BARCELONA -- Fingerprint swiping is so 2014. With fingerprint sensors on phones, you have to make sure your finger isn't wet or dirty and you may have to wait a couple of seconds or slide your finger multiple times to register. What if you could unlock your phone just by opening your eyes?

This week at Mobile World Congress, Fujitsu showed a prototype phone with a special, infrared camera that scans your retinas. This is much more accurate than the primitive facial recognition tech you've maybe seen before on phones like the Galaxy S4. I had the chance to test Fujitsu's device and was impressed with its speed, accuracy and convenience.

When I opened the test application, I was given the option of wiping all profiles or adding a new one. I tapped the button for adding a new user and was prompted to hold the phone a few inches from my face so that my eyes lined up with two circles on the screen. Once my eyes were in the correct position, the application began to draw a status circle around each eye showing how much it had scanned, until it hit 100 percent. The scanning process itself took about 10 seconds.

The software is supposed to recognize your eyes even if you're wearing glasses, but a Fujitsu rep told me that the demo would work better if I took mine off. Presumably a final production model would work flawlessly with glasses or contacts.

MORE: Fingerprint Scanners - What They Are and How They Work

After my eyes were enrolled, I was able to pass a scan test in the demonstration app. When I put the phone to sleep and then woke it again, the Fujitsu phone presented a lock screen that had a black-and-white live camera feed at the top. When I positioned my face so that my eyes were in the box, the camera unlocked in a second or less. Unlike when I had to scan my eyes to enroll, I did not have to get my eyeballs into a narrow space; I merely had to make sure they were somewhere in the preview window that took up the top fifth of the screen.

The prototype phone I saw at Fujitsu's booth had its infrared camera attached to the top of its chassis as a separate module, but company reps said that they hope to deliver a shipping phone with the sensors built-in within the year. Unfortunately, Fujitsu doesn't sell smartphones in the U.S. market, but a company rep said that it might consider licensing the technology to other vendors.

Whether it comes from Fujitsu or another company, iris scanning provides a much better and faster authentication method than fingerprint reading or facial recognition. Many consumers use simple, but insecure unlock patterns or no lock code at all, because it's too time consuming to type a password every time they whip out their phones. The iris scan I used on the Fujitsu prototype was so fast that it was quicker than using my finger to slide unlock.