The Pinch/Punch filter can be used either in small amounts to correct or enhance portraits, or in extreme amounts to create bizarre effects.
Pinch creates a concave spherical distortion (squeezes an area) and Punch creates convex spherical distortion (bulges an area).
This filter can be applied as a non-destructive, live filter. It can be accessed via the Layer menu, from the New Live Filter Layer category.
The following settings can be adjusted in the filter dialog: