It is important to understand your prescription, especially if you are traveling and your lenses break or get lost. Knowing what your prescription means also helps you understand your eyes better. Your prescription is not just a series of numbers, but also an important indicator of your eye health. Higher prescriptions increase your risk of developing serious eye conditions later in life.
If you don’t know how to read your prescription, being able to know what lenses are right for you can get complicated.
What Do All These Letters and Numbers Mean?
The numbers on your eyeglass prescription describe precisely how your lenses should be cut. It’s important to keep your prescription up to date so these numbers accurately reflect your visual needs. Typically, on a prescription, you’ll see several abbreviations and words labeling all of the important data on your prescription.
OD vs. OS Eye
Sometimes the letters R (for right eye) and L (for left eye) are used, but on some prescriptions, you may see OD and OS. OD is short for the Latin term oculus dexter, which means right eye. OS is an abbreviation of the Latin oculus sinister, which means left eye. You’ll often see these terms on eyeglass prescriptions.
Sphere, Cylinder, and Axis on Eye Prescriptions
Sphere: The sphere (SPH) on your prescription indicates the base of lens power you need to see clearly. A minus (-) symbol next to this number means you’re nearsighted, and a plus (+) symbol is meant to correct farsightedness.
Cylinder: The cylinder (CYL) number indicates the lens power needed to correct astigmatism —
when the eye isn’t completely round, resulting in distorted or blurred vision. The CYL is a power number indicating the amount of cylinder power to correct the astigmatism. If this column is blank, it means you don’t have astigmatism.
Axis: An axis number will also be included if you have astigmatism. This number indicates the angle of the cylinder power in the lens to correct your astigmatism.
Other Terms You May Find On Your Prescription
A prescription for correcting eye alignment issues will include a PRISM and BASE value. These are needed to design the lens so that it can accurately correct the eyesight in the event of a misalignment between the two eyes. The base value will show either “in” or “out,” or “up” and “down,” indicating the direction the prism should be angled.
Another part of your prescription may include ADD, meaning Addition. It stands for additional correction that you need for reading. It is used when reading, bifocal, or multifocal glasses are needed. It represents an additional power over the distance prescription.
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- A: Yes. Opticians still sometimes use glass for lenses. However, glass is not used very often because they aren’t as safe. If these glass lenses breaks, they can shatters into many pieces and can injure the eye. Glass lenses are much heavier than plastic lenses, so they can make your eyeglasses less comfortable to wear.
- A: A protective coating can’t be added to a lens after it’s scratched. The coating is applied when the lens is manufactured and can’t be put on later.
Quality Frames For Prescription Eyeglasses & Computer Glasses In Calgary, Alberta. Visit Browz Eyeware for an eye exam and eyeglasses that match your style.
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