MINIMAL DEFECTS IN VISUAL FIELD STUDIES

Abstract

INTRACRANIAL lesions that interfere with the visual pathways will cause defects in the visual fields, the extent depending on the amount of interference. When such interference is great enough, the field defect produced is correspondingly large and is easily elicited with routine perimetric studies and even by confrontation. Since the presence of field defects is often an important means of localizing, lateralizing or even recognizing the presence of an intracranial lesion, it is important to be able to detect any defect in the visual field, however small. Such small defects are often difficult to detect and the recognition of some of them will be discussed in the present paper. In order to recognize minimal defects, one must use minimal stimuli for the various isopters being tested. In other words, if one wishes to explore a certain part of the field for slight defects, one must use the smallest stimulus which