refraction

(rĭ-frak′shŏn)

To hear audio pronunciation of this topic, purchase a subscription or log in.

[L. refractio, a breaking back]

1. Deflection from a straight path, as of light rays as they pass through media of different densities; the change in direction of a ray when it passes from one medium to another of a different density.
2. Determination of the amount of ocular refractive errors and their correction.

There's more to see -- the rest of this topic is available only to subscribers.