Difference between revisions of Diopters
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** The axis is ignored, and the cylinder powers are subtracted without using [[Diopters#Adding/Combining Lenses|lens combination calculations]]. | ** The axis is ignored, and the cylinder powers are subtracted without using [[Diopters#Adding/Combining Lenses|lens combination calculations]]. | ||
* ''diff-norm gap'': differentials diopter minus normalized diopters, ignoring axis | * ''diff-norm gap'': differentials diopter minus normalized diopters, ignoring axis | ||
** For example, if normalized is -2 SPH -0.5 CYL, and differentials are -0.75 SPH, the diff-norm gap is 1.25 SPH 0.5 CYL or 1.5 SPH equivalent. | ** For example, if normalized is -2 SPH -0.5 CYL, and differentials are -0.75 SPH, the diff-norm gap is 1.25 SPH 0.5 CYL or 1.5 SPH equivalent.** The axis is ignored. | ||
** This quantity is generally positive, as more plus sphere is needed for [[close-up]] than [[distance vision]]. | ** This quantity is generally positive, as more plus sphere is needed for [[close-up]] than [[distance vision]]. | ||
==Technical Details== | ==Technical Details== | ||