PuRe Score: Advancing Objective Pupillometry

In today’s fast-paced clinical environment, swiftly and accurately evaluating a patient's neurological status is vital. Yet traditional pupillary assessments—based on visual observation—can be inconsistent and prone to subjective interpretation (Figure 1.). To solve this long-standing challenge, Solvemed Inc. introduces a breakthrough in neurological evaluation: the Pupil Reactivity (PuRe) score.
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‍^{Figure 1. Schematic of pupillary light reflex (PLR) and ambient light influence (Bogucki et al., 2024). Establishing invariance to illumination in the pupillary light reflex (PLR). (A) We recorded the PLR using a Smartphone-based pupillometer. (B) The recording yields pupil diameter as a function of time. The curve can be characterized by eight parameters (see Table 1 for descriptions). Shaded rectangle: flash stimulus window. Below: the rate of change of pupil diameter is used to estimate the velocity parameters. (C) Ambient light conditions significantly alter the baseline pupil diameter. This impacts the dynamics of the pupillary response to light (D) Under bright conditions, the response amplitude is attenuated (lower, pale blue lines), which could potentially be confused with an unreactive pupil (dotted line).}

What Is the PuRe Score?

The PuRe score is a next-generation metric in quantitative pupillometry. Leveraging machine learning algorithms, it compensates for ambient light variations, offering a standardized, objective measurement of pupil reactivity. This innovation ensures more accurate, repeatable results compared to conventional manual methods.

Understanding the PuRe Scale

The PuRe score operates on a scale from 0 to 5, designed to align with clinical assessments (Figure 2.):

• 0 – Non-reactive pupil: a red flag requiring immediate attention.
• <3 – Abnormal or sluggish reactivity: may indicate neurological dysfunction.
• 3–5 – Brisk or normal reactivity: suggests healthy neurological function.

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^{Figure 2. The 0–5 PuRe score scale for classifying pupil reactivity.}

As detailed in Bogucki et al. (2024), the PuRe score delivers a clinically actionable, quantitative view of pupil response.

I routinely use Solvemed’s AI Pupillometer when taking care of critically ill people in the medical, surgical, and cardiac ICU. It's accurate, easy to use, and always available, because it's an app on my phone. I also appreciate the transparency of having an open-source Pupil Reactivity (PuRe) score.

— Dr. Nicholas Mark, M.D., ICU doctor, Providence Swedish

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Backed by Rigorous Science

Developed through extensive clinical validation, the PuRe score has demonstrated robust reliability across diverse lighting conditions (Figure 3.). This advancement enhances diagnostic confidence, especially in critical care, emergency, and neuro-intensive settings.

^{Figure 3. Stability of PuRe scoring across different light intensities (Bogucki et al., 2024).}

Why It Matters

The PuRe score is more than a number—it's a critical step toward objective, real-time neurological assessment. By replacing subjectivity with standardized data, clinicians gain greater diagnostic precision, helping improve patient outcomes and decision-making.

Lighting-invariant quantitative pupillometry marks a new era in pupil assessment. Lighting-corrected parameters are more robust to environmental variations, enabling better differentiation between reactive, sluggish, and unreactive pupils. They enhance the accuracy of pupil reactivity trends - vital for detecting neurological deterioration in critical care - by eliminating artifacts caused by ambient light changes, such as natural diurnal cycles.

This approach ensures reliable assessments across care settings. Using a standard smartphone app without extra hardware, clinicians can perform quantitative pupil evaluations, facilitating wider use in emergency and remote scenarios. Emergency personnel could triage and monitor brain injury patients more effectively, aiding rapid decisions and improving outcomes. Additionally, sharing smartphone-captured data among clinical teams enhances baseline information for diagnosis and treatment planning.

The PuRe score, introduced here as the first lighting-corrected measure of Pupil Reactivity, is clinically applicable, enabling consistent neurological monitoring. Its openly shared formula supports standardization and fosters further research.