ASPHERIC LENSES
 


Aspheric lenses are also specified in another way using what is called the p-value.  Where:

	p=1-e

Relationship of p-value to surface shape:

p=1.0		spherical surface
1<p>0		elliptical surface
p=0		   parabolic surface
p<0		    hyperbolic surface


Q-value is also sometimes used.

  Q = -e