When the eye rotates, switching from one fixation point to another, the perception of motion is strongly suppressed and rarely perceived. During these quick ‘saccadic’ eye movements, other aspects of visual perception become suppressed or compressed as well, with certain effects being stronger or weaker along the plane of the saccade - such differences can help identify the underlying neuronal pathways, since some exhibit directional tuning (e.g. neurons projecting from primate V1 to middle temporal area (MT)), and others do not (e.g. relay neurons linking the superior colliculus to area MT). A briefly presented motion probe was placed at a number of points relative to saccade to plot sensitivity to motion along different planes and directions. The results suggest that saccadic motion is suppressed before the eye begins to move, and is applied evenly across planes and directions.

When the eye rotates, switching from one fixation point to another, the perception of motion is strongly suppressed and rarely perceived. During these quick ‘saccadic’ eye movements, other aspects of visual perception become suppressed or compressed as well, with certain effects being stronger or weaker along the plane of the saccade - such differences can help identify the underlying neuronal pathways, since some exhibit directional tuning (e.g. neurons projecting from primate V1 to middle temporal area (MT)), and others do not (e.g. relay neurons linking the superior colliculus to area MT). A briefly presented motion probe was placed at a number of points relative to saccade to plot sensitivity to motion along different planes and directions. The results suggest that saccadic motion is suppressed before the eye begins to move, and is applied evenly across planes and directions.

This thesis investigates sensorimotor adaptive mechanisms that maintain the accuracy of goal-directed saccades in amblyopia, a developmental disorder characterized by impairment of spatiotemporal visual processing. Saccadic adaptation was induced by displacing the visual target toward initial fixation during the saccade. Eleven visually normal controls and seven patients with amblyopia were tested binocularly and monocularly with the amblyopic and fellow eye (non-dominant and dominant eye in controls) in three separate sessions. Patients with amblyopia exhibited reduced adaptation of saccadic gain compared to controls when viewing with the amblyopic eye and binocularly. Initiation of saccades was also delayed in patients when viewing with the amblyopic eye. It is proposed that the adaptive ability to modify the initial saccadic motor commands for maintaining short-term saccadic accuracy is impaired in amblyopia due to imprecise error signals. Moreover, this thesis reaffirms the notion that the error signals driving saccadic adaptation are visual in nature.

This thesis investigates sensorimotor adaptive mechanisms that maintain the accuracy of goal-directed saccades in amblyopia, a developmental disorder characterized by impairment of spatiotemporal visual processing. Saccadic adaptation was induced by displacing the visual target toward initial fixation during the saccade. Eleven visually normal controls and seven patients with amblyopia were tested binocularly and monocularly with the amblyopic and fellow eye (non-dominant and dominant eye in controls) in three separate sessions. Patients with amblyopia exhibited reduced adaptation of saccadic gain compared to controls when viewing with the amblyopic eye and binocularly. Initiation of saccades was also delayed in patients when viewing with the amblyopic eye. It is proposed that the adaptive ability to modify the initial saccadic motor commands for maintaining short-term saccadic accuracy is impaired in amblyopia due to imprecise error signals. Moreover, this thesis reaffirms the notion that the error signals driving saccadic adaptation are visual in nature.

Thesis (M.A.)--York University, 2006. Graduate Programme in Education. / Typescript. Includes bibliographical references (leaves 77-84). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://proquest.umi.com/pqdweb?index=0&did=1240706441&SrchMode=1&sid=8&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1195584865&clientId=5220

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains viii, 77 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 74-77).

Thesis (Ph. D.)--University of California, San Diego, 1998. / Vita. Includes bibliographical references (leaves 148-158).

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2007. / Title from first page of PDF file (viewed June 11, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 171-178).

D.Phil. / Efficient ocular saccadics with a clear visual memory are essential functions in reading fluently. A child needs to sequence the eyes in a controlled jump called a saccade in order to form a picture in the mind of what is being read. The child is therefore primarily aware of a story rather than individual words. This sequential visual input of the written text contributes to efficient reading skills. The letter sequencing therapy used in this research is designed to improve the ocular saccadics and also to simultaneously develop an efficient visual memory. This improves the reading skills and creates good comprehension. The above exercise program illustrated that visual therapy, in general, done not only as a physical exercise but by improving the visual memory, will integrate very quickly into a child's perceptual development. Visual therapy can therefore improve the learning skills in an effective and efficient manner. The development of learning skills can be expanded to benefit children that have poor reading skills as a result of cultural deprivation. Until recently, due to apartheid and cultural differences at the pre school level disadvantaged children were deprived of the same standard of education as advantaged children. This research compared the average visual skills in reading of educationally advantaged children to educationally disadvantaged children. This illustrated the gap created by apartheid, differences in culture and preschool stimulation in the two levels of education. 167 children with no particular learning or visual problems were randomly selected from a group of pupils at an average middle class educationally advantaged white school and an average middle class disadvantaged black school. 100 of the children came from two standard 2 and two standard 3 classes of the educationally advantaged school while 67 of the children came from one standard 2 and one standard 3 class of the educationally disadvantaged school. All the children were evaluated before the therapy program began with respect to ocular fixations, ocular regressions, reading rate, directional attack, span of recognition and relative efficiency. All the children were given letter sequencing therapy under supervision of the class teacher. Strict controls were applied.

M.Phil. (Optometry) / Please refer to full text to view abstract