The population of people living with visual impairment is estimated at 1.1 billion worldwide and 15% reside in Africa (WHO, 2019). Estimates of one million are blind and three million are visually impaired in Nigeria (Sightsavers). The data from different research look inconsistent because the criteria for classification are mostly different. Anyway the population of blind and visually impaired is significant and there is a need for adequate attention to their needs and especially their educational needs.
Among the important and compulsory subjects learnt in school is mathematics because of the pivotal role it plays among other subjects, development of technologies and day-to-day activities of human beings. Among the important topics to be learnt in mathematics is Geometry. Geometry is a branch of mathematics that deals with the measurement, properties, and relationships of points, lines, angles, surfaces, and solids. Conventionally, geometry involves pictorials which need vision majorly to learn. Rosenblum et al. (2020) observed that the visually impaired struggle with mathematics graphics and that they complain of not meeting the same standard as their sighted classmates on mathematics problems involving graphics (Zebehazy & Wilton, 2014). Adelakun (2020) also reports that because of loss of vision, learning mathematics and science becomes a challenge as in diagrams and graphics in geometry. Students with visual impairments tend to face more challenges than their peers without disabilities, even when learning the most basic mathematical concepts (Beal & Shaw, 2008). These difficulties include problem-solving and gaining access to information including those involving diagrams and calculations. Mathematics is highly visual and often uses graphics to convey important information presenting an additional obstacle for students with visual impairments (Smith & Smothers, 2012). It is important for the visually impaired to learn mathematics skills at the same level as their sighted peers.
The visually impaired can access print documents such as books through braille, a standard writing system for perception through touch. However, this format of writing has not provided the visually impaired with access to diagrams and pictures. When it comes to the semantic and cognitive processing of visual information, the tactile modality has been proven to be the most similar to vision, It is even rated superior to vision at processing material characteristics of shapes and objects Luo et al (2017). Through touch, tactile diagrams allow the perception of two-dimensional images. They are embossed outline drawings that are specially made to help the blind and visually impaired convey visual information. Dahiya and Valle (2012) opined that tactile sense conveys diverse sensory information, such as pressure, vibration, pain and temperature, to the central nervous system, assisting humans in perceiving their surroundings and avoiding potential injuries
To make geometry accessible to the BVI, tactile diagrams should be designed and produced. Edman spent over 30 years producing tactile graphics and recommended that more research is needed to produce understandable and useful tangible tactile graphics (Edman, 1992)
Geometry Tactile Diagrams are embossed diagrams produced for teaching Geometry in mathematics to BVI. The Diagrams in the examples and exercises contained in the lecture manual are prepared to be used by the teachers while teaching in an inclusive classroom. Each diagram has prints and braille labels as recommended in Adelakun (2020). This makes the GTD different from existing tactile diagrams. It is developed to ease the use of tactile diagrams by sighted teachers who are non-specialists in the education of BVI teaching in special schools or inclusive schools.
Agrawal (2004) suggested that while preparing material for visually impaired pupils, suitable principles should be kept in mind. There is a need for modification of format and content for necessary adaptation. To do this, some technologies are required.
Technology has provided new opportunities for people who are visually impaired to be independent at work, school, home and anywhere they find themselves. These advances have allowed them to live independent lives, compete successfully with sighted learners and have equal access to printed information (Kursweil, 1997). Many ways are explored to provide tactile graphics for the BVI. Rendering the graphics information in text form was the early effort made to present graphics to BVI. This is followed by the manual design of images and thermoforming of the designed tactile image and recently automated ways. Thevin and Brock (2018) design and create audio-tactile contents from existing objects. A particular one involves designing on the computer, printing on swell paper and then passing through the embosser. This usually involves the use of special printers such as Index Braille Everest-D, PIAF, ViewPlus Tiger, and IRIE Embossers. Each has its limitations regarding functionality and adaptability.
Wu et al (2022) observed that most tactile diagrams designed consider only one factor. In their research, they identified that there may be interactions among scale, representation, and complexity factors and thus (line drawing, (LD), and texture picture, (TP)), into a textured-line drawing, (TLD) were identified for the representation. Their research pointed out that the presentation of tactile graphics determines its usefulness.
Statement of the Problem
Mathematics as a subject is often considered a field beyond the capacity of visually impaired persons. Efforts have been made by researchers and educators over the years to make diagrams accessible to the visually impaired. Mukhiddiniv and Kim (2021) opined that large information is presented graphically and the visually impaired cannot receive this information. They depend on tactile illustrations. Tactile graphics are considered an important factor for students in the science, technology, engineering, and mathematics (STEM) fields seeking a quality education because teaching materials in these fields are frequently conveyed with diagrams and geometric figures’ (Mukhiddinov & Kim, 2021).
The time required to prepare the manual and or thermoforming tactile graphics is high compared with the automated or computer-designed one; however, the latter is very expensive. Creating audio-tactile graphics for blind children from real objects using augmented reality methods brought a new direction to the field, although the cost and the unstable electricity among other predicaments make it unsuitable for Nigeria at present.
A lot of insight was obtained from the review of 257 studies conducted between 2015 and 2021 on the development and use of tactile diagrams. In summary, image processing methods and audio information for designing tactile graphics are widely in use. Though the research is more in some countries than others, many countries are represented. It is however identified that producing tactile graphics is still difficult and most time-consuming. The use of 3D has taken the process to a new level, though it requires a specialist touch to design meaningful STEM graphics. The design involving swell paper has commendable appraisal ‘All the participants noticed that the diagram representations produced with swell papers were more natural and intuitive’ The diagrams are more natural. is also a recommendation for new research in this area.
This study is interested in determining the roles of geometric tactile diagrams in teaching geometrical concepts in mathematics to blind and visually impaired students. Mukhiddinov and Kim (2021) review over 250 original research on the various tactile graphics developed to make graphics accessible to the visually impaired. It was concluded that refreshable displays are still very expensive for low and middle-income earners and that lack of training data sets for machine learning is also a problem. Therefore, other formats of developing tactile graphics are encouraged. According to previous studies, the sensory system associated with the feeling of touch is superior to the visual and auditory systems in perceiving accurate and complete characteristics of objects (Mukhiddinov & Kim, 2021). Therefore, tactile diagrams should be made available to the VI instead of exempting them from STEM, since it is found that the sense of touch is superior to visual and auditory senses. Tactile graphics are an essential means of studying and understanding the world, especially STEM. Wu et al (2022) recommend from the findings of their research that small-scale graphics was more accurate than medium-scale and for TLD mode small and medium-scale graphics was more accurate than large-scale graphics. They also found that TLD performed better than LD. It is recommended that graphics size should be the type that could be explored with two hands.
Purpose of the Study
i) To investigate ways by which geometry tactile diagrams can be used to teach Geometry to students with visual impairment.
ii) To find out the effect tactile training has on BVI use of GTD
Significance of the Study
This study will help the professionals (teachers) to be aware of the procedures and tools which would be used to teach the visually impaired students Geometry. Also, this study serves as an insight for Federal, State and Local Government institutions of learning and non-governmental bodies to provide GTD to schools to facilitate the teaching and learning of mathematics to students with visual impairment.
Research Questions
RQ1: How effective has GTD made Geometry accessible to BVI college students
RQ2: What effect does exposing tactile graphics to BVI before using GTD have on their performance
Hypothesis
H01: There is no significant difference between the mean achievement scores of students in the Control group (students taught without geometry tactile diagram) and those in the experimental group (students taught with geometry tactile diagram).
H02: There is no significant difference between the performance of students exposed to tactile graphics before the introduction of GTD and those not exposed to tactile graphics