When you order brand name contact lenses with vision correction, you must usually have a current contact lens prescription which specifies the power of the lenses, the size of the lens, the type and brand of lens. However, a few online retailers do offer non-prescription color lenses with no lens power which can be purchased purely for cosmetic purposes. In these cases, it is highly recommended that you consult with an eyecare professional for proper instructions on how to insert/remove the lens, how to care for the lens, and to verify that the contact will fit your eye.

A contact lens prescription is not the same as an eyeglass prescription. In addition to the lens power, your contact lens prescription contains several other pieces of information related to the size of the lens.

Your prescription will also contain an expiration date. By law contact lens prescriptions must be valid for at least one year. However, in many jurisdictions, prescriptions are typically valid for two years from the date the contact lenses were fitted.