a lens with two different optical powers at right angles to each other for the correction of astigmatism.
Used to correct astigmatism, a lens containing a cylindrical (or out-of-round) surface. A toric surface is ground with two different curves at right angles to each other with the weaker of the two curves located on the cylinder's axis. Go to Top
A curved lens on which one of the surfaces has two powers worked in order to correct astigmatism.
Refers to any cylindrical lens having a base curve other than zero (flat).