Optical art is an art style based on optical illusions. It is one of many art styles of the 20th century which emerged as a result of numerous social changes. Aware of the complexity of perceptive processes which sometimes result in perceiving something incorrectly, artists create compositions which test the visual system. To create these illusions, they use elements of art such as line, shape and colour as well as composition principles such as rhythm and contrast. This style significantly grew in popularity in 1965 with the exhibition “The Responsive Eye” in the New York Museum of Modern Art. This exhibition made the style more popular and brought fame to many op art artists. The most famous op art artists are Victor Vasarely and Bridgite Riley. Optical art in Croatia started out on the foundations set by the group EXAT-51, and grew within the international movement of New tendencies which placed Zagreb into the European centre of art. Some especially prominent Croatian artists are Miroslav Šutej and Ivan Picelj. For this diploma paper, optical art pieces were used to initiate creative work among children. The classes were held at the Ljudevit Gaj Primary School in Krapina and all four primary education grades took part in them. This resulted in a total of 100 student created works, of which 96 individual and 4 group works created by using the following techniques: felt-tip pen, paper collage and grattage. This paper contains an analysis of the art process and a formal analysis of a couple of selected pieces. The students were motivated, they had a good time and they enjoyed the class. For this reason, optical art should be more commonly used in art class. It is often avoided, mostly because it is thought to be too complicated for students in primary education or because of its links to graphic art techniques. A creative, competent and flexible teacher can adjust any art piece to the needs of their students and realise it in all techniques.