Reading Your Glasses Prescription

Here's a quick guide to help you understand your eyeglass prescription:


 Rx SPH CYL Axis Prism ADD
OD -2.25 -0.50 173 - +2.00
OS -2.50 -0.75 60 - +2.00
PD: 63 - - - - -

1. Right Eye (OD) and Left Eye (OS):

Eyeglass prescriptions will generally start with "OD" for the right eye and "OS" for the left eye. These abbreviations are used to indicate which eye the prescription information is for.

2. Sphere (SPH):

This indicates the lens power that is needed to correct nearsightedness (-) or farsightedness (+). A negative number corrects nearsightedness, while a positive number corrects farsightedness.

3. Cylinder (CYL):

If you have astigmatism, a CYL value will be present. This shows the lens power needed to correct astigmatism in your eye. It can be either a negative or positive value.

4. Axis:

This accompanies the cylinder value and defines the position of the astigmatism correction, measured in degrees from 1 to 180.

5. Addition (ADD):

If you have a reading requirement, this will be the additional magnifying power for the lower part of the lens. It corrects presbyopia, which makes focusing up close more difficult as you age.

6. Pupillary Distance (PD):

Your PD is the distance between the centers of your pupils, measured in millimeters. It ensures that the lenses are positioned correctly over your eyes and that you are looking through the correct spot on the lens.

Note: Remember that the values can be different for each eye. Also, if your eyeglass prescription includes terms like "Prism" or "Base," it may be an indication of more complex vision issues. Youtop Optical is unable to create lenses with either of these corrective features.


How do I know if I need single vision or progressive lenses?

Your prescription will typically indicate whether you need single vision or progressive lenses. Here are some of the things to look for:

Single Vision Lenses:
If your prescription shows the same spherical (SPH) correction for both eyes (e.g., -2.50 for both eyes) and doesn't include any additional values or symbols related to reading power, it is usually an indication that you need single vision lenses. Single vision lenses correct vision for one specific distance, either for seeing things up close (reading glasses) or far away (distance glasses).

Progressive Lenses:
If the prescription shows an "ADD" value, usually indicated with a plus sign (+), it's an indication that you require additional power for reading or close-up tasks due to presbyopia. For example, if your prescription reads +1.50 ADD, it means you need an additional +1.50 diopters of correction for reading or near vision. This suggests that you need progressive lenses to address both distance and near vision.