Transition Lenses

[foreseenfuture]

Hello all,

I'm hunting around for information about transition glasses. My original prescription when I started wearing them six years ago was -1.25 in both eyes. A couple of years later I was told that my eyesight had worsened by 'a very minimal amount' but I don't have that prescription handy. I'm guessing it was -1.5 or something. While my prescription isn't very strong, I'd like my transition glasses to be as minimal as possible. I've stopped wearing glasses altogether except for driving (it says on my license that I legally have to wear them). So I'm wondering what the prescription would probably be for the 20/40 vision I need for driving. Should I just go with the -1.25, or can I go higher, like -1? -.75?

Thanks for your help!