Aim To investigate the effects of physical exertion on pupillary light reflex (PLR) metrics in sports participants, with the aim of determining whether exercise-induced changes could potentially confound concussion assessment using PLR.

Materials and methods Twenty-five adult rugby players underwent PLR assessment, using the MindMirror™ smartphone application, before and after a 30-55 minute rugby practice session or game. PLR metrics included latency, maximum and minimum pupil diameters, maximum constriction velocity, and pupil size correlation. Paired t-tests were used to compare pre- and post-exertion PLR metrics.

Results No statistically significant differences were observed between pre- and post-exertion assessments in any of the measured PLR metrics (p > 0.05 for all metrics). The most notable, though still non-significant, change was in maximum constriction velocity (mean difference: 1.47 mm/s, p = 0.08 for pupil 1; 1.09 mm/s, p = 0.27 for pupil 2).

Conclusion This study suggests that PLR metrics, as measured by a smartphone-based pupillometer, do not appear to be affected by rugby-related exertion. These findings support the potential use of PLR assessment in concussion screening protocols without the need to account for exercise-induced changes. However, further research with larger sample sizes and in full-contact situations is needed to confirm these results and their applicability in concussion assessment.

Plain language summary Pupil size and reactivity have been critical components of the clinical assessment of patients with head injury and concussion for decades. Pupillary examination may provide critical information related to new or worsening intracranial pathology, and quantitative PLR examination is increasingly used outside of the hospital setting, particularly for concussion assessment in sports medicine. Exertion-dependent changes could confound valid measurement, however, and compromise the detection of concussion, so we investigated PLR assessment with the MindMirror™ smartphone application. We found no systematic differences in PLR variables between exertion and non-exertion groups.

Tweetable abstract A novel smartphone-based AI tool did not reveal exertion-related differences in pupillary light reflex measurement in rugby players.

Statements and Declarations

Non-financial interests: Dr Davies and Professor Middleton act as unpaid medical advisors to MindMirror inc.

Financial interests: Mr. Buzytsky is a cofounder and CTO of MindMirror, Inc.

Ethics approval This study was performed in line with the principles of the Declaration of Helsinki, and under the SWSLHD Human Research Ethics Application (HREA) approval 2023/ETH00741: The Australian Pupillary Light Response Registry (APLRR). Informed consent was obtained from all volunteers.

Non-financial interests: Dr Davies and Professor Middleton act as unpaid medical advisors to MindMirror inc. Financial interests: Mr. Buzytsky is a cofounder and CTO of MindMirror, Inc.

This study did not receive any funding

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study was performed in line with the principles of the Declaration of Helsinki, and under the South Western Sydney Local health district (SWSLHD) Human Research Ethics Application (HREA) approval 2023/ETH00741: The Australian Pupillary Light Response Registry (APLRR). Informed consent was obtained from all volunteers.

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Yes

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All data produced in the present study are available upon reasonable request to the authors