The paper describes the first hundred years of the history of eye tracking as a research method, dividing it into three phases of development. It starts by presenting the studies on tracing eye movements in reading in the end of the 19th century and the creation of the first eye trackers. The further part presents how the eye tracking technology was improved in the time of film recordings, ceasing to be invasive for the eyes. It also shows how in this time the main focus of research shifted to practical aspects due to the development of the behaviourist movement in experimental psychology. The third phase starts in the 1970s, when researchers turned more towards the dependence between the perception and mental processes. It was linked to the establishment of a theoretical and methodological basis for cognitive psychology.