Difference between revisions of Diopters
Ninebalasan (talk | contribs) mNo edit summary |
Endmpiauser (talk | contribs) fix formatting |
||
| Line 1: | Line 1: | ||
Diopter is a measure of the [ https://en.wikipedia.org/wiki/Optical_power optical power ] P of a [[ lens ]] (or mirror) and is equal to the reciprocal of the [[ focal length ]] in meters . The most common unit symbol for diopters is dpt, D, or m <sup> - 1 </sup> . | Diopter is a measure of the [https://en.wikipedia.org/wiki/Optical_power optical power] P of a [[ lens ]] (or mirror) and is equal to the reciprocal of the [[ focal length ]] in meters . The most common unit symbol for diopters is dpt, D, or m <sup> - 1 </sup> . | ||
<math>P = \frac{1}{f} = - \frac{1}{d}</math> | <math>P = \frac{1}{f} = - \frac{1}{d}</math> | ||
* In [[ EM ]] , we use the [[ cm measurement ]] to calculate the diopters needed to correct [[ refraction]] of the eye. If you can see clearly at 50cm, your diopters will be <math> - \frac{1}{0.50}= - 2 dpt</math> . | * In [[ EM ]] , we use the [[ cm measurement ]] to calculate the diopters needed to correct [[ refraction]] of the eye. If you can see clearly at 50cm, your diopters will be <math> - \frac{1}{0.50}= - 2 dpt</math>. | ||
* Serial lenses add their powers: if you wear - 2 diopter contact lenses ( [[ vertex distance | adjusted for glasses strength ]] ) and put on reading glasses +1 diopter on the lenses you actually wear - 1 diopter. | * Serial lenses add their powers: if you wear - 2 diopter contact lenses ( [[ vertex distance | adjusted for glasses strength ]] ) and put on reading glasses +1 diopter on the lenses you actually wear - 1 diopter. | ||
| Line 29: | Line 29: | ||
|} | |} | ||
== Gap and ratio == | |||
Comparisons between two diopters are usually expressed using one of these terms: | Comparisons between two diopters are usually expressed using one of these terms: | ||