Difference between revisions of Guide:Reading glasses prescriptions
Added some explanation that makes room for plus lenses |
→Cylinder: Added a table "Effect of including cylinder correction" |
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| Line 9: | Line 9: | ||
Cylinder correction means your eye has some level of [[astigmatism]]. | Cylinder correction means your eye has some level of [[astigmatism]]. | ||
Since cylinder correction is in addition to spherical correction, what the cylinder correction does depends on the spherical correction: | |||
{| class="wikitable" | |||
|+ Effect of including cylinder correction | |||
! !! Minus Cyl !! Plus Cyl | |||
|- | |||
! Minus Sphere | |||
| Increases myopia correction || Decreases myopia correction | |||
|- | |||
! Plus Sphere | |||
| Decreases presbyopia correction || Increases presbyopia correction | |||
|} | |||
==Axis== | ==Axis== | ||
[[Axis]] is the degree at which cylinder values are relevant. The correct cylinder value but the wrong axis value would make the correction pretty worthless! When reducing your correction, you should never ever change the axis, especially if you've had that value of axis for a long time. | [[Axis]] is the degree at which cylinder values are relevant. The correct cylinder value but the wrong axis value would make the correction pretty worthless! When reducing your correction, you should never ever change the axis, especially if you've had that value of axis for a long time. | ||