Research suggests small pupil size shifts could offer insights into moment-to-moment attention in children with ADHD, though not yet a standalone diagnostic tool, with medication influencing pupil patterns.
A new study in Scientific Reports suggests that tiny shifts in pupil size may offer clues about moment-to-moment attention in children with ADHD, although researchers say the measure is far from ready to stand alone as a diagnostic tool. The paper, published on 9 September 2026, examined whether pupil dynamics during a working-memory task tracked performance and whether stimulant treatment altered that pattern.
The researchers followed 50 children in Chile, aged 10 to 12, including 28 with ADHD and 22 without the disorder. Using an eye-tracking system that recorded pupil movement 1,000 times a second, the children completed a 30-minute visual memory exercise while scientists compared how their pupils changed from one question to the next.
Among children with ADHD who were not taking medication, pupil size varied more from trial to trial than it did in children without ADHD, a difference the researchers estimated at about 23%. That gap did not remain statistically significant after correction, but the same group also answered more quickly while making more mistakes, suggesting a speed-accuracy trade-off. In the 17 children tested both on and off medication, methylphenidate was linked with steadier pupil patterns and stronger dilation during decision-making, bringing their responses closer to those seen in children without ADHD.
The findings build on earlier work, including a 2017 Scientific Reports study and related research indexed by PubMed, which also linked pupil size to performance and reaction-time variability in children with ADHD. Separate work in European Psychiatry found that methylphenidate can significantly alter pupil diameter, reinforcing the idea that medication may influence these eye-based measures. Even so, the authors and earlier researchers stress that pupil size reflects more than attention alone, meaning it may one day support assessment, but not replace established cognitive and clinical testing.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
