The sphere (SPH) value indicates the main lens power you need to correct nearsightedness (indicated by a minus sign, like -2.50), farsightedness (indicated by a plus sign, like +1.00), or astigmatism (a combination of both, like -1.00 -1.50 x 90°). It represents the degree of correction required to focus light on your retina.

The cylinder (CYL) value shows the additional lens power needed to correct astigmatism. It’s noted with a minus or plus sign, just like SPH. For example, if your prescription reads -2.00 -1.50 x 90°, the -1.50 CYL corrects astigmatism.

The axis is measured in degrees from 0° to 180° and indicates the orientation of the cylinder (CYL) correction. It tells the eyewear manufacturer where to place the astigmatism correction on the lens. For instance, in the prescription -2.00 -1.50 x 90°, 90° specifies the horizontal axis.

Your Pupillary Distance (PD) is the measurement between the centers of your pupils, usually expressed in millimeters (mm). It ensures that the optical centers of your lenses align with your eyes correctly. While your optometrist provides this measurement, you can also measure it at home or request it during an eye exam.