Eye tracking technology: How does it work? 

I’ll start by answering the inevitable question I always get when someone first sees me using my eye gaze: “Yes, I am doing that all with just my eyes.”

In this article, we’ll look at eye tracking technology, or eye gaze, and the following information:

• What it is
• How it works
• What you can do with it
• Common challenges for eye gaze users

What is eye gaze?

Eye gaze, or eye tracking, is pretty much what it sounds like; it is a way of controlling a device simply by looking at it. The tracker monitors the user’s eye movements, and then uses that data to understand what spot on the screen is being looked at. By adding a few mouse command features and a virtual keyboard to the screen, the user is able to completely access their computer without moving any other part of their body! While this may appear to be a marvel from the future, it has actually been in the making for a few decades. In recent years, though, the eye tracking industry has made progress that continues to advance the capabilities and increase the popularity of such technology. 

How does it work?

It’s a two part thing: Hardware and software. 

The “typical” hardware looks like a long bar positioned along (or built into) the bottom edge of the computer screen. This bar has three sets of near-infrared lights (left end, center and right end) and an optical sensor that are directed in the general direction of the user’s eyes. The tracker and computer will evaluate where the reflection of the light is on the eyeball, in comparison to the location of the pupil, then use the collected data to tell in which direction the user is looking. 

There is another type of eye tracker which looks more like a traditional camera. This type may gain in popularity as the technology is further developed and becomes more widely available.

The software will generally have multiple screens with a variety of options (keyboards, types of clicks, etc…). The user can customize the settings to their liking, deciding exactly how they want to interact with each of the components and how long each selection will take.

What can you do with it?

Even within this one form of assistive technology, there is a large range of what can be done and how the user benefits from its use. Some users may rely on an eye gaze enabled device to communicate by selecting pictures or symbols from a grid, while others are able to type everything they want to say on a full keyboard. With the addition of mouse features, the user can have complete control of their computer! Web access, game playing, and environment controls all become accessible with eye tracking technology.

Common difficulties eye gaze users

Menus:

– The drop-down list of options only appears when you hover your cursor over it. If you click on it (trying to get the drop-down list) you are taken to a page before seeing the options.

Video controls:

– Audio and video controls are hidden until mouse is moved over the proper area.

– Images with links that are in a rotating format (like a perpetual slideshow) change too quickly to allow for proper selection. If this sort of feature is needed, there should be pause/play, previous, and next controls.

Buttons:

– Buttons are not shown until the mouse is moved over a certain area.

– Buttons are too small, making it difficult to hit the target.

Gestures and Interactions: 

– Swiping/Dragging is difficult. This can include tasks like swiping through pictures, turning pages, or making an adjustment on a slide-bar. Adding the ability to use a simple left-click to achieve the same goal would be helpful.