Hello everyone. I am sure someone can help me with this. A patient comes in and decides they want a new frame. They want too cut down their old lens too fit this new frame. Usually smaller then their old. How do you determine if the lens will cut down for this frame. Usually they have a bifocal or progressive lens. Is there a formula that I can use for this? And then how do you go about blocking it to cut it down. This Optiboard is a great place!!! I always come here when i need a question answered. I don't feel so stupid. Like I do at work sometimes. Thanks too everyone.