Hello, I am an optician apprentice and lab technician in lenscrafters, (at least until they close all the labs soon) and I have a question about aspheric lenses. I am a hyperope, so I'm sure you all know I have a plus prescription. Irecently had a new pair of glasses made with aspheric lenses, and I am used to spheric lenses, however I notice a discernible lessening of power in the periphery. I am able to accommodate to counter it, but I was under the impression that aspheric lenses are supposed to actually have a more uniform power across the entire lens. I verified with the lensometer and the power does in fact gradually change, at about 10 mm from the optic center the power is about .25 diopter lower than in the center, and gradually reduces to about .50 -.75 less than the prescription at the far edges of the lens. I know that with spheric plusses the increase in vertex distance creates a slight increase in power in the periphery, and that the changing front surface of the lens of an aspheric is supposed to correct this. So shouldn't the power be uniform across the entire aspheric lens and not reduced by a quarter to half or even .75 diopter as I look in the periphery? Also, they were made from semi finished lens blanks with a 4 base, but isn't the change in the front surface of an aspheric lens supposed to be modified depending on the prescription? Like for a plus lens the surface becomes flatter in periphery and steeper in minuses? So doesn't using a semi finished lens defeat the purpose of an aspheric design? at least as far as power changing in the periphery is concerned. I mean if you use the same blank to generate a plus and a minus prescription, wouldn't this cause the change in power I'm seeing in the periphery? It seems like it's the exact opposite of the result I should be having with an aspheric lens.