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Personal care

How to use your smartphone to check your vision

EyeQue attaches to your phone screen to measure your eyes at home. Just don't expect that you can ditch the doctor altogether.

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The EyeQue VisionCheck straps onto your smartphone and presents you with a series of exams to check your vision.

Tyler Lizenby/CNET

Scientists expect blurry vision to plague 50 percent of the population by 2050. That's a lot of people who will need to flock to an optometrist to get a prescription to correct their vision.

But what if you can't afford to go to the doctor? Or don't want to go in every year for minor vision changes? With the help of MIT researchers, EyeQue developed EyeQue VisionCheck, a device that makes it easier for people to check their vision. 

This small device that looks like half a pair of binoculars promises to help anyone correct their vision, and it won an Innovation Award at CES 2019 -- but can it really replace going to the eye doctor? I tried it to find out.

Read more: How to find your eyeglass prescription without getting an exam

Now playing: Watch this: The weirdest stuff we saw at CES 2019
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What is EyeQue VisionCheck?

At the eye doctor, you peer into what's called an autorefractor -- that bulky machine where you rest your chin and forehead on plastic stabilizers, peer into some peepholes and tell your doctor about the images you see. 

Autorefractors shine light into your eye and measure how the light bounces back from the retina using a technology called Shack-Hartmann, named after the scientists that developed it.

EyeQue uses a technology patented by MIT researchers called Inverse Shack-Hartmann, which is essentially a self-administered, manual refractor. 

Where to get it: Find VisionCheck in the EyeQue store

Cost: The EyeQue VisionCheck device retails for $69, which includes a one-year all-access membership to EyeQue for one person. After the first year, an annual membership costs $4.99. 

You can share a single VisionCheck device among many people, as long as each person has their own account and membership to ensure personalized and accurate results. If you and a friend used the same account, the results would become void because VisionCheck averages all of the test results in a single account to provide a prescription.

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EyeQue VisionCheck gives you Eyeglass Numbers, which are similar to a prescription, but they don't have a doctor's sign-off. You can use your Eyeglass Numbers to purchase glasses at online retailers.

EyeQue

How does it work? 

Using the VisionCheck is simple, but not necessarily easy: 

  • First, charge your EyeQue VisionCheck device, download the app and register your device with your serial number.
  • After you've set up an account and answered a set of introductory questions, strap the device onto your phone using the included silicone strap. 
  • Take the practice exam.
  • Take the series of three exams that unlock your "Eyeglass Numbers."

The exams involve nine attempts on each eye to overlap red and green blocks to make one yellow block. You'll peer into the VisionCheck and use the buttons on the top of the device to bring the blocks close together or move them apart. When you think you've successfully overlapped the red and green blocks, move onto the next attempt. 

EyeQue does not provide people with prescriptions, and instead calls them Eyeglass Numbers, presumably in an attempt to ensure customers don't replace their annual eye exam with the VisionCheck tests (more on that below). 

However, the presentation of the Eyeglass Numbers looks very similar to the prescription sheet your optometrist gives you. You can still use them to purchase glasses at online retailers such as Eye Buy Direct, but the Eyeglass Numbers are intended as a sort of intermediate check-up between comprehensive annual exams. 

My Eyeglass Numbers from the EyeQue VisionCheck 

Amanda Capritto

Putting EyeQue to the test

When I received my EyeQue device in the mail, I eagerly opened the box and then immediately put it aside until I got on a demo call with EyeQue's director of marketing, Phoebe Yu. Right out of the box, I could tell this device would need some explaining. 

While I'm sure many people could figure the device out on their own, it's definitely a bit complicated at first. It takes a bit of fiddling to properly strap the VisionCheck to your phone, and I personally had trouble looking into the device with my left eye at first. Unless I seriously squinted my right eye, it was like I was peering through a peephole into a room with blackout curtains. 

Eventually, I figured it out, and it's good that I did: Yu said that the device is looking for distance discrepancies, so it works best if you gaze at a faraway object with your non-testing eye. 

The initial learning curve is pretty sharp, but I got the hang of it after some practice. It took me about 10 minutes to complete the practice exam, but only about 12 minutes to complete all three exams and unlock my Eyeglass Numbers.

Overall, the experience was pretty fun -- it felt kind of like playing an old-school video game. 

So, did EyeQue get my prescription right?

Yes and no. 

Not the answer you were expecting? Let me explain. 

My eyeglass prescription is sphere -0.5, a very small nearsighted prescription. I wear glasses when I need to focus on things at a moderate distance: while driving, watching movies, going to art exhibits, walking around new cities (so I can read signs), etc. 

Eyeglass prescriptions give you three numbers:

  • A spherical number, which indicates a correction for nearsightedness or farsightedness
  • A cylindrical number, which indicates a correction for astigmatism 
  • An axis, which indicates where the astigmatism is on your eye and which direction (vertical, horizontal or in between) your eye curves. 

If your prescription contains a cylinder number, it must also contain an axis. If your prescription contains no cylinder, it either means you don't have astigmatism, or your astigmatism is so slight that it's not really necessary to correct it. 

My EyeQue Eyeglass Numbers? Sphere -0.25 and cylinder -0.25 for both eyes, with an axis of 166 for my right eye and an axis of 39 for my right eye. 

When I protested with concern, Yu explained to me that optometrists sometimes combine the sphere and cylinder numbers into one when they're both very small like mine. Often, the single number (in my case, -0.5), can correct blurry vision and/or astigmatism.

I called my eye doctor to confirm, and he said that Yu was right -- sometimes it's just not worth giving patients a more complicated prescription with different measurements for each eye -- though he couldn't confirm that that's what he did for me unless I were to come in and take another exam. 

Read more: The best places to get cheap glasses online

More on blurry vision

To understand how EyeQue VisionCheck gets your Eyeglass Numbers, it helps to consider some basics about eyes and why people need glasses in the first place. 

Light enters the "window" of your eye, or the cornea, and passes through your pupil, the dark center of your iris. Behind your iris sits a lens that focuses the light coming into your eye. The lens automatically flattens to see far away, and shortens to focus on items close by. 

The cornea, pupil and iris work together to focus the light on your retina, located on the back surface of your eye. Hundreds of thousands of light-sensitive cells line your retina and send electrical signals through the optic nerve to your brain, where the image you see projects. 

Blurry vision is caused by the shape of your eye and can occur in three main ways: 

  • If your eyeball is too long, the light will focus in front of the retina, causing objects in the distance to appear blurry. That's nearsightedness or myopia (you can see near, but not far).
  • If your eyeball is too short, light focuses behind the retina and cause objects nearby to appear blurry. That's farsightedness or hyperopia (you can see far, but not near). 
  • If your cornea is not smooth, light focuses on multiple areas within your eye, which causes astigmatism. Astigmatism causes objects both far away and nearby to look blurry. 

Whichever way blurry vision presents, it's referred to as "refractive error," which the VisionCheck device measures with its red-block-green-block exams. 

Read more: Should you be using blue-light blocking glasses?

Does it really replace my annual eye exam? 

No -- even EyeQue's staff will tell you that you still need to see your optometrist. EyeQue's technology is smart, but it's still not a replacement for the accuracy and expertise of a trained professional. 

Also, your eye doctor conducts a comprehensive eye health exam and looks for much more than just your eyeglass prescription. Optometrists check for signs of degenerative conditions, colorblindness, eye strain, dry eye and more, which the EyeQue device can't check.

Who should get it?

I'm no eye doctor, but I wouldn't recommend EyeQue to anyone who's never gotten their prescription checked by a professional. If you think you might need glasses but have never had them before, definitely see an optometrist. 

EyeQue can be a great complementary device for people whose prescriptions change often. For example, as you get older, you may notice that you have more and more trouble looking at nearby objects, such as your computer screen. This is called presbyopia and worsens over time, so EyeQue could help you stay on top of a progressing prescription. 

As someone who only wears glasses as needed, I can't see EyeQue as a significant part of maintaining my eye health, but the concept is certainly cool and worth keeping your eye on -- pun totally intended.