I have a +4.25 with a 2.50 add that I promised thin lenses; she ordered transitions ft drill-mount and I find out no aspheric blank is made in a drillable material. 1.56 does not count in my book as a worthwhile option.
I asked my lab to surface on a digital machine as a blend, but they are not set up to run on an apsheric blank either. They ran a set and got a low add power after bumping it up, but we are wondering what the formula might be that would get us closer than we are. They are expensive blanks to play with for demo's.

The problem is that each curve on an Aspheric lens has a different drop causing the add power to come out differently on any given RX based on the add power and curve being used. If we had a formula to calculate the add power, we might be in good shape.

Thanks for any help and this is the next generation of free form when they can utilize and aspheric blank when it makes sense.


Craig