<< When we read, our eyes don’t scan a page smoothly but perform a series of jumps, darting from one section of text to another. After each jump, known as a saccade, the pupil typically wobbles for a moment. Now researchers have developed a model for this wobble that involves only physical characteristics of the eyeball >>
Why Your Pupils Wobble. Apr 27, 2018
https://physics.aps.org/articles/v11/41
Bouzat S, Freije ML, et al. Inertial Movements of the Iris as the Origin of Postsaccadic Oscillations. Phys Rev Lett. 120, 178101. doi: 10.1103/PhysRevLett.120.178101 Apr 27, 2018.
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.178101
Also
2146 - is not as simple as one might think (chaos in reading). Sep11, 2007.
http://inkpi.blogspot.it/2007/09/2146-is-not-as-simple-as-one-might.html