Question

why goggle lenses do not have any power even though their surfaces are curved?

Answer 1

Sunglasses don't have power becausethe lenses are two curved surfaces with the same radius of curvature. Theconvex (outside) surface produces magnification, and the concave (inner)surface (the surface near the eye) produces demagnification of the same strength and the two cancel.

Answer 2

Here it is..
》As convex surface in our lenses produce magnification and the other concave surface produce demagnification and as we know that..
Both are canceled by each other hence,goggle lenses do not have any power even through their surfaces curved.