The eyeglass lens prescription that you receive from your eye doctor will include an expiration date. The expiration date is the last day that you can use the prescription to buy new eyeglasses or replacement lenses.

According to the Federal Trade Commission (FTC), eye care professionals in the United States are required by law to give you a copy of your eyeglass prescription at the conclusion of your eye exam, even if you don’t ask for it.

Also, your eye doctor cannot require you to pay an extra fee for your glasses prescription — writing and giving you the prescription is considered part of the eye exam.

Your doctor also cannot require that you purchase your eyeglasses where you have your eyes examined or make you sign any sort of form that waives any of your rights associated with your glasses prescription.

Glasses prescriptions have expiration dates for good reason: Your eyes can change over time, causing your current prescription to become inaccurate and no longer adequately correct your vision. Eyeglasses made with an out-of-date, inaccurate prescription can cause eye strain, headaches, and possibly a serious accident due to blurry vision.

Even if your glasses prescription stays the same from exam to exam, you should have routine eye exams to make sure you're not developing potentially sight-threatening eye conditions like glaucoma, diabetic eye disease or macular degeneration.

Eyeglass prescriptions valid for one or two years

Eyeglass lens prescriptions typically are valid for a minimum of one year, or the minimum required by state law. It's very common for the expiration date on an eyeglass prescription to be the date two years from the day of your eye exam when the prescription was written and given to you.

However, the expiration date on a glasses prescription might be shorter (one year rather than two years, for example) if you are at higher-than-normal risk of your eyes changing more quickly. An example of this is an eyeglass prescription written for a child whose nearsightedness is worsening year after year.

Contact lens prescriptions also have an expiration date. Typically, the expiration date on a contact lens prescription is one year from the date of the exam when the prescription was written.

Contact lens prescriptions typically have a one-year expiration date because your eyes should be evaluated annually if you wear contact lenses to make sure your contacts aren't causing harm to the front surface of your eyes or putting you at risk of eye infections.

Check your prescription's expiration date

Do not try to purchase replacement eyeglasses or contact lenses online (or elsewhere) if your prescription has expired. It's illegal for anyone to sell you eyeglasses or contact lenses without a valid prescription.

Check your eyeglasses and/or contact lens prescription right now. If it's near or past the expiration date(s), find an eye doctor near you and schedule an eye exam.