Difference between revisions of Cylinder
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Cylinder | '''Cylinder''' lenses correct for the most common kind of [[astigmatism]]. It's represented as CYL on [[prescriptions]]. The lens is shaped like a cylinder rather than a sphere, bending light in one direction, but not in the other. The direction is specified by the [[Axis]]. | ||
==Positive vs. Negative Cylinder== | |||
Eyecare professionals have individual preferences for writing out positive vs negative values for cyl. For discussion with other [[reduced lens method]] participants, it is usually recommended to convert positive cylinder values into their negative equivalent, as the negative cylinder values are potentially more intuitive from a reduction point of view. | |||
* For example, there are participants who get surprised [https://www.youtube.com/watch?v=AJQEdXwKiNA&t=1363s when they remove plus cylinder, and then find that the glasses they order are too strong]. | |||
* [https://www.aclens.com/positive-cyl-converter There are tools that will convert between equivalent prescriptions of plus or negative cylinder] | |||
* [https://www.youtube.com/watch?v=0AyE1BmKUh8 Gemily's video explaining plus vs negative cylinder] | |||
==See also== | |||
* [[Astigmatism]] | |||
==References== | |||
{{reflist}} | |||
[[Category:Articles]] | [[Category:Articles]] | ||