Most sv lenses had the cyl on the front even the first generation plastic lenses followed the norm of the time with front cylinders. All bifocals except some Ultex style had the cyl on the back. Rx’s were written with + cyl because that is what was taught in school to the ophthalmologist’s who only used a trial frame for refractions O.D. Used a phoropter so they refracted in minus cyl form.
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