The contact lens prescription is essential for the proper vision correction and fit of the lenses. Without the prescription, you cannot, by law, obtain your lenses. You can, however, obtain your prescription from your eye care provider and then choose where you want to buy your lenses. Whether you are just considering contact lenses or a long time wearer, it's a good idea to understand your contact lens prescription and to know how to use it to get the best price on your contacts lenses.
History
Until 2004, only a few states required that patients be provided with a copy of their contract lens prescription. In 2004 the federal laws changed to require that all patients be given a copy. Now, when contact lenses are prescribed, you can shop for the lowest rate on lenses with your prescription.
Contact Lens Fittings
In the United States, contact lens are only available with a prescription. Fittings are performed by a licensed optometrist or ophthalmologist and, in some states, by an optician. This is because contact lenses are considered medical devices. Contact lenses that are for cosmetic reasons only, such as a change of eye color, still require a prescription. If they are not properly fitted, they can be uncomfortable and can cause irritation, inflammation and can damage the eye.
Function
The contact lens prescription provides information necessary to create a lens for each eye that will provide proper vision correction. Your name, the date of examination, the prescription date, and the name, phone, and address of the prescriber are all on the prescription and are required by federal law.
There are also a number of different parameters in the prescription. Refractive power is the value, in a unit called a diopter, of the correction the lens provides to bring vision as close to 20/20 as possible. The base curve is the curvature of the back of the lens and is necessary for a proper fit to the eye. The diameter is the distance from one edge of the lens to the other and is also important for fit. The cylinder, measured in diopters, and the axis, measured in degrees are required for correcting any astigmatism. Bifocal lenses will also need a measurement called the add, which is the power of the secondary lens portion. Color indicates any tint desired. The brand can also be specified.
Prescription Expiration
Contact lens prescriptions are, by federal law, valid for one year, or the minimum amount of time defined by state law, if greater than one year. Once a prescription expires, you will not be able to use it to obtain contact lenses and will need to have it updated.
Your Prescription
Obtain a copy of your prescription after your eye appointment. File your prescription in a convenient place for safekeeping. If you decide to use a contact lens retailer other than the optical professional that issued it, send a fax or copy of the prescription and retain the original. The retailer will verify the prescription with your eye care provider.
