astigmatism

English Thesaurus

1. (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point (noun.state)

hypernym	:	condition, status,
definition	:	a state at a particular time (noun.state)

domain category	:	optics,
definition	:	the branch of physics that studies the physical properties of light (noun.cognition)

2. (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people (noun.state)

hypernym	:	ametropia,
definition	:	(ophthalmology) faulty refraction of light rays in the eye as in astigmatism or myopia (noun.state)

hyponym	:	keratectasia,
definition	:	abnormal bulging of the cornea of the eye (noun.state)

hyponym	:	keratoconus,
definition	:	abnormal cone-shaped protrusion of the cornea of the eye; can be treated by epikeratophakia (noun.state)

domain category	:	ophthalmology,
definition	:	the branch of medicine concerned with the eye and its diseases (noun.cognition)

3. (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point (noun.state)

antonym	:	stigmatism,
definition	:	(optics) condition of an optical system (as a lens) in which light rays from a single point converge in a single focal point (noun.state)

derivation	:	astigmatic, astigmatic,
definition	:	of or relating to a defect in the eye or in a lens caused by a deviation from spherical curvature which prevents light rays from meeting at a common focus and so results in distorted images (adj.all)

antonym	:	stigmatism,
definition	:	(optics) condition of an optical system (as a lens) in which light rays from a single point converge in a single focal point (noun.state)

derivation	:	astigmatic, astigmatic,
definition	:	of or relating to a defect in the eye or in a lens caused by a deviation from spherical curvature which prevents light rays from meeting at a common focus and so results in distorted images (adj.all)