Which glasses prescription is worse?

Question

some person(nearsided) with -5,50(in both sides) D with -2D astigmatism

or sum1 which has -7,50D(in both sides) and does not have asigmatism at all

Answer 1

I agree with Spectacle.  But myopia and astigmatism cause different kinds of distortion, so it's hard to make a clear comparison (pun intended).  The "sum1" with the -7.50 prescription would have a greater overall blur than the -5.50 person.  Two diopters of astigmatism, though, is a fair amount and will cause things to look slanted or streaky.  Combining this with the blur already from myopia causes quite a bit of distortion.

Answer 2

The latter is the stronger Rx, as the first one has a spherical equivalent of -6.50 so it is still a whole diopter less over all than the -7.50.