Astigmatism

//əˈstɪɡmətɪzm̩// noun

noun ·Uncommon ·Advanced level

Definitions

Noun
  1. 1
    A defect of a lens such that light rays coming from a point do not meet at a focal point so that the image is blurred. countable, uncountable
  2. 2
    (optics) defect in an optical system in which light rays from a single point fail to converge in a single focal point wordnet
  3. 3
    A disorder of the vision, usually due to a misshapen cornea, such that light does not focus correctly on the retina causing a blurred image. countable, uncountable
  4. 4
    (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea; common in nearsighted people wordnet

Example

More examples

"Contact lenses are more able to correct strong astigmatism."

Etymology

From a- (negative prefix) + stem of Ancient Greek στίγμα (stígma, “mark, point”) + -ism. Coined by English polymath William Whewell in 1846.

Related phrases

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.