Global motion processing depends on a network of brain regions that includes extrastriate area V5 in the dorsal visual stream. For this reason, psychophysical measures of global motion perception have been used to provide a behavioral measure of dorsal stream function. This approach assumes that global motion is relatively independent of visual functions that arise earlier in the visual process...

To examine the spatial scale of the mechanisms supporting the perception of motion in depth defined by binocular cues, we measured stereomotion speed discrimination thresholds as a function of stimulus size using a two-interval speed comparison task. Stimuli were either random dot stereogram (RDS) bars featuring both the changing disparity (CD) and the interocular velocity difference (IOVD) cue...

The spatial and temporal organization of stereoscopic depth perception were compared in normal and strabismic observers. The minimum and maximum disparities for stimulating static and dynamic stereopsis in strabismus were examined as a function of spatial separation of disparate stimuli. Disparities and their spacing were produced by spatial modulation of two vertical lines viewed haploscopical...

The goal of this study was to determine the relationship between stereoacuity and proficiency in fine and gross motor skills. Stereovision is one of the information sources for accurate perception of objects in depth, and it is related to performance on motor skills tasks. Studies have shown that children of primary school age with mild intellectual disabilities perform worse than typically dev...

Kabuki syndrome is characterized by long palpebral fissures, large ears, a depressed nasal tip, and skeletal anomalies associated with postnatal dwarfism and mental retardation. There have been few prior detailed descriptions of strabismus or stereopsis in these patients. We report a patient with Kabuki syndrome who showed small-angle strabismus and poor stereopsis. This case illustrates the ne...

I have read and understood The University of Edinburgh guide lines on plagiarism and declare that this written dissertation is all my own work except where I indicate otherwise by proper use of quotes and references. 2010 i Acknowledgements Time flies, words cannot describe how this year in Edinburgh has influenced my life. First of all, I would like to thank my supervisor Dr. Richard Shillcock...

With isolated binocular targets, the best depth discrimination is found in the fixation plane (Blakemore, C., Journal of Physiology 211 (1970) 599). More recent studies have suggested that stereoscopic thresholds are not always a simple function of absolute disparity, but depend on the relative disparities in the stimulus. Here, we explored the effects of relative disparity in more detail, taki...

PURPOSE Variation in stereoacuity was examined in a large group of observers with Snellen acuity of 20/30 or less. METHODS Threshold retinal disparity for 2.78 degrees x 2.28 degrees rectangular test stimuli was determined as a function of the retinal disparity (varied from 55 arcmin uncrossed to 55 arcmin crossed) of a 5.57 degrees x 4.8 degrees rectangular pedestal stimulus in 160 observers...

PURPOSE To evaluate the effectiveness of graded (adjustable intraoperatively) partial vertical rectus muscle tenotomy at the insertion in correcting small degrees of hypertropia. METHODS All patients with best-corrected visual acuity of better than 6/30 in both eyes who over a 30-month period underwent partial tenotomy of vertical rectus muscle(s) only (no concurrent oblique muscles) were inc...

OBJECTIVES To explore associations between specific learning disorder with impairment in reading (dyslexia) and ophthalmic abnormalities in children aged 7 to 9 years. METHODS Cross-sectional analysis was performed on cohort study data from the Avon Longitudinal Study of Parents and Children. Reading impairment was defined according to Diagnostic and Statistical Manual of Mental Disorders, Fi...