astigmatism
1. (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people • Syn: astigmia • Derivationally related forms: astigmatic (for: astigmia), astigmatic • Topics: ophthalmology • Hypernyms: ametropia • Hyponyms: keratectasia, keratoconus 2. (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point • Syn: astigmia • Ant: stigmatism • Derivationally related forms: astigmatic (for: astigmia), astigmatic • Topics: optics • Hypernyms: condition, status
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