Visual Field

Abstract

The visual field refers to the number of degrees of visual angle during stable fixation of the eyes. Monocular measurement of the visual field by perimetry, shows that the left and the right half of the visual field are not the same size. The temporal visual field, extending from the vertical meridian toward the periphery, is considerably larger than the nasal visual field. Measurements along the horizontal meridian show that targets even beyond 90° eccentricity can be detected on the temporal side; the limit of light detection is 50–60° on the nasal side. The upper and lower halves of the visual field appear to be equal, with the limits at approximately 50–60° eccentricity, although there are large individual differences. If the visual fields of the two eyes are superimposed as in normal vision, the binocular visual field Covers more than 180° along the horizontal meridian. The most eccentric part of the temporal visual field that lies beyond the border of the nasal visual field of the other eye is called monocular crescent. Thus, binocular vision is provided only up to the border of the nasal visual field; the far periphery on the left and right side is seen monocularly.