The Galaxy S4, which will be unveiled on March 14 and released soon after, will feature the software and hardware to perform eye tracking. According to a Samsung employee who spoke to The New York Times, this technology will allow for automatic scrolling and page turning when your eyes reach the bottom of the screen — and, presumably, it might also allow for eye-controlled video games.

At this point you are probably thinking about the Galaxy S3, which was also rumored to feature eye tracking. In the S3’s case, it turned out that Samsung was merely using the front-facing camera to perform face detection — as in, detecting whether there’s a face in front of the camera or not. As you can imagine, you can’t do a whole lot with such technology, except for turning the display off when no one’s looking. If the NYT’s report is to be believed, the Galaxy S4 will feature real eye tracking that can work out exactly where you’re looking.

As for how this technology will actually be implemented, though, remains to be seen. Eye tracking solutions tend to involve some kind of headset, or at least a camera that’s situated quite close to your eye. Tobii, which has developed eye-tracking hardware that can fit in the bezel of your laptop (pictured right) or desktop monitor, probably has the smallest eye-tracking solution on the market — but it’s much too big to squeeze into a smartphone. Tobii has demoed a pair of eye-tracking spectacles, but still there’s too much hardware to squeeze into a smartphone. (See: Tobii’s eye-tracking implementation in the new Hyundai concept car.)

In all likelihood, we’re probably not looking at full, mega-high-resolution eye tracking in the Galaxy S4. It won’t be as gimmicky as the S3, but don’t expect to play the next Call of Duty title on the S4 using your eyes. The most likely implementation will probably involve some software that fuses together a bunch of signals from multiple sensors. One front-facing camera might track your eyes, while another might track your head movements (which need to be subtracted from your eye movements). Throw in some inertial data from the smartphone’s accelerometer and gyroscope and you might be able to work out when your eyes reach the bottom of the page.

It’s worth noting that Samsung has registered the trademarks for Eye Scroll and Eye Pause, where Eye Scroll is described as “computer application software having a feature of sensing eye movements and scrolling displays of mobile devices.” Presumably, then, this feature will have enough resolution to at least detect your eyes moving up and down. It remains to be seen how much CPU time and battery life these features will consume, but I suspect it won’t be cheap. Maybe we’ve finally stumbled across a reason for the Galaxy S4 to have an eight-core Exynos Octa SoC… (See: Our full Galaxy S4 hardware and software explainer.)

Now read: Eye tracking is the future of high-speed, maximum accuracy input