Context switching eye typing using dynamic expanding targets

Text entry by gazing on a virtual keyboard (also known as eye typing) is an important component of any gaze communication system. One of the main challenges for efficient communication is how to avoid unintended key selections due to the Midas' touch problem. The most common selection technique by gaze is dwelling. Though easy to learn, long dwell-times slows down the communication, and short dwells are prone to error. Context switching (CS) is a faster and more comfortable alternative, but the duplication of contexts takes a lot of screen space. In this paper we introduce two new CS designs using dynamic expanding targets that are more appropriate when a reduced interaction window is required. We compare the performance of the two new designs with the original CS design using QWERTY layouts as contexts. Our results with 6 participants typing with the 3 keyboards show that the use of smaller size layouts with dynamic expanding targets are as accurate and comfortable as the larger QWERTY layout, though providing lower typing speeds.