There are three columns of numbers on your prescription, labelled Sph, Cyl and Axis (or sometimes the actual words). It's the numbers under Cyl that concern your astigmatism, so if the -4.00 isn't that number then you still have that option. A Cyl as high as -4 doesn't leave you with many options, though. However, that would be an unusually high Cyl so yeah, double check your prescription. Glad you were able to find a lens style that worked, though.