Search Result for "astigmatism": 
Wordnet 3.0

NOUN (2)

1. (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people;
[syn: astigmatism, astigmia]

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, astigmia]


The Collaborative International Dictionary of English v.0.48:

ametropia \am`e*tro"pi*a\ ([a^]m`[-e]*tr[=o]"p[i^]*[.a]), n. [Gr. 'a`metros irregular + 'w`ps, 'wpo`s, eye.] (Med.) A visual impairment resulting from faulty refraction of light rays in the eye. Subtypes include myopia astigmatism and hyperopia. -- Am`e*trop"ic ([a^]m`[-e]*tr[o^]p"[i^]k), a. AS [1913 Webster +PJC]
The Collaborative International Dictionary of English v.0.48:

Astigmatism \A*stig"ma*tism\, n. [Gr. 'a priv. + ?, ?, a prick of a pointed instrument, a spot, fr. ? to prick: cf. F. astigmatisme.] (Med. & Opt.) A defect of the eye or of a lens, in consequence of which the rays derived from one point are not brought to a single focal point, thus causing imperfect images or indistinctness of vision. [1913 Webster] Note: The term is applied especially to the defect causing images of lines having a certain direction to be indistinct, or imperfectly seen, while those of lines transverse to the former are distinct, or clearly seen. [1913 Webster]
WordNet (r) 3.0 (2006):

astigmatism n 1: (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people [syn: astigmatism, astigmia] 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, astigmia] [ant: stigmatism]