[Klaus]

The delta between the solid and dotted curves at 30 lp/mm is fairly marginal so astigmatism is quite low.

Astigmatism = whether the rays of the sagittal plane are focused at a different point than light rays in the tangential plane. If the curves don't match, you will see a line instead of a point (center to corner direction)

Coma = rays don't focus in a point on the plane resulting in a comet-like form.

I haven't thought about coma too much so far but the corner MTFs are high so I'd conclude that the coma is low.