Any interruption in the blood supply of the visual pathway will cause a field defect. Visual Fields Visual Field - the portion of space visible to an eye as it fixates straight ahead. It is measured in degrees from fixation and is recorded as the patient sees it. It peaks at fixation, and the slope varies in steepness according to the rate of change in sensitivity. It has no visual receptors.
General depression is all isopters are smaller than normal.
Local depression is restricted to one area. The Amsler Grid maps out any scotomas, gray area, or metamorphopsias. It may be used at home to follow progression of macular disease. Confrontation Fields - the gross examining technique. The target is then moved in from the periphery by the examiner, and the examiner compares the patient's field to the examiner's field.