The importance of good vision for acquiring a sound fundamental base in reading and writing skills, in early years, has implications for scholastic achievement and future prospects in adult life. Where the underlying problems in children, who have difficulties in school, are not related to intellect, the ocular and visual systems need to be examined. This thesis is based on observations of 1153 school-children, aged from 7 to 14 years, who had been found to have problems with reading and writing but had no intellectual impediments to learning. The results have shown that the vast majority 72% of these children demonstrate binocular vision problems that can be treated. Treatment options for convergence insufficiency and convergence excess were trialled. It was found that prismatic correction, reading glasses and muscle exercise therapy were effective. Reading speed and efficiency could be improved to normal levels within a period of four weeks. These findings indicate that there is significant plasticity in the visual systems of the eyes of children and that any dysfunctions should be rapidly treated. The thesis has also shown the basis on which the level of prismatic correction is derived. It is also the first to show a comparison of calibrated reading tests in German and English. The physiological mechanisms in the developing and growing eye may have an influence on other measures. Muscular forces within the eyeball (controlling accommodation) and externally placed (controlling eye movements) may have an influence on the pressure with the eye. Little is known about the normal variations with age in intraocular pressure in children. This study has shown that there is an age-related increase in intraocular pressure that plateaus after age 9 and that there are differences between children with binocular vision problems and controls. Reasons for these differences are discussed and further investigations suggested.