There are computer based programs that can track eye movements, and some that track tiny head movements, both of which can provide support for (but not prove) an ADHD diagnosis.

I think that Google, Apple, and others probably can make quite accurate diagnoses of ADHD, through monitoring eye movement, head movement, overall hyperactivity, as well as seeing how readily one is distracted by information on the screen, how long one pursues a line of inquiry, and how responsive to external sounds and other information while doing such surfaces. But so far, they're not sharing their algorithms for such.