Understanding Prescriptions
Understanding Prescriptions
Ever wondered what those numbers and terms on a prescription card means? Let us break it down for you!
This is how a typical prescription looks like if you do not have any astigmatism:
In this example, the "degree" (SPHERE) for the right eye will be 550 (-5.50D) and 475 (-4.75D) for the left eye. The pupillary distance (PD) is 68mm.
This is how a prescription looks like if you have astigmatism:
In this example, the "degree" (SPHERE) for the right eye will be 275 (-2.75D) and 100 (-1.00D) for the left eye. The "astig" (CYLINDER) for the right eye is 125 (-1.25D) and 50 (-0.50D) for the left eye. The pupillary distance (PD) is 64mm.
For those with presbyopia and require reading glasses / progressives, this is how the prescription looks like:
In this example, the "degree" (SPHERE) for the right eye will be 350 (-3.50D) and 75 (-0.75D) for the left eye. The "astig" (CYLINDER) for the right eye is 75 (-0.75D) and 100 (-1.00D) for the left eye. The near addition (ADD) is 150 (+1.50D) for both eyes. The pupillary distance (PD) is 61mm.
What Do All These Terms Mean?
Sphere (SPH)
Also commonly referred to as "degree". A minus sign (-) indicates that you are shortsighted and a plus sign (+) indicates that you are longsighted. If you are neither shortsighted or longsighted, it will be indicated as plano (PL).
Cylinder (CYL)
The amount of astigmatism that needs to be corrected.
Axis
The direction of the astigmatism measure in degrees.
Pupillary Distance
The distance between the centre of the right and left pupils.