It’s used when your doctor feels that compensation for eye alignment is necessary. Prism only appears on a low number of prescriptions. AddĪdd is used in multifocal lenses to indicate the additional magnifying power for the bottom part of the lens. Axis is measured in degrees and refers to where the astigmatism is located on the cornea. If your doctor has included cylinder power, there will also be an axis value to indicate positioning. If there’s no number in this column, then your doctor hasn’t found an astigmatism or your astigmatism does not need to be corrected. CYLĬYL is an abbreviation of “cylinder” which indicates the lens power your doctor is prescribing to correct your astigmatism. If you’re farsighted (hyperopia), the number will have a plus sign (+). If you’re nearsighted (myopia), the number will have a minus sign (-). SPH is an abbreviation of “sphere” which indicates the power of the lens your doctor is prescribing to correct your vision. This means that your PD for distance vision (or DPD) is 67, and for near vision (or NPD, for reading eyeglasses or. Other abbreviations you might notice on your eyeglass prescription include SPH, CYL, Axis, Add, and Prism. Or, the eye doctor may write the PD as 67/64. In this case you will not only have different parameters for each eye, but also usually a different brand/type of lens as well.Other abbreviations on your eyeglass prescription Though not common, sometimes you can have a regular prescription for one eye, and a toric or bifocal prescription for your other eye.Base Curve values are a bit like clothes sizes - just because you are a Base Curve 8.6 in one brand doesn't mean you will be the same in another brand.If your prescription does not contain a Base Curve value, this is likely because your brand of lens only comes in one base curve. Most lenses come in several different Base Curve values. The doctor fits the lens with the curvature most appropriate for your eye.
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