- astigmatism, astigmia - (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea
--1 is a kind of ametropia
--1 has particulars: keratectasia; keratoconus - astigmatism, astigmia - (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point
--2 is a kind of condition, status