A workman using tools calibrated for spectacle crown glass, n=1.523, is instructed to produce the lens
+3.50DS/-1.00DCx180 in toric form with a +8.50 base curve. After working the sphere curve he discoveres that, in error he had used glass of n=1.618. Which toric tool must be used to work on toroidal surface in order that the lens may have finally the correct power?
Thank you for any kind of help.
Bookmarks