Your eye doctor is legally required to provide you with a copy of your prescription immediately after your eye examination. This document contains the specific measurements needed to correct your vision, which is the entire purpose of the refractive portion of the exam. Many patients mistakenly believe the prescription is only valid if they purchase their eyewear from the doctor who performed the exam. The reality is that the prescription is your property and allows you to buy glasses or contact lenses from any vendor you choose.
The Federal Mandate: Your Right to the Prescription
The right to receive your eye prescription is protected by federal regulations enforced by the Federal Trade Commission (FTC). These requirements are outlined in the Eyeglass Rule and the Contact Lens Rule. The core purpose of these mandates is to ensure market competition by allowing patients to shop around for the best price for their corrective lenses.
The Eyeglass Rule requires that your eye care professional must automatically provide you with a copy of your eyeglass prescription upon the completion of a refractive eye exam. The doctor cannot charge an additional fee for releasing the prescription or condition the release on the purchase of glasses.
Similarly, the Contact Lens Rule mandates the immediate release of the contact lens prescription after the fitting process is complete. The prescriber is prohibited from requiring a liability waiver or disclaimer. These federal rules ensure you have the portability to purchase your lenses from a retailer, an online store, or another practice.
Different Requirements for Eyeglasses Versus Contact Lenses
Although both glasses and contact lenses correct vision, the prescriptions for each are fundamentally different because of how they sit relative to the eye. An eyeglass prescription, also known as a spectacle prescription, includes the sphere (lens power), cylinder and axis (for astigmatism correction), and often the pupillary distance. This prescription accounts for the fact that the lenses rest approximately 12 millimeters away from the eye’s surface.
A contact lens prescription requires several additional measurements because the lens rests directly on the cornea. This proximity changes the required lens power, meaning the sphere value is often slightly different from your eyeglass prescription. The contact lens prescription must also specify the base curve (BC), which matches the shape of your cornea for a proper fit.
The lens diameter (DIA) is also a necessary measurement to ensure the lens is sized correctly. Because different manufacturers use varying materials and designs, the prescription must also specify the exact brand and material of the approved lens. This additional complexity means a contact lens prescription typically requires a separate fitting examination before the final prescription is issued.
Expiration and Usage of Your Prescription
All eye prescriptions include an expiration date, typically one to two years from the date of the exam. This expiration is a medical safeguard to ensure your eye health is regularly monitored. Vision changes over time, and wearing corrective lenses with an outdated prescription can lead to eye strain, headaches, and blurry vision.
Contact lens prescriptions often have a shorter expiration date, commonly one year, because of the direct contact with the eye. Annual exams are important to check for potential complications like corneal irritation. Once you have your valid prescription, you are free to use it to buy lenses from any seller. If your prescription is nearing or past its expiration date, you will need a new eye examination.