what they are pointed at: one reads the static pupil and iris, one reads the reflex over time, and the third is a cut-down build we are still testing.
Static morphology, plus PLR
Pupil–iris ratio, ellipseness, decentration, pupil-margin zone findings and the collarette, with age-normalised reference bands and a longitudinal timeline across every scan on file.
What it measures PupilMetrics NeuroThe reflex, over time
Dark-adapted baseline, calibrated flash, latency, constriction amplitude and velocity, T75 recovery and PIPR — plus the three-trial habituation protocol and the Drug Effect Monitor built on it.
PLR, habituation & drug effect PupilCheck — betaThe Android tester build
A cut-down single-purpose build we are recruiting testers for. Sideload, run a handful of captures, tell us where it falls over.
Join the betaThe reflex arc runs straight through the midbrain
Light reaches the retina, the signal crosses to the pretectal nucleus, and two efferent limbs — one parasympathetic, one sympathetic — set the size of the pupil against each other. Every one of those relays sits somewhere a clinician would like to be able to see.
What disturbs the arc shows up as a number
Direct brainstem injury. The pretectal and Edinger–Westphal nuclei lie in the midbrain, exposed to the rotational acceleration that is the hallmark of concussion. Even mild diffuse axonal injury slows PLR latency before clinical signs appear.
Rising intracranial pressure. Herniation compresses CN III. The earliest sign is a sluggish, asymmetric reflex — measurable before the pupil looks abnormal to the eye.
Autonomic dysregulation. Disruption of the hypothalamic–brainstem network produces abnormal resting size, delayed sympathetic redilatation and increased pupil unrest.
Loss of cortical modulation. The frontal lobe normally damps the reflex across repeated stimuli. Losing that input produces either excessive habituation or paradoxical sensitisation — which is what the three-trial protocol is for.
One flash is a measurement. Three are a pattern.
In a healthy, unmedicated brain the reflex damps slightly across repeated identical stimuli. The size of that damping is the habituation index, and CNS-active drugs push it in class-specific directions — which a single trial cannot see at all.
- Trial 1 full amplitude, the reference
- Trial 2 after two minutes' rest
- Trial 3 the amplitude the index is computed from
| HI range | Interpretation |
|---|---|
| Negative | Sensitisation — a paradoxical increase across trials |
| 0–15% | Normal cortical modulation |
| 15–30% | Moderate habituation — warrants monitoring |
| >30% | Excessive habituation — disrupted cortico-midbrain feedback |
Thresholds are taken from the apps' own built-in manual, so the site and the software say the same thing. The Drug Effect Monitor is this protocol with a longer flash and an extended recovery window.
Who we are and what we are trying to settle
Mission
CNRI advances the science of pupil-based neurodiagnostics by preserving historic clinical insights, developing modern analytic tools, and conducting rigorous research into the relationship between ocular micro-structures and systemic health. Our aim is to validate and expand neuro-optic biomarkers that can support early detection, monitoring and non-invasive assessment of autonomic and neurological function.
Vision
A future in which standardised neuro-optic biomarkers complement mainstream clinical assessment — earlier detection of imbalance, more personalised care, and a deeper understanding of the body's autonomic responses.
We want to be the institution that bridges historical clinical investigation and modern scientific rigour, so that decades of prior work are not lost but elevated, validated and expanded with contemporary technology.
Where the work comes from
The observational base is a body of clinical work carried out in Russia and Korea through the 1980s and 1990s. CNRI brings modern imaging, pattern recognition and data-driven method to it, to investigate how far subtle pupil irregularities do or do not reflect autonomic and neurological function.
We conduct non-invasive human studies, develop the analytic frameworks, and collaborate with researchers internationally.
What that inheritance does not buy
A historical association is a hypothesis with a long paper trail, not a validated finding. The zone-to-organ correspondences in PupilMetrics Research are labelled in the software as research-derived theoretical frameworks, and they are reported that way here too.
None of our instruments is a cleared medical device. Nothing in them has been validated against a reference pupillometer. The list of studies that would be needed is published rather than glossed.
Do you have a human pupil research project?
We collaborate on study design, provide instrumented builds with machine-readable export, and are interested in anyone in a position to run the method-comparison work our own instruments still need.