IF the Thinning prism be cancelled ,what will be affected except cosmetic?

[copland]

IF the Thinning prism be cancelled ,what will be affected except cosmetic?

[braheem24]

Depends on material, rx, patient needs.

[copland]

I mean if the prism be cancelled in the progressive lenses, that would affect the adaptability of patient?

[braheem24]

Possibly, bd prism in a high plus rx not only helps cosmetics but also alleviates some of the chromatic aberration in the reading, then again it also introduces more CA in the distance. In an aniso rx thinning may help alleviate some of the vertical imbalance in the near, again it's done at the expense of the distance vision.

This is all theoretical, hence the reason for b&m providers.

[copland]

Thank you for your reply. and what means the CA?

[braheem24]

Ca= chromatic aberration