Motor and communication disabilities are common conditions that may implicate restrictions in daily life. With development of eye tracking technology, a solution referred to as eye-gaze interaction has been generated to support people with their limiting conditions to solve communication and computer access issues. By using eye tracking technology, which calculates the user’s eye-gaze location on a computer screen, user’s are able to control computers with their eyes as an input. This interaction method is quite unique and complex since the eyes serves both as an input and output source. Usability aspects revolving human information processing are therefore important to consider when designing user interfaces. In collaboration with Tobii AB, the study evaluated two separate eye-gaze interaction systems for controlling computers. 7 participants conducted user tests, one for each application, and answered interview questions during the tests regarding their usability experience. Based on the collected data,17 design guidelines was established with a purpose to enhance usability for eye-gaze interaction systems.