We need a name to describe that sensation you often get, in an office or out in public, that someone’s looking at your computer screen from behind you. Screen-dropping? Shoulder-surfing? Whatever it’s called, it’s annoying – and a potential security threat. A Baltimore company, Oculis, has developed a program that tracks an authorized reader's eyes to show only them the correct text. Anyone else looking at the screen will see only gobbledygook.

Chameleon is a combination of gaze-tracking software and camera equipment that, apparently, takes just 15 seconds to learn a subject’s screen-viewing patterns. After that, only the sweet spot on which your eyes are resting will be legible. Everyone else will see dummy text that constantly and randomly changes. It’s a very high-end way to protect the contents of a screen and, unfortunately, it has an equally high-end price. At around USD$10,000, it’s only going to interest defense and intelligence agencies.

Happily, Oculis have a stripped down – and much more affordable - version for everyday folk. Private Eye Professional is a software application that needs only a standard webcam connected (or built-in) to your computer. The program will display data only when you’re looking directly at the computer. Turn away, and it instantly blurs the screen so no-one else can read it. Which lets you safely chat to someone without worrying what they’re seeing on your desktop.

This version also has a neat, rear-view mirror feature. If the webcam catches someone looking over your shoulder while you work, it immediately opens a thumbnail video window in the corner of your screen showing the offender’s face. You know they’re there, and they know they’ve been spotted.

It’s certainly a much neater solution to office security than those awkward plastic privacy filters, and it’s cheaper, too. PrivateEye Professional is available online from Oculis Labs for USD$59.95.