diopter

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diopter

 [di-op´ter]
a unit of refractive power of lenses: the reciprocal of the focal length in meters is the refractive power in diopters. Symbol D.

di·op·ter (D),

(dī-op'tĕr),
The unit of refracting power of lenses, denoting the reciprocal of the focal length expressed in meters.
[G. dioptra, a leveling instrument]

diopter

/di·op·ter/ (di-op´ter) a unit for refractive power of lenses, being the reciprocal of the focal length expressed in meters; symbol D.
prism diopter  a unit of prismatic deviation, being the deflection of 1 cm. at a distance of one meter; symbol Δ.

diopter (D)

[dī·op′tər]
Etymology: Gk, dioptra, optical measuring instrument
a metric measure of the refractive power of a lens. It is equal to the reciprocal of the focal length of the lens in meters. For example, a lens with a focal length of 0.5 m has a diopter measure of 2.0 (1/0.5) and when prescribed as a corrective lens for the eye should make printed matter most clearly focused when it is held 0.5 m from the eyes.

di·op·ter

(D, Δ, δ) (dī-op'tĕr)
The unit of refracting power of lenses, denoting the reciprocal of the focal length expressed in meters.
[G. dioptra, a leveling instrument]

Diopter (D)

Unit describing the amount of focusing power of a lens.

diopter

a unit adopted for calibration of lenses, being the reciprocal of the focal length when expressed in meters; symbol D.