This course of entails mathematically altering a spectacle prescription written in plus cylinder kind to its equal in minus cylinder kind. This conversion maintains the refractive energy of the lens however modifications the illustration of the astigmatism correction. For example, a prescription of +2.00 +1.00 x 90 could be reformulated as +3.00 -1.00 x 180.
The observe of rewriting prescriptions affords benefits in lens manufacturing and becoming. It permits for higher compatibility with lens grinding tools and facilitates the utilization of sure lens designs optimized for a selected cylinder conference. Traditionally, the business has shifted between most well-liked codecs, and understanding this interconversion is essential for practitioners to interpret and work with prescriptions from totally different sources or eras.
