Abstract
Background:
Sport-related concussions (SRCs) are a common concern among young athletes due to their frequency and potential for long-term consequences. Diagnosis of SRC is challenging and is often based on subjective factors and sideline assessment tools, which can be inconsistent in young athletes and those with a history of previous concussions. The use of quantitative pupillometry (QP) to measure the pupillary light reflex (PLR) after concussions offers a promising objective tool for detecting concussion-related autonomic dysfunction and may aid return-to-play decisions. This systematic review evaluates current evidence on QP use in athletes with SRC.
Hypothesis:
We hypothesize that QP reveals consistent and measurable alterations in the PLR among individuals with sport-related concussion compared to healthy controls. Variability in measurement protocols and reported outcomes is expected given the emerging nature of this research area.
Methods:
Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a systematic search of PubMed, Embase, Cochrane Library, and SPORTDiscus was conducted. Studies using QP in athletes or active military personnel with SRC were included. The Joanna Briggs Institute (JBI) critical appraisal tool was used to assess risk of bias.
Results:
Of 2,401 results identified in the database search, nine studies were included. Collectively, 488 individuals with current or prior SRC were assessed. Eight studies reported statistically significant differences in QP measurements between concussed individuals and healthy controls. Average and maximum pupil constriction velocities were consistently reduced in concussed cohorts. Additional QP metrics commonly altered included increased constriction latency and prolonged 75% recovery time. In two studies, greater constriction velocity and larger total change in pupil diameter were associated with faster symptom resolution and earlier return to military duty.
Conclusion:
Quantitative pupillometry is a promising objective tool for assessing SRC severity, monitoring recovery, and guiding return-to-play decisions. It offers clear advantages over symptom-based evaluations and may have particular utility in youth athletes for whom other diagnostic tools may be less reliable. Validated smartphone applications could enable rapid, low-cost sideline evaluations. However, further research is needed to address variability in measurement protocols and outcomes.