Your prescription describes the degree your eyes are out of focus and specifies the lens strength needed to correct your vision. An optician will use your prescription to provide you with the appropriate strength of glasses or contacts.
How to Read Your Eyeglass Prescription
Your prescription generally has three numbers. For example, it could read -5.00 -1.50 x 180.
The first number indicates the power of the lens required to correct your nearsightedness or farsightedness. If this number is negative, you are nearsighted, or you have difficulty seeing distant objects. A positive number indicates you’re farsighted, or you have difficulty seeing close objects. The higher this first number is, the thicker and stronger your glasses will need to be.
The second number is a measure of your astigmatism, an uneven or oval shape of the front surface of your eye that results in blurred vision. Many people who are nearsighted or farsighted have some astigmatism.
The third number, ranging from 0 to 180 degrees, represents the axis or direction of your astigmatism.
If you have further questions about your prescription, speak to your doctor.
Contact Lens Prescription
Your contact lens prescription differs from an eyeglass prescription and can only be obtained during a contact lens consultation and fitting.
In addition to the information in your eyeglass prescription, your contact lens prescription also contains:
Information specifying the central curve of the contact lens' back surface
The contact lens diameter
The specific manufacturer and brand name of the contact lens
As contact lenses rest directly on your eye, the strength of your contact lens prescription can and often does slightly differ from your eyeglass prescription.