Use this app to determine your glasses prescription

Image for article titled This app finds your prescription by scanning your glasses

Photo: IhorL (Shutterstock)

Sometimes you just need (or want) a new pair of glasses, even if you can see just fine with the ones you already have. In situations where your glasses aren’t enough and you probably need a new prescription, that’s the job of an optometrist or ophthalmologist. But let’s say your current prescription is still working and you want to order new glasses online, but you don’t have a copy of your prescription.

you could try request a copy since the last place you had an eye exam, but if it’s been more than a year or two since your last appointment (this varies by state), your prescription may have expired and they may not transmit it. Or maybe the office where you had your last eye exam has since closed or you need your prescription out of hours. For those 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 is courtesy of the online eyewear retailer Liingo, who presumably offers the service in hopes that you’ll buy your new glasses from them. (Warby Parker and GlassesUSA have similar tools.) The process is relatively simple: 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 glasses (with a prescription that currently fits you), a smartphone, a computer with a screen of 12 inches or larger, and what they call a ” magnetic card”. which is the size/shape of a credit card or driver’s license. It takes about 10 minutes in total and involves holding your glasses between the computer screen and your phone.

One thing to remember from my experience: I started with a “swipe card” with a white background, but there wasn’t enough contrast on my skin, so I had to try again with a darker card so that that works. Other than that, it was pretty straightforward.

Does it work?

We tested the app to see how accurate it is. I still have the original prescription for my current pair of glasses and used the Liingo app to see if it would work the same. For the most part it did. The spherical part of the prescription (the part where there are numbers for your left and right eye that start with a plus or a minus, like -1.75) matched perfectly, as did the cylindrical power (which measures astigmatism , that I have ).

My pupillary distance was off a bit: my previous prescription said mine was 63 millimeters, while the Liingo app put it at 59 millimeters. Finally, my axis number differed quite significantly. (The 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 my right eye axis as 125 and my left eye as 6, while the Liingo app lists these angles like 14 and 15 degrees, respectively.

Other things to know

If your prescription has expired, it is strongly suggested whether you visit an ophthalmologist in person to get a new one, as well as to have your regular eye health checkup done. The Liingo app – and others like it – does not replace seeing an optometrist or ophthalmologist. But given that we are living through a global pandemic, office visits are not always possible, or an option for people with weakened immune systems.

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

Previous Answers to the Amazon Ray-Ban Sunglasses Quiz
Next Ray-Ban sunglasses are up to 47% off Prime Day 2020