People with Locked-in syndrome (LIS) suffer from complete loss of voluntary motor functions for speech or hand-writing. They are mentally intact, retaining only the control of vertical eye movements and blinking. In this work, we present a one-dimensional typing interface controlled exclusively by vertical eye movements and dwell-time for them to communicate at will. Hidden Markov Model and Bigram Models are used as auto-completion on both word and sentence level. We conducted two preliminary user studies on non-disabled users. The typing interface achieved 3.75 WPM without prediction and 11.36 WPM with prediction.