Visually impaired students' concept images and representations in some mathematical concepts

The purpose of this thesis is to investigate concept images and representations of visually impaired students in some mathematical concepts. Phenomenology and case study, as the qualitative research designs, were used in our research. The participants of the study are five totally blind students. The tools used in data gathering process were semi-structured interviews, materials that the students constructed, researcher?s observation notes. In the process of data analysis, we used qualitative research techniques used in grounded theory; such as, open, axial and selective coding. In the light of analysis, we have the following main results: -It is determined that the students used mostly their concept images and never took into account the concept definitions. -When answering the questions/problems, the students entirely used a heuristic approach. -It was identified that students focusing on specific values and geometric figures have more than one understanding; such as, understanding that can be totally or partly in contradiction with each other or can be coherent for the same condition -It was identified that students followed wrong knowledge insistently, even though they defined the concept as acceptable in theory. Thus, students encountered with difficulties in practice. Also, it was identified that students were not aware of the contradiction that they fall into. -Visually impaired students were able to describe, name and distinguish the basic geometric shapes. However this situation was not enough for students to have correct understanding of the concepts. In the light of results, we have several suggestions to mathematics teachers, researchers, authors of mathematics textbooks, and mathematics educators.