### Dioptre

A dioptre, or diopter, is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres (that is, 1/metres). It is thus a unit of reciprocal length. For example, a 3-dioptre lens brings parallel rays of light to focus at {frac|3} metre. The same unit is also sometimes...
Found on http://en.wikipedia.org/wiki/Dioptre

### Dioptre

• (n.) A unit employed by oculists in numbering glasses according to the metric system; a refractive power equal to that of a glass whose principal focal distance is one meter.
Found on http://thinkexist.com/dictionary/meaning/dioptre/

### Dioptre

Di·op'tre noun [ French See 2d Dioptric .] (Optics) A unit employed by oculists in numbering glasses according to the metric system; a refractive power equal to that of a glass whose principal focal distance is one meter.
Found on http://www.encyclo.co.uk/webster/D/70

### Dioptre

A measure of the focal length of a mirror or lens, equal to the inverse of the focal length measured in metres. See also: Focal Length, Focal Point.
Found on http://www.diracdelta.co.uk/science/source/d/i/dioptre/source.html

### Dioptre

A measurement of the refractive power of a lens element, as a portion of a metre.
Found on http://www.encyclo.co.uk/local/21361

### dioptre

Optical unit in which the power of a lens is expressed as the reciprocal of its focal length in metres. The usual convention is that convergent lenses are positive and divergent lenses negative. Short-sighted people need lenses of power about -0.7 dioptre; a typical value for long sight is about +1.5 dioptre
Found on http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0020491.html

### dioptre

The unit of measurement of refractive power of a lens.
Found on http://eyediologyopticians.co.uk/pages/Eye-terms-explained.html

### dioptre

unit of measurement of power of lens or eye
Found on http://phrontistery.info/d.html
No exact match found