An optical system with<unk> is one where rays that propagate in two perpendicular planes have different foci. If an optical system with<unk> is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances. The term comes from the Greek α- (a-) meaning "without" and στίγμα (stigma), "a mark, spot, puncture".
Astigmatism 
Paragrammatism
Apophlegmatism
Agrammatism
Social-emotional agnosia
Boanthropy
Integrative agnosia
Visuospatial dysgnosia