There is good news for Coloradans with less than 20/20: You can now update your prescription from the comfort of your home. Trendy eyeglass company Warby Parker rolled out its new mobile prescription app, Prescription Check, today in the Centennial State after launching the app earlier this year in select locations.

The app lets almost anyone aged 18 to 50 with an expired eyeglasses prescription get a new one without leaving the house, using a smart phone and a computer. The service is only available in certain states and, for now, users must have distance prescriptions (rather than bifocal or reading lenses, for example) to be eligible.

After determining eligibility, customers take a series of eye tests by standing 12-feet away from a computer screen and answering corresponding questions on their iPhones. According to the company, the tests will measure for refractive error to pin down any prescription changes. Doctors review the results and respond within 48-hours with either an updated prescription, or, if the person’s vision appears to have changed, a recommendation to get a comprehensive eye exam. The company stresses that the service can’t be used to replace regular appointments with an eye doctor.

While the app is free to download and use, users may be charged a $40 fee if they end up getting a new prescription.

The Prescription Check mobile app is Warby Parker’s third vision-check service: The company also offers the Prescription Check technology in-person, and has in-store eye exams available at some locations out of state.