As shown by several studies, programmers’ readability of source code is influenced by its structural and the textual features. In order to assess the importance of these features, we conducted an eye-tracking experiment with programming students. To assess the readability and comprehensibility of code snippets, the test subjects were exposed to four different snippets containing or missing structural and/or textual elements. To assure that all subjects were at an equivalent level of expertise, their programming skills were also evaluated. During the eye-tracking experiment, the subjects were also asked to give a readability and comprehensibility score to each snippet. The absence of textual features showed to increase the average fixation duration. This indicates that for the test subjects the textual features were more essential for the comprehension of the code. Gaze pattern analysis revealed less ordered patterns in the absence of structural features compared to the absence of textual features.