Are the vision correction lenses in your masks an after market "stick on"?
No. All the standard vision correcting masks offered by Dive Gear Express have the correction ground into the lenses themselves. The correction is not aftermarket 'stick on', each of the lenses are ground just like you would expect on a pair of eyeglasses. Please note that the bifocal gauge reader versions are a two layer lens bonded at the factory during manufacture.