Dwelling is an essential task to be performed to select keys from an on-screen keyboard present in the eye typing interface. This selection task can be performed by fixing eye gaze on a key for a prolonged time. Spending sufficient amount of time on each key effectively decreases the overall eye typing rate. To address the problem, researchers proposed mechanisms, which diminish the dwell time. We conducted a within-subject usability evaluation of four dwell-free eye typing techniques. The results of first-time usability study, longitudinal study and subjective evaluation conducted with 15 participants confirm the superiority of controlled eye movement based advanced eye typing method (Adv-EyeK) than the other three techniques.