See also: Diopter
diopter (plural diopters)
- A unit of measure of the power of a lens or mirror, equal to the reciprocal of its focal length in meters. Myopia is diagnosed and measured in diopters.
- The dioptre adjustment mechanism of a pair of binoculars.
- (obsolete) Any lens system, such as a telescope.
- (obsolete) A theodolite or similar surveyor’s angle measuring device.
- (obsolete) An alidade.
- (obsolete) A surgical speculum.
- (obsolete) An instrument for drawing the skull by projections.
unit of measure
alidade — see alidade
speculum — see speculum
instrument for drawing skull