refraction

refraction
n.
1) the change in direction of light rays when they pass obliquely from one transparent medium to another, of a different density. Refraction occurs as light enters the eye, when it passes from air to the media of the eye, i.e. cornea, aqueous humour, lens, and vitreous humour, to come to a focus on the retina. Errors of refraction, in which light rays do not come to a focus on the retina due to defects in the refracting media or shape of the eyeball, include astigmatism and long- and short-sightedness.
2) determination of the power of refraction of the eye. This gives the degree to which the eye differs from normal, which will determine whether or not the patient needs glasses and, if so, how strong they should be.

The new mediacal dictionary. 2014.

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Synonyms:
(of rays),


Look at other dictionaries:

  • réfraction — [ refraksjɔ̃ ] n. f. • 1270; lat. refractio, de refringere « briser » ♦ Phys. Déviation d un rayon lumineux ou d une onde électromagnétique, qui franchit la surface de séparation de deux milieux, dans lesquels les vitesses de propagation sont… …   Encyclopédie Universelle

  • Refraction — Réfraction Le pinceau nous paraît brisé à cause de la réfraction de la lumière lorsque celle ci traverse le dioptre eau air. La réfraction, en physique des ondes notamment en optique, acoustique et sismologie est un phénomène de déviation d une… …   Wikipédia en Français

  • Refraction — Re*frac tion (r?*fr?k sh?n), n. [F. r[ e]fraction.] 1. The act of refracting, or the state of being refracted. [1913 Webster] 2. The change in the direction of ray of light, heat, or the like, when it enters obliquely a medium of a different… …   The Collaborative International Dictionary of English

  • refraction — Refraction. subst. fem. Brisure. Ce qui arrive quand un rayon passe par des milieux differents. Un baston dans l eau paroist rompu à cause de la refraction …   Dictionnaire de l'Académie française

  • refraction — [ri frak′shən] n. [LL refractio] 1. the bending of a ray or wave of light, heat, or sound as it passes obliquely from one medium to another of different density, in which its speed is different, or through layers of different density in the same… …   English World dictionary

  • Refraction — Refraction, so v.w. Brechung. R. der Lichtstrahlen, s. u. Licht F) …   Pierer's Universal-Lexikon

  • Refraction — Refraction, s. Strahlenbrechung; Refractor, ein dioptrisches Fernrohr …   Herders Conversations-Lexikon

  • refraction — (n.) 1570s, from L.L. refractionem (nom. refractio) a breaking up, noun of action from pp. stem of L. refringere to break up, from re back (see RE (Cf. re )) + comb. form of frangere to break (see FRACTION (Cf. fraction)) …   Etymology dictionary

  • refraction — ► NOUN ▪ the fact or phenomenon of being refracted …   English terms dictionary

  • Réfraction — Le pinceau nous paraît brisé à cause de la réfraction de la lumière lorsque celle ci traverse le dioptre eau air …   Wikipédia en Français

  • Refraction — For the property of metals, see refraction (metallurgy). For the magic effect, see David Penn (magician). For the refraction in atmosphere, see Atmospheric refraction. Light on air–plexi surface in this experiment mainly undergoes refraction… …   Wikipedia

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