How to Interpret Your Prescription.
The term “sphere” means that the correction for nearsightedness or farsightedness is “spherical,”
This indicates the lens power, measured in diopters.
A minus sign (–), indicates you are Myopic (nearsighted).
A plus sign (+), indicates you are Hyperopic ( farsighted).
The term “cylinder” means that this lens power added to correct astigmatism.
This indicates the amount of lens power to correct the astigmatism. If nothing appears in this column, you have little or no astigmatism that requires correction.
The number in the cylinder column may be preceded with a minus sign.
Cylinder power always follows the sphere power in a prescription.
This describes the lens meridian that contains no cylinder power to correct astigmatism. The axis is defined with a number from 1 to 180. The Axis is preceded by an “x” when written freehand.
Meridians of the eye are determined by superimposing a protractor scale on the eye’s front surface.
This is the added magnifying power applied to the bottom part of Bifocal lens to correct Presbyopia.
The number appearing in this section of the prescription is always a “plus” power, even if it is not preceded by a plus sign.
Generally, it will range from +0.75 to +3.00 D and is usually the same power for each eye.
PD – Pupillary Distance
This is the measurement from the centre of the pupil of your one eye to the centre of the pupil of your other eye.
This measurement is needed for the centration of your prescription lenses .
This is also used on out Virtual Mirror to ensure the sizing of the frames/ sunglasses are correctly sized in relation to your face size.