Fig. 16. Central exploration of the vertical meridian. A. Simultaneous color comparison for subtle central depression of the temporal hemifield, especially helpful in early chiasmal syndromes. Target 2 appears desaturated. B. The border of the field defect along the vertical meridian is corroborated by the patient's objective perception of increased color intensity as target 2 crosses the midline and moves into the intact hemifield. C. A single large colored target brightens as it is moved across vertical from temporal field (T) into nasal field (N).