astigmia
  散光
  astig·mia /-mɪə/ 名詞
  散光
  astigmia
       n 1: (ophthalmology) impaired eyesight resulting usually from
            irregular conformation of the cornea [syn: astigmatism]
       2: (optics) defect in an optical system in which light rays
          from a single point fail to converge in a single focal
          point [syn: astigmatism] [ant: stigmatism]