Deciphering your eyewear prescription can sometimes feel like navigating a foreign language. However, understanding the details of your prescription is essential for ensuring that you receive the correct lenses for your vision needs. Your eye care providers at New Vision Optical Wilmette don’t want you to have any problems getting the right care, so we made this guide to help you break down the components of your eyewear prescription.
The Basics of Your Prescription
An eyewear prescription includes several key components that indicate the specific requirements for your lenses. These components are usually divided into sections for each eye, labeled as "OD" for the right eye and "OS" for the left eye. In some cases, you may also see "OU," which refers to both eyes.
Sphere (SPH): The Power of Your Lenses
The sphere measurement, often abbreviated as "SPH," indicates the lens power needed to correct your vision. This value is measured in diopters and can be either positive or negative. A positive value indicates that you are farsighted (hyperopia), while a negative value signifies nearsightedness (myopia). The larger the number, the stronger the lens required to correct your vision.
Cylinder (CYL): Correcting Astigmatism
If you have astigmatism, your prescription will include a cylinder measurement, abbreviated as "CYL." This value indicates the lens power needed to correct the irregular shape of your cornea. Like the sphere measurement, the cylinder value is also measured in diopters and can be positive or negative. If there is no astigmatism present, this section may be marked as "DS" (diopters sphere) or left blank.
Axis: The Orientation of Astigmatism Correction
The axis measurement is crucial for people with astigmatism and is expressed in degrees, ranging from 1 to 180. This value indicates the orientation of the cylinder correction needed to address the irregular shape of your cornea. The axis measurement works in conjunction with the cylinder value to ensure that the lenses you get at New Vision Optical Wilmette provide the appropriate correction for your vision needs.
Add: The Power for Bifocals or Progressives
If you require multifocal lenses, such as bifocals or progressives, your prescription will include an "Add" measurement. This value indicates the additional lens power needed for reading or close-up tasks. The "Add" value is typically a positive number and is added to the sphere measurement for the near vision portion of your lenses.
Pupillary Distance (PD): The Distance Between Your Pupils
Pupillary distance, abbreviated as "PD," is an important measurement that indicates the distance between your pupils. This measurement ensures that the optical center of your lenses aligns with your eyes. PD is usually expressed in millimeters and may be listed as a single value or as separate measurements for each eye.
Understanding Your Prescription Format
Eyewear prescriptions can vary in format, but they generally follow a similar structure. A typical prescription from your Wilmette, Illinois, optician may look like this:
● OD: SPH -2.00, CYL -0.50, Axis 180
● OS: SPH -2.50, CYL -0.75, Axis 170
● Add +2.00
● PD: 62 mm
In this example, the right eye (OD) requires a spherical correction of -2.00 diopters, with an astigmatism correction of -0.50 at an axis of 180 degrees. The left eye (OS) has a spherical correction of -2.50 diopters, with an astigmatism correction of -0.75 at an axis of 170 degrees. The "Add" value indicates the additional power needed for near vision, and the PD measurement ensures proper lens alignment.
Stay Informed about Your Eyewear Prescription
At New Vision Optical Wilmette, we want you to feel that you are making informed decisions about your vision care. By familiarizing yourself with the components of your prescription, you can confidently select the right lenses for your needs. If you have any questions about your prescription or need assistance choosing eyewear, call our optical center near you in Wilmette, Illinois, at (847) 251-3330.