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This App Finds Your Prescription By Scanning Your Eyeglasses

This App Finds Your Prescription By Scanning Your Eyeglasses
Credit: IhorL - Shutterstock

Sometimes you just need (or want) a new pair of eyeglasses, even though you can see perfectly well using the ones you already have. In situations where your glasses are no longer cutting it and you probably need a new prescription, that’s the job for an optometrist or ophthalmologist. But let’s say that your current prescription still works, and you want to order new glasses online, but don’t have a copy of your prescription.

You could try requesting a copy from the last place you had an eye exam, but if it’s been more than a year or two since your last appointment (it varies by state), your prescription may have expired and they may not pass it along. Or maybe the office where you had your last eye exam has since closed, or you need your prescription outside of business hours. For these cases, there’s an app that scans your current glasses and provides you with your prescription. Here’s what to know and how to use it.

How to use Liingo

The app comes courtesy of online eyewear retailer Liingo, which presumably offers the service in the hopes that you’ll buy your new glasses from them. (Warby Parker and GlassesUSA have similar tools.) The process is relatively straightforward: You download the Liingo app and the voice of a nice British lady walks you through everything.

To get your prescription, you’ll need a pair of eyeglasses (with a prescription that works for you currently), a smartphone, a computer with a screen that’s 12" or larger, and what they refer to as a “magnetic card,” which is something the size/shape of a credit card or driver’s license. It takes about 10 minutes total, and involves holding your glasses between the computer screen and your phone.

One thing to note from my experience: I started out using a “magnetic card” with a white background, but there wasn’t enough of a contrast against my skin, so I had to try again with a darker card for it to work. Other than that, it was pretty simple.

Does it work?

We gave the app a whirl to see how accurate it is. I still have the original prescription from my current pair of glasses, and used the Liingo app to see if it would come up with the same thing. For the most part, it did. The spherical portion of the prescription (the part where there are numbers for your left and right eye that begin with a plus or minus, like -1.75) was a perfect match, as was the cylindrical power (which measures astigmatism, which I do have).

My pupillary distance was a little off: my previous prescription indicated mine is 63 millimeters, while the Liingo app put it at 59 millimeters. Finally, my axis number differed pretty significantly. (The axis indicates the angle (in degrees) between the two meridians of an astigmatic eye, and ranges from 1 to 180.) My original prescription lists the axis for my right eye as 125 and my left eye as 6, while the Liingo app lists those angles as 14 and 15 degrees, respectively.

Other things to know

If your prescription has expired, it is strongly suggested that you see an eye doctor in person to receive a new one, as well as to have your regular eye health check-up. The Liingo app—and the others like it—is not a substitute for seeing an optometrist or ophthalmologist. But given that we are living through a global pandemic, in-office visits may not always be possible, or an option for people with compromised immune systems.

In some cases, it’s also possible to do an eye exam online, which is something we covered in detail back in April. Also keep in mind that those with a stronger or more complicated prescription may want to steer clear of buying glasses online in general, for reasons we discussed in February. Otherwise, here’s our guide to buying glasses online, including six factors that can make or break your shopping experience.