The aim of this study was to investigate the online process of reading and analyzing sketchnoting – the special type of a polycode text — on Russian language material. The eye-tracking method was used to examine the effects of using different types of sketches while reading four biographies of Russian poets. We randomly assigned 20 high-school children to 4 reading conditions: (a) text only; (b) linear sketch; (c) radial sketch; and d) path (trajectory) sketch. We measured 1) the total dwell time, the total fixation count, interest area dwell time, interest area first run dwell time, interest area fixation count for each verbal and non-verbal zones of the texts, for horizontal and diagonal zones; (2) deviation from the trajectory when examining the sketch; (3) the number of correct answers to the factual and analytical questions concerning the comprehension of the text; (4) subjective difficulty of different stimuli on the results of the responses to one of the questions after each biography. Results showed that readers process different formats of texts differently, sketches being easier to process and understand than a verbal text of the same content. We revealed that the sketch structure is one of the means that helps to resolve ambiguity while reading polycode texts. The best format of sketches is of the trajectory type. The analysis of participants’ eye movements while reading the stimuli made it possible to propose a number of recommendations for creating sketches.