Pupillary examination remains one of the most fundamental components of the neurological assessment. In the neurocritical care unit, subtle changes in pupil size or reactivity can serve as early indicators of a wide range of pathophysiologic processes. For decades, clinicians have relied on subjective visual estimation using a penlight, an approach that is fast and familiar, but also highly variable between examiners and sensitive to environmental factors such as lighting, patient positioning, and examiner experience.

The limitations of subjective assessment have driven the growth of objective pupillometry, aiming to standardize measurements, reduce observer variability, and create a quantifiable neuromonitoring parameter like vital signs. Infrared pupillometers have become increasingly common in ICUs because they provide precise measurements of pupil diameter, latency, constriction velocity, dilation velocity, and other dynamic metrics. These devices have been useful in detecting early deterioration, aiding neuroprognostication after cardiac arrest and offering reproducible data for trending over time. However, they can be costly, require maintenance, and often rely on dedicated hardware that is not always immediately accessible at the bedside.

A New Direction: Smartphone Enabled Pupillometry

With advances in computer vision and machine learning, newer approaches have emerged that aim to deliver objective pupillometry using more universal tools, such as smartphones. One example is the Solvemed PuRe Pupillometer, which represents an effort to shift from hardware dependent pupillometry toward a software-based solution.

This system uses the smartphone camera to capture a brief video of the pupil response and applies AI based segmentation algorithms to measure pupil size and reactivity. The software is designed to account for variations in ambient lighting, an important challenge in pupillometry, by using computational corrections that allow more consistent measurements across clinical environments. A key output is the “PuRe Score,” a numerical scale intended to quantify overall pupil reactivity.

Unlike traditional infrared pupillometers, this approach does not rely on additional physical equipment, which may make assessments more accessible in settings where hardware devices are limited or unavailable. Because it is software based, it can also integrate directly with electronic medical record systems and facilitate rapid documentation.

Potential Clinical Applications and Considerations

For neurocritical care teams, the potential advantages of smartphone based pupillometry include portability, rapid availability, and reduced dependence on specialized hardware. These features may be particularly useful in emergency departments, smaller hospitals, or during patient transport.

However, software based pupillometry comes with several limitations. Variability in smartphone hardware and user technique can influence image quality and pupil detection, with potential effects on measurement reliability. Successful adoption therefore depends on thoughtful workflow integration, device compatibility, and validation within an institution’s own patient population.  Given these factors, smartphone-based approaches should be evaluated alongside standard infrared pupillometry in varied clinical contexts to determine their respective strengths.

Conclusion

Objective pupillometry has become an increasingly important component of neurological monitoring. With ongoing advances in technology, clinicians now have access to a broader range of tools, from established infrared pupillometers to newer software-based approach, each designed to enhance the precision, repeatability, and accessibility of pupillary assessment. Smartphone-enabled solutions, such as Solvemed’s PuRe platform, represent one such approach, offering an alternative way to obtain quantitative pupillary reactivity data. As clinical research and validation efforts continue, these innovations may help extend the use of objective pupillometry and support more consistent neurological assessment across a variety of care settings.