Anastigmat

An Anastigmat or anastigmatic lens is a photographic lens completely corrected for spherical aberration, coma, and astigmatism. Early lenses often included the word Anastigmat in their name to advertise this new feature (Doppel Anastigmat, Voigtländer Anastigmat Skopar, etc.). All modern photographic lenses are close to being anastigmatic.