Cylinder Distribution on Progressive Lenses

Written by Optician Club on . Posted in Conventional Progressive Lenses, Progressive Lenses

This section will give you an idea about  Cylinder distribution on progressive lenses.

The Progressive umbilical line determines how the lens behaves in a region around this line, that we call Minkwitz zone.

Cylinder distribution

Minkwitz zone does not depend neither on the PAL model or the design. Two lenses with the same umbilical profile will have exactly the same Minkwitz zone.

Cylinder distribution

Outside the Minkwitz zone, the astigmatism can be almost distributed freely. We can concentrate it (the gradient and maximum level of unwanted astigmatism increases) or we can spread it, (the gradient and maximum level of unwanted astigmatism decreases).

§Results on concentrating astigmatism (Hard design):
–More gradient (more distortion), higher maximum astigmatism. More difficult adaptation.
–Higher visual acuity and increase in clarity perception.
§Results on spreading the astigmatism (Soft design):
–Smaller gradient (less distortion) and smaller maximum astigmatism. More comfortable at the beginning and easier adaptation.
–Smaller visual fields and decrease in visual sharpness

For order a progressive lenses with less astigmatism distortion, you can check our related article of Customization of FreeFrom Lenses

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