What is "dioptrics"

Dioptrics \Di*op"trics\, n. [Gr. ? ?: cf. F. dioptrique.] (Optics) The science of the refraction of light; that part of geometrical optics which treats of the laws of the refraction of light in passing from one medium into another, or through different mediums, as air, water, or glass, and esp. through different lenses; -- distinguished from catoptrics, which refers to reflected light.

n. 1 (plural of dioptric English) 2 the study of the refraction of light, especially by lenses

Dioptrics is the study of the refraction of light, especially by lenses. Telescopes that create their image with an objective that is a convex lens ( refractors) are said to be "dioptric" telescopes.

An early study of dioptrics was conducted by Ptolemy in relationship to the human eye as well as refraction in media such as water. The understanding of the principles of dioptrics was further expanded by Alhazen, considered the father of modern optics.