Lense thicknesses interchangable?

[Irving]

Pardon me if this question seems ridiculous. I am a layman trying to find out as much information as possible about the mysterious world of progressive lenses. When my eyes were examined in the opticians' shop, I was given a prescription for a 1.6 lense. Would the same prescription be valid for a 1.5 lense? Or would the prescription need to be modified?

Here in Spain, they mentioned the possibility of "thinning" a lense. Is this practive advisable, or is merely for asthetic purposes? Thanks.

[chip anderson]

Mostly asthetic and weight. Yes, precription would be the same.

[QDO1]

Your prescription will be a dioptric value, and not specify an Index. If the prescription has an index on it then it is a suggestion, rather than a direction. Most progressive designs will be the same thickness as each other in the same index and mounting. The main variant would be the ammounts of prism thinning in the design of any compared set of lenses