You'll need to download Warby Parker's Prescription Check app to determine your eligibility, which means you're between 18 and 40 and live in a state that has the company's program (NY, CA, FL and VA so far). You also need to be a current Warby Parker customer, have no history of eye disease, have had a comprehensive exam within the last five years and only need a single-vision distance prescription (no bifocals, please). Oh, and your prescription can only have a current lens strength (SPH) between 0 and -6.0 and an astigmatism value (CYL) between 0 and -2.0.

If eligible, you'll load up WarbyParker.com/Test and your phone and computer will pair up. Next, you'll need to stand 12 feet away from the screen to take the basic vision test. When you're finished, the app will send the results to an eye-doctor. If they're the same as your previous prescription, the doctor will provide you an updated one to use for new frames from Warby Parker. If your vision has changed, you'll get a referral to get a new exam at an optometrist. The company says the entire process takes about 20 minutes and that you'll hear back on your results within 24 hours.

Warby Parker has been working on this technology since 2015, while other companies, like Smart Vision Labs, have found ways to use mobile phones for in-store eye exams in 2016. While it's no substitute for a comprehensive eye exam if your vision has changed since your last one, those of us who just want to grab a new pair of frames based on a still-valid expired prescription can do so from the comfort of our own home.