Testing usability with eye-tracking enables to understand a new dimension of user interaction. We can research areas that are most interesting for users and what behavior patterns causes it. It is possible to identify page elements that attract attention and to which the user is blind. The eye-tracker device is very accurate, it can measure up to 120 times per second the position of the eye on the screen. Using research data it is possible to draw gaze plots report and heat map chart for further analysis. In my opinion the greatest challenge for performing eye-tracking research is to use appropriate methodology, such as set exposure time, fixation length, recruit representatives group, set up relaxing testing condition for users to react in a natural way.