Isolated absence of optic chiasm revealed by congenital nystagmus, MRI and VEPs.

Congenital nystagmus is a rare condition mainly characterised by rhythmic, conjugate, and horizontal oscillations of both eyes that persist in the vertical gaze. This disorder is usually noticed in the neonatal period and persists throughout life. It can be of sensory origin, associated with low visual acuity of various causes, or of motor origin, caused by a defect in the slow eye movement system.

Fundus photography for measurement of macular pigment density distribution in children.

Purpose: To evaluate a photographic procedure for reflectometry of the topographic distribution of macular pigment density in normal pediatric subjects.

Methods: Digitized blue (480 nm) and green (540 nm) photographic images were aligned and subtracted to generate optical density difference maps. An 8 degrees x 8 degrees area concentric with the fovea was analyzed.

See-saw nystagmus and congenital nystagmus identified in the non-decussating retinal-fugal fiber syndrome.

Purpose: The purpose of the present study was to accurately document the oculomotor misalignments and instabilities associated with the non-decussating retinal-fugal fiber syndrome, a rare inborn, isolated, achiasmatic condition. To date, the achiasmatic syndrome described has thus far been identified in three unrelated females. A comparable achiasmatic condition has also been identified in a canine breed.

Visual function and brain organization in non-decussating retinal-fugal fibre syndrome.

Functional neuroimaging, psychophysical and electrophysiological investigations were performed in a patient with non-decussating retinal-fugal fibre syndrome, an inborn achiasmatic state in which the retinal projections of each eye map entirely to the ipsilateral primary visual cortex. Functional magnetic resonance imaging (fMRI) studies showed that for monocularly presented simple visual stimuli, only the ipsilateral striate cortex was activated. Within each hemisphere's striate cortex, the representation of the two hemifields overlapped extensively.

Motoric response inhibition in finger movement and saccadic eye movement: a comparative study.

Objective: To study cortical potentials associated with suppression of intended motoric actions.

Methods: Electro-encephalographic activity was recorded in a Go/NoGo reaction time paradigm. Subjects viewed computer-generated pacing stimuli, which provided information concerning the time at which an imperative Go/NoGo signal occurred.