This study analysed the way of knowing students who enter and graduate from secondary education have in relation to the formation and vision of an optical image. A pre-test – secondary education – post test-type design for different groups was implemented and a descriptive methodology was employed. The results obtained reveal that students, regardless of their formation, explain phenomena from their intuitive ideas or others either incomplete or incorrect in scientific terms which are the result of their school education. The results express the need for the design of proposals to transform the situation found.