astigmatism

n [U] defect in an eye or a lens that prevents correct focusing （眼睛）散光, 乱视; （透镜）像散性, 像散现象.

assume, assumed, assumption, assurance, assure, assure sb. of sth., assured, assured (also self-assured), assuredly, assuredness, AST, astatine, aster, asterisk, astern, astern of, asteroid, asthma, asthmatic, astigmatic, astir, astonish, astonished, astonishing, astonishingly, astonishment, astound, astounding, astrakhan, astral, astray, astride, astringency, astringent, astro-, astrolabe, astrologer, astrological, astrology, astronaut,