Abstract: The critical flicker frequency is the frequency at which a flickering light source is subjectively perceived by a person as luminous. It is shown that the critical flicker frequency method is used for diagnostic purposes when solving various scientific and applied problems. The subject of research is the conditions for using the method of critical flicker frequency. Their limitations are due to the need: a distraction from the work to be performed to measure the critical flicker frequency, to perform measurements in stationary conditions. The aim of the work is to expand the functional capabilities of the critical flicker frequency method by using augmented reality technology. To measure critical flicker frequency, light flashes with varying frequency are formed by a mobile device in the form of augmented reality. The novelty of the proposed technology is: 1) to increase the reliability of diagnostics by the method of critical flicker frequency due to its measurement in the course of the work performed; 2) carrying out diagnostics not only in stationary ground conditions, but also during ground, water or flight movements of the subject, which was previously difficult or impossible.