When the exit pupil gets above 7mm, unless a person's iris dilates to an unusual degree, all that's happening is the front side of the eye is being illuminated around the pupil. A 10mm exit pupil doesn't get more light to the sensor, the retina.
I don't dispute that but the increased exit pupil over 7mm still provides a distinct improvement in clarity with good glass.
Anybody who's had a slow recovery from PRK can attest to the importance of the distinction between clarity and visibility.
