It is now clear (it wasn’t 10 years ago) that fixational movements of the eye are important when measuring the ocular aberrations, becuase they bias the measurement (for more info read documents one and two).The easiest way to measure that movements, just by computing the displacement of the centroid of the aberrometric image.
I show you in this video an image of the aberrometric image (on the left) and an image of the pupil of the eye (right) to show you that when the eye moves the aberrometric image do the same.
The advantages of using the aberrometric image to measure the movements of the eye are:
– Simple (no aditional instrumentation, setups or whatever)
– synchronization (the tracking is made simultaneously with the aberrometric measurement)
So if you are looking for this characteristics, just try the Pupil tracking Hartmann-Shack