i went with bifocals a year ago, my doctor said that i would probably continue down the slope till I reached 2-2 1/2 magnification. I started out with one and sure enough a year later I need to go back and get stronger. If your just starting on this path, I would pass on the prescription sunglasses etc for a couple of years and buy a clip on magnifier till your eyes settle into where they are going to stay for a while.
Eric
"Complexity is easy; Simplicity is difficult."
Georgy Shragin
Designer of ppsh41 sub machine gun