A computerized perimeter for assessing modality-specific visual field loss.

The characterization of visual field loss provides a valuable diagnostic metric for studying the effects of damage to the retina, optic nerve or visual cortex. We describe a tool, the Quadrant Vision Perimeter (QVp), to rapidly and accurately measure visual fields. In addition to measuring the location of visual deficits, the tool can assess modality-specific field loss (e.g., impaired detection of luminance, motion, depth and color) and severity of the deficit. We present validation and normalization for parameters of visual attributes, as well as exemplar comparisons of visual fields obtained automatically using QVp to standardized perimeters for three stroke patients. Patient visual fields are compared among visual features to assess modality-specific deficits, and over time, to measure fine changes in visual fields, due either to spontaneous recovery or visual degradation.