I have about -4.5 spherical and 0.75 cylyindrical (eyes aren't exactly the same but that's about the average). I chose to weaken the spherical on each side by

I have about -4.5 spherical and 0.75 cylyindrical (eyes aren't exactly the same but that's about the average). I chose to weaken the spherical on each side by 1, 1.25 and 1.5 (couldn't decide after holding reading glasses in front of my normal glasses at the grocery store). I didn't correspondingly weaken the cylindrical, though probably should have. Ordered all three from Zenni. If you get high-index plastic but no fancy coatings and a basic frame, this is really cheap enough to be worth experimenting, and they don't care if you upload hacked "experimental" prescriptions. About the only catch is you need your pupil distance. I got it written down for me at a couple of eye exams, a Costco optician measured it using a gadget he had, and I measured it by a method I thought up myself - just look at something distant through binoculars and adjust until the image circles merge, then measure center-to-center on the eyepiece lenses. ALL the numbers ended up different. So I just kinda picked the average. Not very scientific, but all three glasses are OK, and the ones I like best, I really wear them all the time now except for driving.