Which region of the visual field is most useful for recognizing scene gist, central vision (the fovea and parafovea) based on its higher visual resolution and importance for object recognition, or the periphery, based on resolving lower spatial frequencies useful for scene gist recognition, and its large extent? Scenes were presented in two experimental conditions: a "Window," a circular region...

The contribution of the strabismic eye to binocular vision has frequently been studied with stimuli presented solely to the strabismic eye, on a binocular background. These studies revealed a central suppression scotoma in the strabismic eye, the so-called fixation point scotoma. Considering that this scotoma might be an artefact due to the unnatural viewing condition, we employed stereoperimet...

A simulated scotoma was stabilized on the fovea of 23 normal human subjects while they searched for acuity targets in arrays of non-targets. Search time doubled with a 20 min arc scotoma, and eye fixation duration increased by about 15% when compared to no-scotoma control conditions. Search difficulty was graded by adjusting acuity target size, search element density and contrast. Search time a...

Retinal pathology often results in visual field loss. Age Related Macular Degeneration (ARMD) and Stargardt's disease (a congenital disease) typically affects the central macular region of the retina, resulting in visual field loss to the region of the retina with the highest resolution. Due to the central visual field losses, patients with ARMD and Stargardt's disease often experience difficul...

A unilateral electronegative electroretinogram (ERG) was seen in a 94-year-old man with presumed central retinal artery occlusion. Goldmann perimetry revealed central scotoma in the right eye and no abnormalities in the left eye. Full-field ERG in the right eye described a reduction of the b-wave with a relative preservation of the a-wave which is characteristic of electronegative ERG. Hence, o...