This study investigates how mathematics teachers help Visually Impaired (VI) learners to construct mathematics knowledge. This investigation involved identifying the challenges encountered by high school mathematics teachers in teaching mathematics to VI learners, the approaches used and the assistive technology used to adapt and modify the curriculum to accommodate VI learners, and also aid the learners to access and construct mathematics knowledge. A constructivist approach was employed, allowing a discussion of how high school mathematics teachers redefine their position from that of a teacher to that of a facilitator who guides and stimulates VI learners to construct their own knowledge. A case study of two teachers from one of the special schools that offer mathematics up to FET phase was conducted. Data were collected from the teachers through classroom observation and semi-structured interviews. The study revealed that the teachers‘ experience resulted in a variety of challenges in teaching mathematics to VI learners. This finding further reveals that the approaches used to teach mathematics to VI learners are not different from those used in mainstream education. However, modification to the curriculum content is inevitable. Additionally, the selection of the appropriate approach and the effectiveness of using it to assist the VI learner depends on the skill, knowledge and the experience of the teacher in teaching mathematics to VI learners. The study also revealed that assistive technology is essential for enlarging the text to the correct font of the learner and translating print text to braille to help blind learners complete their tasks. For example, while a transformer HD is used to enlarge text, the scientific notebook, Math Type and Duxbury programs are used to generate braille text. Additionally, the Tactile View and View Plus programs are used to produce embossed sketches, while Perkins braillers and talking calculators provide further independence. Due to the limited number of participants in the study and the focus on a single case, the dissertation does not aim to generalise the results to all special needs schools in South Africa. However, the findings will be of great benefit to those teachers teaching mathematics in special needs schools with VI learners to take a step forward in introducing mathematics at FET phase level. / Dissertation (MEd)--University of Pretoria, 2019. / Science, Mathematics and Technology Education / MEd / Unrestricted