People interact with the Samsung Galaxy S4 on March 14, 2013 in New York City. - 

Samsung unveiled its new smartphone, the Galaxy S4, last night in New York. The phones will start shipping at the end of April and have a slew of new features, including one that is raising some eyebrows, literally. Users of the S4 will be able to control part of the phone's functions with their eyes.

"You are not so much using your eyes to control it, it's more like the phone notices when it has your attention," says Jessica Dolcourt, a senior editor with CNET who tested the S4 at last night's launch event. "One thing that you can do that is very cool is if you are watching a video and you avert your gaze, the video will pause, and when you look back the video will resume."

For those who are worried about Big Brother watching you, Dolcourt says the eye control feature can be switched off.

With their latest Galaxy phone, Samsung pulls into the lead of Android phones looking to compete with Apple.

"They never want to be behind, they always want to be in front," Dolcourt says. "Samsung has spent enough money and enough effort to make their brand known that worldwide we can definitely start seeing an eclipse of Apple products."

Follow Jeremy Hobson at @jeremyhobson