Astigmatism means that the part of our eye is more myopic than our whole myopic eye. for example, if our eyes are -3sph and -1.25cyl it means that there are parts of our eyes that are more myopic -1.25D than -3D.
but why do we need less cyl correction in differentials?
Doesn’t looking at close range with a diff with less cyl correction still leave a directional blur?
or reducing the cyl in the differential is only used if we want to improve astigmatism?