Hey George,
Those lenses, I believe they are called 'readables' are for times when you do little reading and need the bottom part to have the same prescription as the top. I have two pair, one pair for indoors and the other pair are darkglasses for working and driving outdoors. I love em! It does take awhile to get used to moving you head to read but, since they aren't really meant to be your primary 'reading glasses' it's no big deal.
My reading glasses are called "progressives" or "computer glasses" which allows clear vision from about 4', looking out the top, to 6", looking from the very bottom. Best of all, no bi-focal lines to worry about. They are a little expensive but worth the price.
Take care,
Pete
"Maybe the problems of two people don't amount to a hill of beans. But this is our hill. And these are our beans!"
- Lt. Frank Drebin
