A recent study reveals subtle pupil responses may indicate attention fluctuations in children with ADHD, highlighting potential future tools for assessment alongside traditional methods.
Scientists have found a subtle sign that could help reveal how attention shifts in children with ADHD: tiny changes in the pupils as the brain works through a task. The findings, published in Scientific Reports on 9 September 2026, do not offer a stand-alone test. But they add to a growing body of research suggesting that pupil dynamics may provide an objective clue to attention, effort and engagement.
The study reanalysed eye-tracking data from 50 children in Chile aged about 10 to 12, including 28 with combined-type ADHD and 22 without a neurodevelopmental diagnosis. The children completed a memory task in which they had to remember dot positions on a grid, ignore a distraction and decide whether a new dot appeared in a previously seen spot. While they worked, an eye tracker recorded pupil diameter 1,000 times a second. Researchers at the Indraprastha Institute of Information Technology Delhi then examined not just average pupil size, but how consistently each child’s pupils reacted from one attempt to the next.
That approach mattered. After adjusting for age, IQ and task difficulty, the researchers estimated that unmedicated children with ADHD showed about 23% greater trial-to-trial variability in pupil response than controls. Within each individual attempt, however, their pupils fluctuated less than those of the comparison group, suggesting that different measures of pupil behaviour may capture different aspects of attention. Among the unmedicated children with ADHD, greater pupil variability was also associated with lower accuracy on the task, implying that the signal may reflect shifts in engagement or focus, even if indirectly.
The study also looked at 17 children with ADHD who completed the task twice, once after pausing methylphenidate for 24 hours and once while taking their usual dose. When medicated, their pupils reacted more strongly and were less variable between rounds, with patterns that looked closer to those of the control group. But the researchers urged caution. Methylphenidate can affect the body systems that influence pupil size, so the changes could reflect the drug’s direct physiological effects, improved attention, or both. The team also noted limits in the design, including a small sample, unknown dose details and a gap of roughly six months between sessions.
The findings build on earlier work suggesting that pupil patterns may be useful in ADHD research. Studies published in recent years have explored machine-learning methods that analyse pupillometric data, as well as wavelet-based techniques and other approaches aimed at identifying objective markers of the condition. For now, though, the message from the new work is restrained: pupil tracking may eventually complement interviews, observations and medical assessments, but it cannot replace them. The eyes may not diagnose ADHD, yet they may help show how attention rises, drifts and returns from moment to moment.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
